When JBS Haldane visited the United States he toured the laboratories. He also went to Bar Harbor in Maine where there was a major group of researchers working on mice and also made... largest collection of inbred strains in the world. And Snell was working on... later on the H2 system, but this was later. When he went there he heard about these tumor transplantation experiments and he knew about the blood group experiments. So apparently it occurred to him that there might be some relationship between the antigens that stimulated the immune system to reject the tumor and the antigens... the blood group antigens stimulating antibodies specific for them by which they... the blood groups were detected. So when he... so he took some inbred strain breeding pairs back into... to London and then gave them to Peter Gorer and said, 'Look this would be a good thing to test whether there is some relationship between the two'. And Gorer did this. Gorer was a pathologist by training and so he was interested in tumors, he was also interested in antigens so it was a good project for him. That was in 1936 and in 1936 he discovered yes, mice have blood groups, and he discovered four antigens and gave them names. Roman I through Roman IV.  And also discovered that... well I think this is not important... but described these four antigens. One of these antigens turned out to be H2. The II... I, II, III, IV... the II turned out to be what would later be called H2. So actually H2 was discovered in 1936, which is the year in which I was born. So it was written in my stars I guess to become involved in... with H2.