"It (The Brains Trust ) owed its popularity to the dramatic contrast of the three principal performers. Cyril Joad (C.E.M. Joad ) (always known as Professor Joad though he never occupied a chair) was a quick-witted, bumptious disciple of Bertrand Russell, who treated The Brains Trust as a competitive sport and a chance for showing off. Julian Huxley took the whole thing seriously, and was irritated to the point of peevishness by foolish answers, especially if they were propounded by the third member of the group, known as Commander Campbell. Julian could not see that some kind of Sancho Panza was a necessary contrast to himself and Joad. Campbell was a genial imposter, who had in fact been to sea and was said to have been a purser. He had been co-opted at the last minute because the man the BBC had invited couldn't be found, and it was said that Campbell was a man who could talk about anything. It turned out to be a stroke of genius. When we were asked to define the word 'allergy', he got in before Huxley and said "I suffer from an allergy. If I eat marmalade my head steams." Huxley and Joad were furious, but next week Commander Campbell said "I've had 200 letters from people whose heads steam when they eat marmalade". (Kenneth Clark, ''The Other Half: a self-portrait'', London, 1977, pp.47–48.)