This article contrasts two American Physiological Societies, one founded near the beginning of the nineteenth century in 1837 and the other founded near its end in 1887. The contrast allows a perspective on how much budding neuroscience had developed during the nineteenth century in America. The contrast also emphasizes the complicated structure needed in both medicine and physiology to allow neurophysiology to flourish. The objectives of the American Physiological Society of 1887 were (and are) to promote physiological research and to codify physiology as a discipline. These would be accomplished by making physiology much more inclusive than traditionally accepted by raising research standards, by giving prestige to its members, by providing members a source of professional interchange, by protecting its members from antivivisectionists, and by promoting physiology as fundamental to medicine. The quantity of neuroscientific experiments by its members was striking. The main organizers of the society were Silas Weir Mitchell, John Call Dalton, Henry Pickering Bowditch, and Henry Newell Martin. The objective of the American Physiological Society of 1837 was to disperse knowledge of the laws of life and to promote human health and longevity. The primary organizers were William Andrus Alcott and Sylvester Graham with the encouragement of John Benson. Its technique was to use physiological information, not create it as was the case in 1887. Its object was to disseminate the word that healthy eating will improve the quality of life.