Page:Popular Science Monthly Volume 86.djvu/101

Rh metabolism. In 1886, von Mering produced an experimental diabetes by the ingestion of phlorhizin. In 1889, von Mering and Minkowski obtained diabetes by an experimental excision of the pancreas. The histological, pathological and clinical studies of E. I. Opie (1901), L. W. Ssobolew (1902) and W. G. MacCallum (1909), indicated that the source of this pancreatic glycosuria is to be found in a specialized group of cells, called the islands of Langerhans. Thus it would appear that the pancreas possesses an internal secretion-as well as a digestive function. The discovery of iodothyrin in the body by Eugen Baumann, in 1896, suggested the relation of the thyroid gland to iodine metabolism and an adjoining pair of ductless glands, the parathyroids, discovered by the Swedish anatomist, Ivar Sandström, in 1880, would appear, from experiment, to have an influence on calcium metabolism. In 1891. Eugen Gley showed that where excision of the thyroid is negative in certain animals, these animals will speedily die if the four parathyroids are also removed. In 1892, the Viennese surgeon Anton von Eiselsberg made a successful transplantation of the parathyroid glands from the neck to the abdominal wall in a cat and showed that tetany may be produced upon its removal from this site. Subsequent experiments by H. Leischner (1907) and by W. S. Halsted, at the Johns Hopkins (1909), showed that the production of tetany is really due to removal of the closely adjacent parathyroids. These observers found as in Schiff's experiments, that the tetanoid spasms will be abolished upon injection of an extract of the gland or after parathyroid feeding; or upon regrafting the gland itself. In 1908 W. G. MacCallum and C. Voegtlin showed, at the Johns Hopkins Hospital, that tetany may be abolished by treatment of the patient with calcium salts. Another ductless gland, the pituitary body, has been shown to have a marked relation to carbohydrate metabolism and, like the suprarenal and parathyroids, to be essential to the maintenance of life. The pituitary body, which the anatomist Soemmering called the hypophysis cerebri in 1778, was, as we have seen, regarded as an organ discharging a mucous secretion into the nostrils until this theory was disproved in the seventeenth century. This structure consists of an anterior glandular lobe (pars anterior) and a smaller posterior lobe (pars nervosa), the whole being connected with the floor of the fourth ventricle of the brain by means of a stalk or infundibulum. In 1838 the embryologist Rathke showed that the anterior lobe is developed by the protrusion of an ectodermal pouch (Rathke's pouch) from the roof of the pharynx and is made up of epithelium derived from the buccal cavity. It lies in the embryonic rest of Rathke's pouch "as a ball is held in a catcher's mitten" (Gushing). The posterior lobe is made up of nervous tissue and is derived from a corresponding prolongation from the anterior