My father had an influence on me in that he stimulated my curiosity about things in nature. He stimulated the idea that research in science was an interesting thing to do, and therefore it was quite obvious that I should study science. My father and I went very often for walks on Sunday, long walks, many hours, and then we talked about... mostly about scientific matters; sometimes also about daily events but mostly about science. So I think this was very important, but I didn't go into the subject, into his subject of physiology. Animals didn't interest me specially, but instead of that I went into the inanimate subject of physical science.

[Q] But you did go into his laboratory?

Well, I collaborated with my father on one investigation that he did with a postdoctoral student about the permeability of membranes which even today is a very important part of biology. And I had the advantage that I knew calculus and so I could make a theory of that permeation of the membrane. The theory had been made a hundred years earlier, but I reinvented it.