THE METABOLISM OF CARBOHYDRATE 435 



dextrose in the organism. Conversely, removal of the posterior lobe 

 is said to endow animals with an increased tolerance to excessive 

 amounts of dextrose (see later, p. 522). 



The interrelation and exact mode of action of all these glands 

 requires far more work before any clear and dogmatic statements can 

 be made in regard to their control of carbohydrate metabolism. 



8. " Salt " Glycosuria. Glycosuria follows the injection of 1 per 

 cent, solution of sodium chloride into the blood of an animal. It has 

 been suggested that the salt renders the kidney cells more permeable 

 to sugar. On the other hand, it is quite possible that the glycogenic 

 centre in the medulla is affected. Injection of a soluble calcium salt 

 (ionized calcium) abolishes the glycosuria induced by the sodium ion. 



Diabetes Mellitus. In this disease, or rather in the collection of 

 pathological conditions grouped under this name, the patient generally 

 passes much sugar in the urine. Cases may be described as mild 

 and severe. In the mild cUses, the glycosuria disappears when carbo- 

 hydrate is removed from the diet, the trouble being due only to 

 defective storage or oxidation of sugar. In the severe cases, the 

 sugar cannot be thus removed from the urine. It is probable that 

 the less severe of such cases derive sugar from protein only, whereas 

 the more severe and rapidly fatal cases derive it from fats also. The 

 acetone bodies which often occur in the urine of diabetics are dis- 

 cussed elsewhere (Urine, p. 468). Under the name diabetes are classed 

 glycosurias of various origin neurogenous, hepatogenous, pancreatic,, 

 etc. a great number of such, but by no means all, being due to some 

 defect in the pancreatic control of carbohydrate metabolism. For a 

 full discussion, textbooks of pathology and medicine should be con- 

 sulted. The tests for sugar in urine are dealt with under Urine 

 (p. 467). 



