The first significant contribution to the function of the adrenal glands was made by Addison, when, in 1855, he discovered their relation to the disease which bears his name. Stimulated by this discovery, BrownSéquard the following year succeeded in demonstrating that removal of both glands in an experimental animal leads to a marked asthenia of the muscular structures of the body such as characterizes Addison's disease. In 1895 Oliver and Shaefer showed that adrenal extract has a powerful effect on blood-pressure—a fact that was independently discovered by Cybulski and Szymonowicz. It has since been shown that this effect is produced by extracts of the medullary portion of the gland only. It is shared, however, by extracts of chromaffin tissue wherever found.1 Probably the most significant discovery of recent years is that the injection of adrenal extract is exactly equivalent to stimulation of the sympathetic (thoracico-lumbar autonomic) nervous system.