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Oral-History:Herman Schwan (1992)

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About Herman Schwan

Herman P. Schwan
Herman P. Schwan

Herman P. Schwan was a winner of the IEEE Edison Medal, a member of the National Academy of Engineering, and a recipient of an honorary doctorate from the University of Pennsylvania. Schwan contributed to the growth of biomedical engineering in several ways. He pioneered new research areas: dielectric properties of biological materials — from molecules to whole organisms-at high and low frequencies, the propagation of electromagnetic energy in biological materials, and the ultrasonic properties of biological materials. He achieved both accurate measurement of properties and explanation of many of the observed values. Furthermore, he applied the resulting biophysical understanding to practical problems: understanding electrode effects, developing new diagnostic and therapeutic instruments, and helping to set microwave safety standards. And he helped build the institutional basis-both at the University of Pennsylvania and in several thriving professional organizations — for the new discipline.

This focus of this oral history is on Schwan's career. See Also Herman Schwan Oral History 1999, where the focus is on Schwan's role as a founder and leader of the IEEE Engineering in Medicine and Biology Society.

About the Interview

HERMAN SCHWAN: An Interview Conducted by Frederik Nebeker, IEEE History Center, June 26, 1992 and July 1, 1992

Interview # 140 for the IEEE History Center, The Institute of Electrical and Electronics Engineers, Inc.

Copyright Statement

This manuscript is being made available for research purposes only. All literary rights in the manuscript, including the right to publish, are reserved to the IEEE History Center. No part of the manuscript may be quoted for publication without the written permission of the Director of IEEE History Center.

Request for permission to quote for publication should be addressed to the IEEE History Center Oral History Program, IEEE History Center at Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030 USA. It should include identification of the specific passages to be quoted, anticipated use of the passages, and identification of the user.

It is recommended that this oral history be cited as follows:

Herman Schwan, an oral history conducted in 1992 by Frederik Nebeker, IEEE History Center, Hoboken, NJ, USA.

Interview

INTERVIEW: Herman Schwan

INTERVIEWED BY: Rik Nebeker

PLACE: Herman Schwan's home in Radnor, PA

DATE: June 26 and July 1, 1992

German Childhood and Early Education

Nebeker:

This is an interview with Herman Schwan at his home in Radnor, Pennsylvania on the 26th of June 1992. The interviewer is Rik Nebeker. You were born on August 7, 1915 in Aachen, Germany?

Schwan:

Yes.

Nebeker:

Could you describe your parents for me? What your father did and so on?

Schwan:

Well, both my parents came from middle-class families. My father became a high school teacher.

Nebeker:

Was he a gymnasium teacher?

Schwan:

Yes. But he was perhaps most interested in science. He published a number of papers in mathematics, geometry particularly, which made him quite well known in Germany. He also published several books on mathematics which were quite well received in Germany at the time. He became closely affiliated with the mathematics faculty at the University of Frankfurt. He had many friends there.

Nebeker:

You were born in Aachen?

Schwan:

I was born in Aachen. I lived there only two and a half years so I have virtually no memory of the town whatsoever. Then my father was active as a teacher in a little town called Bad Kreuznach near the Rhine River, about ten miles south of Bingen. That was perhaps its best time. We lived there for some ten years. That was the time when my father was in close contact with the faculty at Frankfurt, which was reached by train in an hour or so. I think he wrote most of his publications, and his books as well, in Kreuznach.

Nebeker:

I see. Where did you live after you left Kreuznach?

Schwan:

For a few years we lived in Dusseldorf, which is a city north of Cologne.

Nebeker:

When did you move there?

Schwan:

We moved to Dusseldorf about 1928.

Nebeker:

May I ask before we move too far in time about your mother?

Schwan:

My mother also came from a fairly well-to-do family. Her father was in charge of the railway system in Siegen, in north western Germany. They built a large house. They were the first ones to have central heating, gas, and electricity. I remember that house very well since I often spent summer vacations there.

Nebeker:

Did your houses always have electricity?

Schwan:

No. We lived in an apartment in Bad Kreuznach where there was initially no electricity.

Nebeker:

Is that right!

Schwan:

I remember very well. First we had kerosene or oil lamps, and then we had gas lamps. Electricity had not reached the small cities yet. By that time the majority of apartments in larger cities had electricity.

Nebeker:

Did you have siblings?

Schwan:

No. I was the only child.

Nebeker:

Did your father teach at a gymnasium in Dusseldorf?

Schwan:

Yes. He taught mathematics and physics.

Nebeker:

You wrote that in the early 'thirties your father lost a position because of his political views.

Schwan:

That is correct.

Nebeker:

Can you explain that?

Schwan:

By 1933 the Nazis had established a law to recreate the proper ethics in the democracy and officialdom. They used that as a tool to weed out all those that ideologically did not agree with them. It was one of a large series of laws which the Nazis enacted against Jews, against liberals, and against whoever did not agree with their politics. My father was put in "retirement," forcible retirement. They couldn't fire people. He had tenure as a teacher, essentially. He was well known as a teacher, and as a scientist, as I mentioned before. "Retirement" was very difficult for him since he was so young . He was in his early forties when the Nazis forced him out of his job. His retirement benefits accounted for a little more than twenty-five percent of his regular salary. That started a period of great poverty for us as a family, of course, and he couldn't find any other employment.

Nebeker:

What were his political views in particular? Had he been active politically?

Schwan:

He had not been particularly active in organizations. He always voted Social Democratic. The Social Democrats was the strongest party in Germany. Their orientation was quite similar to the Labor Party in England and the Democrats in this country. As in most developed nations, the Labor Party, the Social Democrats, and the Democrats have similar orientations. But he was very outspoken, and in school his views were very well known. He was very critical of the emerging Nazi Party and the nationalistic movement in Germany. To a degree the nationalistic movement led to the demise of Germany in the First World War. He was very bitter about the First World War, which, in effect, brought the Nationalists to power in Germany in 1933. He took part in the opposition and put time into it.

Nebeker:

You were three years old when World War I ended?

Schwan:

Yes.

Nebeker:

I know the economic conditions in Germany were extremely difficult immediately after the war and for some years later. Did that have a noticeable effect on your upbringing, or was your family well enough off?

Schwan:

No. I certainly was undernourished as a baby. Food supplies were very restricted in Germany, of course, at the time. We suffered from that. Right after the First World War, the situation got worse instead of better. A few years later, we experienced tremendous inflation, where we purchased with billion mark notes. The standard of living was low. Even so, we enjoyed a level of security. My father was a good teacher. He had excellent training, and, until 1933, he had a secure position. At least there was regular income. We didn't suffer as much as many other people. From 'twenty-four to the time when the Nazis took over, Germany enjoyed a good economic period where income was rather good, and we enjoyed a relatively high standard of living as well. The years from 1926 to 1930 were particularly good. I like to think of that Germany.[1] Then of course in 'thirty, the big depression came. We had just a few relatively good years between the inflation and the depression. We were all right until my father got released from his job.

Nebeker:

What was your father's subsequent career?

Schwan:

He never had another job. He lived rather meagerly. During the war he moved to Austria, where he felt safer from the bombings. But then after the Second World War, when Austria was again separated from Germany, he moved back to Hannoe-Munden near Göttingen; and there he died. Late in his years, when he was about sixty, after the Second World War, he wrote five scientific papers which got published in mathematical journals in Germany. But his creativity was almost wiped out in the depressed period which followed his forcible retirement.

Nebeker:

Do you think that was entirely a result of the Nazi persecution?

Schwan:

He suffered very much from that. He was very bitter, very disillusioned. He was depressed and had periods where he was close to insanity. Sometimes when he walked through the apartment, he knocked on the walls, suspecting that the Gestapo had hidden microphones there. For people who were not politically accepted, the pressure was very great in that system; there were fearful excesses.

Nebeker:

Was your father was forcibly retired from his position at Bad Kreuznach?

Schwan:

No, that was after Dusseldorf (in 1934). At Dusseldorf he was again transferred to a city quite close to Berlin — and there it hit him.

Nebeker:

That was also the year, that you completed gymnasium?

Schwan:

In Göttingen, yes. My father was temporarily living in Göttingen. He decided that my mother would stay there. My father felt that I should attend high school in Göttingen. As a mathematician he was aware of the reputation of the school in Göttingen. .Hermann Weyl's sons attended my high school. One was in the class above me; the other son was the class below me.

Nebeker:

Did you know the Weyls moved to Princeton?

Schwan:

Yes. Max Born and Courant's children attended the same school. We were all about the same age.

Nebeker:

I can certainly understand the decision to go to high school there in Göttingen. Was the move to Göttingen expressly for that purpose?

Schwan:

My parents had separated. It was my father's wish that my mother should move to Göttingen so that I could receive a good education. The Göttingen years were very important to me. I had an excellent school with excellent teachers. It was a very intellectual environment with good teachers. The school was one of the strong influences in my lifetime.

Nebeker:

What were your early intellectual interests?

Schwan:

In grade school, I had quite a lot of interests. I would say it became apparent by the age of about ten that mathematics and physics were easy for me. That continued through high school and university where I studied physics and mathematics. But I developed many other interests. I took many history classes. I developed a special interest in ancient Greek and Egyptian history. I read profusely about World War I also. I was very much interested in the distribution of responsibilities of various nations leading to World War I.

Nebeker:

Outside of math and science, history may have been your strongest?

Schwan:

Yes. I was also interested in art history and in my own painting. I was fairly active in sports and I also build many radio sets.

Nebeker:

Did you play soccer?

Schwan:

I did not play much soccer. I was active in running, swimming, jumping. I did lots of hiking, and table tennis.

Nebeker:

Was your father a very strong influence on you?

Schwan:

Yes. My father maintained contact with me through my studies. While I studied in Göttingen, I took two detailed term courses in the theory of functions. The theory of functions was at that time taught by a man who was named Herglotz. Herglotz was very famous and considered the leading mathematician in the theory of functions. He held a special seminar on a related topic. I talked with my father about this, and my father said, "I think I can describe it for you better." [Laughter.] A short while later he sent me a big manuscript on that same topic. It was dedicated "pater-filio," from father to son. He did it very beautifully indeed. I still have it.

Nebeker:

When did your parents separate?

Schwan:

In 1930.

Nebeker:

You lived with your mother thereafter?

Schwan:

In Göttingen, yes.

Nebeker:

You were fifteen years old in 1930?

Schwan:

Yes.

Nebeker:

Did your father work with you on mathematics or physics?

Schwan:

School had a primary influence on me. When I was younger, he was not very much interested. I don't have memories that he spent lots of time with me. I think he spent more time sitting in his study and working on his manuscripts, on his book. The first time that he took a strong interest was while I was in high school, when it became apparent that I was mathematically above average. I was one of two in the class who had been elected to write a special thesis. People who could do that successfully were exempted from the final examination which you had to take for the high school diploma in mathematics. I wrote a thesis which was some eighty pages long where I attempted to translate plane geometry, as written originally by Euclides to geometry of the sphere. I derived a number of things which impressed the high school teachers and my father. After that I met with my father fairly frequently.

Nebeker:

You completed gymnasium in 'thirty-four?

Schwan:

Yes.

Nebeker:

How many years did you attend?

Schwan:

I was in Göttingen four years in high school.

Nebeker:

Was that usual?

Schwan:

Yes. I came in 'thirty. On Easter 'thirty-four, at the age of nineteen I got my high school diploma. I graduated with honors. It was one year after the Nazis had come to power. They came to power in January 'thirty-three. As a matter of fact, I was rather good in a number of subjects. I received As in history, in German, in physics, and in math and some other subjects. I was one of three in the class who made it Summa Cum Laude. In fact, and to indicate the level of excellence of the school, our class was the only one in about twenty years where three had gotten the very highest honors. Later on, when I visited Germany, I visited my old math teacher. He told me that he never had as good a class as the one I was in.

Nebeker:

Those were good years for you?

Schwan:

Yes, very much so.

Opposition to Nazis and the Arbeitsdienst

Nebeker:

You stayed on in Göttingen at the university after you completed gymnasium?

Schwan:

Yes. Well, with interruptions. I got my high school diploma with distinction. But the Nazis had established a rule whereby you could only study if you a) had a high school diploma, and b) had a certificate of being politically correct — political maturity, as they called it. Who judged political maturity? The Nazi representative of the school. I didn't get it. One of the two other ones who graduated with distinction, also didn't get it. [Laughter.] Can you imagine that? So we could not study.

Nebeker:

How was political maturity determined? Did the person granting these certificates know you personally?

Schwan:

I don't know how it was determined. The decision was made by a group of people who had been appointed by the Party. They included some of the teachers who were selected from the total group of teachers for their pro-Nazi political views. Most teachers of course had gotten an idea about our political views from our discussions about history, our discussions in German and things like that. It was that mechanism which led to our downfall. The Nazis had also established an Arbeitsdienst, the Working Service. At that time the Working Service was still voluntary. A couple of years later it became mandatory. Those people who hadn't gotten a certificate of political maturity could prove themselves, perhaps, by entering this Working Service. My friend and myself did just that. After I'd gotten my high school diploma, I went into the Working Service. But I became sick in the Working Service.

Nebeker:

What sort of work did you do?

Schwan:

I ended up in a sort of slave labor camp. I could hardly believe it. I'll tell you a typical day. It was unbelievable! We got up at four in the morning to exercise and sing patriotic songs and so on. Then we had to march for about an hour to a certain location where we built an airfield which became a Stuka base in Germany. We arrived there between six and seven in the morning and we worked until about two in the afternoon.

Nebeker:

You worked on building this airfield?

Schwan:

Our activity at that time was just leveling ground. We dug up and put earth into lorries which we had then to push to another site. We shoveled up ground, loaded lorries up, transported them, and unloaded them. It was a very demanding job. We were supervised. Typically we worked in teams of two. We had to load up the lorry within twenty five minutes and transport it and back. At about three, three-thirty, I think, we moved back to the camp to clean up. Twenty minutes later we met again, and we were marched out for military exercises — or pretend military exercises. There was a guy who shouted, "Airplanes!" We had to throw ourselves on the ground and in ditches. That lasted for two hours. After the military exercises we had our evening food. From eight to ten, we had political indoctrination, where the camp leaders, and other Nazis, gave patriotic speeches — our great Führer — and so on. From ten to four we could sleep. Then came the next day.

Nebeker:

How many of the young people there supported the Nazis?

Schwan:

A majority. My class was an exception. My class, it was called the "anti-Nazi" group. Usually, most of them became Nazis. It's very interesting how that happened. It was due to the propaganda, I would say. In the last elections prior to Hitler's becoming Chancellor of Germany in 1932, the Nazis commanded about one-third. They were the strongest party, but they represented only one-third of the population. Two thirds of the population were either very skeptical or very, very negative. Once the Nazis activated the propaganda machine completely including the press, and the radio, the people fell in line within a few years.

Nebeker:

You noticed that? You could see that?

Schwan:

Yes. I never could determine to my satisfaction the precise level of people who remained skeptical about the system. Based on what I sensed people really thought, not what they pretended to think, my best estimate is between five and twenty percent remained skeptical. We developed a sensitivity for that in the system after a while.

Nebeker:

You remained skeptical of the Nazis?

Schwan:

I was very bitter about my father's treatment. I was very skeptical about the Nazis. I remember my mother was also very negative. I remember when Hitler was appointed, the thirtieth of January, and the radios reported the big celebration, my mother was weeping. She said, "Herman, it means the decline of Germany. It surely will lead to war when Germany will be again, this time, utterly destroyed." How prophetic her words were. She was convinced the Nazi government would lead to war, and it became apparent to me that it had to lead to war. A few years later when Hitler marched to the Rhineland, I was surprised that the French didn't counterattack right away.

Nebeker:

Was there a feeling that the working service was military training? Did people feel that they were really being trained as soldiers?

Schwan:

The people at the camp included people who were practically forced to enter in it, like myself; unemployed people; and people who the Nazis had threatened to punish as criminals. The people were not especially violent. I became rapidly sick. I suffered from heart problems. I just couldn't take that physical punishment. I was relieved after a few months, and they permitted me to study. The camp doctor clearly recognized I couldn't stand it. I developed heart murmurs. I had a pulse of 200 when I went up a few steps. So they let me go.

Nebeker:

And gave you this political maturity certificate?

Schwan:

And I got my certificate of political maturity. [Chuckling.]

University Education and Hardships

Nebeker:

You worked through the summer of 'thirty-four?

Schwan:

Effectively, I lost almost a year of study. You know, certain courses such as calculus start at particular times. I wanted to study in Göttingen. I had maintained very close contact with my high school mathematics teacher, and he advised me not to do so. For financial reasons I needed tuition scholarships. And my high school teacher advised me that I couldn't get into Göttingen. He told me that the student organization at the university was aware of my political views. In spite of the Working Service, I had not a chance whatsoever to get any tuition release. My high school teacher also had contacts with Frankfurt. He had worked closely with a Jewish mathematics professor in Frankfurt named Hellinger. Together they edited and published several volumes of the collected works of Felix Klein. Felix Klein was an outstanding mathematician, and the most famous one prior to Hilbert. My high school teacher talked to the Frankfurt people. The Frankfurt people, of course, knew my father very well and encouraged me to come to Frankfurt. I got a scholarship easily through the university.

Nebeker:

Did you have to declare a major in mathematics or physics?

Schwan:

No. I started to study mathematics and physics, the standard curriculum of math courses, physics, physics lab, and chemistry. I clearly wanted to go into one of those fields. I was one year in Frankfurt. When in the second year it became apparent that I couldn't get tuition release in Frankfurt anymore, I moved back to Göttingen where my mother still lived. In Frankfurt I studied very well. The professors noted me fairly rapidly. But I suffered. In order to get my tuition release I had entered a so-called Comradeship House, which turned out to be, again, a Nazi-dominated outfit. I fell in disgrace, unfortunately, fairly rapidly with the people in the so-called Comradeship House. It must have been that I was not too careful about expressing myself politically, even though I tried to be careful. It became known that I was invited to Sunday dinners several times by some of my professors who were Jewish. I interacted with them, of course, strongly.

Nebeker:

Did the other students avoid the Jewish professors?

Schwan:

I wouldn't say so. It just happened that I was the best in my class. When they asked a question of the class, I raised my hand first. I did some things which others didn't. For example, sometimes before class started when the blackboards were all dirty, I wiped them clean before the professor came. Well, they called me "Der Jüden Jüngling." How can I translate that? It means "the Jew boy." I became known as a Jew Boy. One night they beat me up. It was a gruesome experience which led again to my heart deficiencies. I was surrounded by a blanket or sack, and they beat on me with sticks, and on the floor alone. It was an awful experience. I was deep in sleep when it started. It was one of the most miserable things in my life I remember. In the morning I had all sorts of heart problems. I was permitted to leave the Comradeship House. That meant the next year I couldn't get anymore free tuition. It was the same story again. I moved back to Göttingen then, where I studied the second year.

Nebeker:

Were you able to get a tuition release there?

Schwan:

No. Somehow my mother and I saved as much as we could and we borrowed money. After one year our money was all gone. There was no chance for me to continue in Göttingen. Nonetheless, a very productive year. I took very interesting courses. There were still a number of good mathematicians in Göttingen. But even so, the drain of the good professors from Germany was great. Herman Weyl had gone to Princeton, and many other professors, of course, had left Germany. Courant went to New York. Most of the famous Göttingen crowd had left except for the very old Hilbert. I tried one more thing to continue my studies. I moved to Breslau in East Germany which is in Silesia, close to Poland. The Nazis tried to encourage youngsters to study in either Danzig, Breslau or at another east German university. It was their beginning of orienting Germany towards the east and taking back from Poland what they had had.

It became pretty obvious that it was easier to get a scholarship in Breslau than in the West. I went to Breslau, enrolled there, and took some time to see if I could get a scholarship. I didn't get one. I studied there one semester. At the end of the semester, my money was gone. I remember there was a period of time in Breslau when I was at home, sick. I had a vicious flu. I hadn't paid rent for two months. The owner of the apartment was threatening to evict me from the room I rented there. I was thrown out of the university for not paying tuition. I had nothing! At that time a friend of mine, a French student, loaned me several hundred marks, which was a great amount of money.

Siemens and Telefunken

Schwan:

I applied again for a job in Berlin as an engineer. I had already accumulated a lot of knowledge in engineering, physics, and math. During the previous summer I got a job with Siemens. That was my first job in Berlin. And I worked for nearly half a year at Siemens, thereby saving some money.

Nebeker:

At which branch of Siemens did you work?

Schwan:

I worked at Siemens and Halske, which was the more electronic part of the company.

Nebeker:

What were they working on there?

Schwan:

I was involved in a project developing instruments that measured humidity of grain by electric techniques. They had a wide range of products and measuring instruments such as voltmeters, ammeters, and simple impedance meters.

Nebeker:

You worked at Siemens and Halske in Berlin?

Schwan:

Yes. Let me clarify my timetable. I lived one year in Frankfurt, then I stayed one year in Göttingen. When that year was over, I decided to work during the summer. During that summer I applied to Breslau and worked at Siemens. While I was in Göttingen I had decided, in view of our catastrophic situation, to work during the summer periods. During the winter semester, I went to Breslau. When things broke up there, I went to Telefunken.

Nebeker:

Was Telefunken also in Berlin?

Schwan:

Yes, also in Berlin.

Nebeker:

Is that a branch of Siemens?

Schwan:

Telefunken had been founded after the First World War by Siemens and A.E.G. They combined their high frequency interests in Telefunken. During the first six months I was there one of my first jobs was testing and evaluating commercial receivers. Telefunken had purchased a commercial receiver from R.C.A. My task was to evaluate technology. It was a step-by-step process, from the last amplifier all the way to the tuning circuits. I compared that R.C.A. receiver with Telefunken's related products. I issued my findings in a report. That was an interesting task, by the way.

Nebeker:

You examined things like sensitivity and fidelity?

Schwan:

Precisely. I examined tuned circuits and all that sort of stuff. Yes.

Nebeker:

Was Telefunken ahead of, or abreast, or behind U.S. technology in radio receivers at that time?

Schwan:

That's difficult to say. In some areas Telefunken was ahead. In some areas they were behind. It's a mix as far as I could judge. I had forgotten to mention my high school interests, which helped me very much in finding jobs at Siemens and Telefunken. Since my young days, I was very interested in operating radio and making radio sets. I had picked up some knowledge of relevant technologies. During my studies I had taken a number of engineering courses, including applied physics. I was very interested in engineering. Telefunken added very much to my technical competence.

Nebeker:

Was it difficult to get jobs at Siemens and Telefunken?

Schwan:

While I was miserable in Breslau, I applied to three companies. I had to wait. Two turned me down, but Telefunken took me. Telefunken had a record of my work and I got the job. The first month I worked on broad band receivers, things like that. Subsequently I got access to their microwave laboratory. That was very interesting.

Nebeker:

You worked for how long in the radio test field?

Schwan:

I worked in that field for about half a year. I had reluctantly given up on studying. Then something good happened. While I was at Telefunken, I met a former professor from Frankfurt, who knew me from the physics lab, in the cafeteria. He said, "What are you doing here?" I told him my story. He said, "You must continue to study. You must get your Ph.D. It's a shame." So without my knowing, he wrote to some professors in Frankfurt about me. They arranged a job for me as a technician in the Institute for Physical Foundations in Medicine. They would let me take courses, and they would — aside from the very low salary — pay my tuition. That's how I came in touch with Frankfurt.

Nebeker:

This came about from a chance meeting in the cafeteria?

Schwan:

A chance meeting in the cafeteria of Telefunken, yes.

Nebeker:

How long did you work in microwaves with Telefunken?

Schwan:

That happened later. I first started in Frankfurt in October 1937. I had arranged with the Director of the institute in Frankfurt that I would be permitted to get the next summertime free, in Berlin. I liked my work at Telefunken very much. It was during that summer 1938 that I worked in their high-frequency, very high-frequency, laboratory. They were working primarily on transmission lines. They made Smith charts and diagrammed and measured with coaxial measuring systems. I got quite familiar with relevant very high-frequency technology. As a sideline I learned about magnetron development. I believe the magnetron was discovered in England. The people at Telefunken were very interested in it.

Nebeker:

Were they interested in this for radio communications purposes?

Schwan:

It is not quite clear. I think they were strongly interested in radar development.

Nebeker:

They were developing radar at Telefunken?

Schwan:

Oh, yes. As a matter of fact, when the war started in 1939, the Germans developed the fairly well-known Würzburg type of equipment which operated at a wavelength of about one and one-half meters. They were operating at a rather low frequency by comparison with the 2400 megahertz which the United States used later in 'forty-three. They never made it to higher frequencies than that. They operated at lower wavelengths where, of course, resolution is not as good as it is at the higher frequencies. They developed some good magnetrons. It's an irony of history that a few months after the war started in 'thirty-nine the Nazis closed the Magnetron Development Laboratory since they thought it unnecessary for the war. Can you imagine that?

Nebeker:

Had they been developing radar for the military in Germany?

Schwan:

Yes.

Nebeker:

Nevertheless, the Nazis decided this was unnecessary?

Schwan:

Yes. The Nazi leadership thought they had all the equipment they needed for what they claimed would be a very brief war.

Nebeker:

Yes, yes. I know that a long war was not anticipated, and long-term development wasn't supported by the Nazis.

Schwan:

Right! The lab was reopened late in 1943 when they found modern equipment in some Allied airplanes lost over Germany.

Nebeker:

The Nazis didn't close the lab in order to move the radar experts to another location to work on it?

Schwan:

No, no. Curiously enough, they drafted most of the people into the army. They were released a few years later on. But, of course, once you stop work for some years its difficult to pick up where you left off. It takes time to reorganize everything.

Inst. for Physical Foundations in Medicine

Nebeker:

After meeting this professor in Berlin, you went to Frankfurt where you worked and studied. You came back to Berlin to work at Telefunken in high frequency the next summer, 1938?

Schwan:

Right. Yes.

Nebeker:

You were exempt from military service because of your medical condition?

Schwan:

Yes. Quite.

Nebeker:

Otherwise, do you think you would have been drafted?

Schwan:

Yes, I think so. I was almost drafted in 'forty-three. My medical condition was sufficient at the beginning of the war for me to be exempt from war service. But after Stalingrad, my condition was not serious enough to exempt me from service. When the war progressed they drafted people whose conditions were not quite as serious as others. Luckily, the head of the laboratory of the institute in Frankfurt was successful in getting people exempted from military service. I had become very effective in this institute and was considered one of the rapidly developing young scientists.

Nebeker:

By the time you went back to Frankfurt in 1937, you didn't have any special interest in biophysics — what we now call biophysics?

Schwan:

No, no.

Nebeker:

You were in medical physics?

Schwan:

It is very interesting, but when I got that offer, I was skeptical about it being a reasonable job. I was aware of the complexity of biology but my primary interest had been physics, engineering, and mathematics. I could not see how physicists could contribute productively in this messy environment.

Nebeker:

You are referring to the physical basis of medicine?

Schwan:

Yes.

Nebeker:

Can you say just a word about who was running the institute at that time?

Schwan:

Yes. He was a Russian man, named Rajewsky. He was one of the Russians who had left Russia after the civil war and found a job.

Nebeker:

Was he Jewish?

Schwan:

No.

Nebeker:

Otherwise he wouldn't have had this position?

Schwan:

Under the Nazis? Impossible. Yes, he would have been released. As a matter of fact, the man running the institute prior to him had been fired by the Nazis. It was Dessauer. Dessauer founded the institute. The institute was a foundation created by the Oswalts. The Oswalts were a prominent banking family in Frankfurt who set up a trust fund of sorts that contributed significantly to Dessauer founding that institute.

Nebeker:

How did people feel about the future of medical physics?

Schwan:

Some people thought it had tremendous potential. The invention of the x-rays made a great impression on people. With these x-rays you could virtually see your bones in your hands. That was a marvel to the people at the time. Dessauer's major interest was in x-ray technology and in the mechanism of damage which x-rays cause. Dessauer was an early pioneer in the field, well known to the specialists in this country for his early contributions. Under Dessauer the institute became well known for its development of the so-called "target hit" theory. Using statistics, the theory essentially states that in order to damage a human cell, you must hit the sensitive area of the nucleus. Using statistics you could measure the extent of damage as a function of time of exposure, strength of exposure, things like that. It was much later then when I. Fricke [pointing to photo] discovered the real mechanism was radical formation. But that came later. Dessauer had to leave Germany in 1934. That was the same year that my father lost his job.

Nebeker:

Was Dessauer Jewish?

Schwan:

No. He was not Jewish. It was again just his political views. He was outspoken, and he had been active politically. He was a member of the so-called Center Party of Germany, which represented large Catholic and democratic interests. At times he was a member of Parliament, and had campaigned heavily against the Nazis. All of those activities made it impossible for him to stay.

Nebeker:

Rajewsky then headed the institute in Frankfurt?

Schwan:

Yes. Almost immediately after the Nazis came into power, they threw Dessauer into prison. He spent a half year in prison. When he was released at the end of the year 1933, he was forced to give up the directorship of the institute and his professorship, and he left Germany. He first went to Turkey. From Turkey Dessauer went to Freiburg, Switzerland, where he got a professorship. Later, after the war, he returned to Germany and lived in Frankfurt. I met him later when he was probably very old. Professor Rajewsky had come from Russia. He escaped from Russia into Iran when the White resistance broke up. He lived there in miserable conditions for a while. An elderly colleague and friend of his had gotten a job in the laboratories of Curie in Paris. This man, named Janitsky, pleaded with the Joliot-Curie's to do something for Rajewsky. They knew Dessauer very well, and recommended Rajewsky to him. Rajewsky became Dessauer's assistant. He rapidly emerged as a rather able assistant and scientist indeed. But he didn't share Dessauer's views. Rajewsky was an opportunist. In other words, he believed the official philosophy. Many people have thought as much. They know all too well.

Nebeker:

Was he interested in the biological effect of x-rays and x-ray radiation?

Schwan:

Yes, yes. But he added non-ionizing radiation. He discovered this while he studied in Kiev. He was the forerunner in developing the thesis that there are non-ionizing effects of radiation, of electrical fields. He showed his thesis once to me, but I've forgotten the details. That was back when a lot of the technology was very, very poor. Aside from his interest in x-rays, he established one group in Frankfurt concerned with measuring electrical properties and he formed another group to study how the so-called diathermy technology works on people. I was added to that group as a technician.

Nebeker:

How many people were employed at that institute when you went there?

Schwan:

It was fairly small. I would say, altogether, about twenty people. In my area there were about four or five people.

Nebeker:

You could take classes at the university?

Schwan:

Yes. I was permitted to take classes. Rajewsky had to approve them. Rajewsky somehow knew about my political views, and he deserves my gratitude for hiring me nonetheless. I first proposed to Rajewsky that I would once more seek an exemption from tuition fees. Characteristically he said, "No, no. Don't try. Don't try. I will handle that." He covered my tuition fees. He was aware that I was probably suspect in Frankfurt. You know, I was suspect at the time.

