CARBOHYDRATES 187 



leads rapidly to death. If a part of the pancreas be 

 grafted subcutaneously before the remainder of the gland 

 is removed, diabetes does not occur, but it supervenes 

 immediately upon the removal of the graft. This shows 

 that the diabetic condition is due not to the nervous 

 derangement incidental to such a severe operation, but to 

 some chemical influence exerted by the gland through the 

 blood-stream. The same fact is shown by the operation 

 of parabiosis. This consists in making a crossed arterial 

 connection between two animals so that their blood becomes 

 mixed. Removal of the pancreas from one then causes 

 diabetes in neither. When pancreatectomy occurs in 

 pregnant animals diabetes is delayed until after parturi- 

 tion, indicating that the foetal pancreas influences the 

 maternal blood. 



The injection of blood from a depancreatised dog does 

 not cause diabetes in a healthy animal. The pancreas 

 therefore does not act by removing from the blood some 

 disturbing element. Analysis of the hver in this condition 

 shows that this organ has lost its power of forming and 

 retaining glycogen. But more important than this is that 

 the tissues have lost the poiver of utilising glucose. This 

 is proved by the fact that on injecting glucose there is no 

 rise in the respiratory quotient. The blood is therefore 

 flooded with sugar, which leaves it only through the 

 kidneys. Concerning the nature of the pancreatic influence 

 upon the glycolytic powers of the tissues nothing definite 

 is known. 



So far we have seen that the rate of formation of glucose 

 by the liver is subject to nervous influences and to the 

 condition of the suprarenal glands, and that the presence 

 of the pancreas in the circulation is necessary both to 

 restrain glucose formation in the hver and to promote 

 glucose utihsation in the tissues. How far do these facts 

 furnish a reply to the question from which we started, 



