O. G. Mason is best remembered, however, for his clinical medical photography accomplished during his forty plus years at Bellevue Hospital. He was frequently called upon to provide illustrations for monographs published by leading physicians and surgeons associated with the hospital and its medical college, including Lewis Albert Sayre, John Call Dalton, and Francis Delafield. His most notable photographs appeared in the great photographic dermatology atlases written by George Henry Fox.
O. G. Mason is primarily remembered for his clinical medical photography carried out at Bellevue Hospital over a period of more than forty years. He was often asked to provide illustrations for monographs authored by leading physicians and surgeons associated with the hospital, including Lewis Albert Sayre, John Call Dalton, and Francis Delafield. His most notable photographs were included in George Henry Fox's influential dermatology photo atlases.