Nebeker:

Did you think of this as a job that would put you through university or, were you already thinking that this might be a career path?

Schwan:

I became rapidly interested in the field. I was still too young to see if I could make a career out of it. As a matter of fact, in the beginning I thought I would get a Ph.D. in the field. But then I returned to Telefunken. That's why I entered that microwave lab in the summer of 1938.

Nebeker:

I see. You liked the work at Telefunken very much?

Schwan:

I liked it. Oh, yes. No doubt, in normal times, I would have returned to Telefunken and I wouldn't have developed a strong interest in biophysics. I liked the work and the atmosphere very much. It was a good lab. There were a number of capable people there.

Doctoral Work

Nebeker:

You felt you needed the doctorate in order to do the kind of work you wanted at Telefunken?

Schwan:

I wanted always to get the doctorate. I felt I was easily competent enough to get a doctorate.

Nebeker:

How did your studies and work go in Frankfurt? What year was that?

Schwan:

I started in October of 'thirty-seven.

Nebeker:

In the summer of 'thirty-eight you were back in Berlin?

Schwan:

That's right. Yes. Quite.

Nebeker:

How did your studies go in Frankfurt?

Schwan:

Fine. No great problem. By that time I had taken so many engineering courses already, primarily math and physics that I needed to take only specialty courses. I took courses primarily in biophysics, offered by Professor Rajewsky. I took some courses in theoretical physics. I also took some laboratory courses in physics, and an advanced mathematics course in analytical techniques given by a man named Siegel. I don't know if you've heard about him. He eventually went to Princeton. He became very famous. He was also considered one of those geniuses. He left Germany in 'thirty-six and immediately was offered a job at the Institute for Advanced Studies in Princeton.

Nebeker:

You received your doctorate in 1941?

Schwan:

Yes.

Nebeker:

Was that with Rajewsky?

Schwan:

Yes.

Nebeker:

Did you write a dissertation?

Schwan:

Yes. In my dissertation I explored how to differentiate between two theories that explained the high-frequency properties of biological tissues.

Nebeker:

Which properties were you concerned with at that time?

Schwan:

Dielectric constant and conductivity of cell suspensions. I studied particularly blood. There were two alternate theories which had been developed. One was based on the famous Peter Debye's polar dielectric theory. The alternate one, developed in the U.S. by Fricke and Cole, was the so-called Maxwell-Wagner type of theory. [Indicating photos.] That's Rajewsky on the left side. That's Cole on the right side. Cole and Fricke were primarily responsible for giving an alternate to Debye's theory. I proposed certain measurements, certain theoretical approaches on how to make a decision between those two.

Nebeker:

How did it work out? Did you decide that one was clearly superior?

Schwan:

Yes. In my opinion I didn't finish the job completely. I was well underway when Rajewsky said, "I want you to now get your Ph.D." I said, "But I'm not ready yet. I want to do some more work." He said, "You have enough." He was insistent because some of the math professors in Frankfurt were being drafted. I had already registered to take my math examination under one particular professor. Suddenly, while I was at the institute, Rajewsky caught me and said, "He is going to leave tomorrow. You have to take your exam today." I wasn't prepared for the exam at all, but I went over to the professor. Suddenly I was involved in the usual rigmarole on account of my Ph.D. Well, it was all right.

By now, I liked the institute very much. I found that I could contribute a great deal. When I came there from Telefunken, I found electronic instrumentation in a state of neglect. I could clearly upgrade their accuracy a hundred-fold. I liked that very much. My first work as a technician was developing oscillators, Wheatstone bridges, and all sorts of other devices. I also worked on transmission line sections for the study of dielectric properties of tissues. Rajewsky recognized my expertise and supported my work by granting me money to purchase material and so on. It became apparent that I achieved almost a favored spot, based not on political views, but on my performance. I liked to work there very much indeed. A few years later I completed my work on my Ph.D.

Wartime Conditions

Nebeker:

I wonder if you could tell me what living conditions were like in Frankfurt during the war?

Schwan:

Conditions deteriorated slowly. As far as food was concerned, there was not a rapid transition. As a matter of fact, it had started deteriorating already before. In 1938, one year before the war, there was a famous Göring speech, "cannon instead of butter," and butter became rationed. I know in restaurants and coffee houses you couldn't get any more whipped cream. Whipped cream was forbidden. Mild restrictions went into effect in 'thirty-eight. Slowly but steadily, it became more and more severe.

Nebeker:

What was the effect on this particular research group? Were many of them pulled out for military service?

Schwan:

A few. Not many. Rajewsky had good political connections, and he was an excellent politician. Should I say, science administrator par excellence?

Nebeker:

When did the bombing become noticeable?

Schwan:

Much later, I would say. It began in 1942.

Development of Biophysics Field

Schwan:

Oh, there was one thing I should mention. The institute was originally a small one, about twenty people. It was housed in the medical school complex of the University of Frankfurt. In 1938 Rajewsky succeeded to make the institute a Kaiser Wilhelm Institute (what is now called the Max Planck Institute). I don't know if you know anything about the Max Planck organization or the former Kaiser Wilhelm organization. In 1912 many such institutes were created in Germany. First they appointed an institute director, then they gave him a building and money to do research with no strings attached. They set him up well enough so that he could hire staff or assistants. He could spend some money, within the limits of his budget, without having to account for it in detail. The institutes took off with a big bang. The first twelve institutes had all Nobel Prize winners as heads. Rajewsky succeeded in 1938 to get a Kaiser Wilhelm (now Max Planck) Institute of Biophysics.

Nebeker:

Was it called Max Planck Institute at that time?

Schwan:

Max Planck Institut für Biophysik, for Biophysics, yes. It was the first biophysics institute.

Nebeker:

Did the institute get funding from sources in addition to the Oswalt Foundation?

Schwan:

Yes. The institute was now much richer. During the war the total group expanded from twenty to about sixty. Today it's something like 300 or so. It's a very formidable institute now.

Nebeker:

Was the word "biophysics" common in the late 'thirties?

Schwan:

No. It was not common. Rajewsky always claimed that he introduced the word "biophysics," which is not quite correct. I had a reprint of Hugo Fricke's work published by the so-called Biophysics Laboratory in Cleveland. So already in the late 'twenties or early 'thirties, the word "biophysics" was used in this country, at least in Cleveland.

Nebeker:

You must have been one of the first to earn a doctorate in biophysics?

Schwan:

Yes. Again, I would think that the Frankfurt biophysics people were some of the very earliest indeed. But the late Sam Talbot, a man who had a strong effect on the development of the field of bioengineering (he died some ten years ago) told me that he had gotten a degree in biophysics at Harvard in the early 'thirties. There must have been a biophysics program of sorts at Harvard at that time.

Nebeker:

Were you the first at Frankfurt to get a doctorate in biophysics?

Schwan:

No. There were several before me. Not many. Perhaps three or four.

Nebeker:

What did you imagine your career to be at that point? Did you hope to continue doing research in that field?

Schwan:

At that point? Well, Rajewsky offered me an assistantship. By that time it became clear to me that I would have a good chance to enter the academic arena. I had been thinking about going into an academic career. During my second year at Göttingen I took a rather advanced physics laboratory course taught by a famous theoretical physicist named Joost. Joost was apparently impressed with my performance. He told me that I should get in touch with him when I was finished with my regular course work. He thought he might be able to give me a position. In other words, it became apparent to me that several people at the university were interested in my seeking an academic career.

Nebeker:

But biophysics was such an unusual field at the time.

Schwan:

Yes.

Nebeker:

Would it have been possible to get an academic appointment elsewhere?

Schwan:

The field was developing. Also, some people who worked in biophysics — there were some examples in my institute — returned to the standard sciences but continued to do biophysics work. For example, one of Rajewsky's assistants became a professor of physics at the University of Frankfurt and continued to do some biophysics work there. Later on, of course, other biophysics institutions slowly developed. I was fairly optimistic I could make an academic career in biophysics at that time.

Nebeker:

You had decided not to return to Telefunken?

Schwan:

Yes. I was fairly confident. On the other hand, I should say the decision was not a hard one to make. I was not plagued with choices. So long as I was with Rajewsky, I wouldn't be drafted. If I left him I would be drafted right away. It was quite clear I had to stay with Rajewsky.

Wartime Politics and Bombing

Nebeker:

Can you describe the social atmosphere of that institute in those years? Were people depressed because of the war? Or were there many who sympathized with the war and thought that things might work out well? What was the atmosphere there?

Schwan:

The majority believed that Hitler was right, that he would win the war. There was a small group of people at the institute, however, who were violently anti-Nazi. Two men in the group were friends of mine, including a professor who just retired. He entered the institute in 1941, and he worked in the lab next to mine. Our discussions were always very guarded. When I met him I said something like, "Well, what do you think about Rommel's campaign? I heard some rumor that a battle took place at El Alamein. And I can't believe it. They say he was beaten there. That can't be true." He said, "I heard a similar rumor." That's how discussions went, typically. You acted very wary to find out how the other person acted. Within a few days we were spending evenings together at the institute listening to the BBC on my advanced radio receiver. In Germany if you were found listening to the BBC on the radio, you could get the death penalty.

Nebeker:

Weren't you afraid that someone might report you doing that?

Schwan:

I didn't tell other people that I listened to the BBC. Never!

Nebeker:

You must have been very careful in what you mentioned in conversation.

Schwan:

One had to be very careful. Very careful indeed. There was another man at the institute who was anti-Nazi. He later worked in industry. He is also still alive. Most of the others however, were either weak believers or they were Nazi fanatics.

Nebeker:

Were these Nazi sympathizers optimistic in 'forty-two and 'forty-three?

Schwan:

Yes. I tell you, day to day, I can't see it. Were they blind? What was wrong with them? To me it was so obvious how the war was going. I still can't understand how these people could believe to the end that they would win the war. I have no explanation for it.

Nebeker:

Except that, until 'forty-two or so, things had been pretty much going the German way everywhere. The Barbarossa campaign was quite a success at first.

Schwan:

Yes, I was surprised. Originally I was surprised that France didn't enter the war. I was also astonished that England didn't enter the war against Germany earlier. Hitler's success surprised me very much. His success surprised many people. In the fall, just a few months after Barbarossa had started, we witnessed the first sign that things weren't going very well. I'm talking about the battle near Moscow. In late 'forty-one Guderian's total tank army was destroyed. That was the first time that the Nazis lost a complete army.

Nebeker:

You found out?

Schwan:

No, officially the army had "successfully retreated." But for one who has the sense to guess, a successful retreat is not exactly a mystery, you know. [Laughter.]

Nebeker:

The defeat at Stalingrad, a year later, must have sobered a lot of people in Germany. They must have begun to feel that the war might not go as they'd expected.

Schwan:

I suspect that people became more critical. In the apartment house where I lived, we had several people who were very skeptical about the further development of the war. Indeed, Stalingrad was a very catastrophic loss.

Nebeker:

Was that reported?

Schwan:

Yes, it was reported. Then, half a year later and for the first time, the Nazis got stopped in summertime. That, the Battle of Kursk, was the biggest attack ever. That was just a few months after Stalingrad. It was very obvious then that the Nazis were in full retreat; but many believed to the end that the Nazis would win the war.

Nebeker:

What happened to living conditions in Frankfurt in the last years of the war?

Schwan:

The food supply had deteriorated. Bombing had damaged the city significantly.

Nebeker:

There was much bombing there?

Schwan:

Oh, yes. The center town of Frankfurt was completely destroyed.

Nebeker:

Was the institute destroyed?

Schwan:

The institute was heavily damaged.

Nebeker:

Were you ever close to a bomb yourself?

Schwan:

Oh, yes. We had many air raids. In March 1944 we experienced a series of four air raids in less than a week. That series of bombings essentially wiped out Frankfurt. The damage was very, very heavy. My mother's house was half destroyed. Curiously enough my apartment house did not suffer. I rented an apartment near I.G. Farben administrative headquarters.

Nebeker:

That sounds dangerous.

Schwan:

It was completely preserved.

Nebeker:

You're saying the Allied Forces purposely avoided bombing that?

Schwan:

Yes. Absolutely! It was clear.

Nebeker:

Why is that?

Schwan:

Well, there are two interpretations. An executive with Du Pont and General Motors offered one interpretation. I was once invited to his estate on the Chesapeake Bay. At one time or another he had been a chief executive officer. Since I was dating a friend of his daughter, he invited me to the estate and offered to help me. He also invited the president of Sperry Gyroscope to his place. He wanted this man to get me a job with Sperry. He told me that I.G. Farben and Du Pont were heavily intertwined. He claimed that in fact Du Pont owned fifty-one percent of the stock of I.G. Farben, and vice versa. He said to me, "We never had any intention to ruin our own headquarters in Germany. That's our stuff." The second interpretation, which I read later on, was that Eisenhower had decided fairly early that he wanted to have that building complex for his headquarters in Germany. So, I don't know. Anyhow, I didn't suffer much. Windows were blown out, of course. But the building did not suffer much damage. Just two blocks away, however, there was just unbelievable damage.

Radar Evasion Research

Nebeker:

Was it possible to continue doing research in those last years of the war?

Schwan:

Our work suffered more and more.

Nebeker:

Did it continue?

Schwan:

It continued. It continued, oh, yes.

Nebeker:

You continued working on the same topics?

Schwan:

Actually, yes. But our work had shifted. Curiously enough, I continued doing what I wanted to do until 'forty-three. In 'forty-three, Rajewsky returned from a trip to Berlin. The Armed Forces had called a meeting of physicists. They had been instructed that submarines couldn't operate in the Atlantic anymore because they were being detected by radar. The government gave orders to do something about it. Some physicists were to develop materials to cover submarines which would not reflect radar beams. What was radar called in this country? It was called the "snorkel concept." You may have heard about it.

Nebeker:

Rajewsky was asked to work on that?

Schwan:

Yes. He came back from that meeting. Of course, since I was the most advanced in dielectric technology and dielectric measurements at the institute, I was supposed to measure materials which might be useful. It was a fairly small effort. There were three groups of people at a number of different institutes, including theoreticians, who were developing so-called swamp materials. The materials would absorb radiation.

As a consequence, the code name was "Chimney Sweeper," because of the idea of blackness. The theoretical group worked to develop concepts of what combination of materials might be useful. Then there was industry, charged with the problem of how to produce such materials, if possible. Other groups developed methods to test whether the properties met I.G. Farben's specifications. I continued to develop microwave technology to higher frequencies and to measure properties with increasing sophistication.

Nebeker:

Did you have the equipment for that at Frankfurt?

Schwan:

I did, yes. I had first a so-called open-line system, and then I got two coaxial systems from Siemens which were rather advanced and made to our specifications. They were state-of-the-art equipment at that time.

Nebeker:

Were there other groups working on this?

Schwan:

There was one group in Göttingen, and another group at Telefunken carrying out dielectric measurements.

Nebeker:

They served the same purpose?

Schwan:

Yes, but my group was probably the most advanced in terms of know-how.

Nebeker:

Were you in close contact with those two other groups?

Schwan:

Yes. I met them once or twice or so per year.

Nebeker:

Each group worked independently?

Schwan:

Yes. Our group was, perhaps, more active in technology development. Clearly, by that time I had become most technically competent in measuring high-frequencies. I concentrated on development. I was, of course, even less sympathetic to the system. Even though I was reluctant, I had to turn out data. As long as I did development of technology, I didn't necessarily have to provide data. I could say to Professor Rajewsky, "I'm still developing this technology. Give me a few more weeks." Nevertheless, they wanted more data. It led to a severe conflict on my part. At our previous meetings, I'd talk about the upsetting periods of my life. I would mention my tuition problems and my father's difficulties.

Passing Research Secrets to Allies

Schwan:

One day a friend came to me. He had gotten his Ph.D. in physics. He visited with me, and he said, "Herman, we must do something about the system." "What can we do?" I asked. "Well," he said, "a colleague and friend whose name I won't mention to you, who feels like we do politically, has contacted the American or English embassies in Berne, Switzerland. Are you willing to contribute information?" At first I said no. A day later he said, "You think it over. I'll come back." I gave him the frequency range in which "swamp" was operative. I was very afraid. If any people had found out I would have been shot for treason. That was my first act of treason against what was officially Germany. I did it with the conviction that the interests of Germany were not identical with the interests of the Nazis. I believe one has a moral responsibility to do whatever one can to bring a brutal dictatorship down. I don't know if the information was submitted. This friend of mine told me a few weeks later, "The man — I won't give you his name — has been captured, and he is in a concentration camp."

Nebeker:

The man who was to convey that information was his colleague?

Schwan:

Yes, but he didn't know if his friend had conveyed the information to Switzerland yet. But this man who was in a concentration camp survived through the end of the war. During the last period of the war, I was afraid he would squeal. If he talked, I would be done for. I purchased a gun, a Luger, on the black market. I planned to shoot myself when they came banging at the door to pick me up. It was not pleasant to live that way. It was difficult living with the bombing, no food, and the fear. Well, you asked me about how living in Germany was. After the war, I found out that the man who had been sent to the concentration camp was a well-known psychologist. He had been asked by the Nazis to try certain drugs on concentration camp inmates and participate in human experiments. He refused to do so, and for that they put him in the camp.

Nebeker:

Of course you didn't know the reason at the time.

Schwan:

I didn't know that. What times! God, whenever I think about it. Well, you asked me about the social circumstances. These stories must sound unbelievable to you. It's true, I assure you. It's true.

Radar Evasion Research Cont'd.

Nebeker:

You called this system to make the submarines invisible to radar, "swamp"?

Schwan:

Yes. Sumpf. It's a German word.

Nebeker:

Was this system actually implemented?

Schwan:

Yes, it was.

Nebeker:

What kind of material did you use?

Schwan:

It was a combination, a layered material. At each interface reflections take place. You can calculate the reflection coefficient as a function of the layer properties. It's easy to design the properties for minimal reflection.

Nebeker:

Was it known what frequencies the Allies were using for their radar?

Schwan:

Yes, it was known that the twelve-centimeter band was the most popular radar equipment in existence. The Allies had developed the twelve-centimeter radar. The swamp was effective between ten and fifty centimeter wavelengths. The intensity of reflection was decreased ten-fold. That material was applied just to the towers of the submarines, which had to emerge above water to recharge their diesel engine batteries. The German subs became operative for one or two months shortly after the production of this material. It was in late 'forty-four when the Germans were sinking something like 200,000 tons of Allied shipping across the Atlantic each month. But the Germans had nothing later, when the Allies operated equipment at three centimeter wavelengths. That was way out of range.

Nebeker:

How important was your group in developing this material?

Schwan:

We didn't develop the material. We measured its properties. In other words, we had to check if certain specifications were met. The theoreticians developed an idea of what properties they wanted to have realized.

Nebeker:

Did they send you the materials?

Schwan:

The chemists had to produce it, and I had to check what the dielectric properties were. I had become expert in measuring dielectric properties.

Nebeker:

Were you informed on the project as a whole? Did you know what this was being used for?

Schwan:

Not officially. But I learned about it by meeting with other groups. Scientists talk with each other. I put the various comments I got from various people together in my own mind. I went to the I.G. Farben Laboratories, what is now called Hoechst Pharmaceuticals, fairly often. It is one of the three biggest chemical companies today. It's in a suburb of Frankfurt. I brought my results there and picked up new materials. I talked with the people there.

Nebeker:

You've mentioned already that you delayed by working on the measuring equipment rather than delivering data.

Schwan:

Yes.

Nebeker:

I take it that you had scruples about contributing to the war effort.

Schwan:

Yes. I was well aware of the fact that I had to contribute. If not, I would have been drafted. If I blatantly refused, I might have suffered the fate of that psychologist and would have been put in a concentration camp. I was at risk because of my political record.

German Nuclear Projects

Nebeker:

Was there other war-related work done at the institute there in Frankfurt?

Schwan:

By that time most of the people worked on war-related projects.

Nebeker:

Were you involved in any others?

Schwan:

No. That was the main project. I don't know too many details, but one project was concerned about the effect of ionizing radiation on man. Rajewsky was a leading expert on ionizing radiation. He had gotten a large contract. Now, why are there some people interested in ionizing radiation? That had to do with a reactor at Hechingen.

Nebeker:

Where was the reactor?

Schwan:

Hechingen is in the Würtemberg area. The Germans were working on an Atomic Pile Project, which was headed by Heisenberg. The people there were greatly concerned about radiation damage. In other words, they wanted to know what happens "a la Chernobyl." The same thing happened in this country, by the way. I remember very well K. C. Cole telling me once that during the war he stopped his work on dielectric properties of biological materials and worked primarily for the Atomic Energy Commission. He worked with the Manhattan Project exploring the effects of radiation on people who were working with the reactors. The reactor was built in Chicago in 'forty-two.

Wartime Conditions and End of War

Nebeker:

Just a few more questions about the wartime conditions. Were you able to keep in touch with your father and mother in that period?

Schwan:

By and large, yes. Like so many Germans, my mother moved to the countryside to escape from the bombings. She accepted a job helping a farmer's family with the kids and related things. Primarily due to the fact that children were moved to the countryside, moving to hospitals, and such, Frankfurt, originally a city of some 600,000 people, was reduced to about 200,000 people.

Nebeker:

You had a couple of friends there that you could be honest with about your views?

Schwan:

Yes, I mentioned two.

Nebeker:

What happened at the end of the war when the Allied armies were in Germany? They were chaotic times, I understand.

Schwan:

Yes.

Nebeker:

What were your personal circumstances?

Schwan:

Well, before the Allies arrived, most of the people in the Frankfurt Institute had been relocated, on a voluntary basis. Rajewsky had set up two smaller institutes in villages outside Frankfurt. They were not touched by airplanes. Why bomb a village? As a matter of fact, most of the Nazi supporters moved out there to be centrally located in Germany. I decided I wanted to stay in Frankfurt. I anticipated that if the war came to an end, Frankfurt would be taken much earlier than a faraway place in central Germany where the institute had relocated, being close to the western German border. And I proved to be right.

Nebeker:

Was that Oberschlema?

Schwan:

Oberschlema was one institute, yes. And there were two other institutions. I stayed in Frankfurt. I remember very well. That morning of March 15, 1945, I was at I.G. Farben, again, going over data or some discussions with them. At noontime someone came and said, "It was just announced that the Americans crossed the Rhine River a few miles south of here — at Gross Gerau." The radio announced that the Germans had sent in tiger tanks and that the attack was completely under control and had been repelled. In the meantime, Patton was crossing the Rhine and opened up the total southern flank of Germany. Patton would soon be bypassing Frankfurt with his troops and approaching Würzburg with speed. In other words, it happened very fast. The Americans had crossed the Rhine at Gross Gerau in the south, while Montgomery would cross the Rhine in northern Germany. There were practically no German soldiers there at all. All that talk about tiger tanks and so on was once again just typical Nazi propaganda. When Patton didn't find any resistance, he put everything at his disposal and moved through fast.

By nine o'clock that evening the Nazi governor of Hessen gave a speech and ordered the total population of Frankfurt to move out of the city — by foot, bicycle, whatever was at their disposal. That led to unbelievable chaos! It was one of those suicidal orders we all had to face. The streets were all packed up with those poor people trying to move out, intermixed with some military columns. Airplanes were attacking. I would have been insane to go out, and I didn't. I decided to do something else. I crossed the bridge to the south side of the river where the institute was located. Three hours after I had moved over to the south side, the Nazis detonated the main bridges. After a day or two, the Americans were rolling in. I remember the Germans had set up a few German soldiers with either a bazooka or something of that sort across from the institute. I suddenly heard some clanking noise. As I looked out, I saw in the side street American tanks rolling by. I was very excited. The Americans soldiers looked at me. There were not many other Germans greeting them. The tank moved around the corner and fired. Later we found the little nest at the corner destroyed. The tremendous American army invasion into Frankfurt had begun.

Nebeker:

You were staying at the institute then?

Schwan:

I stayed at the institute for a while. While I was at the institute it was occupied by American soldiers. I was asked to show them the rooms and laboratories. They had to clear the area of German soldiers. So I did that. Rajewsky had gone away to central Germany with most of the other people. I was one of the few left. There were about six people in the institute. The others apparently still hoped for the final victory of the Führer. The Americans were sitting on the south side of the Main River. For a while the north side was still occupied by the German Army. The bridges had been detonated. After a few days, the Americans notified the German command that they would bomb the northern section once more in preparation for an attack. The German commander retreated and turned over Frankfurt to the Americans. Fortunately, by then Hitler's power started to break up and many commanders disobeyed his insane orders.

Nebeker:

Did you speak any English at that time?

Schwan:

Yes, I had six years of English in high school but I didn't speak it that well.

Nebeker:

What happened in the first days and weeks after the American troops arrived?

Schwan:

I got all sorts of things done. Rajewsky was gone so no one else was around take care of the institute.

Nebeker:

You were one of the first Germans to get this pass to cross the Main River?

Schwan:

This pass here.

Nebeker:

It's dated the second of April of 'forty-five.

Schwan:

Yes. It says "Working with the U.S. Navy, may cross Main River freely." The first sort of pontoon bridge from south to north Frankfurt had been established on an emergency basis across the main river. I was permitted to cross it. Otherwise, only Americans could cross it, of course. The military government issued me the pass that said I was working with the U.S. Navy. I rapidly received active support from the military government. That proved to be important later. Rajewsky was not there. There was a vacuum of power. I succeeded in getting protection for the institute from the military government. Protection meant, in effect, "Off Limits by Order of the Military Government." No one but authorized personnel were permitted inside.

Nebeker:

Was there a danger of squatters or looters?

Schwan:

Yes. The people who worked in camps — Polish, Russians, French, including those in the I.G. Farbenwerken — were released from those camps and were roaming through the cities. Indeed, lots of houses were plundered.

American Interest in German Research

Nebeker:

How did things go after that? Did it take a long time before the university started functioning again?

Schwan:

The university started functioning a year later, in 'forty-six. In the meantime, Rajewsky returned. He used his influence to introduce me to a number of people, including some important heads of some banks in Frankfurt. He appointed me acting Director of the Frankfurt Institute. Since he was a Party member, he could not act as the institute Director until his political record was cleared. He anticipated the lengthy process which proved to take something like two or three years. He appointed me as acting director of Max Planck Institute in Frankfurt, and a friend of mine to the smaller institute, which was close to nearby Giessen. During that time, I received many visits from commissions of scientists and technicians.

Nebeker:

Were they American and British scientists?

Schwan:

They were primarily American, but also some British. Initially, while the war was still going, they were very much concerned about what was going on in the institute since the institute was primarily known for its scientific publications and its expertise in ionizing radiation fields. The Americans worried very much about the German atomic bomb project, of course. They were strongly interested in the institute. Indeed, the institute had been bombed several times.

Nebeker:

It had been targeted because it was thought that it was part of an atom bomb project?

Schwan:

Yes. I believe so. I don't know the details. During the war, Rajewsky got major equipment installed. For example, they intended to install a huge accelerator in a rather tall, new structure in Frankfurt.

Nebeker:

Was this a Van de Graaff accelerator?

Schwan:

It was not a Van de Graaff but a similar instrument. It was a three-step transformer set-up that produced three million volts and required a high structure. Of course the Allied Forces frequently conducted air inspections over Germany. They must have noticed the structure and from our publications knew what expertise was there. They must have asked themselves, "What's going on there?" A rather small attack took place over southern Frankfurt. Clearly that building was marked. It was hit and destroyed. The Americans sent many commissions and collected information. I offered the Allies information about the high-frequency work, and the snorkel.

Nebeker:

You wanted to cooperate fully?

Schwan:

Oh, absolutely! Yes, I had been waiting for the Americans for a long time now.

Nebeker:

Did some of the people at the institute not want to cooperate fully?

Schwan:

There may have been a few. I divided the Germans into three groups. First there were the convinced anti-Nazis, to which I belonged. Then there were the convinced radical Nazis. Lastly, there were people that could be either influenced one way or the other, depending on who held the power, which in any population is a significant fraction. The anti-Nazis, of course, fully cooperated. The third group cooperated right away as well. The staunch Nazis were more reluctant, of course.

Emigration to United States

Nebeker:

Were the British and American scientists mainly interested in the "swamp" project that you worked on?

Schwan:

Primarily, but not exclusively. As time advanced, other people came with biophysical backgrounds. For example, a lieutenant in the Navy, David Goldman, was a biophysicist who had gotten his Ph.D. degree under K. S. Cole, the same Cole I mentioned before, who had done such pioneering work on dielectric properties of biological materials. By that time we had built advanced instrumentation for the study of dielectric properties. Goldman visited the institute several times, and I talked with him. Some months later, perhaps as a consequence of those visits, I was offered the opportunity to come to this country under unusually favorable circumstances. One day another lieutenant came to me, and said something like "Here is a contract. Think it over. I won't put any pressure on you. I'll come back after a week, and you can tell me if you'd like to accept it or not." The contract specified that I would be transported for half a year to the United States and back. Quarters in the United States and aboard ship would be that of a junior officer. I would be on leave from the university. My salary would continue to be paid in Germany at double the previous rate. In the United States I would get free lodging and food in the officers' canteen, and a per diem of $61d, or nearly two hundred dollars a month. The offer was too good to believe, so I accepted.

That was in 'forty-seven. I came in late August 'forty-seven to the Naval Medical Equipment Laboratory in Philadelphia with the intent of returning half a year later to Germany. Then, to my great surprise, several good things happened to me. After all the fears and suffering in Germany, I experienced a great deal of very pleasant events. The Navy informed me they would like me to work on some projects only part of the time. The rest of the time I would have the privilege of working on projects of my choice, provided they approved. Other Germans who worked for the Navy got the same privilege. We all wrote research proposals. They were checked by colleagues at other institutions. Typically, my proposal was evaluated by scientists at M.I.T., the University of Pennsylvania and the Navy. I made trips to M.I.T., and to Penn. Of the three German proposals submitted from my laboratory, mine was the only one accepted. When state-of-the-art instrumentation became available after the war, I proposed to start a sweeping study of electric and acoustic properties of biological materials and to determine relevant mechanisms. I hoped to extend the range of frequencies to much higher and much lower frequencies than ever used before. I started my work with the Navy, and some years thereafter I got an offer from Penn in 1950. The Navy permitted me to take the equipment I'd constructed to the University of Pennsylvania.

When the Navy renewed their offer after my first six months had expired, I accepted because they promised me the opportunity to set up a long-range research program. I changed my mind. I went back to Germany in 1948 and closed down whatever I had there on a permanent basis, and decided to stay in the United States for a longer period of time.

Nebeker:

Until then, you had imagined that you would continue at Frankfurt or perhaps some other German academic setting in biophysics, doing the same kind of research?

Schwan:

Yes, that's right.

FIAT Reports

Nebeker:

Before asking you about your work in Philadelphia, I'd like to ask you about your work on the FIAT reports. How did that come about?

