This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ... DISTINCTIVE CHABACTBBISTICS OF THE INTERNAL SECBETOBY GLANDS AND THE PRINCIPAL PRODUCTS OF THEIR ACTIVITIES Knowledge of the nature and functions of the internal secretory glands can only be based on the precise determination of the conditions which make of these glands a special system, and then on the discovery of the distinctive characteristics of the products resulting from the activities of these organs. Herein lies the primary and fundamental problem. I. CONDITIONS ESSENTIAL TO INTERNAL SECRETION Three conditions suffice to determine an internal secretion as such, but these three conditions are absolutely necessary: The first is of an histological nature; the second results from chemical considerations; and the third is of a physiological order. That is, the cells of the vascular glands in question must present the characteristics of granular elements and these elements must be in close relation to the efferent vessels of the organ; in these cells and in the venous blood of the gland or in the efferent lymph, a specific substance must be chemically determined; finally, the venous blood of the gland must have the physiological action and properties of this specific substance.1 Undoubtedly, for many of the organs included among the endocrine glands, all 1 For technical reasons which are easily understood, the investigation of specific products in the lymph is even more difficult than in the blood. Up to the present, we have only been able to determine the presence of specific substances in the venous blood of some glands; on the other hand, the attempts that it has at times been possible to make on the lymph have always resulted negatively. (A. J. Carlson and A. Woelfel, "On the Internal Secretion of the Thyroid" (Amer. Jour, of...