Of course, there was awful difficulty and trouble about the writing up of penicillin, and partly because there was a good deal of disbelief about what was the structure of penicillin. But Robinson wrote... Robinson wrote the final paper on the structure, and Robinson does agree with the structure, although he never quite gave up the idea that it was really the oxazolone, and what one saw wasn't quite what he thought one should...

But after that, I was invited over to America - the war had ended - and the Rockerfeller Foundation paid for a fellowship for me to travel to different labs in America, because he thought it good for my education that I should know how far people had got in other places, and also, I could tell people how far I'd got. And it was, I sort of believed in my model more than anything else in the world, pretty well, so I packed it in my suitcase - it took up about half of it, as you can see what it looks like now at Oxford in the Ashmolean. And when I was passing through customs, the officer said, 'Have you got only personal belongings in this suitcase, clothes and so on, I suppose?' and then I said, 'Actually, there are sort of scientific models'. So then he made me show him, you see, so I explained to him what it was, and he thought for a long time over it and then said, 'Well, it may seem very funny to you, but if we just write this down as scientific model, worth less than one dollar, we should get through all right'. So that's what we did.

And the first thing that happened to me, when I got back to Hans Clarke's house, was we met du Vigneaud there, sitting on the sofa. Now du Vigneaud had, as you probably know, worked up this preparation of the oxazolone structure, and shown that the product of this was a penicillin compound with the right activity and all the rest of it. So the first thing he said when he saw me was, 'Are you quite sure you know the structure of penicillin?' And it was quite sort of funny being met by this degree of disbelief at this moment.