“Soup” or “sparks”: Alexander Forbes and the synaptic transmission controversy

Department of Philosophy, Baylor University, Waco, Texas, USA

On 29 April 1939, a symposium was held in Toronto, under the auspices of the American Physiological Society, to explore the controversy over transmission of the nerve impulse across the synapse. The then prevailing theory of synaptic transmission was the electrical conduction of a nerve impulse across the synapse. One of the participants at the symposium was Alexander Forbes of the Harvard Medical School, who gave the concluding address. During the late 1930s, the electrically oriented Forbes incorporated the notion of chemical synaptic transmission into his understanding of neurophysiology, although he remained ambivalent about the role of chemical transmitters in synaptic transmission. He blithely referred to them as the “soup at the synapse,” as compared to the “sparks” of electrical conduction. In his symposium paper, ‘Problems of Synaptic Function,’ Forbes compared the controversy of neurophysiologists over synaptic transmission to that of physicists over the nature of light. Forbes suggested that “the electrical and chemical theories of synaptic conduction may also prove not to be mutually contradictory after all” (Journal of Neurophysiology, 1939, p. 470). This symposium served as a watershed, after which the chemical theory of synaptic transmission gained prominence among neurophysiologists. In this paper, I examine the rise of the chemical theory of synaptic transmission from 1921 to 1939 and Forbes’ role in resolving the controversy.

Session X
Friday, 8 July 2005, 3.30 - 4.00 pm

Tenth Annual Meeting of the International Society for the History of the Neurosciences (ISHN) and
Tenth Meeting of the European Club for the History of Neurology (ECHN)

St. Andrews, Scotland, 2005