698 A. S. WAKTHIK 



5. In cases of human diabetes pathologic changes are found with 

 great frequency in the pancreas and in the islands especially. Some in- 

 vestigators never fail to find changes in the latter that they consider 

 degenerative. 



All of these facts taken into account, together with an immense amount 

 of experimental investigation on the metabolism of the depancreatized 

 animal and on the human diabetic, support the viewpoint that the pancreas 

 is a gland of 'double secretion, producing in its acini the pancreatic juice 

 which passes through its ducts into the duodenum for intestinal digestion, 

 and in its islands an internal secretion which controls an important part 

 of the intermediary metabolism. As to the exact nature of this internal 

 secretion nothing is known, and we also are still in the dark as to the 

 mechanism of its action. It is assumed to be of the nature of a hormone 

 or enzyme which controls (inhibits) the consumption of sugar by the 

 body-cells, or controls the synthesis of glucose into glycogen. Diabetes 

 could, therefore, result from a deficiency of the pancreatic endocrinal 

 secretion, either as the result of a too rapid conversion of glycogen into 

 glucose, or from a failure of the tissue-cells to oxidize glucose, or their 

 inability to fix glycogen. 



While the conception of diabetes as the result of a deficiency in the 

 endocrinal activity of the islets of Langerhans is accepted by the great 

 majority of writers on diabetes at the present time, there exists a minority 

 that does not accept the dictum that there can be no diabetes with a normal 

 pancreas. This view they regard as too one-sided, holding that the internal 

 secretions of the adrenal medulla, the thyroid and probably of the hy- 

 pophysis also take part in maintaining the balance of sugar-metabolism, 

 while a central nervous regulation is furnished by the sugar-center of the 

 medulla (Claude Bernard puncture). From such a point of view there 

 are many theoretically possible causes of diabetes, a failure of the incretory 

 pancreatic function being only one of them. This broader constitutional 

 viewpoint, according to its adherents, receives support in that, in the most 

 severe forms of human diabetes with a history of heredity or familial 

 occurrence, changes in the pancreas and in the islands have not been noted 

 by trained, competent observers, If this is true, and if further studies 

 show cases without lesions of the islets, then it is evident that in explana- 

 tion of such cases we must either assume that there is no primary pan- 

 creatic diabetes, or that there is a one-sided deficiency of the inhibiting 

 factor, or a stimulation of the exciting, or a lability of the depots. The 

 fact that pathologic changes have been found in diabetics in other endo- 

 crin organs, thyroid and hypophysis, gives support also to the theory of a 

 pluriendocrinopathic etiology of diabetes. 



A neurogenic theory in explanation of certain cases of diabetes re- 

 mains also to be considered. 



