In our efforts to interpret these events and put it in some scientific context, after having ruled out the possibility that the cells were running out of some important nutrient that they couldn't produce in cell culture, and after eliminating virtually any explanation we could think of in conversations with a bunch of people at the Institute – most of them knew about our work as we did of theirs – I don't recall with... with certainty who first proposed an answer, whether it was me or someone else is a bit foggy, but essentially unimportant because whoever, whether it was me or someone else... we became excited about the explanation that this had something to do with ageing. And the reason we thought that was a good idea is because we could not exclude it. And it made... since ageing, the biology of ageing, was in a very primitive area of research, nobody knew virtually anything about it at that time, we thought this was a good way out of the trap of explaining, putting our work in some context. That's how insignificant we thought that interpretation was and indeed it was stated in the original paper. Of course, my next paper that I authored alone pretty much convinced us, or came close to convincing me at least, that we were being told something about the ageing phenomenon in respect to this event but we didn't take it all that seriously in the first paper.