Mental blow or shock is further capable of inducing chronic changes in the nervous system, leading to the development of at least one special disease, namely, diabetes, the definition of which is given at page 65. I notice diabetes as originating from men tal shock once more because it affords so remarkable an illus tration. The disease is one which is ordinarily known as being attended with a profuse discharge of renal secretion, such dis' charge constituting, in fact, the marked demonstration of the dis ease. For ages past it has been known that mental disturbances determinately influence this secretion, rendering it sometimes co pious and pale, and at other times causing it to be charged with deposits of pale pinkish color. Now we know that diabetes, in which a large amount of grape-sugar is imported into the secre tion, may be induced by mental as well as physical shocks affect ing, primarily, the brain. The production of the disease through the mental shock may be actually startling, as in the following instance, which came under my own cognizance. A healthy boy, eleven years of age, was sent by his father, a carpenter by trade, to a wood-yard, to give an order for some timber. In the yard there was chained up a large and savage dog. The child, not aware of this, passed down the yard, and before seeing danger was suddenly set on by the furious animal. He got out of reach of the chained brute, but was so paralyzed by fear he could not for some seconds stir away. He now became faint, was carried home in a state of extreme prostration, and from that hour was stricken of diabetes, from which malady, in three months, he died.
Diabetes is an affection which can be artificially or syntheti cally produced by physical injuries of the cerebral organ. I have shown that it may even be caused, temporarily, by a disturbance in the circulation of the brain, and that men engaged in the art of coloring a ceiling produce, by the act of holding back the head for a long time, a derangement of the cerebral circulation suf ficient, in some cases, to lead to the affection during the time they are at work.
The effect of mental shock, in causing diabetes, will possibly lead to other systemic diseases being traced to a similar cause, and to the connections that exist between physical and psychical influences affecting mankind.