Schwan:

A commission suggested that people at the institute — particularly me — write such reports.

Nebeker:

That was so that scientists elsewhere could learn what work had been done in Germany during the war?

Schwan:

I don't know precisely what the purpose was. I believe the reports were written under the auspices of the U.S. Department of Commerce. FIAT means Field Information Agency, Technical. I think their primary purpose was for the Americans to learn what was going on in industry and in science. I don't know how the information was dispersed in America. But I know that my longest report with the theoretical portion of my second doctoral work was distributed in the U.S. During my first interview at the University of Pennsylvania at the Engineering School, I noticed that a colleague had one copy of my report there on his desk. [Chuckling.] They also adopted the technology I had developed.

Nebeker:

One viewpoint on what happened right after the war is that the Americans and the Soviets competed at plundering German scientific know-how and, in some cases, appropriated equipment. How did it appear to you?

Schwan:

Well, I mentioned the Americans made me an offer with almost unbelievably favorable circumstances. I would have been a fool not to accept. Germany had been isolated scientifically since the Nazis came to power. Here I had a chance to catch up in knowledge again, and hopefully do some good work. As it turned out, I could practically write my own ticket. I didn't feel coerced at all. I felt very privileged, very privileged, at that. Others were not so lucky. Not every German proposal was accepted, and a number returned to Germany. I would say I was an unusual case. The majority of the Germans who came over under the so-called "Paper Clip Program" were military scientists. Von Braun's group. There was the rocket group, the jet engine people, etcetera. I think that there were several major groups. The jet engine had been successfully developed in Germany to a high state of perfection. The rocket group and the airplane design people worked on similarly well-defined projects. Most of those scientists were technically oriented. So the more basic scientists, like myself, were in a minority. Most of those who went back to Germany were elderly academic people. Those who worked on rockets and the jet engines had no chance, being elderly at that, to return to Germany later on. They stayed in this country. A number of the younger scientists with more basic interests returned. I guess that between one-third and forty percent returned, particularly those who could not set up their own research programs as I was privileged to do.

Habilitation Work on Instrumentation

Nebeker:

Could you tell me about your Habilitation? Was that entirely independent work?

Schwan:

Yes. It was primarily a discussion of my work on developing high-frequency technologies. I had to develop precision techniques for measuring the dielectric properties of highly conducting materials during the war. After the war was over, as I got my instrumentation together again in Frankfurt, I started right away to measure biological stuff. You see, some materials which I measured during the war had a certain similarity with biological materials in that they are very highly conducting materials. They have a dielectric constant and are highly conductive. Rajewsky and I were to publish a paper on the dielectric properties of blood in the frequency range one-tenth to one gigahertz. That paper was noticed here at the University of Pennsylvania and made me known in this country as well as in Germany.

Nebeker:

Because of your technical background in this instrumentation that you'd developed during the war you had a great advantage over most researchers in biophysics?

Schwan:

No doubt about it.

Nebeker:

But the habilitation was reporting results on biological materials?

Schwan:

No. It was on measuring technique. Condoning the dielectric properties of conducting materials, especially biological materials. But the technique could apply just as well to other materials.

Nebeker:

It was more the instrumentation than —

Schwan:

Yes. All the chapters are concerned with instrumentation and development.

Nebeker:

Your degree is listed as a doctorate in physics and biophysics.

Schwan:

Yes.

Nebeker:

Why is that?

Schwan:

At the time it was decided that I should get a combined title. I have to explain a little bit more about this. I call it a Ph.D., but there is no real equivalent to my Dr. Habil. in the United States.

Nebeker:

Right. It doesn't exist here.

Schwan:

It doesn't exist in this country. The Dr. Habil. is an advanced doctorate degree. Once you have gotten your Ph.D., and continue to do scientific work over a period of five years, you could apply for it. You could not get it faster than five years after your Ph.D. By that time, you are supposed to write a thesis of a more advanced type than your Ph.D. thesis. In addition you are supposed to document that you have established at least a national reputation in your field of specialization. Once you have accomplished that, you are permitted to apply to become a so-called "docent," which is roughly the same thing as an assistant professor. I say often that I became an assistant professor in 1946. I became a docent. You can teach at the university where you become docent. As a matter of fact, you are supposed to teach at least one course. In America, you can become an assistant professor right after you get a Ph.D.. It wasn't that way in Germany. You had to develop further before you got that privilege. The German and American systems are different. In American departments we have many professors — full professors, associate professors, assistant professors. In a German department there is one boss the full professor. There may be one or two associate professors and a few assistant professors, but only the department chairman could become a full professor. The pyramid was steeper and the base was smaller in a German institute at that time. So that may be the reason to make it more difficult to get up the pyramid structure.

Nebeker:

You taught at the university then?

Schwan:

Once, yes. I did. But I taught only a brief period of time. I got the Dr. Habil. degree in 'forty-six, and in 'forty-seven I came to this country.

Nebeker:

Did you teach biophysics?

Schwan:

Yes. I did for one semester. I was on leave from the University of Frankfurt as a faculty member from 1947 to 1955. In 1955 I gave it up. They kept me on the faculty without pay, all that time, in case I decided to return.

Nebeker:

Is a docent similar to a tenured position?

Schwan:

Once you are a docent, you have entered the academic career.

Nebeker:

You mentioned two other docents, I think from Frankfurt, who also came to this country at about the same time.

Schwan:

From the institute.

Nebeker:

Right, from the institute. Were those similar circumstances?

Schwan:

Well, yes and no. They came about a year later. One worked with the Army at Knoxville, and the other one joined the naval facilities in Pensacola, Florida. But they did not establish much contact with universities. They stayed with the Army or the Navy, respectively.

Nebeker:

Both of them stayed in this country?

Schwan:

Yes.

1941 Biophysics Conference

Nebeker:

I wanted to ask you about what you suggest may be the first Biophysics Conference, a conference that took place in 1941 in Oberschlema and Joachimsthal. Can you tell me how that came about?

Schwan:

Rajewsky was interested in founding a biophysical society. To accomplish this, it's a good thing to organize a first meeting. He found support from a number of other biophysicists in Germany, including I.Timofeeff-Ressovsky, a Russian colleague of his then working in Germany.

Nebeker:

Where was he working?

Schwan:

Timofeeff-Ressovsky worked at what is now a Max Planck Institute in Berlin-Buch, which is a district of Berlin. He was a well-known geneticist with strong biophysical interests. He had a decent background in physics, and was an enthusiastic supporter of the idea of a biophysical society.

Nebeker:

The clear purpose was to form a society? This was the first gathering of those people? How many people attended, would you guess?

Schwan:

Not many. I would say about fifty.

Nebeker:

How many were from the Frankfurt Institute?

Schwan:

Perhaps six or eight were from the Frankfurt Institute.

Nebeker:

What about the satellite institutes Rajewsky had set up?

Schwan:

At that time there was only one. It was in Oberschlema.

Nebeker:

Were there any other sizable groups doing biophysics?

Schwan:

Oh, yes. There were no other formal biophysics institutes, but there were laboratories and subdivisions of departments doing biophysical research. In particular I remember there was a small group in Berlin. There was a group in Freiburg. A variety of groups conducted biophysical research. There was a group also in Munich.

Nebeker:

This was in the second half of 'forty-one? Was it still pretty much business as usual for these researchers?

Schwan:

By and large, as long as we were not drafted. We could do what we wanted. It was amazing! That condition continued to exist right until the aftermath of Stalingrad.

Nebeker:

Weren't there problems bringing these people together? Many of them must have had to travel some distance to the meeting place?

Schwan:

We didn't experience many problems. Once the meeting was postponed by a month. I don't know if you read that in the article.

Nebeker:

Yes, I read that.

Schwan:

It took place at the same time as the Barbarossa campaign took place, of course. But it wasn't too bad. Things worked well until late November when Hitler was stopped at the gates of Moscow.

Nebeker:

You say in the article that the effects of ionizing radiation were a primary topic of that conference.

Schwan:

Yes.[2]

Nebeker:

Can you remember other matters that were discussed there?

Schwan:

I believe I gave a brief talk, and one of my friends — the man who went to Pensacola — gave a talk about biological effects of diathermy and what was then known of dielectric properties.

Diathermy

Nebeker:

Was diathermy a clinical practice at the time?

Schwan:

Oh, yes. Diathermic techniques were emerging very strongly in the 1930s, if not already in the 'twenties. They are still in use today. They declined in use when modern chemical treatments such as the sulfa drugs and then the penicillins and the other antibacterial drugs came into use.

Nebeker:

How much of your work was directed toward understanding or improving diathermy?

Schwan:

I would say my interest was split between the biological effects of electric fields and the determination of electric properties — and remained so through much of my life.

Nebeker:

What was your principal motivation for work on the determination of electrical properties — conductance and so forth?

Schwan:

If you want to understand the interaction of electricity with the human body or any biological material, you must know, first of all, the electric properties. Without knowing the electric properties, you don't know what current is induced by a certain electrical field.

Biophysics and Bioengineering

Nebeker:

Were you also working on understanding interactions of biological materials with electromagnetic fields?

Schwan:

Yes. There were some very early beginnings. I became aware of work which had been conducted in the late 'thirties in Vienna. One scientist there tried to develop a theory to explain so-called pearl-chain formation, which is the alignment of particles in a high-frequency field. This later on became very important in biotechnology, for example. This primitive theory attracted my attention at that time. It was 'thirty-eight already. Interest in the biological effects of electrical fields was generated almost simultaneously with the interest in electric properties. Both things go hand in hand.

Nebeker:

I gather that you were most innovative in the instrumentation in this area?

Schwan:

I made major advances in instrumentation, yes. I began my work in Germany, but I did most of the work after I came to this country.

Nebeker:

You say also in the article that there was, in fact, the formation of a biophysical society in 1943. What were the activities of this society?

Schwan:

We primarily conducted organizational meetings. Not many meetings took place during the war. Immediately after the war, meetings started up again. Traveling became more and more difficult after Stalingrad. After the initial meeting, not much happened for the remainder of the war. But after the Second World War it started right away again with a series of meetings in or near Frankfurt.

Nebeker:

Right about this time, I think it was 1944, Erwin Schrödinger published What Is Life?. That book attracted a number of physicists to biology with the promise that physics could offer explanations of biological phenomena. Were you aware of that publication at the time?

Schwan:

Not immediately. Yes. I certainly became aware of Schrödinger book, eventually.

Nebeker:

Was there a feeling among the biophysicists in Germany at that time that this was a field with great promise? Or was it more that there were certain well established areas — radiology and so on — where physics had a role?

Schwan:

Yes. By that time, of course, my view of the field had become much more detailed than it had been originally. When I was first approached about biophysics, I thought that you couldn't mix physics with biological material. As I became aware of what was happening in electrophysiology and the ionizing radiation field, my ideas changed. I began to believe that we were now at the threshold of more to come of this sort. A consequence of my being at Frankfurt and coming to the States was that I went a step further than Rajewsky. I became interested in something which appeared perhaps ridiculous at first. I wanted to do physics of biological objects. This seemed revolutionary to me. In other words, I was not primarily motivated to study the effects of x-rays since x-rays are good for cancer treatment. And the side effects you get and so on. I was not interested primarily in questions raised by medical people or biologists. I wanted to look at the complicated life matter with a physicist's eye, and simply ask myself, "Can I, as a physicist, do what physicists have done through history?"

Physicists have done essentially two things: they have studied matter — gaseous, fluids and the solid state. And they try to understand the structure of matter. Once they understood the structure of matter, they knew how energy interacted with matter. They studied how radiation is absorbed. Today they understand the composition of matter down to the subatomic size. As I said, only a few had done systematic research of the sort with biological materials. In the United States I set out and formulated a broad program to study the properties of biological matter and the interaction of energy with biological matter over a much wider frequency range than done before.

Nebeker:

You were interested in electromagnetic fields and acoustics energy forms?

Schwan:

Primarily. Yes.

Nebeker:

So you directed your studies to the properties and relevant interactions with those fields?

Schwan:

Precisely. My intellectual roots go back to Frankfurt, and even to Göttingen. But this conception of doing biophysics — not motivated as coming from the medical world or from the biologists — was perhaps new. Some of my early colleagues at the medical school at Pennsylvania claimed it to be heresy. They couldn't see it at all.

Nebeker:

Yes. "Biophysics" is an ambiguous term, as is the term "biomedical engineering." One might look at most of your publications and say that it's the work of a biophysicist. Yet I know from your work that your engineering background and training is crucial to your work.

Schwan:

Yes. Right.

Nebeker:

But maybe this is the time to ask how you regard yourself. Do you think of yourself primarily as a biophysicist or as an engineer?

Schwan:

Both. I clearly studied both sides of the field. I contributed to the theoretical as well as the applied field of biophysics. For example, consider my work which relates to the hazards of microwaves. That problem belongs more to bioengineering than biophysics. Of course the more basic part about the origin of properties is considered more biophysical. Engineering strongly influenced instrumentation development, practical applications, and even some of the acoustics work. I've been very active in the emergence of bioengineering in this country on an administrative as well as a scientific level. I participated in the IEEE, the AIEE, IRE, and many government committees. I was very active in promoting bioengineering training. We were the first biomedical Ph.D. program in the country.

Nebeker:

Bioengineering, as I said, is ambiguous. One style is that you use engineering expertise to investigate biological phenomena. That's mainly a matter of instrumentation. In another kind of bioengineering, you use engineering expertise to build some device — prosthesis or some other device — that may replace or serve in place of biological functions. How do you define the field of bioengineering, or biomedical engineering?

Schwan:

Yes, we discussed that. Primarily during the early years when the field was being defined, terms were used interchangeably. Still, in the field of medical electronics, some people wondered. At that time, our society adopted a broader definition. I suggested "the concepts and methods of the physical and engineering sciences in biology and medicine" (Article III of Constitution, 7-19-68). That is a rather broad, yet appropriate definition.[3]

Nebeker:

Bioengineering or biomedical engineering is anytime engineering skills are used in solving biological or medical problems.

Schwan:

Yes.

Aeromedical Equipment Laboratory

Nebeker:

In 1947 you came to this country, initially for a six-month period, to the Aeromedical Equipment Laboratory. What did you do? You said that you were given the opportunity to suggest your own research program.

Schwan:

Yes. I had to work part-time on other assignments.

Nebeker:

What assignments were you given initially?

Schwan:

The primary assignment led to low-frequency acoustics. The Aeromedical Equipment Laboratory dealt, as the name implies, primarily with airplane medical problems for the U.S. Navy's air force.

Nebeker:

This was space medicine before people went into space.

Schwan:

Precisely. The test stands where they tested jet engines, made a terrific noise. It was just unbelievable! I got involved in developing so-called "ear defenders," things that you put in your ear. I was involved in designing them to optimally absorb the noise which could ruin your hearing if you worked on those jet engines. I was also interested in problems of hearing from a biophysical point of view.

Nebeker:

That sounds like a new line of work. Had you worked with it previously?

Schwan:

Yes, it was a new line of work.

Nebeker:

It was a new line of work for you.

Schwan:

Entirely new.

Nebeker:

It was of course based on physics. But it was not the kind of work that you were doing before.

Schwan:

Right.

Nebeker:

Did that work yield anything useful?

Schwan:

We developed some of the physics of ear defenders, and wrote a couple of reports. That's about all. Originally I was committed to that contract for at least fifty percent of my time. In the last years of my Navy time, I got more and more freedom. I became more and more engrossed in my own activities, and they let me do what I wanted. Letting the Germans make proposals was a very wise policy, don't you think so? I mean, you get some of them placed in your lab and you ask what can you do best? You try to evaluate their proposals and send it out to experts in the country. Based on what the experts say, the Navy would give you the means to do it. That's a good investment policy. Everyone is happy with the sort of thing.[4]

Nebeker:

You started your own research program at the Aeromedical Equipment Laboratory?

Schwan:

Yes. After it was approved. It had to be approved.

Nebeker:

Do you remember when approval came through?

Schwan:

That was, I think, at the beginning of my second period.

Nebeker:

You returned to Germany only for a brief period?

Schwan:

Yes. I can't remember precisely when it came through.

Nebeker:

You were employed there until 1950?

Schwan:

Yes.

Nebeker:

You'd gotten a fair amount of equipment?

Schwan:

Yes. As a matter of fact, while at the Navy I had already developed two abilities which had a profound influence on my later scientific work. I had learned a great deal about high-frequency technology and microwave measurements in Germany. While I was in the Navy I learned how to measure the capacitance of highly conductible materials at low frequencies. It follows from general principles that such measurement is an extremely difficult task entailing high resolution accuracy problems. I was permitted to develop an instrument that provided more accuracy than any other existing device at the time.[5] With this device, near the end of my Navy time, I conducted measurements of muscles and found an entirely new electric mechanism. I discovered the so-called Greek "ALPHA" relaxation mechanism. It was an entirely new type of relaxation mechanism, which has been subsequently of great interest to many people. This was unknown before. Without this instrument I would not have found it.

Nebeker:

Does it have significance for interaction of the fields with muscle tissue?

Schwan:

Yes and no. Its significance is not directly related to interaction. It is important to understand relaxation mechanisms on a fundamental level.[6] We demonstrated later on that the same effect is true for all colloidal systems and suspension of particles. The relaxation mechanism became of great interest in physical chemistry. The effect relates and characterizes the charge distribution on particles, caused by surfactants, i.e. materials which coat a particle to keep them in suspension. The primary importance of that discovery relates to the understanding of sedimentation, coagulation of solutions and stability of solutions. Our research had an effect on the chemical industry from a practical point of view, and increased our knowledge of the biophysical properties of biological cells and tissues.[7]

Nebeker:

It's interesting that you discovered that with a very complex biological material. Was that rapidly picked up by physical chemists?

Schwan:

It was picked up by a few physical chemists and later confirmed by others. Then it got quiet. But in the last ten years there was a sudden outburst. People confirmed the effect. They rediscovered it. Dozens of publications have appeared in the last ten years about it and related phenomena. It's a fairly active field. But it was sort of forgotten for a while.

University of Pennsylvania

Nebeker:

Tell me how your connection with the University of Pennsylvania began.

Schwan:

Yes, another fortunate accident in my life. I had published a paper in Germany with Rajewsky on the high-frequency properties of blood. Many papers certainly had been published on this but our paper went to higher frequencies than other work. That paper had been read by some scientists at the University of Pennsylvania who had a relevant interest, in particular, a Dr. Hüber, also a German. Hüber had left Germany in 1936. His wife was Jewish. He was president of the University of Lübeck, I believe, another German university. The Nazis told him either to get a divorce or to leave. So he left for the United States. He had gotten a research assistant professorship at the University of Pennsylvania. In 1910, during his younger years, Hüber had published a paper titled "First determination of the electric properties of blood cells." My work was an extension of Hüber's work, establishing the properties of red blood cells and its interiors more accurately than Hüber had done.

Nebeker:

What was Hüber's motivation for his work?

Schwan:

He was a physiologist by training, and at the time he had an interest in red blood cells. He had done a lot of work with red blood cells. He found something very interesting, namely that the red blood cells displayed different conductivities at high and low frequencies. That was an important finding. He deduced from those differences in properties that there was a cell membrane separating the interior and exterior of the cell. He was one of the early scientists to recognize the existence of biological membranes. It was a great breakthrough, of course. Hüber's work was heavily disputed at the time. Of course, people eventually accepted it. The existence of membranes had been established just a couple of years earlier. Bernstein usually gets the credit. Based on the electric technology at the time, Hüber confirmed it and used a more rigorous technique to establish that there are membranes. Hüber had seen the paper I had published in Germany, and he learned that I was working for the Navy. A colleague of mine in the Navy had been a student of Hüber's before he joined the Navy lab. This former student of Hüber's then introduced us. Hüber asked me to give a seminar for the Physiological Society of Philadelphia and the Department of Physiology at the University of Pennsylvania Medical School. I gave my seminar on my blood research. That was the start of my affiliation.

Nebeker:

You were doing blood research there in Philadelphia?

Schwan:

Not at the time. I talked at the seminar about the German work, what I had done in Germany. Two other people joined the seminar. One was E. Carstensen, a student, who studied physics at that time. He has just retired from the chairmanship of Biomedical Engineering at the University of Rochester. The other was C. Kay, who was in charge of cardiology in the Department of Medicine at the University of Pennsylvania. They contacted me after the seminar and met with me repeatedly. Carstensen taught a course on elements of physics in the Department of Physical Medicine & Rehabilitation related to diathermy techniques while he was still a student. After the seminar and in the laboratory discussions, he said they had developed good insight in diathermy techniques. Kay became interested in tissue measurements and tissue properties as they relate to electrocardiography. His specialty was diagnostic techniques, especially ECG technology. He wondered how electric properties were affecting the electrical heart signals on the ECG. In a short while I became a consultant to several departments — to Medicine, to Physical Medicine — and then got my appointment eventually in 1950. Of course, thanks to Hüber, and then to the accident that there were related interests, both in cardiology and in physical medicine, and at the Moore School of Electrical Engineering at Penn. Carstensen was a member of one of the earliest Electromedical Laboratories founded in the United States and located in the Moore School.

Nebeker:

Were you offered a full-time position in 1950?

Schwan:

Yes. I had to leave the Navy. It was full time.

Nebeker:

Did you have a year-by-year contract with the Navy, or just an indefinite commitment?

Schwan:

I think the crucial time was after the first year. Until then my contract was automatically renewed. The total arrangement changed after the first year. The initial contract paid me a salary in Germany. In the United States the Navy provided me officer's quarters and a small per diem. The next year I received a regular contract. I got a regular salary in this country and they stopped paying me in Germany. I had to establish my own living facilities here in the U.S. I got about $6,000, which was somewhat higher than an assistant professor got at that time. As a matter of fact, three years later, when I went to Penn, and became an assistant professor, my total income including a regular salary in Physical Medicine and a contribution from cardiology, amounted to $6,000 or $7,000. I read, interestingly enough, in Feynman's book that when he was an instructor at Cornell University he got $3,000 for his salary. So I had a good salary, generally speaking, even though it's not much today.

Nebeker:

How did you like the Philadelphia area?

Schwan:

Well, again I was fortunate because initially I was supposed to live in Navy barracks, but they were overcrowded. So the Navy rented a private room for me. That was on the Main Line, in Bala-Cynwyd. The Main Line, coming from destroyed Frankfurt, appeared like a paradise. [Chuckling.] I have lived on the Main Line ever since. The Main Line is a well known part of the north-west Philadelphia area composed of suburban villages.

Nebeker:

Tell me about your transition from the Navy lab to the University of Pennsylvania? Were you given a laboratory?

Schwan:

I had first one laboratory. Space was at a premium at the time. My laboratory was in the basement of the Medical School and borrowed from the Department of Anatomy. It was about twelve by twenty feet, I suppose. I had a total of 250 square feet. A year later, I moved from the basement room into two somewhat larger rooms upstairs, in the Department of Anatomy. Now I had some 700 square feet. In 'fifty-two I was appointed as head of the Electromedical Laboratory, which was located in the engineering school, the Moore School, where we occupied another 300 square feet. We had altogether about 1,000 square feet of space. In 'fifty-five I convinced the director of the Moore School that I had a good chance to get more money for building projects. When the time came, the Moore School built a new research wing. I applied to NIH, and I got the money for the additional lab which provided us with 5,000 square feet of space.

Nebeker:

In one place?

Schwan:

In one place. Then I switched over to the Engineering School in 1957 and gave up the quarters in the Medical School. Three to four years later I repeated the same thing. Everyone predicted I wouldn't have a chance to get it. The vice president in charge of medical affairs said to Brainerd, the Director of the Moore School, "Schwan: has not a chance." [Chuckling.] I got the money for another 10,000 square feet in the new research center. So it worked out all right, space-wise.

Nebeker:

I see.

Schwan:

But it started very simple, very slow.

Nebeker:

You said that the Navy permitted you to take the equipment you'd built there?

Schwan:

Yes. They were very generous, I thought. Very nice.

Nebeker:

How much of this was off-the-shelf equipment, and how much had you had to have built?

Schwan:

Most parts were off the shelf, I would say. But the combination was unique. In particular, our choice of the conductance box to make it a working unit at the intended level. The calibration procedure was novel. I went through a complicated, very unusual technique to calibrate the equipment to do the job.

Nebeker:

And you set that up at Penn?

Schwan:

Yes.

Nebeker:

Were you working alone initially?

Schwan:

Initially, yes. Even though I was not affiliated with the Moore School of Electrical Engineering, the student I mentioned earlier, Carstensen, took an interest in my work. Carstensen was sort of looking around for ideas. He had not focused in yet on a Ph.D. topic, and I suggested topics to him. Then I became his supervisor, and I provided funds which sustained him.

Nebeker:

Where were those funds from?

Schwan:

I was supported by the Department of Medicine and the Department of Physical Medicine for the first two years starting in 1952. But I didn't have tenure. As it turned out, I found out that my salary came from the Infantile Paralysis Foundation. After two years the department chairman said, "Herman, you are still an assistant professor, but I have no more money for you. Get your own money." [Laughter.] By that time I had met with several people from the Naval Laboratory in Bethesda, the Office of Naval Research. They had contacted me. Elizabeth Kelly, who's still alive and active now at Indiana University, was in charge of the physiology branch of the Office of Naval Research. She had heard about my work about the biological effects of high-frequency currents. She visited me and encouraged me to submit a contract proposal to ONR. That was my first contract before the departmental support ran out. Shortly thereafter I also got an NIH grant.

I wound up with grants that aren't a fortune by today's standards, but adjusted for inflation, they were very nice. Shortly thereafter I obtained an Air Force grant. By 1953 I had three grants and contracts underway, totaling about $40,000, while my salary was about $7,000. The $40,000 in 1953 was like getting $400,000 in 1992. At that time the university overhead was percent.[8] Now it's near sixty percent. So I had a million per year for research, so to speak.

Nebeker:

Did you use that to hire some assistants?

Schwan:

To hire additional people, yes.

Nebeker:

Buy equipment?

Schwan:

I used the grants to support students, and to buy equipment. As a result the group started to grow. That's why I needed also more space, of course.

Microwave Hazard & Safety Research

Nebeker:

What was the reason that most people were interested in the biological effects of high frequency fields?

Schwan:

That was an interest of the Navy that went back to the Second World War when some people were concerned about the dangers of radar equipment. After the war the Navy decided to look a little bit deeper into the general question of how radiation might effect people.

Nebeker:

So it was maybe not on every one of your research projects, but the ultimate motivation was specifically radar, the microwave frequency radiation?

Schwan:

Yes. I would say NIH primarily supported some of the basic research or electrical properties, while the Navy was primarily interested in practical applications; namely how non-ionizing radiation interacts with the human body. At that time there were very few people interested in that field. I was virtually alone when I developed this approach. The first open meeting about microwave hazards that took place in this country was in 1955 at the Mayo Clinic.

Nebeker:

Had the Navy set some kind of tolerance or safety standards for microwaves for radar workers during the war?

Schwan:

No, not during the war. The Navy held the first meeting to my knowledge in 'fifty-three. That was organized by the Office of Naval Research. There were just a few people involved which was quite typical for the field at the time. The well-known biophysicist Kenneth S. Cole was there. A man who knew a good deal about non-ionizing radiation in the infrared, Jim Hardy, from the University of Pennsylvania, was there as well. David Goldman, Cole's student, the one who had visited me in Frankfurt, also attended, and myself. There the first proposal for standards were made. The committee first decided that 100 milliwatts per square centimeter would be the safety standard. But then I went home, thought it over, and submitted a memorandum to the Navy suggesting ten milliwatts per square centimeter. That became the inside Navy standard for years to come.

Nebeker:

In 1952, you became a naturalized citizen.

Schwan:

Yes.

Nebeker:

Obviously you decided that you weren't returning to Germany.

Schwan:

Right. Oh, may I show you something in this context? This little book is one of the things I'm sort of happy about. There were several distinct events. The first was, I believe you have that on tape, the meeting which had been called by the Navy. Shortly thereafter, a student and myself published a paper on standards in the Proceedings of the then-IRE. Then I published another paper in the IRE Transactions of medical electronics, recommending the ten milliwatts per square centimeter standard. The Navy had adopted that standard — but there were no further activities in the field until the Mayo Clinic meeting, in 'fifty-five. But not too much happened until the Air Force became interested in the subject matter.

Nebeker:

Was the Navy the only one that had set a standard until the Air Force became interested?

Schwan:

Yes. In 1959 the National Standards Institute, at that time called ASA — American Standards Association, developed an interest in the field. They asked me to become chairman of a new committee to be established, the C-95 Committee. I chaired that committee for five or six years.

Nebeker:

What years were those?

Schwan:

That was 'fifty-nine or 'sixty to 'sixty-five. It's in my CV. The first thing I did was to divide the activity of the committee into four subcommittees. Subcommittee 4 was concerned with hazards to mankind. Other subcommittees were concerned with hazards to explosives and things like that. While I was chairman of the overall committee, I appointed Colonel North from the Air Force as chairman of Subcommittee 4, to explore the human exposure hazards. He had started a big research program at Rome Air Force base that distributed money to various universities. For various reasons not too much happened with the Subcommittee 4 under North. Eventually I assumed the chair of Subcommittee 4, in addition to my responsibility for the total committee. Then I appointed a small subcommittee which had a representative from the labor unions and included Goldman, Tom Ely, who had done a good job while he was in Bethesda, and Momford from Bell Laboratories, who had worked out a standard for Bell.

Nebeker:

Oh, they had a standard?

Schwan:

Yes.

Nebeker:

What was their standard?

Schwan:

Their standard was one milliwatt. We met together and worked out a proposal. After lengthy discussion the ten milliwatts per square centimeter standard was adopted by the total committee. It was the first general standard to be established. It was reconfirmed twice and then modified towards a somewhat more frequency-specific standard than it was originally.

Nebeker:

I could imagine that in the first years, there just wasn't much research out there to base your decisions on.

Schwan:

Yes.

Nebeker:

But I assume more and more work was done?

Schwan:

Quite.

Nebeker:

Was there work done in other countries that was helpful to that section?

Schwan:

Not much. When I left, the related activities at the Frankfurt Institute continued with some people, but it was not highly effective, and eventually it completely ceased to exist there. There was some activity going on at Siemens Research Laboratories in Germany. That work was of good quality but primarily limited to diathermy developments, both microwave radio frequency and ultrasonic. You may have read about it in some of my articles. But that is all. It didn't go beyond that. The real important work in dosimetry was done in this country — first by us, and then at the University of Washington, Seattle, by W. Guy. An article I wrote will appear in a special issue of the Bioelectromagnetics at the occasion of his retirement, as a Festschrift. It will be published in December 'ninety-two. That is a special issue in honor of Guy, who retired from the University of Washington.

He did excellent work. Then another strong group emerged in Salt Lake City. That group included Durney and Ghandi. Durney is a Mormon, and Ghandi's from India. They are both members of the same department of electrical engineering. They have done excellent work, also.

