THE PANCKEAS AS AN EKDOCKIN GLAND 731 



kidney of the nature of the primary glomemlar injury. Moreover, the 

 hydropic or vacuolar degeneration of the islets upon which Allen 'lays 

 so much stress as a positive diagnostic sign of diabetes is probably, as he 

 himself recognizes, not an expression of diabetes itself but of cellular de- 

 generation due to diabetes or is possibly glycogen or fat deposit. It is, in 

 that case, of less diagnostic value in the pathologic diagnosis of diabetes 

 than is the glycogenic vacuolation of the loops of Henle in the kidneys. 

 This occurs only in association with glycosuria, but the islet degeneration 

 is found when no glycosuria is present. 



Heredity appears to be an important factor in certain cases. The 

 familial occurrence of diabetes is well known. It may, in such diabetic 

 families, be associated with other constitutional peculiarities, as the gouty 

 or arthritic constitution, or with other endocrin-complexes (thyroid, pitui- 

 tary). In many of these familial cases the pancreatic pathology is indi- 

 vidual (agenesia or hypoplasia of the islands, absence of inflammatory 

 changes) . 



Considering the broader conception of diabetes as an endocrinopathy, 

 the etiology of the disease becomes more complicated and of greater pos- 

 sible variety. Lesions of the sympathetic, hypophysis, thyroids and 

 adrenals, as well as of the pancreas, must be considered in the etiologic 

 problem. Disturbances in any other member of the endocrinal complex 

 concerned with carbohydrate metabolism may throw upon the pancreas a 

 greater functional load leading ultimately to exhaustion, unstable his- 

 togenic equilibrium, lowering of resistance, and nutritive disturbances 

 that ultimately express themselves in morphologic and chemicophysical 

 changes of the islets, or of islets and parenchyma. Such a functional dis- 

 turbance of the organ might even determine the occurrence of secondary 

 or terminal infections of the pancreas, or increase its susceptibility to 

 a generalized infection like syphilis. 



Conclusion 



That the pancreas is a gland of internal secretion is now universally 

 accepted as a firmly established fact of physiology and pathology. Of the 

 nature of this internal secretion we know nothing but that it is essential 

 to the carbohydrate metabolism and is apparently of the nature of a hor- 

 mone inhibiting the utilization of sugar ; and is antagonistic to the secre- 

 tion of the adrenal medulla, and influenced by the internal secretion of 

 the thyroid and probably by that of the hypophysis, while its nervous regu- 

 lation is furnished by the sugar-center of the medulla and the sympathetic 

 system. 



The majority of the writers on the pancreas regard the islets as the 

 seat of this hormone production ; a minority hold that both islets and acinar 

 tissue are concerned in the production of an internal secretion. 



