THE METABOLISM OF FATS AND CARBOHYDRATES 145 



complete loss on the animal's part of the power to oxidize 

 dextrose. In other words, a process not occurring in the 

 pancreas at all, but in the tissues at large, is arrested by the 

 removal of this gland. What is the natural explanation of 

 this condition? Evidently that something proceeds from 

 the pancreas through the circulation to other parts of the 

 body, without which the cells in general are incapable of 

 decomposing the sugar. 



This imperfectly known product of the pancreas is an 

 example of what has been referred to as a hormone. One 

 is tempted to think of it as an enzyme, but it cannot be 

 accurately described by this word. If it were a typical 

 enzyme we might expect it to cause the destruction of 

 sugar in solutions to which it has been added. No marked 

 disappearance of sugar occurs when the experiment is 

 made. In view of this it is wiser not to commit ourselves 

 as to the precise character of the body in question. The 

 fact seems to be that neither the pancreatic extract by itself 

 nor an extract of muscle will particularly promote the 

 oxidation of sugar, but that a combination of the two is 

 necessary. 



Diabetes. If, owing to a lack of the pancreatic hormone, 

 the ability to utilize sugar is lost, the continued absorption 

 of carbohydrate will raise the percentage in the blood, with 

 the result which always ensues under this condition. The 

 kidneys will steadily excrete the surplus sugar. Unlike 

 alimentary glycosuria, this overflow of sugar will not be 

 limited to times of free feeding with carbohydrates, but 

 will attend the ingestion of the most moderate amounts. 

 (As a matter of fact, sugar will still be excreted when 

 carbohydrates are excluded from the diet and in fasting. 

 The explanation of this fact must be deferred to the next 

 chapter.) The difficulty of keeping up nutrition when the 

 cells can make no use of glucose will be evident in a measure 

 even at this point, and we shall find additional reasons 

 later. 



Whether human diabetes is necessarily associated with 

 some disorder of the pancreas cannot be stated with cer- 

 10 