Nebeker:

But the Siemens group did some work partly because of diathermy?

Schwan:

Primarily, yes. They developed some good diathermy equipment.

Nebeker:

Was the research in this country focused specifically on this question of the possible hazards of microwaves from radar? I'm wondering about the research that was of value to your committee in setting the standards.

Schwan:

I used a combination of fields. I used basic physiological knowledge about metabolic rates and tolerances of the human body with regard to heat as one yardstick. I learned a great deal about infrared and the thermal regulatory system of the body from Jim Hardy. I worked with him while he was still at Pennsylvania, before he left for Yale. The second input I had was based on our own work about the mode of propagation; namely, what percentage at what frequencies are reflected from the body surface, from the boundaries of subcutaneous tissues versus deep tissues and things like that. I concentrated on the effect of the curvature of the body, and measured microwave scattering cross sections of man. I call all of those studies macroscopic dosimetry. They provide details about how energy is distributed inside the body. That information pertains to standards. The diathermy experience provided a third body of knowledge. True, it's not whole body radiation; it's local body radiation. But nevertheless it gives you an idea of what can be tolerated by the human body. So in my deliberations I combined four different fields as I drew from the literature as it developed with time.

Nebeker:

Was this standard specifically for microwave frequencies?

Schwan:

Initially the standard was set to extend through the microwave range and the radio frequency range.

Nebeker:

Also radio frequency?

Schwan:

Yes. From 100 kilohertz or so up to 100 gigahertz. It didn't go to low frequencies initially.

Nebeker:

People became concerned for safety standards in different frequency ranges. You said the initial concern in this country was specifically for radar. Were there any other electromagnetic fields in the 'fifties and 'sixties that people were concerned about?

Schwan:

Yes. People were not only suspicious about the radar frequency range, but were also concerned about any antenna system. You know, we all have some somewhere near our backyards. Recently I testified for Sun because they have a relay system. There is a tower in Valley Forge which picks up information from one direction, amplifies it, and sends it out further. A large part of the telephone system is carried that way by microwave beams. People living nearby relay towers worry about the extent to which this might affect them.

Nebeker:

Were there people concerned about radio frequency waves in the 'fifties and 'sixties?

Schwan:

Not in the 'fifties. I would say concern over radio waves developed in the 'sixties. Reports emerging from Russia confused the American public. They had done research in the field, and had established hazard standards for both microwave and radio frequencies which were about 1,000-fold lower than those I had recommended — microwatt instead of milliwatt. That shook some people very much, and they wondered about it. A number of people paid more and more attention to the Russian literature, and things started to backfire. The press became interested. Then the microwave oven came. Consumer Reports issued a warning that people should not purchase microwave ovens. Concern about the hazards snowballed.

Nebeker:

What was your estimation of this Russian research?

Schwan:

I didn't think much about it. Let me be more precise. My counterpart in Russia was a Dr. Gordon, a woman whom I met several times. She was a very pleasant and kind woman, for whom I have high personal regards. I met her at international meetings on medical electronics and biomedical engineering in London in 'sixty and in Paris in fifty-nine and New York in 'sixty-one. I worked closely with her in 1973 at a meeting in Poland, where we compromised our points of view and drafted recommendations for the World Health Organization. I was aware of the Russian work. I got many of her publications from meetings she organized in Russia. Most of the work they did reported effects in the range between one and ten milliwatts per square centimeter, not in the microwatt area. But then they applied safety factors of 10s and 100s, thereby coming down. The effects, ranging from one to ten milliwatts per square centimeter, were subtle but important. Let me differentiate between dangerous effects, such as heat leading to heat exhaustion due to excess of microwaves, and subtle effects, such as the perception of warmth when you stand in the sun. Perception is a biological effect, but it's not dangerous. But over-stressing your system is dangerous. Typically you have a range of 10- to 100-fold difference between the point of perception of subtle level and dangerous levels.

Nebeker:

I see. You knew what evidence they were basing their standards on?

Schwan:

I think so. I knew a great deal about the Russian work — probably more at the time than other Americans. I was well informed.

Nebeker:

But that didn't change your estimation of what was a safe level?

Schwan:

No.

Funding and Academic Appointments

Nebeker:

I want to try to stay in chronological order a bit. In the 'fifties you were successful in getting funding from ONR, NIH and the Air Force?

Schwan:

Yes.

Nebeker:

You said at one point that the Air Force was interested in more practical questions.

Schwan:

ONR was interested in the electromagnetic hazard area, like the Army. NIH supports more basic work with electric properties. The Air Force supported the acoustics work during the 1950s.

Nebeker:

I see.

Schwan:

Air Force interest existed at the Wright-Patterson Air Force Base in Dayton, Ohio. It serves as a major research center for the Air Force. It's there to this day near Columbus, Ohio. They had established a directorate which was headed by a man named Gagge. Gagge is an environmental physiologist, and he's also a member of the National Academy of Engineering. His background is as an engineer and physicist, and he also became interested in physiology. He did a good deal of work on thermal regulation from an engineer's point of view. If I may briefly summarize some of what he did, he was perhaps the first to model the human body's thermoregulatory system. Compartmental thermoregulation studies show how the body functions from a temperature regulation point of view. He was the first to start that sort of work. Later my colleague Jim Hardy from Penn started working with him at Yale. I just saw Gagge recently at a reception at Yale. Bromley, the Science Advisor to the President, gave a lecture there. Gagge's program was aided by Henning von Gierke. He is another German with biophysical interests, who is also a member of the National Academy of Engineering and had strong biomechanical interests. He worked for the Air Force and set up a stress technology laboratory for them. They were interested in questions like what happens to a pilot who crash lands, what acceleration can a pilot's body take, and the problem of blackout when a plane dives. He also became interested in the ultrasonic program at Penn. Von Gierke and Gagge were in good part responsible for our research in bioacoustics.

Nebeker:

Can you explain why the Air Force is interested in the acoustic properties?

Schwan:

It was never quite clear to me. I think von Gierke motivated the work. One colleague of his also working with the Air Force at the time worked on the low-frequency acoustic properties of tissues. They developed a special physical model to explain them. He was perhaps sympathetic to the type of work I promised to do, since it was related.

Nebeker:

Did he approach this as a biophysicist just interested in the properties?

Schwan:

Yes. I think so.

Nebeker:

Did he have a particular application in mind?

Schwan:

Yes. But I'm by no means sure. I am just guessing. I'm not completely sure what motivated the Air Force to give us the money. But they were probably intellectually oriented towards our endeavor.

Nebeker:

But the work you did for the Air Force then was on a fundamental level of acoustic properties.

Schwan:

Of tissues, yes. That lasted only four years. But the Navy effort and the NIH effort extended up to almost my retirement. In other words, both efforts were supported for more than a quarter of a century. They were long-range efforts.

Nebeker:

Did you receive these grants annually?

Schwan:

Yes. At times the Navy granted me funds for a period of three years. NIH grants extended to five years. It was always a great event. Aside from those grants, another thing that helped us greatly was money for a very large training program for the training of bioengineers. In 1960 NIH funded that program at a level of $120,000 per year. At that time that was a large amount of money, considering the low overhead.

Nebeker:

Maybe I could try to figure out your appointments at the University of Pennsylvania. Initially you were an assistant professor of physics and medicine in the School of Medicine.

Schwan:

In that department I had appointments in physical medicine and in medicine. My primary appointment was in physical medicine, and my secondary appointment was in medicine.

Nebeker:

In 'fifty-two you received a secondary appointment at the Moore School?

Schwan:

I was an assistant professor. At the same time I was appointed as head of the Electromedical Group which existed there.

Nebeker:

That's still a secondary appointment. Your primary appointment was still in the medical school?

Schwan:

Yes.

Nebeker:

In 'fifty-five you became an associate professor at the Moore School?

Schwan:

Two years after I came to Penn, in 'fifty-two, I was advanced to an associate professorship in physical medicine, yes.

Nebeker:

In 'fifty-five you were an associate professor at the Moore School, and in 'fifty-two at the School of Medicine.

Schwan:

Yes.

Nebeker:

The School of Medicine appointment remained your primary appointment?

Schwan:

I don't know. No one seems to know. [Laughter.] I moved in 'fifty-seven into a new 5,000 square-foot facility in the Moore School. Since I practically provided my own salary, no one seemed to care. I think there was once a resolution between the vice president of the engineering school and the vice president in charge of medical affairs which decided that since the medical school provided my first, primary, and tenure appointment, it would remain, ultimately, my primary appointment. But for all practical purposes, I had a primary appointment in the engineering school, where I received a professorial appointment in electrical engineering.

Nebeker:

You were physically located in the Moore School?

Schwan:

Yes. From then on most, but not all, of the people who joined me came with an engineering background.

Nebeker:

What connections continued with the School of Medicine?

Schwan:

Several. I taught a course on the biophysics of diathermy and related topics in the Department of Physical Medicine. I continued that for a long time. I cooperated in a variety of research programs with people in the Department of Physical Medicine and the Department of Medicine as well. Physical medicine interests were related to so-called impedance plethysmography. The connection with medicine was not by directly participating in research work but by coordinating on a planning stage. Let me give an example. In the early 1960s I came back from Germany. In Germany I had become acquainted with work which was going on at the Helmholtz Institute in Aachen. Their preliminary work with ultrasound indicated the possibility to study the valve motion of the human heart, the mitral valve. When I came back I brought it to the attention of Dr. Kay, whom I mentioned before, the head of cardiology.

Accidentally, at the same time, I got an application from Jack Reid. Jack Reid had as a student worked with a man named Wild in Minnesota, introducing ultrasonic visualization technology. Wild has just this year received a $300,000 Japan prize for this work. Jack Reid should have been included in that. Jack wanted to do Ph.D. work with me, knowing that we had a good acoustics laboratory. I suggested to him that he concentrate on heart motion studies. That became his Ph.D.. He introduced with Joyner what's now called echocardiography in this country. It is one of the most powerful techniques. No department of medicine, no cardiologist is without echocardiograph equipment these days. Since Jack was a student, he couldn't get money. So I wrote up the grant application. Again I got money from NIH. We were the first ones to get a grant from NIH for such work. I believe I had an intellectual impact on Jack Reid  But my link with echocardiography was primarily administrative. I gave occasional seminars and had discussions with the people there and at NIH about the acoustics work. Another strong project was electrocardiography, which started earlier. David Geselowitz was the best man I had met in electrocardiography work. The National Academy recognized him for that work. He became a leader in the country in that field. So my work was a mix of engaging in scientific research, overseeing administration and initiating projects.

Nebeker:

How much teaching did you do in the 'fifties and 'sixties at Penn?

Schwan:

I started slowly. When I joined the Moore School in 'fifty-two I started to give a course which I called Medical Electronics. A few years later, somehow the course became Medical Electronics I and II to be taught in subsequent semesters. Then I got some other of my co-workers to organize courses, including Ed Carstensen. In short order we had four courses. Then we replaced the medical electronics title with specific types electric properties, interactions, electrocardiography, hemodynamics. The initial course developed rapidly into approximately half a dozen courses. It was at that time I received a large training grant for biomedical engineering training from NIH.

Nebeker:

Can you tell me about the growth of your research group? You started out in 1950 with yourself.

Schwan:

Yes.

Nebeker:

You added more people to the group as you received new grants?

Schwan:

Yes.

Nebeker:

Did you have graduate students working with you?

Schwan:

Yes.

Nebeker:

When did additional appointments at Penn then become possible for your group?

Schwan:

Additional academic appointments? We rapidly added at a lower level, research associates. I hired several Ph.D.'s in this capacity and some foreigners — Germans and Japanese. In those early years the Japanese and Germans were eager to come to this country. To them this country was a learning experience. You could get them to work at a reasonable price. They added tremendously to our research enterprise. I appointed some of the people who got their doctorate in my lab to faculty positions.

Nebeker:

You were allowed to do this?

Schwan:

I proposed them. It had to be approved by the administration.

Nebeker:

You had the funding for the positions?

Schwan:

I had the proposals, and I had the funding. Yes, I had to organize the funding. At that time I practically financed the total operation, and the university's support was small. It changed later on, however. The university committed more and more funds later. I would say that the university initially looked on with interest but they remained skeptical. They seemed to be saying, "We don't believe that this thing will come off. But as long as Schwan: can obtain funds, why not?" Our group grew from two to six academic appointments by the time I retired from the chairmanship. The total number employed there was about double to triple that much. In addition we had about sixty graduate students. Then we established an undergraduate program, including about 100 undergraduates. Since my retirement from the chairmanship, it has grown substantially. The department now has some 250 undergraduate students, about 100 graduate students (one and a half times as many graduate students as I had), and twelve faculty members. The department is now called Bioengineering at Pennsylvania. Of all the engineering departments it is the one that is most attractive to young students. It attracts more high-quality applications than electrical engineering or computer science.

Nebeker:

In 1956 you were the Visiting McKay Professor at the University of California at Berkeley.

Schwan:

Yes.

Nebeker:

How did that come about?

Schwan:

I think it was primarily due to a man named Charles Susskind. You may have heard about him. He had an interest in the history of electrical engineering. I have some of his books here. This text was very well referenced. The book is about Heinrich Hertz. If you don't know it, maybe you'd be interested in it. Charles published several books like this. I suspect that he recommended me for the Visiting Professorship at Berkeley.

Nebeker:

Why were you interested in going to Berkeley?

Schwan:

Charles Susskind was also somewhat interested in the biological effects of non-ionizing radiation and biomedical engineering. He suggested that the department set up a laboratory of sorts under my leadership. The department asked if I would be interested in an associate professorship with tenure. Penn offered a full professorship. Penn gave me a full professorship in 1957 which I might not have gotten except for Berkeley.

Nebeker:

How long did you stay at Berkeley in 'fifty-six?

Schwan:

About one or two months. It was not very long. I gave a number of seminars, including some at Stanford. Charles let the other people in the bay area know that I was there.

Vladimir Zworykin

Nebeker:

Since we're in the right time period, let me ask you about your contact with Vladimir Zworykin, who became very interested in medical electronics. How did you meet him?

Schwan:

I have a number of interesting experiences. He had been president of a meeting organized by the International Federation of Medical & Biological Engineering in Tokyo. I attended that meeting.

Nebeker:

What year was this roughly?

Schwan:

That was about 'sixty-five. My first trip to Japan was in sixty-five. That was an international meeting. After that I continued on to Taiwan and then to Bangkok. On the flight from Taiwan to Bangkok, I happened to sit next to a man who revealed that he was a cousin of a prince of Thailand. He apologized that he couldn't entertain me in Thailand, as courtesy would demand, since he was busy returning with the queen from a trip around the world. But he would write me some recommendations for some restaurants on a piece of paper. I checked into my hotel where I met again Dr. Zworykin and Dr. Flory from Princeton. They were with their respective wives and I was alone. As a result I did many things with them. One evening I decided to try out one of the restaurants that the prince's cousin had recommended. I invited both the Zworykins and Florys to join me. We came to that place, and it was closed. I knocked at the door even though it was closed. I shoved that little piece of paper through the door and the door was opened. We went in. It was a beautiful, plush restaurant. We were the only guests. But we had to lie down as that was the custom in that restaurant. You couldn't sit; there were no chairs. You had to somehow manage to eat lying on your side on pillows. We had a fabulous meal there, all alone in that big place. We were just about through with the dinner when the door opened again. In walked a party headed by Mr. Nixon, and the Prime Minister from Thailand. Apparently that's why the restaurant was closed. But the recommendation of that passenger was strong enough to break that door. I will never forget Mr. Nixon lying there on his side trying to eat.

I knew Zworykin since the early 'fifties, as a matter of fact. I knew him for his committee work in the IRE.

Nebeker:

What work did he do in medical electronics?

Schwan:

He had many relevant interests. He was one of the founders of the IRE Medical Electronics Group, now the IEEE-EMB Society. He was the driving force in founding the International Federation for Medical and Biological Engineering and its first president. He was interested in connecting obviously medically-related industries of all sorts. He became very much interested in telemetry, for example. In the RCA laboratories he developed the technique of a pill that served as a monitor. A person would swallow it and it would go down through the esophagus and stomach and so on. You then could observe all sorts of very useful information including pH and temperatures. The "pill" could send them out to receivers while traveling through the body.

Nebeker:

Did RCA work on such things?

Schwan:

Yes. RCA developed the "radio pill." The radio pill never became very popular because the medical people didn't know what to do with it, really. When Zworykin was vice president of RCA, he was the prime mover in the development of the first American electron microscope. That was a substantial achievement. Then, of course, he developed the video technology, the television technology that made television what it is. It also made possible the imaging technologies which are now so important in the medical field.

Nebeker:

You were saying that there were quite a few things Zworykin had contributed to medical electronics.

Schwan:

Yes. We met fairly frequently. We had quite a discussion about certain regulations and the constitution of the International Federation, which were adopted in due time. There was always the problem of proper representation of countries. I was primarily responsible for the International Federation adopting what I called the logarithmic rule. Not every country has the same vote. Small countries, say up to 100 members, had one vote. Countries up to ten times more had two votes, countries with ten times the population had three votes. That worked out satisfactorily.

When Zworykin became older we sometimes took them to a city in New Jersey where they liked to go, where almost only Russians live. He and his wife were both Russians.

Nebeker:

Oh!?

Schwan:

I've forgotten its name. It was like being in Russia there. I took him there twice, and they liked it. I've forgotten what its name is. We became socially involved. He came and attended the wedding of our oldest daughter.

Nebeker:

What was he like as a person?

Schwan:

He certainly was a gifted man. I think he had a tendency to be a little bit autocratic — as you find frequently in very accomplished men, in particular those coming from abroad. He told me much about his earlier life. He said that he studied engineering in Leningrad (now St. Petersburg again). As a youngster, he had decided to become an engineer and bring "the movies home wireless" — as he worded it as a young man. He told me that his first job in this country was with Westinghouse.

Nebeker:

That's right. It was with Westinghouse.

Schwan:

When he proposed the television idea to RCA they permitted him to develop it. He said that after he got permission to do so, they set up what he called a barn, in Princeton. It then became a research center. They called him a crazy Russian for the ideas he worked on.

Nebeker:

Was this radio pill his idea, do you think?

Schwan:

I'm not quite sure. I could imagine it was. His mind was always active with regard to all sorts of things. He imagined all sorts of practical things. For example, he thought of a little pocket calculator that you can carry with you, which has your total medical information on it. He envisioned a phone hook-up, sort of a modem-like hook-up, where whenever you have a symptom, you could get properly hooked up to a specialist in the country. They listen to your heartbeat and other relevant things. His mind was always active with thinking.

Nebeker:

Can you explain why he became especially interested in the medical field in his later years?

Schwan:

No. It was not only in his later years. I believe that television interested him very early. Of course that was not specifically limited to medicine. Certainly medical science motivated the development of the electron microscope. I remember a man named Hoffman issued some publications out of Princeton University in cooperation with Zworykin's laboratory which provided pictures of the surface of a erythrocyte, an indication about membrane structure. That was in the early 'fifties. That was done in cooperation with Princeton University though apparently motivated by Zworykin. Medical applications were not his only interest, but they emerged fairly early in his life.

Nebeker:

Was he always absorbed in his engineering work? Or did he have other interests?

Schwan:

Not very many. I don't think he was a good businessman. He lived modestly. His house was rather simple. It became rapidly apparent to me that in spite of all his achievements, he did not benefit financially very much. Look what he potentially set in motion.

Nebeker:

When you'd get together with him, was it for basically conversation and going out to eat?

Schwan:

In later years, yes. In earlier years, we met at scientific conferences. Subsequently we established personal contact — visiting each other in Princeton and Philadelphia. He inquired about an affiliation with the University of Pennsylvania. We would go out to dinner or have dinner at home. We sometimes invited them to our house at the seashore. Another colleague of his who died recently, also a member of the National Academy of Engineering, also visited with us. I've forgotten his name. Rajmanson, something like that. He was also vice president of RCA.

Interview: Second Day

Relationship with and between Parents

Nebeker:

This is the second day of the interview with Dr. Herman Schwan. It's the first of July 1992. The interviewer is Rik Nebeker:. You wanted to make some comments about the earlier session?

Schwan:

Yes. I would like to add a few comments. I haven't talked very much about my mother. I think I mentioned briefly that my parents separated.

Nebeker:

Right.

Schwan:

As a matter of fact, their marriage was not a very happy one. They both came from well-to-do, upper-middle-class families. The disaster in Germany — its defeat in the First World War — and the subsequent stories which I've told you about inflation, depression, and my fathers dismissal, meant a tremendous reduction in the standard of living from what they'd experienced in their parents' houses. They were unaccustomed to poverty of course. The second thing I would say, they were both very liberal. My mother, in addition, was a strong feminist. She quite openly campaigned for women's rights in the early days.

Nebeker:

Is that right!

Schwan:

My father didn't quite share her feminist feelings. But both were very liberal. They were anti-nationalistic, and democratically-oriented. They separated for the first time in 'thirty, came together again in 'thirty-four, and separated finally three years later. They never divorced. But of course separation enhanced our financial difficulties.

Political Choices Under Nazis

Schwan:

A second point which I was going to mention is one which is very critical to understanding what happened in Germany, in Russia, and, as a matter of fact, under communism elsewhere. We originally felt that you could fight dictatorship if you were determined to do so. We gave very little thought about how to accomplish that. My premise is that an unorganized minority without weapons has little chance to fight an organized, well-equipped majority.

The third comment which I want to make pertains to one's responsibility under such circumstances. Clearly, one cannot go out on the street with a gun and shoot Stalin or Hitler. That's impossible. One would be captured way before one even could attempt to undertake that sort of thing. One's chance to do something about such a system is to spread the decent message and try to establish contact with others. Another, one must try to transmit important information to the outside — at the risk of being called a traitor. Those are the only means available. Some tried the first strategy. Several assassination attempts were made on Hitler's life during the Nazi regime. The problem was that sooner or later, a spy would enter the organization, and the group would explode. That happened several times in Germany, and no doubt happened frequently in Russia, as well.

The next comment pertains to loyalty and disloyalty in general. How far should you go with your responsibilities in this regard? Well, I chose to try to transmit information to the outside. I didn't tell you about another experience I had which had a negative effect on me. After the war, Rajewsky approached me and asked me to sign a statement that he was always anti-Nazi in spite of the fact that he had been a member of the Nazi party. He wanted me to attest that he saved a number of Jews from persecution, hiding some of them in his house.

Nebeker:

Were those statements true?

Schwan:

I didn't know. I was initially weak enough to sign the statement. I had considerable qualms about signing it. A couple of days later I came back to him and said, "Herr Professor, I've written another statement in which I stated that although you knew that I was an anti-Nazi you gave me a job." I believe that was the case indeed. I said, "I shouldn't have signed the other statement. I don't know anything about your hiding Jewish people and so on." He gave me back the original certificate and accepted the weaker, second statement. But I know he considered me disloyal. Once again, I had run into that problem in my life, of not being loyal. Loyalty to one's nation and to one's employer is very important, you know. In retrospect today, I don't know if I would take those two actions again. I'm convinced that nine out of ten people — if not 99 out of 100 people — wouldn't act as I had acted on similar occasions. It's very, very demanding, of course. While Rajewsky frequently recommended me for all sorts of things like the Rajewsky Prize and other things, he nevertheless felt that I couldn't be trusted. His wife told me later that he admired me but that he felt that I was not trustworthy. So much about loyalty and one's responsibilities to mankind and one's society. It's a very delicate thing. Well, I sort of add those comments for whatever it's worth.

Confiscated Equipment

Nebeker:

I had another question or two about the World War II period. You say in something you've written that you had one or more magnetrons, that you could get ten to twenty centimeter microwaves during the war. How did you get those magnetrons?

Schwan:

From Siemens. I got two pieces of coaxial equipment, and they were driven by fixed-frequency magnetrons.

Nebeker:

When did you get these during the war?

Schwan:

I got them after the U-boat war started in earnest. Sometime after Rajewsky came back from Berlin. I used them on the project I told you about, the Chimney Sweeper project.

Nebeker:

That was the name of it — Chimney Sweeper?

Schwan:

Chimney Sweeper. That was the project, yes. About a year later, 1944, I got the two advanced high-frequency measuring systems. Apparently at that time the Germans were able to produce some magnetrons of low power output and operating at those frequencies.

Nebeker:

You also mentioned in one of your writings that after the war that equipment, including the magnetrons, was confiscated.

Schwan:

Yes. I didn't describe that in detail. Right after the Second World War, I was contacted by all sorts of people — scientists, technical personnel, all sorts of commissions, including English and American. I established a fairly good relationship with them. They were very helpful in many respects, and I tried to take care of the institute as best I could. All my equipment had been transported to central Germany.

Nebeker:

Most of it?

Schwan:

Yes. Most of the Germans — Rajewsky and most of his co-workers — moved away from Frankfurt. I decided to stay alone. How could I stay alone in Frankfurt? I had managed to get a statement that I was needed to carry on in Frankfurt from some sympathetic people at I.G. Farben. This statement had been endorsed by their Nazi official. I was determined that if I was found to be one of the very few people at the institute by some SS patrols, they might have said, "What are you doing here? You were supposed to go out." Then I could have shown them that piece of paper, thereby safeguarding myself. It was ridiculous to move farther on into Germany. The war was over. But all my equipment had been transported away. I knew where it had been transported. I told that to the Americans. One day two soldiers — a lieutenant and a soldier — came, and I drove a jeep with them to central Germany.

Nebeker:

Where was it? Do you recall?

Schwan:

It was northeast of Frankfurt about a hundred miles. We practically moved into the still-moving battle zone between the Americans and the Germans. I remember at various points we saw American trucks lying alongside the street which had exploded after hitting land mines. As a matter of fact, the soldiers were very anxious to avoid mines. At some spots we stopped, left the jeep, moved carefully aside, and one daring soldier drove over the suspected mine area.

Nebeker:

Goodness!

Schwan:

I shared their C-Rations with them during the trip. Well, anyhow, we came to that spot where I found all my equipment.

Nebeker:

It had been used by others in the group?

Schwan:

It was just stored there. I transported the equipment back with the help of the Americans. They turned over the lower-frequency transmission line systems to me. But I never got back the high-frequency coaxial lines and the magnetrons.

Nebeker:

They must have been technically knowledgeable to ask for them?

Schwan:

These men weren't just soldiers. They were all members of special teams with scientific and technological backgrounds.

Nebeker:

Do you think they were particularly interested in radar and radar-related work?

Schwan:

Yes. Very much so.

Nebeker:

Let me ask a question that relates to this equipment. What was your success in getting a hold of more high-frequency equipment in Germany? Or was that just not possible in those couple of years after the war that you worked there?

Schwan:

No, I couldn't get anything further. As a matter of fact, the equipment which I was permitted to keep, extended up to one gigahertz frequency range. Almost within months, I'd established the equipment to work again. Then I carried out extensive measurements on blood, which led to the paper which I published together with Rajewsky. As I mentioned earlier, this paper became known to Hüber here at the University of Pennsylvania and led to my contact with the university.

Low-Frequency Measurement

Nebeker:

When you moved to the Navy lab in Philadelphia, did you take any equipment with you?

Schwan:

From Germany? No. I left everything behind. It belonged to the institute. At the Navy I established very low-frequency equipment. The transmission line system in Germany operated between 100 and 1,000 megahertz, up to one gigahertz. In the Navy I concentrated on equipment measuring between ten hertz and 100 kilohertz. In Germany I worked with very high-frequency precision equipment. In the Navy I developed low frequency, high precision equipment which led to the discovery of entirely new phenomena at low frequencies.

Nebeker:

Can you describe this equipment a little bit more? These are devices for generating the electric fields at those frequencies?

Schwan:

No. Generating the fields was standard technology.

Nebeker:

Are they used for measuring?

Schwan:

Yes. The unresolved problem, or the inadequacies of the problem, was how to measure capacities of materials which were highly conductive. It follows from general principles that you need very high resolution to do this. Standard equipment was useless to achieve that high resolution. One important achievement was the calibration of the equipment. In other words, to get variable conductances to compare with the test samples and whose capacitive properties were known precisely. You couldn't purchase them. They were unavailable at the time. I developed a special technique in order to calibrate them. That required, however, the very high resolution of the equipment again, which had been made available. (See also endnote #5, on bridge design considerations.)

Nebeker:

Was this conductance you were measuring?

Schwan:

I measured both conductance and capacitance of biological samples.

Nebeker:

You were doing that by essentially matching those properties with some standards?

Schwan:

Yes, precisely.

Nebeker:

And the problem, as you say, was getting well-known standards?

Schwan:

Right. Precisely.

Nebeker:

Were there other people working on that problem?

Schwan:

Not to my knowledge. Except for some biophysicists, there was no interest in the capacitance properties of highly conducting biological systems. Most people are interested in dielectrics, which have very low losses. I was virtually the only one at the time who was working on the electric properties of biological systems at such low frequencies.[9] Cole and Fricke had done that at higher frequencies where the problems were much less pronounced. No one really had attempted to do anything about the low frequencies.

Nebeker:

Was the neglect because of the instrumental problems or because the intellectual questions seemed to be used on the higher frequencies?

Schwan:

Originally it was easier to measure both capacity and conductive problems at higher frequencies. That had been done by Cole and Fricke. Let me make a simple diagram. The ordinate is E, the abscissa F. Epsilon stands for capacitance dielectric constant. That is frequency f. Sigma stands for electric conductance. That diagram is for muscle tissue. You see, the properties change in three distinct steps, which I have labeled alpha, beta, and gamma. Likewise, conductivity here, here, and here. Now the general problem is not only to measure such properties, but why those steps exist. What are the underlying mechanisms? Cole and Fricke had essentially explained the beta step. I refined their mathematics for the beta step and I added the gamma and the alpha steps to it. I also explained the gamma and the alpha steps.

Nebeker:

Had they measured the capacitance within those ranges?

Schwan:

No. At that time the equipment was not available at those high frequencies. You couldn't generate the high frequencies in their time. That was at first possible after the Second World War. And at the low frequencies their equipment had insufficient resolution for the reasons which I just stated to you. Originally no one anticipated this alpha step here. Some people did anticipate perhaps the gamma step here, but no one knew anything about it. There were no indications whatsoever. That came in entirely unexpected.

Nebeker:

When did you first find evidence of that low frequency alpha step? Do you recall?

Schwan:

Rather early. I think it was already late 'forty-eight — one and a half years after I came to the Navy. By that time the equipment was finished. I put it to use. The very first time that I measured muscle properties with it, I saw it emerging.

Nebeker:

And you were the first one to make such measurements in that range?

Schwan:

Yes. Now I don't know if it was late 'forty-eight or early 'forty-nine. Say, middle 'forty-nine. Shortly thereafter, in early 1950, I presented that result at the American Physiological Society.

