Studies on the Conditions of Activity in Endocrine Glands Y. the Isolated Heart as an Indicator of Adrenal Secretion Induced by Pain, Asphyxia and Excitement

Knowledge of the conditions under which the endocrine glands become active or manifest increased activity is important for several reasons. Such knowledge is valuable as an extension of our acquaintance with a realm of physiology which is still largely unexplored. It permits correlated studies of other bodily processes which vary under the same conditions. And it gives a basis for inquiry into the functions performed by the endocrine glands, for the service of an organ should reasonably be looked for in relation to the times of its special activity. With such ideas in mind, the present series of studies was entered upon. In two papers published in 1911, Cannon, in collaboration with de la Paz (1) and with Hoskins (Z), brought forward evidence that the adrenal medulla was stimulated to secrete by emotional excitement, by “pain” and by asphyxia. Adrenal secretion had previously been proved to be subject to sympathetic stimulation by way of the splanchnits; and as excitement, pain and asphyxia were conditions well recognized as accompanied by sympathetic activity (manifested, e.g., by inhibition of digestive functions), an attendant adrenal secretion was naturally to be expected. In a series of papers which followed these first two, experiments were described showing that adrenal secretion was serviceable in lessening muscular fatigue (3) and in accelerating coagulation of the blood (4). An interpretative paper (5) pointed out that excitement, pain and asphyxia were conditions which in natural existence would commonly be associated with struggle, and that the visceral changes, including adrenal secretion, which accompany these three states, would be useful in great muscular effort. This interpretation presented a new view of the function of the sympa-