Henry S. Tanner after 21 days of his 40-day fast at Clarendon Hall, New York City. Photograph, 1880.

Dr Henry S. Tanner, a Minneapolis physician born in England, responding to a challenge from Dr William A. Hammond and the New York Neurological Society, fasted in New York City for forty days, from 28 June to 6 August 1880, and received $1,000 prize money. His aim was to demonstrate the therapeutic value of abstinence from food. He subsequently wrote and lectured on fasting. He died in San Diego, California, in 1919. See Linda Burfield Hazzard, Scientific fasting: the ancient and modern key to health, New York 1927, part 1