Nebeker:

Were there other people working in that area by that time?

Schwan:

No. There were some people somewhat knowledgeable, particularly Sam Talbot, whom I mentioned in many of my papers, and Otto Schmitt, whom you also may have heard about. It was at that meeting that I met Otto and Sam Talbot for the first time. I remember very well. Both those people — who were to become close friends of mine — doubted the result. They thought is was an electric artifact, really caused by electrode polarization. Believe me! [Chuckling.] I knew at the time a lot about electrode polarization.

Nebeker:

Did they express those doubts at the meeting?

Schwan:

Not openly, but they talked to me in a private discussion after my presentation.

Nebeker:

When did people replicate this in other laboratories?

Schwan:

The muscle work took quite some time to replicate elsewhere. The first replication came about at first in 1964 at a British laboratory headed by a Nobel Prize winner. It was Cole who brought my work to the attention of the British physiologists, and they decided that must be checked. That was important stuff.

Nebeker:

Whose laboratory was that?

Schwan:

Katz's Laboratory. The work was done by Falk and Fatt. They published two long articles in the Proceedings of the Royal Society about it, confirming and extending my work. And then there was a flutter of publications about it. It turned out to be physiologically very significant.

Muscle Cells and Relaxation Effect

Nebeker:

And how do you explain the vacuum and the fact that suddenly, in the mid-'sixties, a lot of people were interested?

Schwan:

The fact that there was first a vacuum simply resulted from the fact that people didn't understand what I was doing. Cole and Fricke, yes. I met Cole and Fricke. But most of the physiologists didn't even understand Cole. I remember very well when I came to the University of Pennsylvania, that the physiologists often said to me, "Herman, you seem to understand that work of Cole. Can you explain it to us? We have no idea if that's important or not." I tried my best, of course, to do so. The physiologists and early biophysicists just were not trained enough to understand the relevance of this work. It took quite some time. I think an interest in such biophysical investigation started to develop very slowly.

Interest increased after two British physiologists, Hodgkin and Huxley, got the Nobel Prize for their work on the electric properties of nerve axons. Then interest in that sort of work grew fairly fast. Cole told me that he brought my work to the attention of Falk and Fatt. My first presentation was in 1950 at the American Physiological Society meeting in Columbus, Ohio. Then I tried to publish it in physiological journals. There was no biophysical journal at that time. I was turned down twice, by two journals. I was very discouraged. And then I submitted it to a German journal where it was published in 'fifty-five — five years after the Columbus meeting. By 'fifty-six I did have a reputation in the field and I was asked to write a review article on electric properties of biological materials. I wrote a long review article which was published in 'fifty-seven, where I reported for the first time in English about all that sort of work. There was only that German publication before and the abstract, which doesn't say much. This review article was a great success. I think it has been quoted in the Citation Index almost a thousand times. It's still being quoted since it was the first really comprehensive treatment of electrical properties of biological materials. Apparently Cole sent a reprint of this article to the British investigators sometime, I don't know when. They published their work in 'sixty-four.

Nebeker:

Were the British interested because of the implications for biological research and possible applications?

Schwan:

They were interested in both fundamental scientific achievements as well as the possible applications. Microscopy had made substantial advances. Using advanced microscopic techniques, it was found by 1964 that muscle cells possessed a so-called tubular system. In other words, tube-like structures from the outside of a muscle cell penetrate to the interior. It's called the sarcoplasmic reticulum, or tubular, system. People started to suspect that the mechanism of contraction in muscle tissue involves a conduction of electricity inside the tubular systems. We developed a method to measure this phenomenon, what I called alpha effect. This revealed the frequency-dependent capability of the electric charge to penetrate from the outer membrane into the tubular system. This alpha dispersion effect was proof that this hypotheses was correct. Our work was fundamental. Later, the British recognized that it related to the practical question of the relationship of the electric tubular system and muscle contraction. Yes, that was a very important question indeed.

But there was another development which had taken place in the meantime. I had observed first in 1954 or 1955 that this alpha effect also occurs with dead material, e.g. suspensions of glass particles and in colloidal systems. The similarity with biological stuff was stunning to me. Fricke had already measured suspensions of glass particles. But due to the inadequacy of his equipment he could only observe the start of the alpha step. Since he could only see the beginning, many people suspected that it was an electrode artifact since such artifacts can do precisely that sort of thing. I was able to do things with my high precision equipment which Fricke couldn't do with his older equipment. I could extend the frequency range to lower frequencies with higher accuracy. As a result I could see that the electrical properties of particles suspensions had saturated again. This was what we called a true relaxation effect. We published that first in 1957 and then in detail in 'sixty-two in the Journal of Physical Chemistry. That was at once recognized as a breakthrough in dielectrics. I got letters from leading dielectrics people calling it the most significant breakthrough in twenty years and after the Second World War in the field of dielectrics.

Nebeker:

I see. This is 94 on your publications list, "Low frequency dielectric dispersion of colloidal particles?"

Schwan:

Yes. With Schwarz, Maczuk and Pauly.

Nebeker:

Did that explain that alpha effect in biological materials?

Schwan:

Only partly. Later scientists discovered that the tubular system in tissue has electrical charges stored. They also found that effect occurred on the surface of glass particles and colloidal particles. A cloud of counter charges oscillates around the charged solid particles. They are responsible for the alpha-effect of colloidal suspensions. Actually, today I differentiate between a variety of alpha effects responsible for the dielectric behavior of cells and tissues.

Nebeker:

I see. It sounds like one way that you've operated is by careful measurements over some range, looking for steps or changes, and then trying to identify the mechanisms for those.

Schwan:

Precisely. Yes. Not only measuring them, but trying to find out what's behind it. Why are the data such as observed?

Nebeker:

And it has turned out that it's not a single effect in some of these cases.

Schwan:

Yes.

Nebeker:

To return to the question of the instrumentation, I'm very interested in that side of your work because I know that's been an important contribution of yours to the field. Could we carry the story of your instrumentation on a little bit further?

Schwan:

All right, yes.

High-Frequency Measurement

Nebeker:

So at the Navy lab you developed these techniques for the low frequency measurements of conductance and capacitance. What were the next improvements in instrumentation that you made?

Schwan:

The very high frequency range. Right away I constructed a refinement of the equipment which I'd had in Frankfurt at the University of Pennsylvania.[10] I used commercial equipment to measure in the radio frequency range. As a matter of fact, Fricke, who was not doing anymore experimental work, was so kind as to give me his equipment. But at that time his equipment was outdated. I decided to get all sorts of commercial equipment available then and made out better with it. Another early advance was acoustics. There we made substantial headway, primarily due to Ed Carstensen. He is now also a member of the National Academy of Engineering. He just was awarded the IEEE EBS Achievement Award. I called him up on Monday to congratulate him.

He became a very well-known man. We included acoustics in this master plan that I told you about — to measure properties and apply them for clinical diagnostic and therapeutic purposes. He primarily carried the acoustics part. I was heavily involved, too, but he developed the project. He got his Ph.D. for such efforts. He developed high precision substitution techniques. So, we worked together in the acoustics field. As a matter of fact, while he carried the ball in the acoustics field, I did the equivalent in the electrical field. You'll find here some publications we worked on together in the acoustics field. Ed and I took measurements together and we shared publications. You'll find about a dozen publications we did together in the list of references.

Acoustical Work and Echocardiography

Nebeker:

Yes, I noticed that three of the four of your ultrasound or acoustic papers that were honored in that benchmark volume were with Ed Carstensen.

Schwan:

Precisely. That was rather novel equipment. Again, what we created was equipment of the highest resolution yet available. We could see acoustic properties which couldn't be seen before. We recognized the mechanism which was responsible for sound absorption in blood which before was unknown.

Nebeker:

How did your background help you develop that equipment? Was it the background you had in the measurement of electrical properties, or Carstensen's background?

Schwan:

Carstensen was the stronger one since he had more experience with ultrasound. I believed that only substitution technology and focusing on mechanism could do the trick in solving the problem. But his background in acoustics was excellent. During the war he had worked at a Navy Laboratory in Orlando, Florida, on acoustic device techniques for submarine detection, I believe. Then when he came to Penn, in order to get his doctorate, he got in touch with the Department of Physical Medicine, where he gave courses on diathermy and things like that. I think I mentioned that to you last time. He was one of the people who established early contact with me while I was still with the Navy.

Nebeker:

What were the motivations for studying acoustic properties? I know that a kind of acoustic diathermy was being used in those years.

Schwan:

Yes, that was developed first in Germany. As a matter of fact, it was in Germany where I first came in contact with acoustics. When I was put in charge of the institute in Frankfurt, a young man, J. Lehmann, entered the institute. He approached me, and I gave him a working-place. He was a medical doctor and he was very interested in acoustics. By that time Siemens was not building electrical equipment.

Nebeker:

They weren't allowed to do that?

Schwan:

Precisely. So they concentrated on acoustics. They introduced bioacoustics work and ultrasonic diathermy. They and Lehmann became interested in the biological effects of ultrasonic diathermy. While I didn't directly participate in Lehmann's work, I endorsed it nevertheless. I followed it with the keenest interest. So I had already developed an interest in the field when I met with Ed Carstensen and was aware of relevant current developments.[11]

Nebeker:

And Ed had worked with such equipment during the war?

Schwan:

Ed had worked with under-sound listening devices during the war, and he knew how to focus ultrasound and about acoustic transducers. He had working experience with instrumentation.

Nebeker:

What was his motivation for working in this area of acoustic properties of biological materials?

Schwan:

I don't know precisely, it was so long ago. I met him while I was still working for the Navy, he had not yet focused in on a particular problem for his Ph.D. thesis. He was just about finishing taking courses. He had established an interest in biophysics, broadly speaking, due to his contact with the Department of Physical Medicine. But he hadn't formulated a topic yet. I think the topic emerged based on discussions with me.

Nebeker:

Had you already decided that acoustic properties of biological materials would be part of your program?

Schwan:

No. Originally my program broadly addressed electric properties. I had an interest in acoustics, but I didn't feel competent to undertake such work on my own. It was due to Ed establishing contact with me that we added the ultrasonic part. We called it the Electric and Acoustic Properties Program. So he had a significant influence on me, and I, of course, on him.

Nebeker:

Since we've gotten into the acoustic properties area of your work, maybe we can follow that a bit more. Did you continue to work in that area?

Schwan:

Yes. Ed left us in 1955 to take a position with the Army, the Army Biophysics Laboratory in Fredericksburg, Maryland. There were several good biological laboratories and there was a biophysics division where he could do biophysics work. He moved there, and applied his electrical expertise gained at Penn by establishing a laboratory to measure electrical properties of bacteria and so on. I, in turn, continued to maintain the equipment which he had developed and trained people to use it. In particular, there was Helmuth Pauly, who came from Germany, who rapidly gained competence in using the equipment, and then subsequently wrote one of the classical papers in the bioacoustics field. The Pauly-Schwan: paper on the acoustic properties of liver tissue is also a benchmark paper. To this day it's considered a pioneering job about acoustic properties of tissues.

Nebeker:

That was done in your laboratory at Penn?

Schwan:

That was done in my laboratory, yes. And as I say, when Pauly joined us for three years, I familiarized him with the acoustic equipment; he learned it rapidly, and did an excellent job. He was a very outstanding man. Later on, after he left, Peter Edmonds joined my lab. Peter Edmonds had established an excellent acoustic background in England. By then we had a national reputation for doing good acoustic work, and he approached me. He wanted to work in my laboratory, and he carried on with acoustic work. He's now at the Stanford Research Institute; he continues to be very much interested in the subject matter and is supported by NIH even though he is approaching retirement age. He was with us quite some time until he was hired by the IEEE. Do you remember the old Secretary, Emberson? He was a major figure at IEEE, carrying the day-to-day load as Secretary of first the IRE and then the IEEE. He retired about ten years ago. Emberson and the IEEE had become very much interested in engineering in medicine and biology and wanted to establish an administrative emphasis. They hired Peter Edmonds. So Peter Edmonds joined the staff in New York and was there for, oh, I guess, about ten years. And then he moved to Stanford where he still is.[12]

After Peter Edmonds left, I tried to get competent people to carry on the acoustics work. I had two students who did quite good work, but by 'seventy-three, my chairmanship and my being head of the laboratory ceased. My time was over, and I reduced my activities. Since that time no acoustic work has been carried out.

Nebeker:

I see. Was there a direct connection between the acoustic work and the electrical work in your laboratory, or were those separate lines of research?

Schwan:

As far as instrumentation was concerned, entirely different.

Nebeker:

What about the practical?

Schwan:

Many basics are similar. The total intellectual approach is to sort of take tissue apart and measure what components contribute to the processes and properties. In the acoustic case, we tried to characterize the frequency dependence by dispersive effects, as we called them. Again, the rationale we used was almost identical. The relevant mathematics and the applicability of the so-called Kramers-Kronig integral relationships is the same in the acoustic case as it is in the electric case. Intellectually there is so much in common. Also some practical aspects are identical. Typically the physics of diffraction of acoustic waves in front of an acoustic transducer, and that in front of a radar dish, is identical. And so there are many others.

Nebeker:

I see. What about the applications in diathermy?

Schwan:

Again, I would characterize the mode of propagation as similar. The focusing of waves into hot spots and all that is pretty similar. Our first papers with Ed Carstensen on the application of diathermy of electric acoustics tied the two approaches together. That was our common paper which won a prize, "The application of electric acoustic impedance measuring techniques to problems in diathermy." It was published by the AIEE in 'fifty-three. We carried that theme out through our work. So there's much in common within bio-acoustics and electricity.

Nebeker:

It's not transfer of technology but transfer of experimental approach?

Schwan:

Yes. And intellectual approach.

Nebeker:

Yes. Even some of the mathematical analysis is the same.

Schwan:

Yes. There are common relationships, diffraction, the relaxation mathematics, and things like that; these were basically identical even though numerical results are quite different.

Nebeker:

What about the modeling of biological materials with layers or spheres or whatever? Was there some carry-over there as well?

Schwan:

Yes. But with entirely different results. In the electric case, the analysis proved that cell membranes played a very important part, a dominant part, with the electric characteristics. In our work on acoustics, it turned out, to our surprise, that membranes have very little importance. But proteins and macromolecules are responsible for the dominant part of the ultrasonic absorption processes. So the entire response was very different.

Nebeker:

Well, that's very interesting. Is there anything more you'd like to comment on now on that, the line of acoustic or ultrasonic research?

Schwan:

I think I have said most of the stuff which needs to be said at the moment about acoustic properties. Oh, pardon me! I forgot something very important. It's good that you asked me that. There was another person, who did acoustics work in my lab between Edmonds and Pauly, I think I mentioned him already to you. His name is Jack Reid, and is now at Drexel. He was the man who introduced echocardiography in the US. That was a very practical thing, of course. That was a very important development.

Nebeker:

What part of your lab was involved in the development of echocardiography?

Schwan:

I thought I mentioned that before. Well, let me briefly summarize. Scientists in Germany and Sweden made the first successful attempts to monitor the motion of the heart by ultrasonic means. When I came back to the United States, I brought it right away to the attention of my cardiologist friend, Francis Kay. At the same time, John Reid applied for a position in my laboratory with the intention to get a Ph.D. in bioengineering. He was joined by Claude Joyner who did clinical work in cardiology. Jack Reid did instrumentation work and realized the echocardiography. Joyner was financed by Kay, and I was able to finance Jack Reid. I sent an application — probably the first application about echocardiography that was sent to NIH. It was approved, and that gave me the ability to support his Ph.D. thesis work. I supervised it of course. I was very much interested in it, but it was entirely Jack's work. Echocardiography has become very important in this country. There's no Department of Medicine without echocardiography equipment. As a matter of fact, echocardiography proved to detect heart defects which were unknown before. It revealed problems such as the inversion of mitral valves, which is called a prolapsed valve condition. It is a special condition, very frequent. My wife has it, too. That can't be seen with other techniques. It was beautifully recognized with echocardiography.

Yes, so we had a number of good people in acoustics. All very well-known in the field, starting with Ed Carstensen, followed by Pauly, Jack Reid and Peter Edmonds. Very excellent. I was very happy to have been able to develop this whole effort in acoustics and to be associated with these friends and coworkers.

Nebeker:

The acoustic work was always separately funded?

Schwan:

It was separately funded. I think I mentioned to you that I got the work with Carstensen funded by the Air Force. Later on it was funded by NIH. Edmonds got support from NSF on his own.

Electrical Properties of Biological Materials

Nebeker:

Let's turn now to your main line of research, the electrical properties of biological materials. Was it your view that those fundamental properties of the materials should be precisely measured over a wide range of frequencies, because one could then calculate other properties of the materials, such as how much energy is absorbed or reflected?

Schwan:

Originally, at the very early conception of the program, a purely scientific spirit prevailed. Namely, I wanted to look at biological materials as a physicist. Normally a physicist becomes interested in some material, he measures its properties without any question about how he can apply it. As he measures the properties, he asks himself Why are the properties as observed? To this he can then add another thing. Namely, he can add the question. Now knowing why the properties are such as observed, how do energies interact with the material? If he knows why the properties are such as observed, he can explain how energies interact. Out of this comes, then, intelligently undertaken applications. Not, therefore, just going blindly at something — at cancer or so; but intelligent applications. Those applications that we envisioned early pertained to cardiology and physical medicine primarily. The engineering part to all such applications requires precise measurements of electrical properties and acoustic properties and play an important part in developing various diagnostic techniques in all sorts of areas.

Nebeker:

I'm wondering why you chose to focus on these two fundamental properties — electrical and acoustical properties — of the materials. There must be other properties one could investigate.

Schwan:

Yes. Two reasons. Some work had been already done in acoustics. The electric part had been only partially employed. The electric part had been only explored by Cole and Fricke in the radio frequency part, but they couldn't do it at high and low frequencies. I developed the instrumentation to do so, and after the Second World War it was possible to do this. I significantly extended the range of observations into areas where no one else had done work. A good amount of work was going on in optics already. I didn't apply myself to that work. I decided I would have been spreading myself too thin by also entering a well-developed field. So I chose a different area. And last, but not least, my background from the Frankfurt Institute, led me in that direction.

I'll just point out two examples. If you know electrical properties of materials, then, say, if you have a beam of radiation hitting a body of material, the electrical properties of the material and the shape of the body determine the mode of propagation of that beam. In other words, to what extent it's scattered or focused and where the focal point is. All those things you can calculate. You can do that by Mie Theory — M-I-E. A mathematician named Mie had developed the mathematical techniques of how to predict what happens with any form of radiation — optical, sonic, or electromagnetic propagates. He showed mathematically how it gets focused or how it gets dispersed in the medium. His technique was further advanced and found a place in leading textbooks. Stratton, still a leading textbook in this country, has a chapter about Mie Theory. The intellectual tool is there which enables us to predict how the radiation penetrates in the tissues, and how deep. You can determine precisely where it goes, in principle. But if you have a difficult body surface with curvatures, and with all sorts of bones and different materials, there is too much complexity to permit numerical solutions.

But Mie's is theory fundamentally macroscopic. With a microscopic approach we blow up the tissue. We look at how it's composed of individual cells, which are all divided by membranes. Inside is something conducting outside is something conducting. Now if you know the field at a particular location, as predicted by your macroscopic consideration, then your knowledge about these mechanisms can tell you how strong the field strength is in the membrane, how strong inside, how strong outside, at any particular frequency. Consequently, you can predict how it interacts with the membrane, how it interacts with proteins, the nucleus, nucleic acids, and so on. So the knowledge it gives you is microscopic and pertains to real mechanisms inside. Mie Theory applies macroscopically. Both approaches are necessary. The macroscopic may be called the bioengineering approach. The biophysics approach explores the details on the microscopic level. So you see, all that we do is directly relevant. Electric properties get at the principal mechanisms and on a larger scale they give you the macroscopic dosimetry. We were the first to use both processes then many others adopted the practice. Originally we were practically alone, but we were then joined by many others of course.

Computation and Resonance Effect

Nebeker:

You mentioned here the difficulty of carrying out the computations sometimes.

Schwan:

Yes.

Nebeker:

I noticed in your list of lectures that in 1961 you gave a talk on UNIVAC computations of radar absorption. I'm wondering about your use of computers, how you happened to have the use of a UNIVAC.

Schwan:

We got fairly early involved with computer technology in our laboratory. First we rented computers. But eventually we purchased our own computer.

Nebeker:

For your laboratory?

Schwan: for the laboratory, yes. I got an NIH grant to purchase equipment from Digital Corporation.

Nebeker:

Do you remember this 'sixty-one talk on the use of the UNIVAC?

Schwan:

I can't remember. What talk was that? Where did I give it?

Nebeker:

I'll have to check your list of talks here. That talk was given at the Fifth Annual Meeting of the Biophysical Society in February of 'sixty-one.

Schwan:

Oh, yes. At the Fifth Annual Meeting of the Biophysical Society, yes. That's right. I remember the topic. The topic was related to the macroscopic absorption process and the Mie Theory, as presented by Stratton in his text about electromagnetic fields. We were concerned how models of the human body — curved as they are — interact with the radiation. The calculations are numerically complex. You have many equations. And the convergence is very slow, near the resonance state. There are certain resonance conditions the closer you come to the resonance, the slower is the convergence. So you need more massive calculating power. We had to get large computing power to solve the problems. We were the first ones to carry out such calculations on the microwave cross section of man and discover the resonance effect.

Nebeker:

You discovered it numerically using these calculations?

Schwan:

Yes. We also confirmed it experimentally in a microwave exposure facility which we built. It was the largest at the time existing on the East Coast.

Nebeker:

Do you recall if this discovery of the resonance effect was written up?

Schwan:

Yes. It was written up.

Nebeker:

Can you locate the article?

Schwan:

That article, let me see. Here's a digest. That was, perhaps, the first one.

Nebeker:

Number eighty-eight?

Schwan:

Yes, also numbers ninety-five, ninety-six, etcetera.

Nebeker:

You discovered that microwave energy would be strongly absorbed at certain frequencies?

Schwan:

Yes. At particular frequencies which relate to the size of man.

Nebeker:

You discovered that numerically and confirmed it in the laboratory?

Schwan:

Experimentally, yes. Well, we certainly have ninety-five and ninety-six here. There is another more detailed article about it, but I can't locate it right now.

Nebeker:

Well, we can locate it later.[13] This line of work of yours is the study of non-ionizing radiation and its bioeffects.

Schwan:

Yes.

Nebeker:

Of course you were very familiar with the earlier study of ionizing radiation.

Schwan:

Yes.

Biological Effects of Non-ionizing Radiation

Nebeker:

You were interested in the biological effects of ionizing radiation. Speaking generally now of these investigations, did the study of non-ionizing radiation follow in the footsteps of the earlier studies of ionizing?

Schwan:

Only approximately. I would say that I perceived from the ionizing work the rationale, as I stated before study properties, interactions and relevant mechanisms. Don't only observe properties. You must understand what's going on, then you gain predictive power. So the general rationale was similar. But of course the details were entirely different.

Nebeker:

They used different instruments?

Schwan:

Yes. Exactly. The work required entirely different technologies. So we come now to a different topic here. You remember, we talked about properties primarily — acoustic properties, electric properties. Now we start to talk about interaction presumably. I want to show you two documents. One I have here, and the other is outside. They might be of interest to you. This one is a recognition which we got in spite of controversy. It recognizes my contribution to bioelectromagnetics and the development of bioengineering.

Nebeker:

This is the d'Arsonval Medal.

Schwan:

Yes. I was the first one to get it in 'eighty-five. For a while there was a great deal of controversy in the media about me and other skeptics. I point out those two awards in order to illustrate that there was no doubt in the minds of the professional organizations of the impact I had in the field. The criticism stems from rather uneducated sources and is not shared by the vast majority of scientists in the field.

Nebeker:

I wanted to ask another one or two very general questions.

Schwan:

Yes.

Nebeker:

If you look back now on this long-standing research area of biological effects of non-ionizing radiation, what were the main instrumental advances, not only yours, but in general, that made possible the progress of this field?

Schwan:

In terms of instrumental advances, not much has to be said. The people researching non-ionizing bioeffects essentially use those instruments developed by electrical engineers. There's nothing particularly specific to the biophysical/bioengineering efforts in the field as far as instrumentation is concerned.

Nebeker:

I'm thinking about new devices that you've already mentioned. When the higher frequencies were clearly generated, or when the computer becomes available to do some analysis, are there any other things of that magnitude that affected the field? There was some work done before there was very much electronic measurement. In the postwar decade did the availability of very sensitive electronic measuring devices make an impact?

Schwan:

Nothing comes immediately to mind, I must say. There was a reorientation and that is perhaps significant to point out. As we discussed before, there was an interest in therapeutic and diagnostic applications diathermy techniques, echocardiography, things like that. But then later interest in the deleterious effect developed. Hazards, in other words. That also developed in the electromagnetic case. During the war, the Navy had had some concern about the ship radar. But the diathermy interests continued stronger than the interests in health hazards. Then by the late 'fifties, interest in hazards was sufficiently strong so that the IEEE and the Navy cosponsored the American Standards Institute. Committee C-95, and in 'fifty-nine I became chairman of the committee.

We discussed a summary of the scientific work. We covered it largely but not completely. We didn't cover our electrode studies. There are other aspects which we shouldn't forget. I became known for my organizational contributions to the development of bioengineering in the IEEE and other societies. I developed a national reputation through my establishment of training programs, activities with NIH and my national activities that had an effect on the field. I would like to talk about that activity some more.

Electrode Studies and the Pacemaker

Nebeker:

I certainly want to cover that. Could we talk first about the electrode work?

Schwan:

Okay. Yes.

Nebeker:

I know that you've done important work in identifying electrode artifacts and studying electrode polarization. Can you first explain for a lay audience the significance of these studies?

Schwan:

Yes. It relates to our scientific work, as well as to practice. Let me give you some examples. I indicated before, understanding electrodes is basic to defining the various steps which characterize biological materials' electric properties. The electrode effects tend to mask biofrequency properties, i.e. at low frequencies observed properties are caused by the electrode but not by the material itself. When we carried out our measurements to ever-lower frequencies we ran into this problem more and more. I was forced to learn about electrodes in order to be able to minimize their effects and to optimize my high resolution techniques so that the disturbing effect of the electrode was prevented.

Let me briefly explain. If you want to measure electric properties, you have to conduct an electric current through the material of interest. Then you would apply the voltage, and measure the current. The ratio gives you, by Ohm's Law, the impedance of that material. But suppose now, at the interface of the electrode with the material, that there is a voltage jump resulting from electric polarization. This voltage jump has to be subtracted from the total voltage in order to get the voltage which is properly applied to the material. If you don't know about that voltage jump, you get a wrong impedance calculation. No impedance work is possible unless you know how good your electrodes are and how to correct for potential electrode problems. If the conductivity of the material to be measured is low and the impedance is high, the effect is minimal. But with biological material, their conductivity is high. Consequently you have to be aware of the electrode effect. So we developed a number of techniques on how to correct for this effect, and studied the effect in detail as a function of frequency and of current density, etcetera, etcetera. This field has been of interest to a limited number of engineers and biophysicists who came into contact with this sort of thing. Yesterday I was informed about the last issue of the Annals of Biomedical Engineering, which is published by the Biomedical Engineering Society. The Annals of Biomedical Engineering published a special issue on electrodes with some ten contributed papers collected to honor my contributions in the field. I myself have contributed to this issue. I haven't gotten it yet. The editor of the issue wrote a good statement of what electrodes are all about.

Nebeker:

Good. I'll look at that.

Schwan:

But I don't have it here. It just came out yesterday.

Nebeker:

What about previous work? Had that been a specific focus of investigation before?

Schwan:

It always had been, yes. We were not new in that field. Other people had recognized problems with electrodes. The first one to recognize the phenomenon of electrode polarization lived around the turn of the century. But, as it usually goes, the concepts about electrode polarization were more refined in subsequent steps. The first who worked on them theoretically was Warburg who formulated a first theory about electrode polarization. Then Hugo Fricke, my old friend and teacher, measured biological impedance and became interested in electrode polarization. He wrote an important paper on electrode polarization in Philosophical Magazine in 1932, which refined Warburg's modeling of electrode polarization.

Later on, with more advanced instrumentation, we further refined the modeling of electrode polarization over an extended frequency range and signal strength level. When the current becomes strong, its impedance properties decrease. That nonlinear behavior was not studied with care before. Of all the technologies which bioengineers have introduced into medicine, the pacemaker has been perhaps the most successful. More important than NMR technology and other imaging techniques. More important than echocardiography and than diathermy techniques. The pacemaker has saved and/or extended hundreds of thousands, if not millions, of people's lives, more than any other medical technical device. So that is a very important development. Peacemakers couldn't operate if they were not driven in the nonlinear part. If they were operating in the linear part, their polarization impedance would be large and prevent any energy from reaching the heart.

Nebeker:

You were saying that pacemaker function is related to the nonlinear effect?

Schwan:

Yes. They operate with such strong signals that the polarization contribution of the electrodes to the total voltage is minimized. In other words, as you increase current strength more and more, the ratio of the voltage that is lost at the interface to the voltage that gets into the tissue changes in favor of the tissue. This non-linear behavior is true for many devices. It should be also valid for transistor materials. That's a fairly broadly existing characteristic. All electric properties eventually change as a function of a stimulus. Typical muscle tissue changes its properties above one volt per centimeter. That's due to the biological membrane channels. Similar non-linear or rectifier effects, of course, led to the interest in semiconductor devices and their function. If they were not nonlinear, they couldn't rectify. They must be nonlinear, otherwise they wouldn't function.

Nebeker:

Was your work in this area of understanding electrodes concentrated in any short period of time?

Schwan:

No, it was pretty much distributed, I would say.

Nebeker:

Judging from your list of publications, it seems true of all these areas of your work.

Schwan:

Indeed, you are quite correct. You see things popping up again and again.

Nebeker:

Yes, you seem to continue to deal with health hazards over a long time, electric and acoustic properties, and the mechanisms.

Schwan:

Yes. All the demands reflects typically. I've been invited to go to Finland where there's a meeting of Bio-Impedance. I think I mentioned it to you. They want me to give two leading plenary lectures there. They asked me to talk on those two topics here that I'm still working on. So, you see, the old topics came up again. People are still interested.

Nebeker:

Well, it's also because those areas are very closely related.

Schwan:

Yes. That is so.

Nebeker:

Understanding the properties, the mechanisms and the health effects, are all related.

Schwan:

Right.

Electrical Properties of Membranes

Nebeker:

Another area we haven't talked about is electrical properties of membranes. I mean, we've talked about it in general, in biological materials, but I take it that's been a focus of your work?

