CHAPTER VIII. 



PARASITES OF THE DIGESTIVE APPARATUS. 



Parasites of the digestive apparatus are extremely common in 

 ruminants, some, like the infusoria of the rumen, being of no importance, 

 others, on the contrary, appearing to play a predominating part in the 

 development of certain forms of anaemia and serious wasting diseases, 

 such as the various forms of gastro-intestinal strongylosis, coccidial 

 enteritis, etc. 



GASTROJNTESTINAL STRONGYLOSIS IN SHEEP. 



PARASITIC CiASTRO-ENTERITIS. OVINE PASTEURELLOSIS. 



Verminous diseases of the abomasum are common in the sheep and 

 goat, but (in France at least) appear rare in the ox. 



Causation. Gastro-intestinal strongylosis is produced by various 

 parasites of the genus Strongylus, such as Strongylus contortus, 

 Stronfjijlus conroluttis, Sfroiuii/his instahilis, Strongylus circumcinctus, 

 Strongijlus ^fiUcoUs, which occur not only in the abomasum, but also 

 in the small portions of the first intestine, sometimes in very large 

 numbers. 



The first is a threadlilce worm, pointed at both extremities, and from 

 ^ to 1 inch in length. It exhibits a red tint, which zoologists refer to the 

 presence of blood in its digestive apparatus, derived from the host's in- 

 testinal mucous membrane. Some doubt has been thrown on the nature 

 of this coloration, however ; and certain Italian authors, in common 

 with Lignieres, have declared it due to a certain red pigment developed 

 in the tissues of the parasite, the spectroscopic reaction of which differs 

 from that of haemoglobin. 



The strongyles are said not to penetrate the mucous membrane, but 

 simply live on the intestinal contents. This may be true of certain 

 varieties, but it is none the less certain that others penetrate the mucous 

 membrane deeply, even to the extent of becoming half-embedded in it. 

 Particularly is this the case with Strongylus circuujcinctus, found in the 

 epizooty which occurred at Grignon, and also found by Moussu in grave 

 epizootics which he has from time to time investigated. 



According to Lignieres this gastro-intestinal strongylosis only plays a 



