Who is the mathematician "Jacques" in this anecdote, which I read on p. 260 of The Mathematical Magpie by Clifton Fadiman, who quotes it from the 1942 memoir The Last Time I Saw Paris by Elliot Paul?
The "album" had a collection of photographs which left little or nothing to the imagination except to make one wonder, when halfway through, what possibly could be left for the remaining pages to portray. To what extent the "album" at Madame Mariette's place made things easier for fading clients I cannot say, but it changed the course of the life of a young Frenchman I knew who was attending the Sorbonne in the early 1920s. Jacques was brilliant but had no ambition and no plans for the use of his excellent mind. He was at school because his parents could pay for it and university life was more carefree and less onerous than a job in a bank or the executive offices of some factory. One day when he was idling away an afternoon at Mariette's, in perusing the "album" he was struck with the infinite number of variations contained in a few simple acts involving two, three, and in extreme cases four parties. He began thinking in terms of numbers: permutations and combinations. That same evening he plunged avidly into his neglected mathematics textbooks and soon led his class in higher algebra and integral calculus. Today he is one of the most distinguished theoretical mathematicians in London and freely admits that he owes it all to Mariette.