196 PARASITES IN THE STOMACH. 



PARASITES IN THE STOMACH. 



Though many infusoria develop probably in certain con- 

 ditions of the contents of the stomach, we rarely find entozoa 

 occupying this cavity as their natural habitat. Ascarides 

 and strongyli are occasionally carried up into it, but of the 

 round worms or nematoda, the only specimens found there, 

 and not usually elsewhere, except in the lower end of the 

 oesophagus, are the different species of Spiroptera. Thus 

 sp. megastoma is found in the hypertrophied coats at the 

 cardiac end of the stomach of the horse ; sp. strongylina, in a 

 similar situation in the pig, and sp. sanguinolenta in the dog. 

 These parasites are peculiarly interesting to the medical 

 zoologists, and the tumours they become imbedded in are 

 worchy of the special notice of the pathological anatomist. 

 Galleries or canals pierce the thickened coats in every direc- 

 tion, and on cutting into these, the coiled but active little 

 worms are displaced in large numbers. These are never 

 recognised as existing in the stomach during the lifetime of 

 animals, in which they may be accidentally discovered after 

 death. 



Practically it is also of little importance to trace the Am- 

 phistomum conicum, which is the only sucking worm, lodged 

 in the gastric cavities of ruminants, it being sometimes found 

 in the rumen of the ox, goat, or sheep. Strongylus contortus 

 is the only round worm of the true stomach of the sheep. 



THE HORSE EOT OESTRUS EQUI. 



In 1815, Bracy Clark published his Essay on the Bots of 

 Horses, and other Animals, and was for long referred to 

 as the only authority on the subject. With his usual in- 

 genuity, Clark explained the derivation of the term Bot. He 

 says that "lexicographers appear to have been at a loss 



