I did one mouse experiment which was- I- had something to do with the future. It was good. Which was to show that if you irradiated mice, you got a better transferred response. What was the response? I've actually forgotten, but some immune response. They- the irradiation helped a lot. And that led me to go and spend a couple of months in- in Harwell, in the Atomic Energy Research establishment where there was a Medical Research Council unit led by John Lightet and I did work in parallel with work which was done there by Ford who showed- they showed that in an irradiated animal you could re-colonise the spleen as judged by chromosome markers. And I showed that if you irradiated an animal you could re-colonise the spleen as judged by transplantation antigens. It was an all transplantation antigen tests, which was almost all anyone knew about apart from these chromium plated red cells, and they both get the same result This was with bone marrow? This was with bone marrow, or spleen, there was enough hematopoietic cells in spleen to do it.