IN 1889, AT A MEETING OF THE SOCIÉTÉ de Biologie of Paris, a physiologist named Charles-Édouard Brown-Séquard described the results of an experiment he had recently performed on himself. He had painstakingly mixed an elixir of blood, semen, water, and “juice extracted from a testicle, crushed immediately after it has been taken from a dog or a guinea-pig,” and then injected the fluid into his arms or legs 10 times over a three-week period. His goal, he told the audience, was to see if he could reverse some of “the most troublesome miseries of advanced life.”
Brown-Séquard, who was in his seventies, had a shiny pate, a halo of snow-white hair, a neat beard, and bags under his eyes—not unlike the Travelocity gnome. He had been a distinguished and prolific…