lOlJf-^ AcTiojf OF Various Diuretics 35 



The microscopic examination of the urine constantly showed 

 the presence of erythrocytes, usually few in number, and tube 

 casts. Early in the nephritis, with the first appearance of al- 

 bumin, the hyaline cast predominated, but later when the 

 alubuminuria had become more marked, granular casts predomi- 

 nated over the hyaline type. 



When such animals which were nephritic, glycosuric, and 

 polyuric were anesthetized by either Grehant's anesthetic or by 

 morphine-ether, they grouped themselves, so far as their re- 

 sponse to diuretics was concerned, into two mains groups: an 

 anuric group and a diuretic group. 



The physiological study of these two types of animals with 

 special reference to their response to diuretics, showed, in the 

 first place, that no change had been induced in the height of 

 general blood pressure to account for the difference in the out- 

 put of urine in the two groups. Secondly, oncometric deter- 

 minations of the local renal circulation showed that the response 

 of the renal vessels in both gToups was either normal or hyper- 

 active. This was true for substances such as caffeine and theo- 

 bromine which are supposed to influence the renal circulation 

 principally through a local vascular effect, as well as for such a 

 substance as digitalin, whose local effect on the blood supply 

 of the kidney is induced through its general effect upon the 

 circulation. 



As a result of the above mentioned study of the general and 

 local vascular response of the nephritic animals, the cause of 

 the stoppage of the urine flow in the anuric group was thought 

 not to be due to any vascular change. 



The histological study of the kidneys from the diuretic and 

 from the anuric groups showed a marked difference in the degree 

 of epithelial involvement, whereas the vascular pathology in the 

 two groups was practically identical. 



In those animals that remained diuretic following the anes- 

 thetic, the epithelial involvement was slight or absent. The cells 

 were not only not increased in size, but frequently they showed 

 an undoubted shrinkage with an associated increase in the size 

 of the lumen of the tubules. The cells stained well, the nucleus 



