HUMAN DIABETES 531 



splitting of the long hexose chain, rather than in the oxidation 

 processes themselves. 



HUMAN DIABETES 



Diabetes, being characterized by a long-continued glycosuria, 

 we may imagine it to be due to any or all of the causes mentioned 

 in the preceding discussion. As a matter of fact, however, it 

 is in most cases related more closely to pancreatic glycosuria 

 than to the other forms. 



Diabetes from an increased permeability of the kidneys, analogous 

 to phlorhizin glycosuria, has not been established as a definite 

 condition in man, although its existence has been suspected and 

 urged more than once. On the other hand, the development in 

 a diabetic of renal lesions, especially chronic interstitial 

 nephritis, may greatly reduce the excretion of sugar in the 

 urine. 



True diabetes from excessive consumption of carbohydrates is, 

 of course, out of the question, but often in its earliest stages 

 diabetes presents the symptom of glycosuria only when excessive 

 quantities of carbohydrates are taken in the food. Diabetes 

 from overproduction of sugar in the body is also unknown 

 the abnormally great formation of sugar from proteids (and 

 probably from fats) that occurs in diabetes, is secondary to the 

 loss of sugar and not primary. 



True diabetes may, however, result from purely nervous 

 causes, exactly analogous to glycosuria following Bernard's 

 puncture of the medulla. This has been observed in a few 

 instances in persons suffering from tumors, hemorrhages, soften- 

 ing, etc., in the vicinity of the diabetic center. There is also 

 much evidence that in diabetes generally the nervous system 

 plays an active part, and nervous shock, depression, etc., are 

 known to exert an unfavorable influence on the course of 

 diabetes. The favorable therapeutic effects obtained in diabetes 

 with opium have been ascribed to the reduction of nervous 

 excitability. 1 It is quite probable that the discharge of glyco- 

 gen from the liver, which is so marked a feature of diabetes, is 

 brought about by nervous stimuli, similar to those which empty 

 the liver of glycogen when the glycogenic center is irritated. 

 These stimuli presumably arise from the tissues, which are in a 

 condition of sugar starvation because of their inability to 

 utilize sugar, and, therefore, send stimuli calling for more sugar 

 to the glycogen storehouses. 



1 See Meyer, Zeit. exp. Path. u. Ther., 1906 (3), 58. 



