PANCREAS 63? 



after total extirpation, and the resemblance to human diabetes 

 becomes closer. The animals rapidly deteriorate if supplied with 

 too much carbohydrate, while they may be kept alive for a long 

 time in good health if the limit of their tolerance for carbohydrates 

 is not exceeded (Thiroloix, Allen et al.}. 



Although as yet we are ignorant of the precise manner in which 

 the pancreas influences the metabolism of the body, it is impossible 

 to doubt, in view of the facts we have mentioned, that, like the liver, 

 in addition to carrying on the exchanges necessary for the prepara- 

 tion of the ordinary or external secretion, the gland has other 

 important relations with the circulating fluids, giving to them or 

 taking from them substances on the manufacture or destruction of 

 which the normal metabolic processes depend. It has been sug- 

 gested that the pancreas neutralizes or renders harmless some 

 toxic substance formed elsewhere in the body, the action of which 

 produces glycosuria. But no evidence of the existence of any such 

 substance has been obtained, and the transfusion into a norma 

 dog of blood from a depancreatized animal, which ought to be laden 

 with the hypothetical toxic material, does not cause glycosuria. It 

 is much more probable that the hyperglycaemia on which the 

 glycosuria depends is caused by the absence of something normally 

 produced by the pancreas, and which is indispensable for the due 

 regulation of the sugar-content of the blood. This something, as 

 already pointed out in discussing pathological diabetes, may be 

 necessary to regulate the transformation of sugar into glycogen, 

 or eventually, it may be, into fat, so that too great a surplus oi 

 sugar does not remain unchanged ; or to regulate the transformation 

 of glycogen into dextrose, and prevent too hasty and too extensive 

 action by the glycogenase ; or to regulate the production of sugar 

 from sources other than the carbo-hydrates ; or, finally, to regulate 

 and to aid in the normal utilization of the sugar in the organs 

 (p. 553). 



While the liver contains less than the normal content of glycogen, 

 its power to form glycogen is certainly not abolished. On the con- 

 trary, there is some reason to think that a great deal of this reserve 

 carbo-hydrate may be synthesized in the diabetic organism, and 

 that the comparative poverty of the hepatic cells in glycogen may 

 be due to rapid glycogenolysis, despite the hyperglycaemia, in 

 response to the insistent demand for sugar on the part of the tissues, 

 which in the midst of plenty are hungry for dextrose on account of 

 their inability to utilize it, or some of its decomposition products, 

 in the normal way. It has indeed been shown by numerous ex- 

 periments that interference with the formation or with the hydrol- 

 ysis of glycogen, although it may be a factor, is not of itself sufficient 

 to explain pancreatic glycosuria. 



Failure in the katabolism of dextrose, as already mentioned 



