176 Veterinary Medicine. 



The wounds caused by gastric parasites may become the 

 starting points of molecular degeneration and ulceration. In the 

 horse the spiroptera megastoma, s. microstoma, and the larvae of 

 the various oestri ; in cattle and sheep the strongylus contortus, 

 s. convulutus, s. filicollis and s. vicarius ; in swine the spiroptera 

 strongylina, Simondsia paradoxa, and gnathostoma hispida ; in 

 dogs spiroptera sanguinolenta, and in cats the oUulanus tricuspis 

 act in this way. 



Gastric catarrh debilitates the affected mucosa and lays it open 

 to necrotic microbian infection especially in the pyloric sac and 

 on the summit of the folds. 



Interruption of the local circulation in the deeper parts of the 

 mucosa as in inflammation and capillary thrombosis, arterial em- 

 bolism, venous thrombosis, may lead to local .sloughing and ul- 

 cerous infection. This may be seen in the petechial fever of 

 the horse, malignant catarrh, rinderpest, and anthrax in cattle 

 and sheep, and in canine distemper in dogs. Vogel found ulcers 

 resulting from a gastric aneurism in the dog. 



Tumors and infective growths in the walls of the stomach may 

 prove an occasion of ulceration. Thus sarcoma, epithelioma, 

 actinomycosis and tubercle may be the primary morbid lesion in 

 different cases. 



Gastric ulcers have also been attributed to morbid nervous in- 

 fluences as in dogs they have been found associated with lesions 

 of the dorsal myelon, and the corpora quadrigemini, and faradi- 

 sation of the vagus has apparently led to their production. 



General constitutional debility has been alleged as a factor, 

 and experimentally in dogs, the hypodermic or intravenous in- 

 jection of various microbes or their toxins (diphtheritic toxin, 

 Enriquez and Hallion, .staphylococci, Panum, Lebert. IvCtuUe, 

 and a bacillus of dysentery in man, Chanteme.sse and Widal), 

 have produced gastric ulcers. 



Symptoms. In horses and cattle these are very obscure, being 

 mainly in the nature of chronic gastritis. In both there are re- 

 current attacks of .slight colicy pains, with tympany in cattle, and 

 gradual emaciation. Vomiting has been exceptionally seen in 

 both class of animal and if the rejected matters are very acid and 

 above all if mixed with blood it is more suggestive of ulcer. In 

 the horse the attacks of colic are mostly in connection with eating, 



