In the field of immunological tolerance, Milan Hasek had made an important discovery with parabiotic eggs. If you join two eggs together then the chickens which hatched from them would accept one another's skin grafts or tissue. And, you know, he's one of the penumbra of people around any Nobel Prize who had a claim, but he certainly got himself into a mess by putting down a lot of stuff about the parabiotic and vegetative hybridization, and the baleful influence of Lysenko on Eastern science. Now for me, that baleful influence was perhaps more an attraction than- than a despicable toadyism. I wondered if, behind all that- I was still- I hadn't accepted fully that Delbruck was opposed to the Sonneborn feel about cellular inheritance, and I just worry- still wondered if there was something there. So that was two reasons for wanting to go. Another reason for wanting to go was to find out about, you know, Europe and the rest of the world, and it would be nice to- I'm sure I thought it would be great to- if really good science was done outside of the USA and outside Britain. So how was that period? Was it useful, productive? Scientifically no I don't think so. I don't really think I got very much done there. Oh, I remember. I published a paper, which was supposed to show vegetative hybridisation. It was a big mistake, big error. That's a little story, if we've got plenty of time for me to tell it to you. My idea was that we would make vegetative hybrids in birds by transplanting pieces of spleen from turkeys onto the egg membranes of chickens and vice versa. And that we would then- we would have antibodies which would recognise chicken cells and antibodies which would recognise turkey cells. And so- In Milan's lab I did that experiment. And lo and behold, when you looked at the cells of the embryos, their red cells reacted with both of the antibodies. Both anti-chicken and anti-turkey. Whoopee! Vegetative hybridization. So that was published with an English and a Russian abstract at the end, as was the custom then, in the "Journal of the Czech Academy of Sciences"- "Folia Biologica", and I think probably just as soon as it appeared, Morten Siemensen turned up in Edinburgh, the great Danish transplantation- student of transplantation biology, and became a very close friend in the long run, very wonderful man. And he discovered the graft versus host reaction. So very quickly, I was able to show that the antibodies which had been made by immunising chicken cells with- sorry, immunising chickens with turkey cells and vice versa, the red cells hadn't been washed perfectly, I don't know, they'd been done three times, but they contained antibodies of, eventually, immunoglobulins against the antibodies of the other one. So what I was recognising on these chickens cells was chicken antigens, and with the anti-turkey cells, I was recognising, actually, chicken antibodies sitting on the- the foreign cells, graft-versus-host reaction. So that wasn't a great production.