PANCREAS 623 



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, fit 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. I But no evidence of the existence of any such 

 substance has been obtained, and the transfusion into a normal 

 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 of 

 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- 357)- 



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 

 (p. 545), has been asserted by some observers and denied by others. 

 A great production of sugar from proteins (i.e., from amino-acids) 

 has been demonstrated, but it is quite possible that just as much is 

 produced from this source in the normal organism, although here 

 its formation is masked by a corresponding utilization. 



ghe clearest evidence that the pancreas produces something of 

 i importance in carbo-hydrate metabolism has been obtained 

 by experiments in which animals were united Jn such a way 

 that substances could pass from one to the othc3)(parabiosis, see 

 Chap. XIX.). When two young dogs were so uniteoand the pancreas 



