But in the meantime, I took advantage of Oxford. For example, I had to go and get phages, so I got them from across the road in the pathology department when I met some people there that were working on phage as phage… were working for Sir Paul Fildes, who was a member of the old school of microbiologists, you know; came every morning to the lab in a bowler hat and striped car… trousers and so on – a very nice man. One of the important people for antimetabolites, the whole background of, you know, sulphonamides and so on, and what that led to, and I got to know them, and I got to know some people there; I got to know people in the biochemistry department, because I had to learn about bacteria. I actually got to know people in the organic chemistry department because I had discovered that some phage mutants were also tryptophan deficient. That had been known, but I got one of these and I decided to go and find out why they were, so I started to work on tryptophan biosynthesis and I got a theory of what might be happening, if I had to go and make one of the intermediates. And so I went across to the Dyson Perrins Laboratory where I got hold of a bench and was doing there. One morning, Sir Robert Robertson… Robertson swept in and started to ask me what I was doing, got very interested in, and I couldn't explain to him that I was a... an intruder and apparently, about a week later, he came in and asked where this interesting person had gone, because I'd done my work and disappeared and so… but in fact, again, you see, that is very interesting because if you want to… I needed these intermediates; you couldn't get them anywhere, so the best thing is to go and make them. I mean, how do you make them, you get hold of a paper and it says, you know, take two teaspoonfuls of this compound and stir well in, so I did it, you see, and I made it, I crystallised it, but this is something you can always do… it's open to you. There's no magic in this and I think the whole of the philosophy that says unless you've gone through this way, if you're an old chap of 25, you can't do it. What you have to be is 18 and naive and go to a course and learn how to do it. This is just absolutely untrue.