I started working in, with the, with Ernst and Norman Heatley, and Edward Abraham and the rest of them as soon as they began.

[Q] Right.

Of course, they were at that time only working on trying to degrade the molecule and get bits out of it that they could think how they should be put together in, sort of, the usual chemists' way, and we were just helping them find what these bits were by just making cell dimension measurements and... and density measurements and finally, essentially, the molecular weights. And the important point was reached somewhere, I think, in '43, about, where we knew, essentially, what both halves of the molecule were - the penicillamine half with the amino acid, penicillamine, and the sulphur atom then attached, and the... making the thiazolidine ring system, and then the other half, which, effectively, was aldehyde. But they're drawn out there, two halves of them, if you wanted, you know. And, once you had these two halves of the molecule, you just could make up chemical structures for the whole of penicillin.

[Q] And this is on page 310?  

And the two most obvious ones in my memory is that they were drawn out in our lab the same day, but I don't know who of the chemists regards themselves as most important for each, though I know that Robinson had the idea of the thiazolidine oxazolone, and once he got this idea, he never could think of the other idea, which was the beta-lactam idea. The beta-lactam was, in fact, drawn up by one of them. My memory was that it was probably Wilson Baker, but Edward Abraham's memory is that it was himself. And we just kept them both in mind, and the group here at Imperial College and around Heilbron drew up more complicated ones, which were called a trisactic one, and... and there was another, similar one because of the particular derivatives that had been obtained, it had three rings in them to begin with.