PHYSIOLOGY OF CYTOST ACTION 93 



experiments, it will be recalled, the mustard first in- 

 duced merely a hyperemia. This was followed later 

 by degenerative changes and subsequent active pro- 

 liferation of the cells, as evidenced by the occurrence 

 in sections of many karyokinetic figures. Further, 

 these changes continued to take place even after re- 

 moval of the mustard, the latter merely acting as a 

 trigger to release the cytost from the mucosal cells 

 in the same fashion that trauma or burning releases 

 it from epithelial and muscle cells. 



While burns and other injuries always produce 

 acute lesions of the lungs and liver, these, if not ex- 

 tensive, may clear up rapidly, leaving little or no 

 evidence of any tissue damage. This difference be- 

 tween the other organs and the kidney, wherein, as 

 stated above, cytost may produce a chronic injury, 

 may in part be attributed to the single functional 

 blood supply of the latter, which depends almost en- 

 tirely on the renal vessels and a few auxiliary anas- 

 tomoses. During blood stasis, therefore, the kidney 

 is more severely taxed than are the other viscera, which 

 have a double vascular blood supply. Again, the kid- 

 ney cells are known to be very sensitive to toxic sub- 

 stances, such as the salts of mercury and uranium and 

 various organic compounds. In this respect they re- 

 semble the endodermal cells of the liver, lung, 

 stomach, and intestines. Hence it seems probable that 

 the kidney cells may be more easily injured by cytost 

 than are other tissues. Photomicrographs showing 

 congestion of the glomeruli, venous stasis, and clump- 

 ing of the corpuscles in the region of the straight 

 tubules are shown in the accompanying illustrations. 