Schwan:

Well, it started to relate to the work on electric properties. Electric properties are determined by various parts of the tissues. We talked about the microscopic effects and things like that. Tissues are composed of membranes, water, proteins, nucleic acids, and so on. So naturally, in explaining tissue properties, we're forced to individually deal with the electrical properties of proteins, nucleic acids, water, and membranes. We did work on all those components. In other words, in order to specifically talk about membranes or proteins, we deal with parts and refinements now of my previous statements about electric properties. The component properties directly relate to electric properties of times and all suspensions.

Nebeker:

Right. Did you have special experimental setups to focus on the membranes themselves?

Schwan:

No. Membranes cause the alpha dispersion. We recognized that the apparent membrane properties, as they appear to be with the standard techniques, seem to change with frequencies in specific ways. We also isolated the various mechanisms responsible.

Nebeker:

You have these tissue fluids separated by membranes, and you know the properties of the fluids, these membrane electrical properties, and you're trying to understand the values you're getting for the biological material as a whole?

Schwan:

Yes. Now the question is, how do you get at the properties of the components? Well, you can do it by measuring some components separately. You certainly can measure water on its own. You can measure the protein solution without membranes. You can create a model of the system of membranes. First just water and electrolytes, then add proteins, then eventually include some membranes systems and so on. That's one approach, and that's indeed the sort of thing we frequently did. With regard to membrane properties, we pointed out the fact that some of the effects which caused the apparent frequency dependence of the membrane, were due to the membrane itself, and others were not. It appeared from the outside that the characteristics of the membrane were responsible. But in reality, it's not due to the membrane, but to effects which take place near the surface of the membrane. It's similar to electrode polarization, i.e. what happens near the metal electrode in contact with electrolyte. So there are extraneous factors and intrinsic factors which contribute to the membrane function. We did a good deal of work in separating all those membrane effects.

Nebeker:

I assume that in all of this, the theoretical modeling of the system is important in separating the effects?

Schwan:

Oh, yes. It all interlinks with such efforts as our investigating glass spheres and colloidal particle suspensions. Colloidal particles have one thing in common with cells they are electrically charged. As a consequence of that, they are surrounded by a cloud of opposite charges which is mobile in the fluid medium. When you apply an alternating field, they pulsate about the particle. This creates what the physical chemists call "induced dipole moments." That is one effect which causes an alpha dispersion. Colloidal particles display that effect very strongly indeed. But in the biological case it's much more difficult than with colloidal particles since in the colloidal particles, the charges are close to the surface. In the biological particle case you have the particle surrounded by a sort of wall-like structure, called the glycocalyx, which extends further out from the particle, and the charges are distributed. That makes its mathematical treatment much more complex. That process hasn't been formulated into a mathematical equation yet. So there are common things and different things. That's a long, complex story about the glycocalyx and how it enters in the account of membrane properties.

Nebeker:

Well, and also the endoplasmic reticulum gives you this incredibly complex structure.

Schwan:

Quite. Yes.

Nebeker:

I've seen mention of the so-called equivalent circuits that had been devised to model some of this.

Schwan:

Yes. We all use them. Cole did, and Fricke did. I used them very often. In my case it's quite understandable since as you know from my radio days, I was always partly an electrical engineer. I learned a good deal of electrical engineering. To me it was always natural to invent models with lumped circuit elements capacitors, inductances and resistors. Cole told me that he learned it from electrical engineers. I think his brother told him that the electrical engineers could simulate properties. A man in Germany called Cauer applied the theory of functions to electrical networks. He discovered this at the same time Foster did it in this country. This led then to the courses of network analysis and network syntheses. These courses were new but they dominated the field of electrical engineering for a long time after the Second World War in this country. Cole became aware of that and studied it and used it in electrical networks.

Nebeker:

That seems to be a case of where electrical engineers, or people with that background, somehow have contributed to this area of biophysics?

Schwan:

Oh, yes. I would say it's spilled over very strongly into what we call systems engineering these days. So it's quite natural that similar approaches are used. The engineers don't talk anymore about what I called sometimes in our discussions the Kramer-Kronig relationships as formulated by physics. They'd rather talk about the Hilbert Theorem. But if you look at the old David Hilbert Theorem, it's the same as Kramer-Kronig. They talk about causality and reality systems which will be causal. That's true for all sophisticated systems, and engineering structures. But it's the same sort of stuff we used analyzing tissues and cell suspensions in terms of dispersion phenomena. The roots are the same, and the networks are the same. It's very closely related.

Nebeker:

This ability to devise equivalent circuits has been useful, I take it, in understanding mechanisms and structures?

Schwan:

Yes. It's also a good pedagogical device for teaching students. I use it extensively in teaching classes.

Nebeker:

But what about in research itself?

Schwan:

We could do without it. It's helpful. I tried to think in circuits at first. But my calculations forced me to use the Laplacian regular theory which is Laplacian essentially. But in class I often use the electric circuits since they are easy to remember.

Nebeker:

They are helpful as a way of abstracting from the biological complexity.

Schwan:

Quite. As it happens so often, it was my interaction with people, scientific and otherwise, which was, I believe, productive. In other words, all the work which I did on biological properties and applications of such knowledge, I did with a number of other people. I enjoyed first-hand cooperation with people. I deserve, perhaps, the major credit for the overall conception and organization of the work. But it was really a very cooperative effort. I've mentioned Carstensen, Reid and Pauly. There were many others. But there are some who are particularly outstanding, like Carstensen. Another one whom I haven't mentioned is Geselowitz. He also became a member of the National Academy of Engineering. The National Academy of Engineering has various divisions, including a section in bioengineering which was established about five years ago. So far about twenty to thirty bioengineer members have been elected to the Academy. Geselowitz, Carstensen and myself are in that number. There is no other bioengineering department in the country with such a strong representation. We had at Penn a strong, cooperative atmosphere. I benefited very much from the interaction with many people. I think our combined impact was very strong in this country.

Nebeker:

A fair number of your papers are co-authored.

Schwan:

Yes.

Graduate Program at Penn

Nebeker:

It may be appropriate here to talk about that further. You've supervised something like twenty Ph.D. dissertations?

Schwan:

At least.

Nebeker:

How many master's dissertations were by people who were electrical engineers or on the engineering side mainly?

Schwan:

Initially, the electrical engineers predominated. The reason is very simple, related to something we haven't discussed the development of the educational aspects of our program. Initially, as I became affiliated with the Moore School of Electrical Engineering, most of my students got their degree in electrical engineering, with the understanding that they didn't have to take all the courses which electrical engineers usually take, but they could substitute some of those with medical electronics courses, as I called them. Later they could take bioengineering courses, which were developed over time. Originally students could earn an electrical engineering degree incorporating some training in bioengineering. But starting 1960, 'sixty-one, we had established a graduate department, with a Ph.D. program, on its own, and we set our own requirements. From there on people got a bioengineering degree, of course. Jack Reid still officially has an electrical engineering degree, even though he took a number of bioengineering courses. But when he started the program in 'fifty-seven or so, we didn't have that bioengineering program yet. So it depends on the time.

Nebeker:

Did that mean that you could better accommodate people who came from medicine or biology?

Schwan:

It was quite apparent that in our program it would be asymmetrical. I took more people who came from engineering and physics than from medicine and biology. The reason is that I felt that if a person must learn mathematics and physics and engineering, he should do it at a young age. In other words, I observed that if people at a young age showed the ability in mathematics and applied it to engineering and physics, they were quite able to add later on knowledge in biology and medicine. But I found it was much more difficult for a medical doctor later on to learn mathematics and engineering. That's a very tough battle for him. It has something to do about how the brain works which makes one route better than the other one. The implication for our program as it developed was, of course, to concentrate on people with a primary background in the exact sciences.

Nebeker:

So the vast majority of these Ph.D.'s were people with physics/engineering backgrounds?

Schwan:

Yes.

Nebeker:

Is it possible to generalize about their thesis work? Was it the case that there were so many topics that were ready to be investigated because of your program there, that you were always able to suggest some topics to them? Or was it often the case that someone came in — as Carstensen did at the very beginning — with some particular background, a particular interest that determined the thesis topic?

Schwan:

Both. Our graduate program leading to a Ph.D. made a powerful addition to the department. I started to get substantial training funds from the government, from NIH. These training funds enabled me to renew and tighten my connection with the medical school. Being able to support students, I found that slowly but steadily a variety of departments — biology, physiology, biophysics, etcetera., medicine — became interested in our students. It eventually led to a situation where I would say half of our students worked in our own laboratory, but half worked in other laboratories.

Nebeker:

Your Ph.D. students worked in other labs?

Schwan:

Toward Ph.D.'s, yes. By that time a number of colleagues typically in physiology had emerged with an interest in systems engineering applications. They had their own research projects and were willing to somewhat contribute to the student's expense. The students took our bioengineering courses and carried out work in those departments. Their thesis topics were not formulated by me anymore. They had to be approved by me since I was responsible to NIH that the students did good bioengineering work, of course. But while I approved them, the problems were formulated by my colleagues. It then became a half-half situation. I think that was very good. I liked that sort of developing intellectual atmosphere in which you cooperate with people in the other fields very much.

Nebeker:

You talked a bit last time about how things developed at Penn. That the first couple of years you were supported by the School of Medicine.

Schwan:

Yes.

Nebeker:

And then you got your own funding and succeeded in getting more and building up your group there. You told me a bit about the early teaching. But how did things develop there as far as the amount of teaching being done and the amount of support given by the university to your group?

Schwan: for the longest while I financed everything. There was very little university support — if any. But later on, after the Department of Biomedical Engineering had been established in 'sixty-one, the university's engineering school contributed fifty percent of my salary. But that was it. Most of the finance still came from the outside at that time.

Nebeker:

Were all the other positions still financed outside?

Schwan:

Yes.

Nebeker:

What about the amount of teaching done by your group?

Schwan:

Teaching was supported by the university. Yes. The teaching increased slowly. I started to give my first course immediately after I entered the Moore School in 'fifty-two. It was called "Medical Electronics I." Then I added "Medical Electronics II." Ed Carstensen added a course. Then Ernie Frank added a course; he was another very significant early member of our lab. In due time we had developed some six or seven courses. Peter Edmonds was teaching another class. So did Nooder Graaf. Many others were teaching. We had a fairly rich list of offerings. But that brings us to another long story my interaction with Sam Talbot and the development of a training program. How should we train people in general? What are the ground rules in the development of biomedical engineering training?

National Developments in Biophysics

Nebeker:

I know you've written about that topic. Can you summarize it?

Schwan:

Yes. I mentioned I had met with Sam fairly early. He was at Johns Hopkins, employed by the Department of Medicine as a biophysicist. I met him at that Columbus meeting, together with Otto Schmitt. That was in 'fifty where I presented first my discovery of that new frequency dispersive effect. Then he started to visit the University of Pennsylvania. He knew Kay, the cardiologist I worked with in the hospital, very well. He was also interested in electrocardiography. Kay financially supported a program in our group concerned with electrocardiographic leads. That program explored how to design them optimally. He came to visit once in a while and we visited him. I started to talk frequently with him. I remember very well that I often brought up the subject matter of forming a biophysical society — as I did with Otto Schmitt. Their interest grew, slowly but steadily. In 'fifty-seven we established a biophysical society. Going through some of my files I found an historical note of interest.

Nebeker:

This is entitled "National Biophysics Conference." "A steering committee of some fifty scientists has organized a national biophysics conference to take place in Columbus, Ohio in March of 'fifty-seven." I see. You were one of the two chairmen of this effort, along with Talbot, to sign this announcement?

Schwan:

Yes. That was the beginning of the Biophysical Society. Columbus had turned out to be very strongly attended, very popular and successful. In Columbus the decision was made to form a biophysical society. I knew Talbot quite well and our discussions about biophysics started to take effect. That was 'fifty-seven. Actually this notice I distributed in 'fifty-six.

A few years later, beginning in 'fifty-eight, Talbot had submitted an application to NIH for funds that was not concerned with biophysics research. The fund was concerned with bioengineering. Namely, he proposed to investigate the feasibility of training in bioengineering. What should be typical course contents? What sort of student should one attract to it? That project was funded. That fund gave him the money to contact several people in the country and to organize some meetings. Initially, he had contacted five universities, Johns Hopkins, Pennsylvania, Yale, Columbia and Rochester. Yale and Columbia eventually dropped out. They had all sorts of internal problems. Even as we became more convinced that such programs were needed, we all observed that it was not easy to establish new departments at a university. There's lots of criticism to be anticipated. Your colleagues don't want you easily to get a department dedicated to a new area. There are many conservative spirits, of course. Naturally it should be difficult, since otherwise poor programs might emerge. So Columbia and Yale ran into difficulties. But at Rochester, Johns Hopkins, and Pennsylvania, we continued our deliberations. We established guidelines of training in the field and published our results in articles. This led, on the one hand, to the establishment of such programs at the respective universities. On the other hand, it had far-reaching consequences at NIH. The NIH established study sections to administer funds and channeled them for a decade or so in order to seed that field and to bring it up in the country. That is the significance of the Talbot initiative. His efforts were very important.

Nebeker:

Did he have any particular influence at NIH? Or did other people at NIH just see that this was a promising field?

Schwan:

It was primarily Jack Brown at NIH that influenced the grants program. He gave a lecture at the 1990 Philadelphia IEEE-EABS meeting, and it was published in the IEEE-EMBS Magazine. Jack Brown believed strongly in the field and did a good deal about it. But as the Talbot effort emerged in bioengineering, there was already a base which existed much longer than in biophysics. Biophysics, as I just demonstrated, started to develop in 'fifty-seven, following discussions with W. Fry, S. Talbot, Otto Schmitt and others. I first had a discussion with Otto Schmitt at a meeting at the Mayo Clinic in Rochester, Minnesota in 'fifty-five. At that time he didn't believe in it too strongly. But we had biomedical engineering activity since 1947. I'm talking now about the annual conferences on Medical Electronics and Engineering Medicine and Biology. I want to show you some materials which I have collected. I want to talk a little bit about the pre-societies of the IEEE the American Institute of Electrical Engineers, and the Institute of Radio Engineers, the AIEE and the IRE, which operated independently until they joined to form the IEEE in the 'sixties. Almost immediately after the Second World War they set up committees interested in this field.

IRE, AIEE and IEEE

Nebeker:

You were saying one milestone was the publication of these IRE Transactionson medical electronics?

Schwan:

Yes. That's the first journal in the field. Here is number two, from October 'fifty-five. Number one I gave to Kay, I never got it back. Number one was on electrocardiographic topics organized by this student of mine named Ernie Frank. Number two was a panel discussion. Then came numbers three and four. Three was papers from a conference on impedance plethysmography. I participated in that one. Then came number four, "Biological effects of microwaves." I also participated in that one. At that time I was already serving on the IRE and AIEE committees when the Transactions came out. But I was not a member of the very first committee, which was founded earlier. That is described in an article by Montgomery, which you might wish to consult.

Nebeker:

When did you become associated with the IRE?

Schwan:

I tried to figure it out myself. I was involved when the Transactions appeared. You can see me listed here as a member on the Administrative Committee.

Nebeker:

That's the second one?

Schwan:

Yes. By 'fifty-five I was clearly affiliated with the IRE Administrative Committee. I think I first became affiliated in about 'fifty-two with the AIEE committee. There are some statistics here, if I may just point out the committee memberships. Here it lists membership in 'fifty-eight, 'fifty-nine, but they are partially incomplete, as you can see. It doesn't list the earlier membership. Now we want to republish that article as suggested by Murray Eden in the IEEE-EMBS magazine. But I will complement that. Since I have the Transactions up to the very beginning, I can add to it the earlier administrative committees to make it more complete. It should be an interesting article if the missing information is added to it.

Nebeker:

Good. I've made a note of that.

Schwan:

I have here all sorts of things, like the constitution of the group as it stood in 'sixty-eight. Our original constitution was approved in 'fifty-three. In other words, the IRE activity in the field began about two years before the Transactions was published. Here are listed members of the group — the IRE Administrative Committee — from 'fifty-one. 'Fifty-one! We were organizing in 'fifty-one.

Nebeker:

It took them a couple of years to get the constitution.

Schwan:

I got involved with the IRE Administrative Committee (AdCom) in 'fifty-five. 'Fifty-five. Here's a gap of one year, apparently. Then I was chairman, vice-chairman, and again vice-chairman, vice-chairman, and chairman and chairman. I was active in the IRE committee for fourteen years, with the exception of that one year, from 'fifty-five to 'sixty-nine. I was chairman of the group for three years and vice-chairman another four years. I was heavily involved compared with most other people.

Nebeker:

Yes. Could I get a copy of this?

Schwan:

Yes. Our editor, William Fry, died. That here was one of the early Transactions, or newsletters. Oh, I'm sorry. It's not identified here. I have to send that. My God! I haven't opened these files in the last years at all. I just brought that material home since you were here. I wanted to look through it in view of my writing more about this magazine article. But that item should be of interest. You can take it, but you must promise me to send it back.

Nebeker:

Sure.

Schwan:

Oh, Richard Emberson was the secretary. You don't know him anymore? He was in charge of technical services in the IEEE for many years but he's now retired. No, that here is all later stuff. I noticed there is a gap of information between the group today and its history. The group today has no old records on file. Apparently professional societies don't have a clear mechanism for how to keep historical archives. Your institute, I believe, is the only one. That's why records with you are very important. The younger people in the EMB Administrative Committee have no more connection, have no idea of what happened through the earlier times.

Nebeker:

You became involved with the IRE committee in 1955?

Schwan:

Yes. Oh, here's something interesting. Here's a letter from Zworykin in 'fifty-five "I'm extremely sorry to hear from you that the present does not permit your active participation on the Organization Committee of the International Research Institute for Medical & Biological Engineering." That was 'sixty-one. Zworykin had become very much interested in the International Federation, and of course the Research Institute. The Research Institute never came off, but the International Federation came off all right. That was 'sixty-one. We had vicious fights about the International Federation, and its original constitution. We got the constitution changed. It was a little bit autocratic. We introduced that logarithmic rule you remember I told you about, and that was adopted in 'sixty-five. It was accepted in Tokyo, in August 'sixty-five. That is the constitution of the International Federation as it still exists. I just pick up the things as they come to mind. Now you see, here is my file on another committee. That is the Committee on Electric Techniques in Medicine, Biology of the AIEE. That's the other committee I mentioned. The AEEE and IRE committees operated independently until eventually they merged.

Nebeker:

Did they get together before the two societies as a whole got together?

Schwan:

Yes and no. I will come to that, and I'll show you documentation about that shortly. We formed a committee to organize common annual meetings in the field. But originally they were independent. They were somewhat different in orientation. As you may know, the American Institute of Electrical Engineering encompassed all electrical engineering aspects but concentrated heavily on power. The IRE also was broad, but it concentrated primarily on electronics. That was reflected in the original orientation of their two biomedical groups and their two Administrative Committees. The power people at that time were very much interested in atomic energy and felt that more ought to be done about the bioeffect of ionizing radiation and related things. Look here. It was typically a mixture of focuses. That was in 'fifty-five. At that time it started to change. Here's a session with papers such as "Control of radio interference for medical electronic equipment." "Use of radio frequency power in making lesions in the brain." Here is a lecture of mine. Then "Radiation monitoring about some of the x-ray divisions." "Performance of a large photoconductive x-ray pick-up tube," by John Jacobs, who later strongly emerged in developing a second-generation bioengineering effort in the field at Northwestern. Most of those people here emerged as important people. Aaronow did fine work in Boston for decades in this field. Jacobs became a very major figure in bioengineering development. And Earl Wood became a famous figure at the Mayo Clinic, very outstanding. They were all present at this meeting even though there are just a few papers here.

Nebeker:

Do you know when the AIEE committee formed?

Schwan:

Yes, I'll try to find out. I thought I would have that here. As we see from those records here, it clearly was in effect in 'fifty-five. I have AIEE records from 'fifty-four to 'fifty-seven. There's a soft implication that it may have come about in 'fifty-four. Let me see when was this letter.... That's 'fifty-seven; that is much later. No, I have nothing anymore to identify. I may have eliminated all that, I'm sorry to say. Again, here's a list of IRE AdCom members in a different form from 'fifty-two. You see, during the very first year Montgomery served as chairman with Ballard and Herrick. They were the first ones. Here's Britton Chance, Grundfest, and Zworykin.

Nebeker:

Oh, and I see it lists Montgomery as the chairman in 1951.

Schwan:

Yes. Quite. And I entered AdCom in 'fifty-five, as we have now determined.

Nebeker:

Were you an IRE member before then?

Schwan:

I believe so, but I'm not quite sure when I became a member of IRE.

Nebeker:

Did you join the AIEE as well?

Schwan:

Oh, yes. As a matter of fact, I was first elected to serve on the relevant AIEE committee. I think I became a member of the AIEE committee in 'fifty-two or 'fifty-three. It was possibly due to the recommendation of Reid Warren, who had an influence on the early development of it. He was a friend of Montgomery, as a matter of fact. I became a member of the AIEE committee something like two or three years before I became a member of the IRE committee, also. I served on the AIEE and the IRE until they merged.

Nebeker:

Were there other people in both committees?

Schwan:

Not many. I was one of the few. Most of the other people in the AIEE committee had somewhat different interests.

Nebeker:

Both of these committees organized conferences?

Schwan:

Yes.

Nebeker:

The IRE started the Transactions, maybe in 'fifty-five, maybe in 'fifty-four.

Schwan:

Yes.

Nebeker:

We'd have to check.

Schwan:

Yes. Here I've got something interesting I'd forgotten about. It is a survey of later discussions from 'sixty-five to 'sixty-seven "The following historical survey has been put together in response to questions which have been received...." Etcetera, etcetera. It starts out in 'sixty-five with a talk on new technologies. A report of the Board of Directors covers several sheets. Then it concentrates on the engineering in medicine/biology field under the chairmanship of Sinclair who became, later on, President of the IEEE. The committee met again in February 'sixty-six. Here is a picture with Flory, Schwan: and Deiniuger. I should study that with greater care. I'd forgotten about that.

Nebeker:

This is something we really should have in the archives. Could I get a copy of it?

Schwan:

Yes, I think so. Let me just put that aside since that is in that period when things moved fairly rapidly — there were all sorts of things going on. There is an IEEE position paper on the expanded support for the EMB area. And a reorganization of schools managing engineering in medicine and biology. 'Sixty-seven was an very important year. Again, the old problem came up, loyalty versus idealistic service for the field. In other words, I became critical of the IEEE. And I became partly responsible for founding the Biomedical Engineering Society. I was one of the four founders of that society. It followed a very prolonged dialogue with the Board of Directors of the IEEE.

Nebeker:

That society was entirely separate from IEEE?

Schwan:

It was an entirely separate, new society. I discussed the issues in some of my historical articles. The issue was simply: Can the IEEE accommodate membership of medical doctors and biologists in an interdisciplinary society of this sort? Experience had shown that it was not the case, for a very simple reason. In order to become a member in the IEEE Society, you must prove that you are an engineer. A medical doctor can't prove that, of course. Since he is not an engineer, he's not eligible for membership. I felt that this was a severe limitation. The membership was one-sided by design. At that time, we only had professional groups. I petitioned IEEE that the Institute replace the professional groups with societies. I proposed that the society have a sort of semi-autonomous stature so that we could set individual requirements for membership.

This was happening when I was serving as chairman for the second time. I served in this capacity for two years. I was working very hard toward that goal. It had support from our own society, the IEEE Engineering in Medicine and Biology Group, but it was eventually defeated. A few years later the IEEE changed the name from "Group" to "Society." The chairman became what's now called the president of the society. But we still do not have the autonomy we wanted. As a consequence, four of us decided to form an independent Biomedical Engineering Society, which I had opposed before. If IEEE would have permitted this to happen, then I wouldn't have seen any need for the development of the Biomedical Engineering Society, of course. I did that while I was chairman of the IEEE Society. Yet, I felt my primary interest was the emergence of biomedical engineering. That's what is alluded to here. Here is the historical stuff which relates to it. There are all sorts of letters about the negotiations with the Sinclair Committee.

Nebeker:

If I could get copies of these things it would be helpful.

Schwan:

Okay. In fact, that consumed an awful lot of my time. There was an awful lot of disappointment. George Sinclair represented the Technical Activities Board, and later on became IEEE president. He was very sympathetic and never critical. Years later I met him at an airport, and he commented about it. We had such a pleasant two-hour discussion while we were both waiting for our respective airplanes. In his opinion my reputation didn't suffer from it.

Nebeker:

Were other members of the IEEE Professional Group offended that you had helped found this other group?

Schwan:

No, I didn't sense anything of the sort. It was just a question which I raised to myself. Remember those discussions we had before about loyalty and responsibility and conflicts which may arise on such accounts.

Nebeker:

Yes, yes.

Schwan:

Here are the records of the Task Force on Interdisciplinary Communications. We set all sorts of things in motion. I got Zworykin appointed. Here's a letter from him. "Dear Dr. Schwan:, Thank you for your kind letter of — advising me that the AdCom has appointed me an Honorary Life Member of the Society. It gives me great pleasure ...," and so on. I wanted him. I admired him very much. I got him appointed in this capacity. I kept only important minutes and things like that. I have them here. I will sift through them and make copies. Now this here is the file about JCEMB. GEMB was the IEEE Group in Engineering, Medicine and Biology, with its Administrative Committee (AdCom); that file is about the International Federation. JCEMB is the Joint Committee of Engineering in Medicine and Biology.

This joint committee was formed primarily between AIEE and IRE. Its primary responsibility being the organization of annual meetings in the field, and deciding what papers were going to be given. This joint committee was also joined by representatives of the ISA, the Instrument Society of America. That made it a three-party affair. But ISA never established a committee on its own. Only AIEE and IRE had committees concerned with Engineering in Medicine and Biology. But ISA simply had representatives in it. There are records in this file which pertain to meetings of the Joint Committee. Aside from being a member of the AIEE and the IRE, I became a member of the Joint Committee of Engineering, Medicine and Biology. I haven't got my details of that. That goes back from 'sixty to here. The Joint Committee of Engineering, Medicine and Biology set out retaining documents through the early years, through the 'fifties and the 'sixties. I have records of correspondence with Senator Hubert Humphrey about medical electronics experts, "regarding progress report on activities in medical electronics." That should be interesting.

Nebeker:

Oh, that's very nice, from Hubert Humphrey. I'd very much like to take a look at that. Maybe later.

Schwan:

We have to look back here into those files to find some early activity of this committee. My reports go back to 'fifty-five, but no further. Here are the minutes of a meeting of the Committee of Electricity in Medicine and Biology in January 'fifty-five. An x-ray man, Trout, gave a summary of the 7th Annual Conference in 'fifty-four. In 'forty-seven the first meeting took place. Then he stated "The chairman reports the appointment of a Joint Permanent Planning Committee for the annual meetings." That is a joint conference of Engineering, Medicine and Biology. So that Committee was formed in 1955. JCEMB meetings took place since 'forty-seven and were organized initially just by AIEE. Since 'forty-seven AIEE had a committee that organized these meetings. In 'fifty-five they joined with IRE and ISA. The IRE organized itself and established a professional group and a committee about 1952. The IRE approved it in 'fifty-three, I believe.

Nebeker:

That was the date of the constitution, I think. But I believe it was founded in 'fifty-one.

Schwan:

That's right. It was founded in 'fifty-one, and got a journal in 'fifty-five.

Nebeker:

Maybe 'fifty-four. It's hard to tell here.

Schwan:

Well, that's October. Issues appeared quarterly, if I remember. Let's just see. Here is number three, November. That would make it monthly. I have numbers three and four. Then there is a gap; number four was the February edition. So it appears to have been issued bi-monthly. That would make it somewhere in the summer of 'fifty-five.

So that's the chronology. The Joint Conference Committee and the joint planning of conferences also came about in 'fifty-five. I became a member of it for some years to come. Initially, attendance was not large. Here the registration was 142 people. Paid registrations amounted to 119. Banquet attendance was forty-one. At that time I became vice-chairman of this committee. Here is listed an article by Gilford and another by Morowitz. They were two able people on electronic instrumentation on nucleonics and medicine. I tell you, I have so much stuff here. You'll have to look it over if you want to study much of the field.

Nebeker:

Yes, I would.

Schwan:

I may not have complete files, but I have files which go back to the very beginning of the field.

Nebeker:

Well, this is very valuable for IEEE archives to have copies of some of these things.

Schwan:

Yes, I would think so. They should be somewhere. Quite. What do I have here? Those are the meeting programs themselves. I don't have them all. The earliest I have is 'fifty-two. That was the fourth. I apparently attended that one, so that's when I entered actively. That was two years after I joined Penn. In October of 'fifty I joined the University. Apparently two years later I became interested in this meeting. That's the program. Here's a paper listed by Zworykin, as you can see. It was primarily about ionizing. He naturally talked about television, medicine, biology. Here is a mechanical heart paper. Ernst Weber was presiding in the afternoon session.

Nebeker:

And then you spoke?

Schwan:

"The application of electric and acoustic impedance measuring techniques." That was a paper I did with Carstensen. Here's the same Gilford, a fine man, who developed a well-known instrument company. He was quite successful in the field of biological instrumentation. So at that time we were giving papers. That was approximately one and a half or two years after I joined Penn. That makes the year 'fifty-two. Here is the Fifth Annual AIEE Conference on Electronic Instrumentation and Nuclear Medicine. In January 'fifty-two, everything did coalesce together.

Nebeker:

You know, this may have been sort of held over from 'fifty-one.

Schwan:

Okay. Yes. That must be it. That was from 'fifty-one. That was the 'fifty-two conference. Okay. That's the 5th. I have the 6th. Here's the program of the sixth, seventh, eighth, and ninth. So you see I have a pretty good record here for the early conferences. Only the very first ones are missing. I, myself, I have to write all that up for the EMBS magazine. I have so much material. That's the program for the eleventh. The tenth seems to be missing. I don't know why. Here's the eleventh and twelfth. Well, so it goes on. You can see how the volume of the program increased. That was the twelfth conference. That was the first one organized in Philadelphia. Compared with the earlier ones, that became a large conference, as you can see. By that time we had some 400 people attending the meeting. That one was organized by Jacobs. What I have here in my files are records of meetings. That file is concerned primarily with the Joint Executive Committee when they organized some meetings with the AIEE. That is IRE and subsequently IEEE and International Federation stuff. That's pretty much the bulk of the material I have.

Nebeker:

The main function of these different committees was to organize conferences?

Schwan:

Yes. Conferences, primarily. Yes. The conferences start pretty early. It's a little bit complicated. The IRE Group did not organize many conferences but organized a journal first. Two or three years after it had come together and organized some small meetings they published a journal. The Montgomery article describes what it did. While the AIEE organized national meetings on a broader and more systematic scale, in those early years the IRE organized national meetings once in a while, as Montgomery describes.

