126 „ Veterinary Medicine. 



Among other causes must be named fermented food, the micro- 

 bian ferments and their products, serving to render the organ 

 torpid, but also to produce fever, lessened secretion and an arrest 

 or retardation of liquid supplies from the. mouth or rumen. 



Chronic heart disease, causing blood stasis in the omasum, ap- 

 pears to induce torpor and favor impaction. 



The ingestion of lead has a very direct action in producing 

 paralysis and consequent impaction. 



Finally, finely divided dry food like meal or bran, swallowed 

 hastily, tends to pass in large amount directly into the omasum, 

 and, before the animal has become accustomed to the ration, is 

 liable to clog the viscus and induce impaction. 



In nearly all cases, the commencing impaction "entails a certain 

 rise of temperature and suppression of secretions, so that the 

 malady tends to move in a vicious circle, each new step tending 

 to aggravate the already existing condition. In chronic cases, 

 which are very common, a careful record of bodily temperature 

 shows oscillations, above and to the normal, at irregular intervals, 

 each rise tending to add to the impaction. 



The most acute and fatal forms of the affection occur in con- 

 nection with a sudden change from dry to rich, luscious, green 

 food in spring, the unwonted stimulus giving rise to general irri- 

 tation of the whole gastric mucosa, with disordered and impaired 

 function of all four stomachs, but especially of the third. Such 

 cases are usually congestive and inflammatory and the suspension 

 of the gastric movements is a grand cause of impaction. In such 

 cases too the brain or spinal cord, or both, are seriously involved, 

 and the early death is preceded by torpor, paralysis, violent 

 delirium or convulsions, following largely the type of acute lead 

 poisoning. 



Symptoms. These vary according to the degree of impaction 

 or gastric torpor, from simple, irregular, or suspended rumination 

 (loss of cud) to the most severe gastric and nervous disorder. 



The slighter or less acute cases are marked by a failure to 

 re-establish regular rumination on partial convalescence from a 

 fever or inflammation. The hyperthermia subsides, but the ap- 

 petite remains poor and capricious, the muzzle dry, the eyes dull, 

 the spirits low, breathing quickened and occasionally accompanied 

 by a moan, especially when moving down hill, slight tympanies 



