160 



THE ARMY FOR HOME DEFENCE 



injection of a mixture of equal amounts of chloride and sulphate 

 of sodium, more sulphate than chloride is excreted, and while the 

 chloride elimination falls to normal in about an hour, at the end 

 of three hours the sulphate content of the urine is above the 

 normal. These results point to the sulphate as having a direct 

 action on the renal cells. It is known to be a cell irritant. The 

 question now is, does the kidney use up more oxygen during a 

 sulphate diuresis than during a Ringer diuresis ? Fig. 27, from 

 Barcroft and Straube, shows that the oxygen used increases as 

 the amount of urine increases. Therefore, one may say that the 

 sulphate diuresis entails energy expenditure. 



The various factors dealt with above as concomitants of saline 

 diuresis may now be dealt with. 



FIG. 27. To show the relationship between the production of urine and the con- 

 sumption of oxygen by the kidney under the influence of Ringer-Solution and of 

 Sodium Sulphate. The black area indicates the amount of urine secreted, the thin line 

 the consumption of oxygen. (Barcroft.) 



1, 2, and 3. Increase in flow of blood, etc., do not play a part. 

 Bainbridge and Evans showed that in a perfused living kidney, 

 sulphate diuresis may occur without any increase in volume. 

 Gottlieb and Magnus are inclined to think from a study of kidney 

 volume that circulatory conditions are less favourable for sulphates 

 than for chlorides. 



4. The corpuscular concentration of the blood has as little effect 

 under sulphate as under chloride injection. 



5. The introduction of a colloid after a sulphate made little 

 difference in the flow of urine, while it diminished it markedly 

 after a chloride injection (Knowlton). 



In short, filtration plays but a small part here. No doubt 

 sulphates have a certain salt action but this is masked by their 

 strong secretory effect. 