Now here is the first IRE session — 'fifty-three. Dr. Herrick organized the PGME session at the International Convention. That apparently was the first one, taking place in 'fifty-three. The Instrumentation in Medicine meetings of the AIEE started in 1949, you know. What was electric photography? That's the same Lion I told you about. He was the one who I visited at M.I.T., who had come from Frankfurt himself and who offered me a job at M.I.T. in my early Navy days. I don't remember that paper from Moon. That's the famous Eldredge and Ginzton, who worked on medical aspects of linear electronic accelerators. Schwan: and Li gave a paper on "Capacity and productivity conductivity of tissues." Schwab gave his paper, "Applications of electronics to medicine." So at that first meeting came together Lion Ginzton, myself and some other people. That was apparently the first meeting which IRE and the Professional Group organized.

Nebeker:

Had the AIEE committee thought of starting a publication?

Schwan:

Apparently, no. They organized meetings some years earlier but they didn't have an independent publication. The reason was the different organization of AIEE and IRE. IRE was organized into a large number of professional groups. Today we have forty groups. Very large. At that time it was already large. AIEE, however, had organized itself only into a few major sub-fields, one of which was electronics and communication. So whatever you wanted to publish in AIEE had to go in communication electronics. There were not fine enough divisions of organizations to accommodate an independence for our emerging field. Typically, that paper with Ed Carstensen was in their communications and electronics Transactions. That is the answer to your question.

Nebeker:

You mentioned that it was difficult to get one of the very first papers you wrote in this country published, and then you got it published in Germany. Was that a continuing problem for people in that interdisciplinary area?

Schwan:

Yes, it was. It was for quite a while. Yes.

Nebeker:

Did you experience much trouble yourself in getting things published?

Schwan:

No. I would say once I got that review article out in 'fifty-seven, I was well established and recognized. I had no problems. But I started much earlier to be active in the IRE and the AIEE. I had no trouble in presenting my stuff at their meetings and in their journals.

Nebeker:

And you indicated that there was this difference in orientation between the IRE group and the AIEE group?

Schwan:

Yes.

Nebeker:

Yet they combined together with the Instrument Society to have these annual meetings. And of course they combined when IEEE was formed.

Schwan:

Yes.

Nebeker:

Can you describe your role on both committees?

Schwan:

At that time I served on all three committees the IRE, the AIEE, and the Conference Committee. That was and still is a major problem. The members came from slightly different fields and one was afraid what field might dominate in this combination. The second great problem was, of course, who should be chairman when IEEE formed? Should it be the chairman of the IRE group or the chairman of the AIEE Committee? Neither wanted to relinquish their jobs. It took endless effort; I've forgotten the details. I was supposed to bring them together, and I finally succeeded in convincing the AIEE chairman to give up his position and let the IRE have it. But it was almost heartbreaking, I tell you. A job I didn't cherish at all. It was awful.

Nebeker:

Was it Ernst Weber who asked you to work at that?

Schwan:

I can't remember.

Nebeker:

I know he has talked about that very delicate matter of merging the two societies. There were some cases where I think it took a couple of years before the two corresponding societies got together. Do you remember how quickly it happened in this case?

Schwan:

When was the IEEE firmly established?

Nebeker:

It was formally established January 1, 1964.

Schwan:

'Sixty-four, yes. Okay.

Nebeker:

It had been approved the previous year.

Schwan:

Of course our discussions started earlier. I remember that while we were not a very important part yet of the respective societies, we had some influence nevertheless. There was considerable interest in applications of engineering to medicine and biology. As you see from our summary of the history of AIEE and IRE, we recognized our common interests early on. We both had our activities, but we sought to coordinate common meetings. Those came about in 'fifty-five? We got that accomplished well before the IEEE was organized. We in the AIEE and IRE could, after all, come together and work toward common goals. I suspect it was our ability to work together that provided one of the stimuli which helped in establishing the IEEE.

Nebeker:

I assume that most everyone in these two committees or groups favored the merger of the two societies?

Schwan:

Oh, yes. Very definitely. There was no doubt about it. Originally there were many people who were engaged in ionizing radiation, x-ray radiation and related activities represented. The committees reflected, in part, people like Lusby and Trout, who came from Westinghouse and GE, respectively. Both companies at the time produced x-ray equipment, as they do today. The medical industry is always a major market of industry. You saw people like Ginzton working on the applications of the linear accelerator in medical practice. There were good people involved, particularly in medical applications. The meeting attendance, as I wrote up before in some of my articles, was diminishing with time. It didn't catch on very strongly.

Then I made sort of a pact with Otto Schmitt. He was serving the IRE committee at the time, but he had not yet joined the conference Executive Committee. We discussed that I would propose his becoming a member of that Conference Committee and to invite him to submit a proposal for a meeting to be held in Minneapolis with him as the chair. We agreed to reverse the procedure with me organizing a conference in Philadelphia. That plan worked out perfectly. Otto established the meeting in Minneapolis under the topic "Computers in Medicine and Biology." That couldn't fail. Participation jumped from 100 to some 300 members. In Philadelphia we had 400 people participate. In a way we had reoriented the field.

Nebeker:

What about this independent society you helped to found?

Schwan:

Yes, that came later. When was it? We just looked it up. Yes, that came in 'sixty-eight. As a matter of fact, while there was a great need for such a society, it had great problems getting off the ground. It's now very well established. It took a long time since it was not handled properly. The four members organizing it were Larry Stark, who's in Berkeley John Jacobs, whom we mentioned several times; Jack Brown at NIH; and myself. But Jack Brown, a physiologist, always wanted to pull it away from the engineering people. He didn't believe in IRE and IEEE. And he criticized the IEEE for excluding some medical people and biologists. He was an advocate for an independent society. I tried to keep it in the IEEE, but failed to do so. The society was set up with our four signatures. We recommended Otto to serve as the caretaker-first president until such time as a proper president was elected. Otto Schmitt did just that. It was primarily my suggestion. I pushed very hard then for a physiologist/biologist, Bob Rushmer from Seattle. Rushmer became president of the society. To this day I believe I made a mistake. Others pushed for him too. He advocated a more restricted view of bioengineering as a science which deals with physiology. That is too restrictive an approach. He manipulated subsequent committees in order to strengthen the representation of physiology. I was not impressed with Bob Rushmer's performance in that regard.

As a consequence of that our independent society never clearly threatened the IEEE. The IEEE maintained a 5,000-member society while the Biomedical Engineering Society could barely attract 200 or 300 participants. Lately it has tried to broaden its approach. It is still suffering somewhat from this previously restrictive image. I criticized it several times in my writings. They didn't respond very well. I don't know if they read what I wrote about it or had just made up their minds. The present editor of Biomedical Engineering was previously an editor of the IEEE Transactions, in engineering, medicine and biology. This Dr. Sun is a close friend here at Drexel. Sun has opened the field. He took the initiative to organize that issue on electro-depolarization. Well, I don't know if that answered your question.

Nebeker:

Yes, yes. I once read an historian who claimed that in the nineteenth century these divisions of knowledge into physics and chemistry and so on worked very well. But in the modern world, where so much work is interdisciplinary — not only within the sciences, but between sciences and engineering or industry or applications or whatever — that it makes less and less sense to try to divide workers this way.

Schwan:

Yes.

Interdisciplinary Nature of Biophysics

Nebeker:

And you've certainly been involved in one of the most confused areas, where the biological sciences, physical sciences, different branches of engineering, and medical practice and so on are all confused. Are you sympathetic to that view?

Schwan:

Basically, yes. Yet what can we do about it? Imagine the question with regard to training of students. I don't know if it would be very sensible to train truly interdisciplinary students. Some people, such as Otto Schmitt, believe it would make sense. But, as we discussed before, I have the impression that at the high school level the gifted students fall in various categories. Clearly, some have displayed a certain ability in mathematics and, closely related to that, engineering and physics. Then there are others who can memorize very well; they tend to drift into chemistry, biology, and medicine, where learning huge amounts of stuff is important. I suspect that training people who combine both might prove a very difficult and risky enterprise.

Nebeker:

So it still makes sense to hold to traditional disciplines?

Schwan:

I suspect so.

Nebeker:

You recommend that students be trained in traditional disciplines and then move to the interdisciplinary areas?

Schwan:

I suspect so, yes. We treated that issue in our early discussion way back with Sam Talbot and NIH. We had to deal with precisely that problem. The demand for traditional training came from the medical sciences as we have discussed. I believed it was important to concentrate on the engineering and physics students in our training and then add biology and medicine rather than the opposite approach. Talbot and the other engineers eventually conceded to my point of view. That became the basis of the first training programs in this country. The largest number of second and third generation training programs essentially followed that rule. Although we accept students from other disciplines, that is still the basic orientation of our training. We gave up on the idea of training the truly ideal person who would sort of sit in the middle and know both disciplines equally.

Nebeker:

You talked about the line, so to speak, between medicine and biology on the one hand, and engineering and physics on the other. What about the line between engineering and physics? Our educational institutions are still pretty divided. They have two lines. People are trained to be physicists or trained to be engineers.

Schwan:

Yes, yes. Right.

Nebeker:

Does it make much sense to distinguish in this area?

Schwan:

As I perceive engineering and physics, no, it does not. As a matter of fact, in this country, the border lines are rather soft. Much of classical physics is now handled by engineering schools rather than by physics departments. It seems to me that most physics departments these days deal with matter at the quark level. In other words, they deal with very small particles with relevant items, and esoteric items like the Big Bang! in terms of the universe and related theories. Very little classical physics, like acoustics or optics, is still going on in physics departments. Yet you find a great deal of acoustics in engineering schools. One of the best ultrasonic acoustics laboratories is Floyd Dunn's laboratory at Urbana, started by William Fry. Interestingly enough, that laboratory is a part of the Department of Electrical Engineering and Computing at Urbana. Our materials science center and materials research here at Penn is all related to the engineering department. It has but little to do with physics. I've observed that at many other universities. I have the impression that a good deal of the classical physics — the non-quark-level-type physics — has moved to engineering schools. That's why I say the division between engineering and physics is to me a soft one.

Role of National Institutes of Health

Nebeker:

You mentioned the role of NIH in biomedical engineering.

Schwan:

Yes. It started to emerge with the Talbot Committee. As I commented before, the decision of NIH to spend seed money was very important. This seed money established the first training grants. A number of universities got training grants. There were the three of us at Rochester, Johns Hopkins and Pennsylvania which established graduate training programs. Within months Drexel had also established one. There were some others. We attracted students, and this led to the development of two academic programs at Penn in this field. Before they didn't exist. There was no formal training in the field whatsoever. Before we developed formal training programs we had an intermediate pattern where we gave people at the Moore School degrees in electrical engineering. We had a soft understanding with the dean that those students could take some of our specialty courses, and be exempt then from taking some other courses in EE proper. But it was not really a true bioengineering program in that sense. With the training funds available, universities began to establish independent Ph.D. programs. We were the first ones. It took longer at Rochester. Rochester to this day doesn't have an independent department. Bioengineering is still in EE. Ed Carstensen was heading it most of the time. It's the same setup as we had originally at the Moore School. It didn't get its full independence there until 'sixty-one. The strong program which has existed at Drexel University for a long time is the Institute of Biomedical Engineering and Science. It's formally a part of the EE department at Drexel. I fought for it at Penn. In 'sixty-one I got the independence of our group, our department.

Nebeker:

And that independence is important because then you can decide what courses are really the best for your students?

Schwan:

Absolutely. Yes. And I could administer my money directly. That was another important thing. There are many important aspects, including visibility. NIH likes that visibility aspect. The NIH prefers an application coming from a department of bioengineering rather than from a small group subject to a hostile department chairman. The establishment of funds was one important aspect. A number of administrative steps were taken within NIH to handle the flow of money. At that time NIH consisted of something like half a dozen so-called institutes, as it does today The National Heart and Lung Institute, the Cancer Institute, etcetera.

In 1960, they established an Institute of General Medical Science. General Medical Science was somewhat more basically oriented. Due to Jack Brown's influence biophysics and biomedical engineering were represented in the institute. However, it was done in the following manner. In order to enhance certain fields, top committees handling long-range grants were established — so-called program project committees. The usual evaluation of applications was handled by study sections. Study sections looked over grant applications with the help of their consultants who are largely professors at universities. But then they established a policy of administering large grants, a minimum of $100,000 a year, which was at that time lots of money. They were usually granted for five-year commitments. Those program projects were evaluated by special program project committees which, of course, were more influential than the study sections. I became the first representative of bioengineering in the program project committee of the Institute of General Medical Sciences and served in this capacity for five years. I hope I had a good influence on the development of the field.

Nebeker:

What major grants were made for biomedical engineering in that period?

Schwan:

The NIH made a number of grants to second-generation programs in biomedical engineering, including ours, following the programs at Northwestern, Case-Western, and Duke University. Berkeley and San Francisco also received grants, I believe.

Nebeker:

Quite a few?

Schwan:

A considerable number, yes. A considerable number of other institutions got training and research grants. We didn't administer training grants specifically. We were primarily concerned with research. We tried to enhance a research climate at those universities with our program project funds. You cannot serve on two committees at the same time. So I served as a special consultant on the training program of the biomedical engineering study section which was established simultaneously. I served in this capacity for several years. Furthermore, I served as a consultant on a variety of other study sections. I served on Study Sections Biophysics A and B, Neurology A and B, Physiology and Radiology. All in all I served on something like ten other study sections as a consultant.

A study section on bioengineering and acoustics was established. As a special study section. It couldn't meet in Washington, but it could meet outside of Washington. I was the first to serve as chairman of this study section in bioengineering and acoustics for about three years. Otto Schmitt followed me as the second. Henning von Gierke was the third.

Nebeker:

It sounds like you were giving a lot of your time to NIH in those years?

Schwan:

I spent as much time for NIH as I spent for the engineering societies. I spent some sixteen years in various capacities in the engineering societies. I spent an equal effort at NIH. I made something like 200 trips around the country to various universities, study section meetings, and so on for NIH. I learned a great deal about the relevant activities of the country at large. It was a very major enterprise. After my term in the program project was over, I was offered the chairmanship of the training grant study section or membership on the Council for National Environmental Health.[14] In the Council I found a mix of some well-known public citizens and top scientists. I was appointed for three years to serve on the National Council in Environmental Health, which dealt with environmental issues including ionizing and non-ionizing radiation bioeffects. Then I felt I had served enough for NIH. But during that time at NIH, we were able to contribute. NIH was influential in the biomedical engineering field in many good ways, of course. So I'm happy if I may say so, not only of my science but my administrative contributions, both at NIH and in the engineering societies. I have never summarized my administrative work in detail before, as a matter of fact. That work was certainly just as interesting. I feel I was blessed in my life to be exposed to many different experiences.

Founding of Biophysical Society

Nebeker:

You were one of the founders of the Biophysical Society?

Schwan:

Yes.

Nebeker:

Can you tell me a little about that?

Schwan:

Well, I just showed you that information about it. First, we became interested in the early 'fifties. My interest in a biophysical society was somewhat motivated by the German Biophysical Society, whose foundations were established I think, in 'forty-three. When I came to this country, I was thinking about biophysics a great deal, of course. I started to talk with Talbot and Schmitt, as I mentioned before. I talked a great deal with William Fry, who was then head of the Bioacoustics Laboratory at Urbana, and also became a very close friend of mine. He visited me frequently and became very interested in biophysics and its proper representation through either a biophysics society or a bioengineering society. He had personally suffered because the existing study sections at NIH had been unable to understand his grant applications in acoustics. He wanted to find out what could be done about it. It's very important to remember how important NIH was to us. Professional societies such as the IEEE have relatively little influence on NSF and even less so on NIH. As a matter of fact, they have virtually no influence at NIH. Yet we scientists get our money from the government agencies. How can we reach them more effectively? This problem was obvious at that time and still exists to this day.

Several other groups formed. There was a group headed by E. Pollard who was a biophysicist at Yale. Some informal meetings and discussions took place. There was disagreement about the meaning of biophysics. They eventually decided to call a more formal meeting, and a committee of four was established. I didn't belong. The committee of four members were Sam Talbot, Otto Schmitt, K.S. Cole, and this E. Pollard. I was appointed to serve in charge of publicity. This sounds like the least important and the least demanding job. But it evolved, in my personal opinion, to one of the biggest jobs. We sent out those announcements as I showed you before. I used a chain-letter type principle. In other words, I asked colleagues for names and addresses of people who had shown an interest in biophysics. I got responses and sent out those letters again. The meeting was attended by about 700 people. Because of my past performance, they asked me to continue to serve on the publicity committee in the society. I did that for four years. I asked for a decent amount of money from the Biophysical Society, which they reluctantly gave me since we didn't have that much in the emerging society. I used the money for organizing press luncheons at the first four or so meetings. I made it a practice at each press luncheon to have Nobel Laureates present a talk about biophysics. I reached all sorts of people that way. Science reporters from The New York Times and the Washington Post attended. It made a good splash for biophysics, of course. I still feel that one must entertain that sort of thing.

In addition to that, I profited from the organization of meetings of engineering societies. The first meeting just after the Minneapolis meeting was in Philadelphia. I was able to solicit a good professional outfit for the Biophysical Society meeting management. This outfit still organizes their conferences — at least it did five years ago. A year later, I was conference chairman of the Biophysical Society meeting in Philadelphia, which I could run quite effectively with that professional team.

I was appointed to the Constitution Committee, where I helped to formulate the constitution of the Biophysical Society. At the time I was greatly concerned about the representation of different fields in biophysics and their relative importance. Again, the same problem erupted. Who will emerge stronger — the biologists, or the physicists and the engineers? I suggested that they establish a council aside from their executive committee. The executive committee was restricted to four or six people including a president, secretary, treasurer, and publications. But the council was to represent different parts of biophysics. I wanted to assure that different parts of the field got representation. The idea was accepted. The council was appointed. But where I didn't succeed was to clearly indicate what different fields should be represented. It was clear why I was defeated.

Subsequently the Biophysical Society was influenced by biochemistry, in good part. Biochemists and physiologists entered strongly. The incentive for engineers and physicists to enter was small. The engineers had their societies, after all. Why should they go to the Biophysical Society meeting in addition to that? As a consequence, as excellent as the Biophysical Society meetings are, they are all oriented towards membranes genetics, DNA structure, and relevant topics such as molecular biology. That dominates the field primarily. It is, in my opinion, removed from the interests of bioengineering. The society has moved strongly towards this direction. So you see the old division between biological or engineering and physics research still exists today. There is no administrative connection between those organizations at the present time. Otto Schmitt and myself tried to work out something to bring it together, but we both failed.

During the last ten, fifteen years, I lost more and more interest in the Biophysical Society. All my personal friends, including Otto and Ed Carstensen, don't go to meetings anymore. But originally all of us were strongly involved. It's very interesting to think about us and the Committee of Four. Cole did work much like mine and was very sympathetic to my point of view. Otto Schmitt certainly was strongly oriented toward engineering himself. Sam Talbot joined. We shared ideas about training and they got incorporated. Only Talbot was a little bit different as a physiologist. In other words, much of what the Committee of Four stood for originally has subsequently gone.

Nebeker:

Well, I'm sure all these institutions get reshaped continually, and there was evidently a need for such a society for those molecular biologists.

Schwan:

Yes. The engineering orientation was very successful for the Biophysical Society. I remember NIH established biophysical study sections, which appropriately handled grant applications in the field. But the NIH bioengineering study section was sort of ad hoc and disappeared eventually. Then applications from the biomedical engineering field were turned over to special study sections — radiation biophysics or physiology. Bioengineering material wasn't properly considered. That situation prevails to this day. That led to the formation of the American Institute of Medical and Biological Engineering, which tries to change the situation. We have a strong IEEE, but IEEE doesn't have input with regard to NIH grants matters so far. Not yet.

If the Academy of Engineering were to come together with the Institute of Medicine and the field would be investigated by the National Research Council, then something might come about. But at the present time it doesn't look good. So the biophysicists made it with regard to getting support, but bioengineering didn't get the money to the same extent. I received money, but the community at large did not. The implications are very interesting. You find people, for example in the imaging field, which is so important these days, who don't portray themselves as bioengineers, but rather as medical physicists. You find that they often prefer, if they have multiple affiliations at a university, to emphasize their affiliation with a department in the medical school rather than with the engineering school. They are more likely to get money. That situation is still sometimes prevalent, I'm sorry to say.

Bioelectromagnetic Society & Health Debates

Nebeker:

I know you've written about it, but perhaps you could comment briefly on the Bioelectromagnetics Society. You were also a founding member of that.

Schwan:

Yes. We were, of course, involved in the field since the early 'fifties. As the field developed, there were several discussions about forming a society. Originally I felt that the society would have too small a base, and I didn't encourage it in the 'fifties. In the early 'sixties, I was approached by someone in the Navy, Tom Rozelle. At that time I thought it might be a good idea, and he went ahead. I didn't contribute much to the formation of that society. The field had become controversial at that time. During the formation of the society, several individuals who felt that my outlook in the field was too conservative tried to block me from exerting influence. They succeeded at the time. But my reputation in the field was established. The society would recognize me in the various ways which I've explained to you. I had established my reputation as being a leader in the field.

But I never became very active in the society. Nor was I asked to do so. My earlier prolonged activity in the National Standards Institute was one of the reasons I did not participate in that society. While I was trying to develop standards of safety in the National Standards Institute, the controversial nature of the topic became clear to me. There were also those relevant reports from Russia coming out. So when we finally got the standards ratified, I decided to step down from the chairmanship and not actively participate in the Standards Committee anymore. I retained my membership so that I would get information, but I decided to respond to inquiries only if I was asked to do so specifically.

Nebeker:

When did you make that decision?

Schwan:

That was in 1965. I made that decision for various reasons. I was heavily involved with IEEE. I was also heavily involved with NIH. It was simply too much. I couldn't carry on with the research either. I was a nervous wreck. I was completely worn out. Also I did not want to participate in controversies.

Nebeker:

There was already controversy on that, in the mid-'sixties?

Schwan:

There was already controversy emerging. There were soft implications that I somehow was able to manage people and wield undue influence to achieve what they felt were my goals. After the first standard was set, I decided I wanted an entirely independent man to continue to do the work. I would not participate even in making proposals as to who that man should be. I wanted others to handle things. I never regretted that decision. As it turned out, the man who took over the chairmanship of Subcommittee 4, Human Hazards, essentially readopted it four years later on, and then in steps they refined it in a very sensible fashion. I couldn't be accused of wielding undue influence over that.

Nebeker:

So your contributions since 'sixty-five or so were more limited?

Schwan:

I played a much smaller role. I didn't do much for the Bioelectromagnetics Society. I frequently gave lectures, of course. I was honored by the society. I retained friendships with many people. I know them all very well. But I did not exert myself too much on an administrative level.

Nebeker:

But what about in other committee work on health problems?

Schwan:

When called upon to do so, I did. I served on a number of committees for the National Research Council. The National Academy of Sciences and the National Research Council had several meetings and I testified before Congress on two occasions. Some of the committee activities lasted a long time. For example, the National Research Council committee was concerned with the Seafarer Sanguine Project, which was about the U-Boat navigation system that operated at very low frequencies. That dragged out for a good two years. That was 'seventy-one, 'seventy-two.

Nebeker:

You were called to testify more than once?

Schwan:

That was an ongoing activity. That committee met every couple of months for several days over a period of two years. The work for that committee was quite intense. That overlapped with the equally extensive hearings in the State of New York which were held to look into high-voltage transmission lines to be built from Canada to the United States. That was also a bitterly fought-about affair. The National Council meeting decided that we shouldn't worry too much about low-frequency effects. There is no solid evidence whatsoever in existence. I've served twice since then for shorter periods of time. The last time was three years ago, before the relevant commission of the National Research Council. Again, those attitudes were upheld. So far, the National Research Council has recognized no evidence for any subtle effects. The Standards Committee has adopted standards which are still based on the old metabolic considerations. They've found nothing in the literature which clearly proves the existence of other effects. But under public pressure, it lowered the standards by establishing larger safety margins for those concerned. I don't see a strong change there either. The Bioelectromagnetics Society never formulated standards. But there was a shift in the Bioelectromagnetics Society. Consider the people who got the d'Arsonval Medal. The first one was me. Two years later Guy, an excellent person, received the d'Arsonval Medal. He has done beautiful work in dosimetry. He is a rigorous engineer doing a wonderful job in the field. But Adey, who represents the belief that weak fields interact, emerged. Then Adey and Bassett received the awards as well. Bassett is from Columbia University. A very nice man, but his work is still somewhat controversial. It's about the effects of electric fields on bone growth. When you apply electromagnetic fields, bone growth accelerates. This is still very controversial. Is it an electric or magnetic field effect? So there is a slight shift in tendency within the bioelectromagnetics community.

Nebeker:

Well, I can understand that those people come to that big question with different backgrounds and different prejudices. Your approach has been more that of a physicist looking at mechanisms and interactions rather than, say, a public health official who's looking at policy.

Schwan:

Yes. Right.

Nebeker:

I know you recognize the need for all kinds of inputs on these things. Is it your feeling that when the statistical evidence is very weak, and when there's no clear case for the physical causation, that one decides then that there isn't a hazard there?

Schwan:

No, I wouldn't go as far as saying that. But I would say yes, if in addition to that there is some evidence available that it is extremely unlikely. In other words, if there is some evidence where it follows from physics that it is virtually impossible that there can be an interaction. For example, quantum physics tells us you need a minimal photon energy to break a chemical bond. And a microwave quantum has an energy which is a million times less than that needed to break a bond. That makes it very unlikely that microwaves can change molecules. There are a variety of physical principles which speak against weak effects. So in view of that, I'm skeptical about a variety of claimed weak effects. Still, I wouldn't go so far as to say that we shouldn't consider the possibility. I consider the likelihood also that if such things take place, it will require a fundamental change in relevant physics, I suspect. Such as you might say Einstein or Planck brought about. It would require modifying thermodynamics, some energy principles. Something very big like that. Yes, the possibility exists, but I consider it unlikely.

I am now concerned with something which scientists don't really clearly outline. I'm concerned about our societal responsibilities. Once again we have to order our priorities. We have a huge national debt, and as you know, the problem gets bigger and bigger. There's great concern about how we should spend our money to save the country. In recommending what sort of science should be done, all of us should keep that in mind. We have a responsibility not to call for more research than needs to be done in this or any other field in view of the terrific national problems which we have now. Scientists have the responsibility to recognize that they must choose what science should do. In view of the physical principles we seem to believe in, work in this field is of a lesser importance than other fields, such as cancer or AIDS research. I don't give it the same priority now. I can't, honestly, give it the same priority presently. But, provided compelling evidence emerges, reorientation of priorities may be called for.

Social Responsibility of Scientists

Nebeker:

I know you have answered the charge that yours and other people's research has been somehow directed — or tainted by — the military or by the power companies. You haven't felt that in your own case? You have not been coerced to define certain findings?

Schwan:

No. These statements came from a, fortunately, very small percentage of people active in the field. They belong to this regrettable category of human beings who try to benefit from the fact that always a little bit of mud sticks. These were largely uneducated people, of low standards, with very low recognized scientific merit. Those people who made such statements have no scientific reputation. Let me set some factors straight. For example, consider how ONR spent its money. Originally it had a few projects with Iowa State, with me, and with Bill Fry's laboratory in Urbana, ultrasonics and microwaves. Critique mounted with regard to insufficient report for the weak interaction field. ONR went then out of its way to support weak interactions by supporting Allen Fry, Jaron and others. The man who was at that time in charge, Tom Rozelle, wanted to avoid attack by those people at all costs. He could only do this by giving them some support. And so he did. They got more money. My contracts were cut down as a matter of fact. So what happened is the opposite.

Now it's very interesting to talk a little bit more about this. A similar situation developed out on the west coast in the Electric Research Power Institute. They had been accused of being blind-sided. They are financed by the power industry and they decided to set up a sort of division which is headed by Dr. Rafferty. Dr. Rafferty established a committee to oversee the subject matter and administer research funds. He never asked me to serve on his committee. Nor were anyone like myself approached with regard to research funding. But he has given research funding to people who claimed the existence of weak electrical effects. Again this is the same pattern. He is sensitive to potential critique, and motivated in orienting his committee and his money accordingly. Once you establish a committee or a branch in any administration to look into a particular subject matter, you will tend to perpetuate it. The pressure on you to do so is great. Say you come to the opinion after three years there is nothing to the field. If you say there's nothing to the field you state, in effect, "Close my division."

Nebeker:

Can you be specific about what committees or groups remained or retained their existence in this way?

Schwan:

No, not very many. As a matter of fact, after a number of years with Tom Rozelle at the helm, ONR decided to pull out of the field. To my knowledge ONR is no longer supporting any activity in the field. They closed out. EPRI is still in existence. But I don't know of any other committees.

Nebeker:

Do you feel that enough work has been done and funded, and that convincing evidence hasn't been produced for these weak nonthermal effects?

Schwan:

Not to my knowledge, yes. I talk about electrical fields. I'm not including magnetic fields. That's a different story. They are maybe more likely. But I'm not as much an expert here to the same extent as I am about electrical fields.

Nebeker:

Have you also served on committees on setting standards for magnetic fields?

Schwan:

No, I haven't. I did not participate in that work. That emerged later, after my time was over in the Standards Institute and other committees.

Standards Institute and Other Commissions

Nebeker:

Now can you tell me just briefly about the Standards Institute? I don't know much about these institutes.

Schwan:

I see, yes. It changed its name several times. Originally when I entered it, it was called the ASA, American Standards Association. Then it became ANSI, American National Standards Institute. And I think recently they changed their name again.

Nebeker:

This is a non-governmental institute?

Schwan:

It is a completely non-governmental standards organization that formulates voluntary standards. In other words, there's no legal pressure behind it to enforce the standards. But it became very powerful, nevertheless. The National Standards Institute's activities cover a broad range, including plumbing, etcetera. In order to finance their work, they needed support. A good part of the work is voluntary. They have some secretaries and in-house staff, just like IEEE. They have a headquarters. So the Standards Institute must be supported by someone financially. The IEEE and the Navy supported research in non-ionizing radiation. In other words, IEEE and ONR was willing to support it at whatever level. But most of the support actually came from the Navy.

Very recently the National Standards Institute decided to pull out of the field. I don't know the detailed reasons. When the Office of Naval Research decided no longer to participate in this field, the Navy also lost interest in supporting the Standards Institute. And at that time the Standards Institute had to rely only on IEEE. I don't know the detailed negotiations. I didn't participate in the debate between the IEEE and the Standards Institute. The IEEE felt that since they are the only supporter, they might just as well be subsumed into one of its committees. I think that the committee still exists. But it meets as an IEEE committee. What the IEEE committee works out will be approved always by the Standards Association. That's the present workings. It's a very large committee, as anticipated at the time when I served in it. I recently participated in a meeting here, and there were something like 100 people. It is an extensive apparatus now.

Nebeker:

You've also served on the NRC — National Research Council — committees. When you look back on this work has it been mainly — or largely — a frustrating experience because of this poorly documented or poorly established weak effects that were often at issue?

