As a five year old I encountered a picture of a young man in a rakish hat and a yellow coat, on the wall of a large classroom. There was something instantly intriguing about the image, but it was also puzzling because it represented neither politician nor prince, the usual fare for Australian school decorations. I was eventually told that this was a reproduction of a painting, the artist was Vincent van Gogh, and that the subject was some young Frenchman. On special days we assembled in that room and during the next several years I found myself gazing beyond visiting speakers at the fellow in the yellow jacket. It was almost another fifty years before I felt properly conversant with the portrait and realized that van Gogh's subject, Armand Roulin, was seventeen at the time ofthe original painting and had died at seventy-four during my schoolboy contemplations. In the interim my enjoyment of the works of the Impressionists and Post Impressionists had grown and I occasionally ran into the name of Dr. Gachet, Vincent's last attending physician, in books and catalog essays. The doctor was my entree to the overlapping charms of medical and art [...] 1987 I had the good fortune to participate as a biochemist in the centenary celebration of the Pasteur Institut in Paris.