136 THE VENOM OF HELODERMA. 



In the large majority of cases both hemorrhage and ulceration are found 

 in the affected areas. The fact that in a large majority of cases the introduc- 

 tion of alkali into the stomach is able to prevent the occurrence of ulceration 

 and hemorrhage renders it almost certain that usually digestion is primary and 

 that in many cases hemorrhage is merely the result of secondary erosion of the 

 vessels. The results of microscopic observation favor this interpretation. 



In the course of ulceration, neighboring blood-vessels become occluded by 

 thrombi. This is secondary and not primary, inasmuch as we were able to 

 show that experimentally produced incoagulability of the blood failed to pre- 

 vent the occurrence of ulcers. Thrombi are, therefore, not the cause of ulcer- 

 ation, but this secondary thrombosis must be considered as a beneficial process, 

 inasmuch as it prevents fatal hemorrhage. 



These facts throw light on hemorrhagic erosions in man, which are, in all 

 likelihood, due to primary digestion. They also indicate that such lesions may 

 be transformed into typical gastric ulcer; at least such is the case in guinea-pigs 

 subjected to the influence of different toxic substances. Whether chronic 

 round ulcer can be produced by a perpetuation of such a condition remains to 

 be proved. 



