Page:Popular Science Monthly Volume 86.djvu/99

Rh function had been allotted. The discovery of the glycogenic function of the liver struck a heavy blow at the whole theory of functions.

No less pregnant of future discoveries was the idea suggested by this newly found out action of the hepatic tissue, the idea happily formulated by Bernard as "internal secretion." No part of physiology is at the present day being more fruitfully studied than that which deals with the changes which the blood undergoes as it sweeps through the several tissues, changes by the careful adaptation of which what we call the health of the body is secured, changes the failure or discordance of which entails disease. The study of these internal secretions constitutes a path of inquiry which has already been trod with conspicuous success and which promises to lead to untold discoveries of the greatest moment; the gate to this path was opened by Bernard's work.

In 1856, one year before Claude Bernard obtained glycogen in the pure state, the doctrine of internal secretions was put upon a firmer basis through the important experiments of Brown-Séquard and Moritz Schiff. Only a year after the publication of Addison's great monograph on suprarenal disease, Brown-Séquard succeeded in producing an exaggerated form of Addison's disease in different animals by removal of the suprarenal capsules, the symptoms being the same and the result of the experiment being rapidly and invariably fatal. If only one capsule were removed, there was no appreciable change in the normal animal, but death would rapidly supervene upon removal, even after a long interval of time, of the other capsule. Furthermore, Brown-Séquard found that a transfusion of normal blood into the veins of an animal deprived of its suprarenal capsules will prevent its death for a considerable time, indicating that the normal suprarenal capsules secrete a material which is necessary for the maintenance of life. In the same year (1856), Moritz Schiff, of Frankfort on the Main, found that excision of the thyroid gland in dogs is invariably fatal. His results were forgotten for over twenty-five years, when, following the description of myxœdema by Gull (1873) and Ord (1878) and the first excision of the thyroid gland for goitre by the Swiss surgeon, Theodor Kocher (1878), J. L. Reverdin of Geneva showed that an "operative myxœdema" is produced in man by complete excision of the thyroid (1882). This was confirmed by Kocher, who found that total thyroidectomy is followed by a "cachexia strumipriva" or "cachexia thyreopriva." Hereupon Schiff returned to the charge and, in 1884, published the results of 60 thyroidectomies in dogs, all fatal, with such significant symptoms as tremor, spasms and convulsions. What is more to the purpose, Schiff demonstrated that these symptoms could be prevented by a previous graft of a portion of the thyroid gland beneath the skin or into the peritoneal cavity of the animal, or by the injection of thyroid juice into a vein or under the skin, or by the ingestion of thyroid juice or raw thyroid by the mouth. This led in time to the remarkably successful treatment of myxœdema by means of thyroid