The soil mechanics at Imperial was very nice, I... I enjoyed it but, I didn’t really care about soil mechanics and my friends all knew that I really wanted to change. And a friend of mine in South Africa — Wilfred Stein — was getting married, and he knew I wanted to get out of... out of soil mechanics and when he was getting married in a town that wasn’t his own — wasn’t his hometown — they said, ‘Get out of the house for the day’ and he went to the local library, and he came across a paper in which Michael Swann and Murdoch Mitchison — two distinguished biologists in Britain — were looking at how cells cleaved, how... how cells, when they divided, there was a constriction and how that constriction developed. And they were looking at the mechanical properties of cells. And he was coming to London — to King’s College — to work on cell biology. And he wrote me this letter that changed my life and said  ‘Lewis, this is what you should do’. And I went to see his professor, Professor James Danielli at King’s College while I was doing soil mechanics and said, ’Really, I’d like to change, and can I come and do a problem here?’ And he said, ‘Hold on a second, you’ve been working on soil mechanics’. And he sent me to see Bernal who was at Birkbeck – the very famous scientist Bernal – because Bernal was interested in the origin of life and it possibly being related to clays and he thought that I would know something about clays. He was very nice to me, he spoke to me for about two hours, I didn’t understand a word and it wasn’t a subject that I was interested in and I tried to persuade Danielli, with... — and I successfully persuaded — that he could take me on as a PhD student. And also very fortunately, the Nuffield Foundation in those days were offering some scholarships for people to change from the physical sciences to the biological sciences and they gave me a scholarship.

So I could then... in 1955, I started studying cell biology at King’s College and doing a PhD and looking at how cells cleaved... how they divide… the mechanics of the membrane in relation to how they divided in...  in... into two. So that... that was quite hard work because also I knew absolutely nothing about cell biology or biochemistry, but... but it went okay and there was an apparatus that I had and I would go to marines... I went to a marine station initially in Wales at Bangor and the cells that I worked on were the early cells of the sea urchin embryo, because after fertilisation of the egg, the cell divided into two and they were easy to get hold of and I could study them and were looking at their mechanical properties. And then, I didn’t want to continue to work at Bangor, I spent one summer working at a marine station in Scotland and I was a bit bored, and then I saw that many people who were studying sea urchins were working in Sweden at a marine station at Kristineberg and I decided to go to Kristineberg to pursue my studies, and I went there and Sweden was magic... was absolutely magical. The Royal Society gave me little travel grants to go there and while I was working on... or trying to work out how cells cleave, I met a Swede — Tryggve Gustafson — who was working on how sea urchin embryos actually developed. And he was taking movies of them. Well first of all... so I’d started in 1955, my first scientific progress, was... I worked with someone at the Chester Beatty, a man called Howard Mercer, who was an electron microscopist and I... I fixed some sea urchin... early cleaving sea urchin embryos and he did electron microscopy of them and we could see in the furrow where... where the cell cleaved, we could see a band and we said: ‘This is the contractile region’. So that was my first paper, my first real scientific paper. I can’t remember, in 1954 or something like that, I can’t remember. No... no, that’s not correct... that’s not right, 1956 or something, I can’t remember. No matter, I worked anyhow then on how cell... It was 1958. So my first real paper in cell biology was a short paper with Howard Mercer on... on the electron microscopy of cleaving eggs. And during this time, I worked out a model for how the cell cleaved and it’s called the Astral Relaxation Theory and it’s a little difficult to describe, but... but here’s the cell and there are two little regions in the cell at the end of the mitotic apparatus and I... from my studies and looking at the mechanical properties of the cell, the cell rounded up before cell division, due to tension in the membrane and then these asters cause the poles to relax, reduce their tension and so the middle bit constricted and that’s called the Astral Relaxation Theory, and I published this in 1960. It’s taken about 40, nearly... it’s taken nearly 50 years for this theory to be taken seriously... then it is now in the textbook. It’s not the only theory but it took a very long time for people to take it seriously. But I did apply my engineering and got my PhD in 1960, the same time as that I published... that paper.