I then started to isolate nematodes from nature to find the best one. And what we knew from the literature is that these had a small number of cells, they were limited… number of cells, and that the other thing they had was rapid growth and that, as it turned out, there were the right possibilities for sexuality in order that you could do genetic experiments. Now, we knew from really classic experiments, Goldschmidt in the early part of the century had done the nervous system of ascaris, and this is a remarkable set of papers, because if you read his life you will see that he did these when he was doing zoology as a student. And he made these dissections of ascaris, which is a very large parasitic nematode, largely of pigs, and that he found he could describe the entire nervous system, it had a few hundred cells, and he could also describe all the connections. When I went to look at the journal in the Jahrbuch der Zoologie in the Cambridge University Library I found all the pages uncut. So I was absolutely certain that no one had ever read that journal until I opened it in the early '60s, and that means it had been there for at least 50 years. And it's a absolutely classic paper. And therefore I said, 'Well, look, this is an organism which will have a wiring diagram. So it should be possible to… to do the following: to determine the wiring diagram in an organism of the nerve cells; to also ask whether all organisms have the same wiring diagram if they have the same genes. So therefore we can say genes specify wiring diagrams.' And the whole sort of conceptual layout was very clear in my mind before even starting – that what one would do is effectively get all the genes that fix the wiring diagram and then work out what they do. Furthermore, it became clear to me then that problems such as the nervous system had to be solved from the genetic point of view in… in a very special way.