During my Honours year, I again expanded my interests into large parts of biology, because that's the one thing this... this enables one to do. But I had started to do things in… in cytochemistry, and, in fact, one of the interesting things was to do something which was called the Nadi reaction. Now, the Nadi reaction has, in recent years, come into favour as a measurement of the cytochrome oxidase system. But I can honestly say that I was the first person to discover that. It had been known as the Nadi reaction and it had measured some enzyme called… which was called indophenol oxidase, and what you did was you took these two components, diphenyl diamine, and you put it in and when you had this enzyme, it made this com… it made this blue dye, indophenol blue. And I did a set of experiments which actually proved that this was related to what had then been called... had then been called cytochrome oxidase. Because what I showed… it was mitochondria that gave you the Nadi reaction, all right? And… and I actually wrote a paper on this and published it as part of the annual meeting of the South African Association for the Advancement of Science in 1946, so it goes back a long way.

[Q] It wasn't your first; that was one of your later papers?

Yeah, that was the second... my second paper, yes.