Well it was one of those purely social accidents. In '48, a person who later became Deputy Director of the Pasteur Institute, came as a post-doctorate researcher to Caltech. He was French, I was French, so a mutual friend introduced us. And then those people very much disliked the apartment that Caltech had found for them, and I knew that there was an apartment vacant next door to where I lived, and my landlady asked me, "Do you know somebody nice to go there?" So I introduced those Frenchmen to my landlady, and therefore became neighbours. Therefore we saw each other very often. That was kind of superficial, but I went, I was invited to a few of Delbruck's parties and it was quite clear that this thing which I was dreaming of was happening; that this man who had this extraordinarily strong knowledge of quantum theory - he was later, well not a greatly significant contributor to quantum theory- had a pure command of anything he wanted, he could learn the mathematics he needed any time, had decided to go all the way to a very soft subject, but to tried to take it by the path which could be the hardest, namely molecular biology, which he in a way introduced, invented, discovered, whatever you want to call it. Now his post-doc's were an extraordinary crowd. I mean a large proportion of my friends, life friends, are from that period. Some of them include the most brilliant man I ever met, who is Carlton Gajdusek; I may speak about him a bit later. They're simply of a very high calibre, and of course I wondered should I go into biology? That was too far, it was too removed, I was probably too engaged and somehow also I would have been too late. I had this feeling that the moment of greatest tension was already past, and Delbruck and his first post-doc's had done it. I was wrong, of course, because it lasted for several more years.