36 JOUENAL OF THE MiTCHELL SoCIETY [June 



was not pyknotic, and the cytoplasm of the cells showed but 

 slight or no vacuolation. 



On the other hand, in those animals which became anuric fol- 

 lowing the anesthetic the epithelium of the tubules of the laby- 

 rinth, and especially of the proximal convoluted tubules, showed 

 an acute swelling, which was remarkable for the rapidity with 

 which it developed. As a result of the swelling, the lumen of the 

 tubules was either greatly encroached upon or completely oc- 

 cluded. In some animals the swelling was so acute that the 

 cells had not had time to undergo any marked degenerative 

 change, while in other animals the epithelium was severely 

 vacuolated, staining was imperfect, the nuclei pyknotic, and the 

 cytoplasm in various stages of necrosis. 



As a result of these observations, I was inclined to the belief 

 that in a unranium nephritis the epithelial changes were more 

 responsible for the reduction in the output of urine than were 

 the vascular changes. 



The continuation of these experiments, which will now be re- 

 ported, serves in great measure to confirm this belief, and also 

 brings into consideration the part played by different anesthetics 

 and by the age of the animals in precipitating these epithelial 

 changes. 



DISCUSSION OP THE TECHNIQUE EMPLOYED IN THE EXPERIMENTS 



The operative technique employed in the following experi- 

 ments has been identical in every particular with that employed 

 in the experiments of the previous investigation. There have, 

 however, been made, for the sake of accuracy, slight changes in 

 the quantity of the nephrotoxic substance employed; and also 

 additional diuretic fluids have been used. In place of giving 

 from 5 to 10 mgs. of uranium nitrate to the animals without re- 

 gard to their weight, there was a determination made of the 

 dose of uranium which was competent to induce a nephritis and 

 a glycosuria without rendering the animals in the least toxic and 

 without inducing gastro-enteric changes, which are usually man- 

 ifested by vomiting and a diarrhoea. 



The dose of uranium nitrate when given subcutaneously in 



