PHYSIOLOGY OF CYTOST ACTION 89 



Incidental to the experiments just discussed, an 

 observation of considerable interest was made. When 

 autolyzed lung tissue from dogs, sheep, beef, rab- 

 bits and horses was applied to cats' paws or adminis- 

 tered by insufflation, the cats usually failed to show 

 any signs of respiratory involvement. Similarly, 

 intravenous injection of such autolysates failed to 

 provoke the symptoms of shock such as result when 

 a tissue autolysate is injected into an animal of the 

 same species. 



These results make it appear that cytost possesses 

 a certain species specificity. This aspect of the prob- 

 lem will be discussed further in a subsequent chapter. 



As a result of these experiments we may conclude 

 that the zone of attack of cytost lies in the endodermal 

 cells of the lungs, liver and upper alimentary tract 

 which are in intimate contact with the endothelium 

 of the capillaries. The injection of cytost extracts in 

 such concentration that immediate shock and death 

 do not ensue leads to a more generalized involvement 

 of the body tissues — particularly of the kidney. It 

 has been known for years that a severe nephritis may 

 follow a superficial burn. As has been shown in our 

 previous discussion, burned tissues liberate cytost. If 

 the burned area is extensive, then shock and death 

 may follow promptly. On the other hand, if the tis- 

 sue damage is restricted the animal may suffer a slow 

 absorption of the toxic cytost. Under such conditions 

 the concentration of cytost in the circulating blood is 

 usually too small to cause coagulation and consequent 

 marked interference with the circulation. Under such 

 conditions, therefore, the cytost is enabled to exert its 

 toxic action on more remote tissues. The kidney dam- 



