One of the attractions of Cambridge was that... that there was... would be electron microscopy there. And one of the attractions, apart from people like Crick and Perutz, Kendrew, was Hugh Huxley. Hugh Huxley was at that time the... I think, the best electron microscopist in the world, in fact it's still a mystery to me he hasn't got a Nobel Prize for the work on muscle; but he was the man, the best electron microscopist, technically superb. Of course, with a very good mind, a very good, brilliant mind, in fact. And so one of the attractions was that we knew what the virus shell should look like so we should really be using electron microscopy because was X-ray diffraction takes a long time, many... many years to solve the structure by X-ray crystallography. Electron microscopy should be able to see something, so Hugh Huxley gave a two-day course, I think you went to a two-day course, I mean, it was a private course. Yes.

Now, the summer before, in '61, I went to South Africa with the family for three months. And they had... I was in the Physics Department, the old department, James had... James had retired by them. And... but they had some... I did some... I actually published a paper on X-ray diffraction of gums, I interpreted the X-ray fibre diffraction pattern. But there was also a microscope there and I remember explaining to them how to do negative staining, which had been invented by Hugh Huxley and given the name by Sydney Brenner. And I began to do... I had to go into the unit every day, so I began playing around with a technician, a man called Chick Fowle. Fowle was his name, F-o-w-l-e, he was called Chick, a very good, very capable technician, and he showed me how to use an RSEA electron microscope they had in the building. And... and I remember being very struck by it that I began taking pictures, so I learnt how to manipulate the microscope and so on. And I was also struck by something which I noticed then, which later stood me in good stead. These were negatively stained Tobacco Mosaic Virus particles, which is the old war horses we always used to look at. And it was negatively stained, which meant that the heavy metal stain was down that central hole. And the central hole appeared where it should be, well, it depends what we're talking about, the film or the print. It should appear dark as no light should go through. And I noticed I was twiddling with it, focussing it and it went white. And I... I didn't know what this was and I realised I must be changing the focus of the electron microscope. And that, I believe, was the origins. Later on, some years later when Erickson came, of phase contrast in focussing to be able to image electron microscopy transparent, as they called phase objects. So that was a pretty... again, one of these chance educational events because I wouldn't have... I didn't... it wasn't done by working out a theory which people had worked out. Later on, of course, I followed the theory.