Eventually what it turned out is that a very famous nematode called Caenorhabditis elegans was the one that worked. Now I'd got this culture, C. elegans, it had been isolated in Bristol and a strain had also been isolated in France where a man called Nigon had worked on it, that was called the Bergerac strain. This other one was called Bristol, and there was, there was a man called Dougherty in the United States - was at Berkeley - and he was interested in nematodes, had been for a long time. He worked in a department of nutrition, and was interested in what did nematodes eat. And so he wrote large numbers of papers on axenic growth. I mean, everybody knew nematodes ate either other nematodes or bacteria or fungi, but he was interested in growing them in liquid medium. And... growing them in defined media where every compound was. And that was his work and he had reduced the culture to a whole lot of amino acids, vitamins and there were tremendous complex things and... plus a horse liver extract. And... and since one of the things I was interested in was to try and see if I could get nutritional mutants of nematodes, because I argued, well, if we could get a biosynthetic gene we'd know how to isolate that, we'd know what the protein is. And so I did a lot of experiments of axenic growth. And out of all of these animals I... I liked very much C. elegans, because it had a beautiful sex life. It was what is called the self-fertilising hermaphrodite. That is first the gonad develops into a testis, and then stops, and then the gonad switches off to make oocytes and then these two fertilise each other. So each animal is the result of a cross of itself with itself, and there's no better inbreeding than to cross yourselves with yourself all the time. So this animal then had the property of being completely isogenic, because each animal would have a uniform genetic constitution, it would be a clone, so to speak. Furthermore, it... you could easily see that when you made mutants, those mutants would then segregate in the cross of that animal, in the Mendelian proportions. Then also these nematodes have occasional males which crop up in cultures and you can use these males to move genes from one animal to another. That gave you the whole basis of doing genetics. They had a very rapid life, they lived on E. coli [Escherichia coli], and it looked as though they might be axenised and so after some... some time of looking at lots and lots of others, we alighted on C. elegans.