Reactions of the Capillary Endothelium 



53 



(d) Hind Quarters. Reactions similar to those of the in- 

 testines, but with less tendency to recovery by the end of eight 

 minutes. 



We have endeavored to determine the mechanism of the 

 changed perfusion resistance by histological methods. The tis- 

 sues have been fixed by perfusion methods at various stages of 

 the peptone reaction. The following appear to be the dominant 

 physiological factors thus far studied : 



(a) Liver. Marked capillary vaso-constriction with stasis 

 and diapedesis in certain areas. Partial capillary occlusion by 

 leucocytic deposits in later stages of the shock. Marked in- 

 crease in tissue lymph, with dilation and even rupture of the 

 lymphatics, edema of the connective tissue structures, and 

 mechanical separation of the capillar} 7 endothelium from the 

 parenchymatous cells. Swelling and vacuolization of the paren- 

 chymatous cells. 



(b) Lungs. Marked capillary vaso-constriction. 



From these observations we believe that the dominant circula- 

 tory factors in canine peptone shock are reactions of the capillary 

 endothelium. According to this conception the fundamental 

 physiological reactions in peptone shock are : 



(a) Pulmonary and hepatic capillary 7 vaso-constriction. 



(b) Capillary vaso-dilation in other parts of the body. 



(c) Increased capillary permeability most marked in the liver. 



The reactions in the extra-hepatic and extra-pulmonary capil- 

 laries are similar to the endothelial reactions recently described 

 by Dale and Laidlaw 3 , Rich 4 , and others in histamine shock. 



3 H. H. Dale and P. P. Laidlaw, Jour. Physiol, 1918-19, lii, 355. 



4 A. R. Rich, Jour. Exper. Med., 1921, xxxiii, 287. 



