What happened when I got to Oxford, as I saw Hinshelwood… and I had discovered this book Viruses, 1950, a little symposium held at Cal Tech and I'd read about phage. And... bacteriophage. And Hinshelwood was then working on drug resistance in bacteria and so he wrote to me and said he'd like me to work on bacteriophage resistance, to show it's an adaptation. I had read about phage and got very excited by Viruses. It's a remarkable book, that Viruses, 1950.

[Q] Who's it by?

It was a symposium at Cal Tech; it's by various people and it is the beginnings of the... the phage… phage ideas there, you know, and really what is a virus? I mean… which you know was going to become clear in the next 20 years. And so I started to work on bacteriophage and I started to read about them. Hinshelwood wanted me to work on resistance because he was a great believer in the time that bacteria adapted to certain situations and then what was inherited was in fact the adapted state and he didn't believe in mutation. Strictly speaking, he said that the evidence that people had didn't support the idea that there were mutants. That was his... his thing. Now, I think in modern language we will see that those ideas are pretty common today, like we don't call it inheritance, we can say the persistence of, or the descent of, a certain determined state, which is not because there's been a gene mutation, but because there's a self-perpetuating state. And of course, he came in, he was very… he was very controversial, and so I started to work on bacteriophage resistance in a physical chemistry lab which was totally unequipped to do any biological work. We had to… we were given a pressure cooker and thirty glass petri dishes and some pipettes and you had to make your own petri dishes and all the pipettes were Pasteur pipettes which you had to plug yourself, and sterilise in an oven. And so each experiment became a logistic effort and amongst other experiments that I did – it's all in my DPhil thesis – is I repeated the Luria-Delbrück fluctuation experiments. I think I'm the only person in the world who's repeated them because Hinshelwood didn't believe... didn't believe in them. And I repeated them, and this got me into the whole area of genetics of mutations and so on, and I started to work on the side, on other problems. What I wanted to work on was lysogeny because I thought that would… Hinshelwoodian theories could easily explain lysogeny – that is, the switch between lysogenic and lytic – and what he was doing was trying to explain resistance. And I'll never forget… and I tried to explain it to him at the end, I said to him… I said, 'Professor, in science as in life, it is important to distinguish between chastity and impotence. The outcome is the same, the reasons are fundamentally different.' Okay. So… that I've used… this is a very important… it's a difference between can't and won't basically. So, mutation says you're bacteriophage resistant, because you lose a receptor to bind the bacteriophage; that is impotence, okay? Now the other is you choose to be chaste, you see, so that can be done by a... a thing like this, and so that I think is a very important way of doing it. However, I was the first person in that group who ever argued with him. It was absolutely unheard of, that one would actually challenge the professor, because we were still in those days you know where the Herr Geheimrat was right at the top and actually I got on extremely well with him and in fact, you know, just argued with him. And… but he was someone who, if you could show him an experiment, that was the thing that convinced him, and I think at the end of the day he was willing to think that some things were due to mutation.

[Q] But you were the only biologist there?

I was the only person with a biological background. Other people were kind of chemists that had done this.