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Summary Article: Bowditch, Henry Pickering
from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

US physiologist who investigated the control of the contraction of cardiac muscle, confirming that the cardiac muscle has an inherent rhythmical power that acts automatically (the myogenic theory) and determining that a certain minimum amount of stimulus is needed to induce a contraction of the cardiac muscle.

Studying cardiac muscle He spent many years investigating how heart muscles contract, using frog cardiac muscle as an experimental model. Since a frog's heart continued to beat for some time after it was extracted from the animal, Albrecht von Haller had earlier proposed the myogenic theory, suggesting that cardiac muscle possesses an inherent rhythmical power that acts automatically.

Bowditch demonstrated that passing fluid under pressure into the apex of a frog's heart produces rhythmical activity even in the absence of its usual nervous stimulation. He could obtain the same result by applying a constant electrical current to the muscle. These results supported the myogenic theory and led Bowditch to propose the ‘all-or-nothing’ rule governing the contraction of cardiac muscle. This rule specifies that a certain minimum amount of stimulus is needed in order to induce a nerve impulse and subsequent muscle contraction. Any stimulus below this set amount has no effect, no matter how long it is applied to the muscle.

Life Bowditch was born in Boston and studied at Harvard Medical School. He obtained his medical degree 1868 after serving in the American Civil War, in which he fought and was wounded. After graduating, he went to work with eminent physiologists in France and Germany before returning to Harvard to teach physiology. He became dean of the physiology department at Harvard 1883 and founded the prestigious American Physiological Society 1887.

He also worked on how spinal reflexes in the body (such as the knee-jerk reflex) work, and on the role of nutrition and other environmental factors on growth in children.

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