Page:Popular Science Monthly Volume 86.djvu/150

The importance of the subject in relation to clinical medicine has been well emphasized by Professor L. F. Barker."^[1]

In how far those sudden and violent excitations of the autonomic nervous system which accompany strong emotions are due to the intervention of the glands of internal secretion, and in how far they depend upon direct neural conduction from the brain, we are as yet but ill-informed. I need only remind you of the vasodilatation of the face in the blush of shame, of the stimulation of the lacrimal glands which yields the tears of sorrow, of the palpitation of the heart in joy, of the stimulation of the sudoriparous glands which precedes the sweat of anxiety, of the stimulation of the vasoconstrictors, the pupil dilators and the pilomotors in the pallor, mydriasis and goose-skin of fright, to illustrate some of these violent autonomic excitations. While we do not yet understand the exact mechanisms of association among the activities of the cerebrum, the endocrine glands and the reciprocally antagonistic autonomic domains and their end-organs, we can begin to see the paths which must be followed in order that more exact knowledge may be gained.

The balance maintained normally between the two antagonistic systems is one of the most interesting of physiological phenomena. Think, for example, of the rate of the heart beat—how constantly it is maintained at a given level in each individual when the body is at rest; the impulses arriving through the vagal system just balance those arriving through the sympathetic system, so as to maintain a rate of approximately seventy-two beats per minute. And a similar balance is maintained in other autonomic domains (e. g., pupils, bronchial musculature, gastric glands, gastro-intestinal muscle, sweat glands, bladder muscle, etc.).

This equilibrium is all the more remarkable when one considers how frequently it is temporarily upset in the exercise of physiological function. The play of the pupils with varying light, the watering of the mouth at the smell of savory food, the response of the heart to exercise and emotion, the flow of gastric juice on adequate stimulation, the opening of the bile duct at the call of the chyme, the transport of the colonic contents through one third of the length of the colon through one vehement contraction every eight hours, the sudden relaxation of the sphincter and contraction of the detrusor of the bladder in micturition, the violence of contractions in the domain of the N. pelvicus in parturition in the female and in the ejaculation in the male, come to mind at once as examples of sudden physiological overthrow of balance.

Another set of correlations advanced by the Vienna school is connected with the causation of diabetes. Eppinger, Falta and Rudinger regard the thyroid, pituitary and adrenals (chromaffinic system) as the accelerators or mobilizers of glycosuria, in that all three increase exchange or metabolism of proteins, the adrenals mobilizing carbohydrates and the thyroid increasing fat absorption. The pancreas and the parathyroids, on the other hand, are held to be inhibitors of glycosuria, retarding protein metabolism and restricting the mobilization of carbohydrates. Diabetes following excision of the pancreas is held to be due to the mobilizing power of the adrenal hormone on the

1. L. F. Barker, Canadian Med. Assoc. Jour., Montreal, 1913, III. See, also, W. B. Cannon, "The Interrelations of Emotions as Suggested by Recent Physiological Researches," Am. Jour. Psychol., Worcester, Mass., 1914, XXV., 256-282.