848 PHYSIOLOGY 



5 parts per 1000. This state of hyperglycsemia and the excretion of sugar 

 in the urine persist "even when the animal is completely starved or is fed on a 

 pure protein or protein 'plus fat diet. Moreover, as in phloridzin glycosuria, 

 we find a constant ratio between the sugar and the urinary nitrogen, the D : N 

 ratio being usually about 2-8. The administration of protein food to an 

 animal previously starved increases the output of nitrogen, but increases 

 at the same time the output of glucose. No similar increase in the glucose 

 excretion is observed as a result of the administration of fat. We must 

 conclude therefore that, in the absence of carbohydrate from the diet, the 

 excess of sugar in the blood as well as that escaping by the urine is derived 

 from the breakdown of the proteins of the tissues. On the other hand, the 

 power of the animal to assimilate or utilise carbohydrate is diminished and 

 sometimes entirely abolished, so that glucose administered to a starving 

 animal with pancreatic diabetes may appear quantitatively in the urine. 

 The amount absorbed by the alimentary canal is simply added to the amount 

 which would have been excreted if no food had been given. In most cases, 

 at any rate during the first week after total extirpation, there is apparently 

 still some power of carbohydrate assimilation, since administration of 

 glucose causes a transitory rise in the respiratory quotient (Moorhouse). 

 Glycogen disappears entirely from the liver; but the muscles, especially 

 the heart, may contain a normal or an increased amount of glycogen. There 

 is a rapid wasting of all the tissues of the body, including the 'fats and pro- 

 teins, and finally the animal is destroyed by the accumulation of the products 

 of imperfect oxidation of the fatty acids. 



It is still very difficult to say definitely why removal of the pancreas 

 brings about this condition or what disturbance of metabolism is primarily 

 responsible for it. Two views have been put forward. According to one, 

 the primary disturbance ' is the diminished or absent power of utilisation 

 of sugar by the tissues; according to the second, an increased production 

 of sugar by the liver. There is no doubt that in the diabetic animal the 

 power of utilising carbohydrates is deficient. This is shown by the low 

 respiratory quotient and by the fact that administration of glucose to 

 the animal causes an almost corresponding increase in the amount of 

 glucose excreted in the urine. But the loss of power of utilisation is not 

 absolute, at any rate in the first week of the disorder. Administration of 

 glucose causes a slight and temporary rise in the respiratory quotient, 

 and if 20 gins, of glucose be administered, it is often possible to recover 

 only about 15 to 18 gins, from the urine. Moreover the increased amount 

 of glycogen in the heart muscle of diabetic dogs points to a persistent power 

 of assimilation of sugar by this organ. The heart from a diabetic animal, 

 if fed with its own blood, can be shown to use up not only the sugar circu- 

 lating in the blood but also its store of glycogen, and this utilisation is 

 especially marked if the heart be made to work excessively by raising the 

 arterial resistance and administering adrenaline ; but taken as a whole the 

 power of utilising glucose is very inferior to that possessed by normal 

 animals. One of the most striking features of the condition caused by total 



