Having got to this stage of — in the early '70s — of extensive analysis of the genetics of this beast, an extensive amount of work on the biochemistry beginning, the anatomy going ahead, the development going ahead, the whole of... techniques of knocking out neurones by laser abrasion, knocking out cells by laser abrasion and having a way of studying development, one felt the ship was, was at sea but it was very unclear where it was heading. And if we want to do something more definitively, which is get down to the molecular basis, we had to have some new technique.