Helen, I have to say, I probably learned as much from her as I did from him. I learnt from Helen the absolute importance of writing down what you see as a scientist, not what you'd like to see or what you hoped to see, but what actually happened, and to write it down at the time and so on. I mean she was a meticulous observer, Helen. Give her an animal and she'd keep it and it would be breeding if you could give her one of each sex, I mean, she was marvellous with animals, she was a marvellous observer. I don't think she was a great theoretician, I mean, in fact, I know she was not. But she was... she was a damned good geneticist, because to be a good geneticist you've got to have the animals, they've got to be alive, they've got to breed, and you've got to write down precisely what happened. And that kind of honesty about the facts is what I learned from Helen, I think. We used to have great arguments. I used to say, 'Look, the way to do science is to think of an important problem and then find the right organism upon which to solve this problem.' And Helen would say, 'No, you must allow the organisms to lead you, keep the animal, keep the plant, and it will tell you what is interesting. And you must observe what it does, you must write down what it does and let the organism decide for you.' I still think I was right and she was wrong, but her way of doing science is a way of doing science.