Schwan:

I would actually say what was most frustrating about it was the publicity. As I indicated before, probably most members of the Bioelectromagnetics Society, the members of the Standards committees, the formulated opinions of the National Research Council, the IEEE Committee on Man and Radiation, and the IEEE all supported the standards. Typically the standards are still far higher than they were in Russia. We found little support for extreme fear. The extreme fear about radiation is generated by a small percentage of the people of lesser standing in the field and from an entirely inappropriate desire of the media to look for sensational material. Reporting that a committee found that non-ionizing radiation, electromagnetic fields, are not dangerous, is not exciting news. But reports that there are indications that it is dangerous to have a microwave oven made the headlines. You may have noticed the initial hysteria about microwaves is all but gone. Now people talk about low-frequency electric power lines and video display terminals. All the fear about microwave ovens are gone. And people live with the microwaves. No formal decision has been made that they are not dangerous. It just got quiet, and no more relevant research work is done. That's what happens often with such activities.

Nebeker:

And that, of course, was the area of your great contribution, the microwave.

Schwan:

Yes, and the radio frequency range. Quite. When the low frequencies appeared, of course we also contributed to committees. We are still active at the present time. But I suspect it will suffer the same fate. I would suspect that ten, twenty years from now, it will have gotten very quiet about it. I would be very surprised it if would be otherwise. I doubt it.

Nebeker:

What about if one compares the situation in this country on establishment of standards of this sort with the situation in Germany?

Schwan:

Most other Western countries have standards very similar, if not identical, with those in this country. I know the people who are responsible for the German standards very well. As a matter of fact, the man who is primarily responsible for it is a former student of that fine man Pauly, who was with me for three years in this country. I met with him just last year. I spent a week with him in his laboratory in Munich. So I know about the standards there, and they are similar to ours here.

Nebeker:

Is there the same problem of media-seeking sensationalism?

Schwan:

There is some, but it's less. The standards in Britain, France, throughout the Western world, are similar. But the Eastern world had entirely different standards. In the meantime we lowered our standards. The basic philosophy still exists. But we provide greater safety margins in view of the anxiety of the public. The Russians have raised theirs. So have all the people in other former satellite states.

Russian "Extraordinary" Science

Nebeker:

I remember an 'eighty-four article of yours in which you discuss the Russian work and the fairly small amount of detailed reporting of their research that's appeared in recent years. Has there been much more work coming out of Eastern European centers?

Schwan:

Oh, yes. There is always some coming out. Yes. It is always of a very curious type. Even though I'm retired, two years ago I was visited by a Russian delegation. A number of Russians still visit with me, and I have them out for dinner. There were four people I saw recently. One was Secretary of the Health Ministry of the Ukraine, and two professors from Leningrad and one from Moscow, respectively. They told me that they were going to organize a meeting in Kiev to deal with cancer treatment by microwave. They invited me to it, and I asked them to keep me informed. The meeting took place. A German from Munich whom I know very well participated in it. He made some sensational claims which I don't believe yet. I know his work well since I frequently inspected it. The German who was invited here taught me a good deal about it.

Then I met some people who did some work in Kiev and in Moscow. They visited here at Temple University. Temple University has set up a series of seminars on extraordinary science. They had invited some Russians and the Russians were presenting lectures. I was invited there. The scientists presented extraordinary evidence for the use of very high gigahertz frequencies. Operating at selective frequencies in the gigahertz range, around forty gigahertz, applying a small micro antenna to an appropriate acupuncture point on the skin, this signal can selectively cure certain types of diseases. But one must find the proper acupuncture point on the skin and tune it to the right frequency.

Nebeker:

This seems difficult to reason and to know its effect.

Schwan:

There was something very interesting, by the way. You remember the 1990 IEEE meeting? I don't know if you were aware of it, but during the meeting a Russian delegation and the president of the Popov Society, sort equivalent to the IEEE in Russia, were there. Our IEEE invited them. Four or five people were there. The head of the Popov Society was also a member of the Supreme Soviet — in other words, he was political figure. He was head of a Electronics Technical Institute of Russia and the Academy of Science in Moscow. An important figure. He introduced a special session on important diagnostic advances they had made.

I was asked to chair that affair. I said, "I have to go to a committee meeting. We can't have a session longer than an hour." There was a Standards Committee meeting going on and I wanted to join it. Since I was chairman, well, I couldn't. We were talking and talking. After one and a half hours, the speaker was still talking. I couldn't get him to stop. When I tried to approach him, he became a bit angry. They were presenting a complicated device of diagnostic technology. It was a combination which involved various technologies for diagnostic purposes x-rays, ultrasound, microwaves, radio-frequency waves, gigahertz frequencies, low frequencies, acoustical measurements at various frequencies, and various other imaging techniques, for measuring infrared radiation, the electromagnetic spectra emanating from the body. They also used an extremely sophisticated software program to evaluate it. Out of this comes the disease diagnosis. You expose yourself to that machine which measures all the radiations, and the software tells you what disease you have.

Nebeker:

Well, that's very convenient.

Schwan:

The authors work at the same institute where work on that other acupuncture technique for therapeutic treatment had been conducted. What more can I say? Let me tell you, if these people ever get access to the IEEE and your histories, and hear the both of us laughing, that won't do us any good.

Biophysics in Germany

Nebeker:

You've done a great deal of traveling and lecturing and other professional activities throughout this country and throughout Europe. I was noticing that, for example, from November of 'sixty-eight to June of 'sixty-nine, you gave at least twenty-six seminars and lectures in Europe and Israel. Even more impressive, from the end of 1980 to August of 'eighty-one you gave some thirty-six seminars. You must find it rewarding to talk to groups around the earth? Are most of these invitations from universities?

Schwan:

Yes. Well, it was a mix. With some institutions, like the Frankfurt Institute, of course, I have a professional relationship. I always gave lectures there. Then there are a number of institutions where I am known. Whenever I go to Germany, they invite me to visit with them and to present a seminar about our latest work or related topics. I have a friend in Göttingen at a famous Max Planck Institute. The man is a Nobel Prize winner, just about sixty-five years old. He usually invites me. I have given something like ten lectures altogether in Göttingen, primarily due to his initiative. Then there are many other colleagues. They hear that I am in town and invite me to speak to their group. Sometimes there are professional meetings taking place, like the three in Erice, Sicily, and things like that. So it's a mixture of all sorts of things.

Nebeker:

You're in a very privileged position in having gotten your education in Germany, worked at the institute in Frankfurt, established the program at Penn, and then being very active in this country and in Europe. You're in a privileged position to compare the development of biophysics and biomedical engineering in the United States and in Germany because you've been in constant touch there.

Schwan:

Yes.

Nebeker:

In one of your papers, in press now, you point to three conditions that were important in the establishment of the fields in this country. I wondered if you would briefly comment on those three points and mention the corresponding German situation, which you don't do in this article.

Schwan:

Yes. Quite. Well, I might just comment about the three points which I raised here. Essentially, I was concerned about the respective developments of biophysics and bioengineering in this country and in Germany. While biophysics organized early in Germany, the advent of biophysical development here — and even more so the development of bioengineering — occurred at a much more rapid pace, and achieved a much higher level of activity than in Germany. The active scientific/technical climate which exists in this country I believe reflects the structure of our universities, where we have the divisions between undergraduate and graduate training. Now our universities — I didn't explain that in detail here — are a mix of state and private universities. In Europe they are all state-supported. This mix in this country guarantees a great deal of independence. Clearly if you have no private universities, the state could put much stricter limitations on the state universities, much more than they can afford to do now. If they did, the state universities would soon suffer by comparison with the private universities and be at an even greater disadvantage. That helps very much to establish an excellent scientific climate.

The climate which exists now at private universities — particularly at the graduate level — is competitive. We compete for the best students. We accept only the best students, according to the notoriety of our departments. By this elitist approach — we have an elitist approach at the graduate level — we establish centers of high competence that benefit science and research. I think the European universities don't have as competitive a system as we do. In Germany all universities are equal under state control, and the incentives for independent new ventures, such as establishing bioengineering programs, do not exist. You can't establish it. Impossible. That's the first point which I make here. The university climate is the problem. By the way, the Europeans have a much better high school training and elementary school training than we have in this country. In Europe after the first four years of elementary school, the system becomes selective. Only a fraction of students go to the higher levels of high school in most European countries. In the U.S. everyone is pushed toward a high school diploma. That means the quality of education must be watered down. American students spend less time in class. The high school training is more elitist, to use that expression, in Europe than in this country. It's just the reverse of what we see at the graduate level of our universities. This elitist attitude still retains leadership for us at the highest level of education. Its the same reason that we are poor at the lowest level. I think you can compare it. That's the point which I tried to indicate in that first paragraph.

Another thing effecting the development of the field was that most interdisciplinary institutes were first research laboratories that subsequently developed training programs.

Nebeker:

That's made possible in this country by these outside sources of funds?

Schwan:

Quite.

Nebeker:

That makes possible the research institute. Then the university institute can provide funding later on, as happened at Penn.

Schwan:

You see, under “B” (sic) I say, "...partially private, partially state structure of the American universities is an important thing." I translate freely The existing competition, free of federal or state controls, aids in creating new branches of science as soon as it becomes apparent that the relevant potential is favorable. Another factor I stress in “B” is, of course, the development of organizations and financing by NIH.

Nebeker:

But Germany has benefited from the money made available through the Max Planck Institute, the Oswalt Foundation.

Schwan:

Quite.

Nebeker:

I mean, those ventures have been interdisciplinary.

Schwan:

Yes. Very worthwhile things, yes. Very worthwhile. Max Planck Institution is a high-quality institution. It was a very good development.

Nebeker:

But when you look at what's gone on in the last thirty or so years in biomedical engineering and in biophysics, you said that this country has been very much in the forefront?

Schwan:

Oh, yes. I think so. Yes.

Nebeker:

The German and French and English institutions have not kept pace?

Schwan:

Yes. There's good work going on, but we in the U.S. are still ahead. Well, we have in Germany just about three or four activities in bioengineering. One is at the Helmholtz Institute in Aachen, and one in Erlangen. Germany is one-quarter the size of America by population, but the number of bioengineering activities there is far less than one-quarter of those in this country. There are several university institutes that do biophysics. There's the Max Planck Institute. They do good work, particularly at Max Planck. Being an honorary member of the German Biophysical Society, I get their programs. Their annual meetings are attended typically by some hundred people. The annual meeting of the American Biophysical Society involves something like 2,500 people. Their Abstracts take up two volumes. It's like a big IEEE meeting. In other words, it's ten times as big as in Germany. It's much more pronounced.

Nebeker:

Is there anything else you'd like to comment on in comparing the United States with Germany or with Europe as a whole?

Schwan:

I think Germany has been coming up, slowly but steadily. After the Second World War it was a wasteland — not only physically due to the destruction of the cities and the undernourishment of the people, but due to the loss of intelligence and capability, since under Hitler a large fraction of the highest competence left Germany, as you know. But it has been improving. A number of Germans have received Nobel Prizes. That is similar to the U.S. on a per capita basis. Germany has been making headway in that regard. Few of them are university people, however. Practically all the people who have gotten the Nobel Prize in the last ten years are affiliated with Max Planck Institutes, which shows, again, how important the Max Planck Society is. Many of the German organizations tried to work closer with other organizations in Europe. That work has taken place in the space field. In astronomy, Europeans appear now to be leading in competition with America. What they have underway is the construction of the largest astronomy telescope in the world. They are building it somewhere down in Chile on a high mountain. In Science they just reported that they got an Italian, one of the best qualified men, to head it. He had been heading a large telescope program in this country. He's supposed to be a brilliant person in that field. Astronomy has become more sophisticated in Europe. They have made advances in molecular biology. I don't want to talk about Germany alone that much anymore. I think I should talk more about Europe. I think that America will be competing with a new world in Europe in the future. More and more cooperative efforts are underway, and that will slowly but steadily become more apparent scientifically and technologically.

Important Contributors to Biophysics

Nebeker:

As you look back on a very productive career that's put you in contact with a great many people, who do you regard as the most impressive figures in biophysics and biomedical engineering?

Schwan:

I can comment, of course, particularly well about people in my own specialties of biophysics. I would say that Hugo Fricke and K.S. Cole, both of whom I have mentioned before, were quite outstanding. In the broader area of biophysics, Max Delbrück, who is now dead, was truly exceptional. He came from Germany. He was a physicist but became interested in biology. He's one of the few outstanding physicists who became very successful in biology. When he left Germany, he became a professor at Cal Tech. During the summer he worked in a famous biological laboratory in Cold Spring Harbor. He was very systematic in his approach, and he believed biologists should start with a single small, relatively simple, live system and study it intensely. That led to his phage course. The phage is a plant virus. He applied modern physical techniques in his research. He had a tremendous influence on many other scientists there. Many of his pupils established the molecular biology revolution. Several of them were awarded Nobel Prizes. He's considered by many as the father of the revolution of biology. He was a physicist in Göttingen, by the way. He certainly had a very strong influence on the field. I knew him only casually. But I knew Hugo Fricke and K. S. Cole personally very well and worked with them.

Another person is Manfred Eigen. Manfred Eigen is at the border line between physical chemistry and biology and became the director of the Max Planck Institute for his applications of relaxation techniques to study chemical processes. He did sort of the same thing that I'm doing with regard to the processes, which determine the electric properties of biological material. We did similar work in acoustics. That's how I first met him. We had related interests. He has an exceptionally clear mind. He is an extremely active person. He produced many publications rapidly that demonstrated his tremendous insight and drew great attention to his work. As a rather young man, he got the Nobel Prize. He has been effectively creating a very large institute with six divisions. I don't know — 500 people may be employed there. It's a famous Max Planck Institute. Well, he's sixty-five now. He is still a very effective person.

But I know many other people, of course. Talbot and Schmitt I commented about. They were very influential people indeed. There were several of my students who were particularly productive. Ed Carstensen, whom I admire greatly, contributed much to the field. Ed Carstensen was not that active on an administrative level. But his work on the electrical properties and in the bioacoustics field made him one of the leaders in the country. He is an excellent scientist. There were others. The man who is in charge of the bioengineering program at Drexel at the present time, Dov Jaron, came from Israel, and got his Ph.D. with me. He's an excellent person. Other former students of mine are on the Drexel faculty. I mentioned John Reid before. Banu Onural was one of my last students. She is reportedly emerging to prominence in our field and has done excellent work. About half of the people who got their degrees with me became department chairmen who set up or organized bioengineering groups somewhere else in this country. Dave Geselowitz I mentioned. He did excellent work in potential theory of heart activity. He organized an excellent program at Penn State, which has been much in the news lately because of its artificial heart program. He was also elected to the National Academy of Engineering, as I mentioned before. The Penn State program is a very fine program.

Role as Industry Consultant & Expert

Nebeker:

I wanted also to ask you about your service as a consultant to industry.

Schwan:

Yes, that involved quite a number of activities of different types and in quite different contexts. Most of my work was as a consultant, either with regard to scientific matters or as testifying before civil or law court on scientific matters. It started fairly early when I was hired by some industrial company producing diathermy equipment in this country. The activities ranged through rather exotic topics. For example, once I did some work for a company in Toledo, Ohio. They had an interesting project. They had developed a rapid hair dryer using microwaves. Why not use microwaves to dry hair? It works. Very fluffy in just a couple of minutes. [Chuckling.] They wanted to get Underwriters' approval. To get Underwriters' approval, we had to discuss effects of microwaves. We were at the peak of the microwave controversy at that time. They didn't like the idea too much, and they wondered if the brain got damaged. [Chuckling.] So I set up a series of tests mimicking the head with all sorts of glass bottles of various sizes with appropriate fluids demonstrating how they were heating up. I also made all sorts of calculations relevant to the experimental setups. That extended over a quarter of a year. In due time, the Underwriters' people came. They were impressed. We worked with them through all of the tests. I let them stick the thermometers into the solutions in the glass bottles themselves and so on and so on. We could prove that the heat load of the head was very minimal. But, nevertheless, it was not within the allowable limits, and we were a little bit uneasy about it. So the company didn't get the UL approval. That was one of the more unusual activities I was involved in.

Other consultant work included Hoffman-LaRoche in Basel and the Coulter Company in Florida. Then I worked for Bell Labs, advising to what extent they should undertake research on microwave health hazards, particularly with regard to vision — eye cataracts. They let out contracts in the field, and I helped to evaluate them. Eventually, after some years, they lost interest after a change in its internal structure. Originally, Bell Labs was interested in microwave technology, pushing for higher and higher wavelengths. But they terminated the project when it became apparent that fiber optics and laser technologies were much more appropriate for carrying 1,000-fold as many messages. But that happened some four or five years later.

I worked with GE a number of times, conducting research, testifying about microwave ovens and diathermy frequency allocations before the FCC in Washington.

I was involved in a discussion with the FCC about wave channel allocations for medical and technical purposes early on. There was a competition within this country between so-called "common carrier" groups and the special interest groups using microwaves for medical and industrial purposes.

Nebeker:

Is it the case that you can't use the same frequencies in medical applications as in communications?

Schwan:

You can't. You would ruin communications. I was involved for a while. Another time, later, was about microwave hazards in connection with microwave ovens which they had on the market, which didn't quite meet the FDA specifications. Then I was involved in a large number of hearings before all sorts of courts.

Nebeker:

Were you employed as an expert witness for a power company?

Schwan:

Yes, I served as an expert witness. I did it a few times for Bell Labs. I enjoyed working for Bell Labs and AT&T since they usually had good people on their staff. They did their own good expert work. They got competent lawyers. So I found it easy to work with them. They understood very well what counts and what doesn't count. They were usually successful.

Nebeker:

There's sort of an editorial on the last page in Scientific American, the last issue or the one before that, about bad science in the courtroom. It complains that a lot of fringe science has been accepted in the court, and how difficult it is to get juries to make a distinction.

Schwan:

Yes. So true.

Nebeker:

And that's something you experienced as well?

Schwan:

Oh, yes. Well, something very much to my surprise is that apparently the courts are not able to evaluate the relative significance of scientific contributions of various scientists. I mean, did this man just get his bachelor's degree, or is it a man who became a Fellow in the IEEE? They are all treated equally since the judge cannot perceive the different scientific qualifications. That appeared insane to me. I think credentials of people reflect the ability of the person, to some degree, don't they? Sometimes this is not quite correct, but on the average, credentials are very important indeed. The courts miss out very badly in that regard.

Nebeker:

Did you find that unscrupulous lawyers are misleading jury members?

Schwan:

Oh, yes. Absolutely!

Nebeker:

What would you recommend? That judges are more critical in their accepting someone as an expert witness?

Schwan:

Yes. They should make an attempt through their respective legal personnel to establish what the scientific credentials of a person mean. It's done in many other professions. They wouldn't accept, say, one first-year law school student who serves temporarily in the summertime as a clerk and weigh his statement just as heavy as that of a famous lawyer, would they? So why don't they do the same thing with scientists? It should be done, it seems to me.

Nebeker:

I see that you've also consulted a number of years for Hoffman-La Roche.

Schwan:

In Switzerland and in this country, yes. I wrote a lengthy report about electric impedance and the brain, and the amount of brain tissue water, extracellular space and things like that. They were very much interested to learn to what extent electric techniques and brain research might be interconnected. There was great interest in this country at the time in the topic. A number of laboratories worked in the field. They hired me as an expert to summarize that total work, and I wrote a long report about it.

Nebeker:

I see. And you were a consultant to HBO? What was that for?

Schwan:

Oh, yes. [Chuckling.] There we lost out. Well, it was a rather embarrassing situation. HBO wanted to establish a new northern New Jersey base involving several microwave dishes transmitting their programs. I was hired by them to testify that it would be safe to do. Measurements had been conducted, and trial tests with the dishes had been already done there on a temporary basis. It was found that radiation levels in a nearby school were a tenth of a microwatt per square centimeter. At the time, the standard in this country was ten milliwatts. In other words, a hundred thousand times higher. Since then it has been lowered, but it is still ten thousand times higher. I testified that it would be safe to have equipment there. It was a very interesting experience. They were not very friendly to me. They told me at intermission time that they did not want that equipment there, primarily for aesthetic reasons. One person said, "We found that you can't lose on that health issue, so we selected it."

Nebeker:

That's particularly effective when it involves school children.

Schwan:

Yes. Precisely. I was subjected to some very inappropriate and insulting cross-examination, though I informed the lawyer of HBO that I wanted to be protected against such behavior. I wanted him to interfere and protect me against insult. He promised to do so. I was assured by the court that this would be done. Indeed. Then one of the same men who had assaulted me, stood up and started to assault me again. I had warned the people from the board that if that happened, I would quit. So I stood up, collected my stuff, said "Cheerio, folks," and walked out of the room. That was the end of my testifying for HBO. I was not going to endure that sort of treatment. HBO didn't hire other consultants. It had become apparent to them that the meetings would be conducted unfairly since the people were determined to use whatever means to stop HBO. They were able to secure some ground nearby in another location, and they had no trouble completing their project.

The last consulting job I did was here in the neighborhood, in Valley Forge a year ago. Again that work involved a microwave transmitter tower. It is one of those towers with lots of dishes on it. My testimony in that case was for the Sun Pipeline Company, which is a subsidiary of Sun Oil. Sun Pipe Line constructs pipelines through which they pump the oil. It is also responsible for constructing the microwave-related technology which controls the operation of their pipelines in this country.

Nebeker:

They have their own communication system?

Schwan:

Apparently. That's what I learned at the time. There is a small facility in Valley Forge with a sixty- or eighty-foot tower. Some people were concerned about the radiation from it. I could demonstrate, based on measurements which had been taken, that the radiation levels were on orders of magnitude lower than all standards in existence. The sort of work which I had done for industry was a mix. At many of the hearings I was insulted. I was assaulted by Paul Brodeur in his book, The Zapping of America.

Nebeker:

I haven't seen the book.

Schwan:

Oh, you haven't seen it.

Nebeker:

But I know the articles about it.

Schwan:

It made quite an impact at the time. It appeared as a series of New Yorker articles. I met Brodeur once after he wrote his first book. We were both asked to debate the issue on the ABC morning show "Good Morning, America." So I met him there. Paul Hartman was still the master of ceremonies of the show, and he recognized that I was a scientist and Brodeur more a science fiction writer. He annoyed Brodeur certainly more than me, and Brodeur didn't make out too well with that interview. Later on I drove with Brodeur back to the hotel. They had a limousine for us that took us back and I talked with him. I found him a very reasonable man at that. I asked him why he didn't ever come to talk with me. He said, "Well, A) I didn't have the time, and B) you didn't fit my concepts." He said in essence, that I wouldn't tell him the sort of things he wanted to have for his book. I said, "Please, before you write something else, visit with me and talk." "I shall do so." Well, recently he came out with that book about low-frequency hazards. Again, he hadn't consulted me and many others with an outstanding reputation in the field. People who write that sort of sensational material avoid experts. Or at least they choose only people who fit their preconceived mind, and who give them stuff that makes a successful and sensational book. Very disappointing.

Nebeker:

Yes. Is there anything else you'd like to comment on?

Schwan:

Nothing else comes to mind. I think that's it essentially.

Nebeker:

Well, thank you very much.

Endnotes (added by Dr. Schwan)

  1. It was probably unsurpassed in scientific and cultural activities. Many of the most famous mathematicians and physicists were there, pushing the development of relativity and quantum mechanics. Expressionism was extremely well represented by many famous painters, and music was equally good. Its foreign policies improved rapidly, in good part due to the long service of Stresemann, an excellent man to head foreign affairs. A number of treaties with the Western nations reduced significantly the burden imposed on Germany by the Versailles peace treaty, and Germany became accepted in the League of Nations. Clearly, Germany was well on its way back to becoming again a highly regarded member of the international community.
  2. The branch institute in Oberschlema was primarily intended to study the effects of radioactive materials on man. Oberschlema and Joachimsthal were both part of a large mining district where Madame Curie had obtained her pitchblende for the production of radium. Many miners died at a young age, and it was suspected that their death resulted from undue exposure to the high radon levels existing in the mines. After World War II, the mines were operated by the Russians and became their main supply of weapons-grade uranium for their nuclear bombs.
  3. The development of special devices, such as prostheses and cardiac pacemakers, has indeed captured the public attention as representative of biomedical engineering. Less visibility, understandably, exists for its more basic contributions. The mechanism of vision, hazards due to non-ionizing radiation, electrode studies (electrodes must be used by pacemakers and many other implanted devices), the electron microscope, and the voltage clamp technology (which was a prerequisite to finding out how nerves work) are but a few examples. Basic oriented work aids the development of devices. A typical example is ultrasound. Early recognition about the mode of propagation of ultrasound into tissues was followed by the decision to develop and market first therapeutic and then diagnostic equipment. Today ultrasound has become one of the most widely used diagnostic techniques, including cardiac echocardiography.
  4. The same procedure has been used by granting agencies such as NIH and NSF for a long time. Research proposals are accepted, evaluated, and funded if judged good enough.
  5. Bridge design considerations The design of the low-frequency bridge was influenced by previous experience gained in Frankfurt. I began in Frankfurt with the construction of precision equipment covering both RF- and low frequencies. No commercial equipment was available and I had to build my own oscillators and amplifiers. I had already a relevant engineering background, and acquired additional knowledge by reading books about vacuum tubes, amplifiers and oscillator design. The shielded bridge had four compartments, one holding the sample and the other three variable electrolytic resistors. Electrolyte resistors were chosen since their capacitive properties were considered more easily controllable than those of commercial resistors. Commercially available variable resistors at the time had unknown small (but for the intended purposes very disturbing) capacitive and inductive properties. Testing the design proved disappointing. At low range frequencies, electrode polarization introduced large additional capacitive components. Their correction proved to be a nightmare, since four sources of error were involved. This work in Frankfurt stopped when I was ordered to turn my attention to the microwave area in 1943. But I had learned a lot about electrode polarization and advanced bridge design. When I designed the low-frequency equipment while working for the Navy, I decided to give up on variable electrolytic resistors. Not only did they suffer from electrode polarization, but they also were temperature sensitive. After some research, I located a manufacturer (Leeds and Northrup) willing to build a variable conductance box (with resistor elements in parallel instead of the usual series arrangement). I designed a step-up calibration procedure which permitted calibration of the reactive properties of the box over the total range of conductances with the necessary high precision needed for the intended use. The construction of the equipment took more than a year and proved satisfactory. The equipment made it possible to measure the properties of interest with the needed high accuracy. It was extensively tested with electrolytes. First measurements with muscle tissue proved that the constant membrane phase angle element predicted by Fricke and Cole apparently did not exist. Instead, an entirely new mechanism revealed itself by the observation of a new distinct "dispersion" (i.e., I observed a more steplike and distinct response instead of the constant smoother gradual change predicted by the constant phase angle concept).
  6. Later, in 1964, Fatt and Falk in England confirmed the effect and suggested that the tubular system of muscle cells caused the relaxation effect. They also suggested that it directly relates to the mechanism of muscle contraction, an important problem still not entirely resolved.
  7. The low frequency dispersion found by us was subsequently also observed with minerals. Understanding of the electrical properties of earth and minerals directly relates to the ability to locate oil and other valuable deposits by electrical means.
  8. Our work on the ultrasonic properties of tissues was a logical extension of relevant low frequency interests. Low frequency acoustic properties are identical with those experienced when tissues are exposed to vibration, sudden accelerations, etc., as experienced by pilots flying high performance aircraft. These days, astronauts are exposed to very high vibration levels when space vehicles are launched. The overall frequency dependence of the mechanical properties of tissues helps to identify mechanism and thereby to provide insight into how mechanical stresses impose unduly on tissues.
  9. The decision to investigate the electrical properties of cell suspensions and tissues at low frequencies was in part motivated by the work of Fricke and Cole at higher frequencies. Both had postulated that the cell membrane properties displayed "constant phase angle" behavior similar to that observed at the interface between a metal electrode and electrolyte. It is characterized by a frequency dependence of both resistance ad capacitance, such that the electrical phase angle of the interface does not change with frequency. But I thought that the behavior at higher frequencies could be explained by different postulates. Variability in cell size and shape and its interior components could simulate observed deviations from single time constant behavior. Such behavior is predicted by an equivalent circuit which puts the membrane capacitance in series with internal and extracellular fluid conductivities. Such single time constant behavior could be anticipated only for uniform cell size and spherical shape and no internal content of organelles and proteins. I also knew that red cell suspensions approximate the single time constant behavior much better than tissues, since they better fulfill at least some of the necessary assumptions. It became apparent to me that extension to lower frequencies would more clearly show if membranes display the constant phase angle law or not. However, it also became clear that this would require equipment of high resolution, able to detect with accuracy the small capacitive current component which reflects the membrane capacity. Conductance determinations alone would be inconclusive since the low frequency conductance is dominated by the strong contribution of the extracellular fluids. The question how the membrane behaves electrically was to emerge as a major topic of biophysical interest. To answer the question raised by the constant phase angle model was therefore important. Today, this constant phase angle concept is no longer used, and the conductive properties of the membrane are linked to its channels, as first formulated by the famous Hodgkin-Huxley model.
  10. Kam Li, another graduate student supported by me, helped test the equipment with electrolytes. We then used the equipment to collect extensive tissue data in the range from 0.1 to 1 GHz. These data were published in the Proceedings of the IRE. They and additional data in other frequency ranges above and below the 0.1 - 1 GHz range (including data I had collected while in Frankfurt) were published in several of my reviews. They provided the fundamentals on which all later discussions of microwave and RF-dosimetry and standards were based.
  11. While at the Navy, I had been exposed to a variety of ultrasonic interests. I helped to evaluate the noise spectrum generated by the powerful afterburners of some of the strongest jet airplanes the Navy had at the time. This noise spectrum extended all the way from ultrasound to below audible, including strong vibrational irregular bursts. The Navy was concerned about health effects. Ear damage had been reported. The design of appropriate ear defenders was a high priority. I also read a good deal about earlier American work concerned with the effects of ultrasound on tissues and cells, including the excellent work by Wood and Loomis. I obtained ultrasonic equipment and studied the effects of ultrasound on red blood cell lysis. I never entirely finished this work since the low-frequency work took over.
  12. Peter Edmond's acoustic work included shear wave absorption and extension of absorption measurements to frequencies in excess of 100 MHz, thereby providing a better definition of the relaxational spectrum characteristic of biological macromolecules. He joined IEEE as the need for evaluating the relationship of the biomedical engineering community to the IEEE became apparent. I have reported in several articles and in this interview on these efforts during the early 1960s. A report by Edmond, "Survey of discussions, 1965 - 1967", gives details and is in my files.
  13. The paper referred to is number 88.
  14. NIH has many study sections helping the Research Grant Division evaluate research grant proposals. Each of the NIH institutes is served by a program-project committee evaluating large long-range research proposals. Furthermore, each institute has a council, which serves as its top advisory body, reviewing the decisions of the program project and study section committees concerning emerging fields of interests and policies.