266 DISEASES OF THE DIGESTIVE APPARATUS. 



depressioD, surrounded by a salient zone ; in addition is observed 

 an intense hemorrhagic enteritis ; less frequently we see signs of 

 furrows or caverns with ulcerated edges, which are irregular and 

 thick — a process which sometimes extends itself to all the layers of 

 the intestinal wall. The parasites may form compact balls, which 

 obstruct the passage of the intestinal canal completely, and at times 

 give rise to an invagination. 



In the horse, Ziirn has described two cases of intestinal perfora- 

 tion produced by the Ascaris megalocephala at the point of 

 mesenteric attachment. Where the intestinal wall offers the least 

 resistance we detect small round openings, surrounded with thick 

 edges, which are cicatricial ; these openings lead to caverns which 

 are furrowed between the two thickened layers of the mesentery, 

 and contain pus and chyme, as well as ascarides. The opening of 

 these intra-mesenteric abscesses has resulted in a purulent peri- 

 tonitis. Generali has found an ascaris in the pancreatic canal 

 which was tumefied and thickened ; the gland itself was not altered. 



In chickens, the intestinal mucous membrane is at times the seat 

 of a catarrhal phlegmasia, sometimes it is much inflammed, ulcer- 

 ated, and covered with a thick and purulent exudate. 



Symptoms. They do not differ essentially from those produced 

 by the taenias. We observe disturbances of digestion and nutrition, 

 diarrhea, constipation, tympanites, etc., a more or less marked ema- 

 ciation, nervous manifestations, and pruritus; the animals endeavor 

 to allay the itching by scratching or rubbing themselves. 



1. In the liorse we observe troubles without any clear significance: 

 diarrhea and constipation, intermittent colics, and when the trouble 

 is old a more or less marked emaciation. The worms may produce 

 death by obstruction or perforation of the intestine. 



In some subjects we observe symptoms which are quite special. 

 In a mare Fréminet detected a very evident tetanic condition 

 (trismus, a special posture being taken by the horse), produced by 

 a reflex, and which disappeared after the administration of an 

 anthelmintic. Damitz has observed a particular spinal affection, 

 paraplegic, which yielded to the administration of anthelmintics. 



2. In the dog the symptoms are identical with those produced 

 by the taenias. In this animal and in the cat fatal intestinal per- 

 forations are quite common ; the manifestations which they produce 

 are similar to those of certain poisonings, and often they are only 

 recognized at the autopsy. 



