540 THE DIGESTIVE SYSTEM. 



adhesions are formed between the wall of the stomach and the neighbor- 

 ing viscera, so that the bottom of the ulcer is closed ; or if the liver, the 

 intestines, or the abdominal wall become adherent, these may be invaded 

 by the ulcerative process, and cavities or fistulae are formed communicat- 

 ing with the stomach ; or, if the adhesions are incomplete, a local peri- 

 tonitis and collections of pus may be developed. Perforation may take 

 place into the colon or duodenum, or into the pericardium or pleura. 



During the progress of the ulcer there may be repeated small haemor- 

 rhages from the erosion of small blood-vessels, or large haemorrhages 

 from the erosion of larger arteries. 



In many cases these ulcers cicatrize, and such a cicatrization may 

 produce various deformities of the stomach. 



FIG. 313. CHRONIC PERFORATING ULCER OF THE STOMACH. 



The origin of such ulcers is often obscure. It seems probable that 

 the nutrition of a circumscribed part of the wall of the stomach is inter- 

 fered with, and that this portion is then destroyed by the action of the 

 gastric juice. But we are in most cases still ignorant of the way in which 

 the obliteration of the arteries is effected. It has, indeed, been demon- 

 strated in animals that an artificial embolism of the branches of the gas- 

 tric arteries may lead to ulcers of the stomach ; and in the human stom- 

 ach we occasionally find cases of embolism of the branches of the gastric 

 artery and ulcers. But the clinical history of most cases of ulcer of the 

 stomach does not correspond with such a mode of origin. A chronic 

 obliterating endarteritis would seem to be a more probable cause. The 

 possibility of a bacterial origin in some cases should not be overlooked. 



Follicular Ulcers, similar to those in the small intestine, are of occa- 

 sional occurrence in the stomach. They are formed by the degenerative 

 changes and necrosis in the solitary lymph-nodules of the stomach. 



For Tuberculous Ulcers, see above. 



