F I WCTIOX O F T VnVL FS 



197 



direct irritant action on the renal (•ells. The (piestion now is, docs 

 the kidney nsc up more oxygen during a sulphate diuresis than 

 during a Ringer diuresis ? Fig. 47 shows that the oxygen used 

 increases as the amount of urine increases under the inlluence of 

 sulphate, that is, sulphate diuresis entails an expenditure of energy. 



The various factors dealt witli above as concomitants of saline 

 diuresis may now be dealt with in relation to sulphate diuresis. 



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

 part. Bainbridge and Evans showed that in a perfused living 

 kidney, sulphate diuresis may occur without any increase in 

 volume. 



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. 



Function of Tubules. 

 Next, one wants to consider 

 what cells the sulphate 

 stimulates. Cushny caused 

 one kidney to secrete 

 against a pressure of 

 30 mm. Hg, leaving the other kidney free. During the height 

 of a NaCl + NagSO^ diuresis he found that for equal weights of 

 urine the obstructed kidney produced a fluid containing less 

 chloride and more sulphate than the kidney with unobstructed 

 ureter. The result of one experiment is appended. 



so. Gins. 



Fig. 47. — To show the relationship between the produc- 

 tion of urine and tlie consumpti(JU of axvfjen by the 

 kidney under tlie intluenre of Kingei-Solutiou and of 

 Sodium Sulpliate. The black area indicates the amount 

 of urine secreted, the thin line the consumption of oxygen. 

 (Harcroft.) 



{a) Unobstructed side . . 24 0-081 0-108 



(b) Obstructed side ... 8 0-014 0-067 



He assumed that the filtrate from Bowman's capsule must be 



of identical composition in both kidneys, as each had a similar 



blood supply. Therefore, some change nmst have taken place 



during the passage along the tubules. In one case (obstruction) 



the fluid remained in contact with the lining cells for a prolonged 



period, while on the other side free passage was allowed. Either 



