346 THE METABOLISM OF THE CARBOHYDRATES 



into sugar cannot at present be considered. In many of these 

 cases, the glycosuria is only slight, and in few of them has the 

 disappearance of hepatic glycogen, so characteristic of piqure, 

 been described. 1 



Perhaps the most interesting of all these forms of glycosuria is 

 that produced by the intravenous injection of solutions of sodium 



salts, for example of 75-100 c.c. of ^ NaCl 2 every fifteen minutes 



into a rabbit. The glycosuria thus induced can be cut short by 

 injecting solutions of calcium salts (vide* ). Solutions of calcium 

 salts themselves do not cause glycosuria. The action of the 

 sodium is probably on the diabetic centre, and not. as has been 

 supposed, on the renal cells, rendering them more pervious to 

 dextrose. 



It is probable, however, that where a mild glycosuria exists, the 

 sugar may be made to disappear from the urine by causing the ex- 

 cretion of urine to diminish. 3 Thus, it has been stated by Walter 

 that atropin diminishes urine excretion, and that, if it be adminis- 

 tered to animals rendered mildly glycosuric by drugs, it causes a 

 disappearance of sugar in the urine. It may be that it is to depressed 

 excretion of urine that is due the disappearance of sugar from the 

 urine which follows a considerable fall in blood-pressure in dogs 

 rendered glycosuric by vagal stimulation. 



Amongst the most distressing symptoms of Diabetes mellitus in 

 man are great thirst and polyuria. J. P. Sawyer has shown that, 

 in many cases of this disease careful treatment of the stomach (e.g. 

 by lavage) greatly diminishes the thirst, that the polyuria almost 

 disappears, and that the sugar excreted by the kidneys becomes very 

 much less in amount. It is just possible, in these cases, that the 

 glycosuria lessens in amount as a consequence of the diminished 

 excretion of urine ; and that, less carbohydrate being drained out 

 of the blood, much of it, which would otherwise have been excreted, 

 becomes utilised in metabolism, and thus spares the excessive proteid 

 break-down so characteristic of this disease. 



1 Of. Bock and Hoffman, however ( 41 ). 



2 m means a sixth normal solution, i.e. the molecular weight in grm. 

 6 



divided by six dissolved in 1000 c.c. water. 



3 Conversly, by administering diuretics to glycosuric animals, the amount 

 pf sugar eliminated is increased. 



