THE EXCRETION OF DEXTROSE 711 



be due to the vital activity of cells. But, it adds yet another 

 possible explanation of some of the experiments directed to eluci- 

 date the action of the glomerulus, an explanation which was 

 contemplated in neither Lud wig's nor Heidenhain's view, and 

 which only adds to our difficulties in coming to any conclusion. 



The Excretion of Dextrose. On Lud wig's view, dextrose 

 must always be passed out by the glomerulus like every other 

 crystalloid in the plasma, and must then undergo almost com- 

 plete absorption by the tubule. According to Heidenhain's view, 

 dextrose is excreted only when it is in excess in the blood, and so 

 stimulates the renal cells to secrete it. Loewi, Pavy, and Lusk 

 believe that dextrose exists in the plasma as a non-filterable com- 

 bination with colloid, and that only unbound dextrose can ever 

 pass into the urine. 



Numerous observers have found that the dextrose in the urine 

 is materially increased during diuresis produced by caffein, theo- 

 bromine, &c., and especially during saline diuresis. Sollmann and 

 others have observed marked individual differences in animals 

 in the ease with which diuresis can be produced in them, and have 

 noted that many good diuretic animals have normally a pro- 

 nounced glycosuria which is increased during diuresis. Such 

 observations suggest that diuresis may cause increased glycosuria 

 in normal animals and tend to give support to Ludwig's view. 

 But the experiments of Brown seem to show that the diuresis and 

 glycosuria do not stand in the relation of cause and effect to each 

 other. Mathews and also MacCallum have shown that solutions of 

 sodium chloride, sulphate, acetate, and citrate, individually or com- 

 bined, produce diuresis, and that solutions of calcium, strontium, 

 or gold chloride could prevent this diuresis, and might even pro- 

 duce complete anuria. Brown showed in rabbits that the same 

 solutions which produce diuresis also produce marked glycosuria ; 

 that small doses of calcium or strontium chloride will stop the 

 glycosuria without affecting the diuresis, and that these same 

 salts will also prevent the glycosuria caused by phloridzin. Many 

 of Brown's experiments show a phenomenon which was noted 

 by Thompson, namely, that quite a small injection of solutions 

 of various anions of sodium lead to a diuresis out of all proportion 

 to the quantity of fluid injected. Brown has assumed that in his 

 experiments the glycosuria as well as the diuresis is produced by 

 the action of ions on renal cells. It is extremely likely that this 



