We put a lot of work into viruses, because the retro viruses were coming into prominence at that time as causal agents of cancer, and so was the small DNA viruses SV40 and its related viruses. The connection with cancer certainly wasn't clear at that time and we had two hopes. One was that the immunology might contribute to the understanding of how these viruses caused cancer, that was one contribution that we could make, and vice versa, that the anti-viral response would provide a useful probe into the immune system. And I think, roughly speaking, the upshot was that both of those views had- well, they led- they were in the right direction, that's the way things worked out. The contributions which we managed to make to them were quite small but you know, there was a small flourishing community of- of viral immunologists.