Don Caspar came... And Don Caspar was an American working in... he was the only American working on the viruses. And X-ray analysis, and he had moved into Tobacco Mosaic Virus around about '56 he'd published the one-dimensional map of Tobacco Mosaic Virus. And Rosalind [Franklin]... he never would publish it, but Rosalind wrote his paper totally from beginning to end. So she could publish her own paper on the nucleic acid free virus.

[Q] Yes.

So the... but what we had done, I have to go forward a bit, or back a bit, we had started working on spherical viruses. This was because the... Bernal had started this again as usual in the late 1930s and it showed you could crystallise various plant viruses. Again, Boardman and Perie had done this, this is the same Perie. And these were, of course, very large crystals, very large unit cell crystals, the unit cell of Turnip Yellow Mosaic Virus was 700 angstroms. And Rosalind thought that I ought to move on to another subject for me to be distinct from her. So she suggested that I take up spherical viruses and that's when... And so that's when, you, John Finch, came to work with me on spherical virus. And Ken... Ken Holmes worked on TMV, but I've forgotten what year that was; it must have been about '56 or '57... you arrived in '55, yes, '55 you arrived...

[Q] Yeah.

So the... and so with spherical viruses, of course, Don Caspar had got some... Tomato Bushy Stunt Virus, I've forgotten where he got it from but he published the first paper showing the evidence of icosahedral five-fold symmetry in... in Tomato Bushy Stunt Virus. And I went on with John and I remember we had a much larger unit cell. I remember we had to redesign the collimators and all that... it was quite a feat to get a decent picture. And we got pictures of TMV which showed that they also had lots of icosahedral symmetry; and so this was the beginning. In '56, yes, Jim and Francis, Jim Watson and Francis Crick published a paper in 1956 at a symposium, the CIBA Symposium on the nature of viruses. And this was a... this... what they were arguing was that the spherical viruses had to be built out of a lot of different sub-units on the model of Tobacco Mosaic Virus then the packing might have to adopt to give you a sphere, it would have to follow one of the point group patterns, either to have tetrahedral, octahedral, or icosahedral symmetry. So they expected, but they didn't say anymore beyond that. Well, it turns out that these viruses, all had icosahedral symmetry and then later when we did polio, that was in 1959, the polio virus also had icosahedral symmetry and built on the same principles. That was... the polio work was quite psychologically important because people used to think that... the virologists thought that all animal viruses were DNA and all plant viruses were RNA. And here was the polio virus, which is an RNA virus, an animal virus, and moreover has the same kind of construction, architecture as a plant virus. And people began to see that these were false distinctions. So we had, so the work was of some general importance, apart from the interest in the structures, sort of educating the virologists.