was adapted from the story. Sources Lowenstein's development of a "rejuvenation serum" derived from monkeys parallels actual treatments popularised in the early twentieth century, notably those of the Russian-born surgeon Serge Voronoff, who had experimented with injections of extracts from animal glands; in the 1920s he popularised the transplantation into humans of tissue from monkey testicles. References Notes Sources External links Creeping Man, The Adventure of the 1923 short stories Works originally published in The Strand Magazine