The experiments which you and I did were to take- we didn't use thymectomy to identify T-cells, we just took cells and immunised them against a protein- T-cells against a protein- in, fundamentally, the same way as Benacerraf and Jale had done, and show that, although these cells would not themselves make a bigger response to the dinitrophenol group, if it was attached to the same protein, they would help bone marrow-derived cells to make that response. So, it was a matter of combining primed T-cells with primed B-cells and then they would get the together and co-operate. And you had to do that all in mice which had the same- which were histocompatible which wouldn't reject other cells. Klaus Rejewsky experiment almost takes too long to explain that here, I think. It was a very important experiment at the time. It involved a tetrameric protein, lactic dehydrogenase and by assembling different subunits of this protein, he could show essentially the same things that we'd shown in London. And the work in London went ahead very fast when Klaus Rejewsky arrive to work with us, didn't it. Our- I think our special contribution there was to show, for the first time, that T-cells could be recognised, not only by their origin, by taking thymus cells and injecting them into another part of the mouse and messing around with them there, but it all must be thymus-derived cells. You could take them from the normal mouse and recognise them by an antibody, and the antibody was one which Arnold Reif had discovered a little bit before, and he called- The antigen was Thy-1, and it turned out that this particular self-protein was present on lymphocytes only on T-derived cells, thymus-derived cells. And then you could do all these transfer experiments. You could use that antibody to- if you showed to- It's ridiculous that I'm telling you about this, but I'm speaking to the camera. You're not telling me. Yes, exactly. That antibody could be used to stop the thymus-derived cells working, but- and thus showing that without them the B-cells wouldn't work.