394 Obstruction of the Mesenteric Arteries. 



Glage found aneurysm of the anterior mesentery in fifteen, varying in size from 

 a walnut to a fist. 



The following figures about the frequency of thrombotic infarction of the intes- 

 tinal wall are given from various sources: Dresden Clinic, 1899-1908, in horses dead 

 after attacks of colic, 9.5%; Berlin Clinic, 1891-1907, in 3%; Prussian army, 1892- 

 1908, 6.67f ; Budapest Clinic, 1900-1909, 14.4%. Wall claims that thrombotic-em- 

 bolic disturbances of the intestines are quite rare. Indeed there seem to be great 

 differences in the frequency of the aft'ection, according to periods of time and to 

 various countries. 



Etiology. According to the investigations of Sticker, 

 thrombosis of the mesenteric arteries of the horse is caused by 

 the larvae of sclerostomum vulgare Looss (Sol. bidentatum 

 Sticker). 



The mode of the migration of the sclerotomae larvae into the in- 

 testines and from there into the mesenteric arteries of the horse is at 

 present not yet known with certainty. According to Leuckart and Wil- 

 lach, the ova of the mature worm, inhabiting the large intestines of the 

 horse, are voided with the feces, and from these free ova the larvae are 

 hberated in water, on moist walls of barns, in manure. From here they get 

 again into the horse with drinking water, or with food contaminated by 

 manure, etc., and on moist marshy pastures. The correctness of this view 

 is confirmed by the observation of ]\Iieckley, who prevented the appear- 

 ance of verminous aneurysms in the foals of the Beberbeck stud by 

 having them drink only filtered w^ater ; Ostertag found in the unfiltered 

 water of this stud strongylus larvge. Other authors claim that the em- 

 bryos are already set free in the animal host. 



It is claimed that when later on the larvse bore into the intestinal 

 Avail, some of them may quite accidentally get into the veins and with 

 the blood current into the liver, from where they reach the lungs, tbe 

 larger circulation, or the mesenteric arteries. (Colin, "Willach, Olt.) 

 According to other authors, however, the larvae get into the arteries in 

 their regular cycle of development (Leuckhart, Railliet, Sticker, Glage). 

 Poppel believes that intrauterine infection of the embryo is possible, 

 because he once found a verminous aneurysm of the size of a pigeon's 

 egg in a ten-days-old sucking foal. He thinks that this mode of infec- 

 tion may easily occur, since the embryos of sclerostoma are microscopic 

 in size (see also chapter on palisade worms). 



In horses as well as in other animals there occurs excep- 

 tionally a transportation of emboli into the mesenteric arteries 

 in consequence of cardiac disease, endocarditis and aneurysm 

 of the thoracic aorta. The emboli in the mesenteric arteries are 

 usually not followed by serious consequences on account of 

 their small size. The authors have seen the case of a dog 

 where an ulcerative endocarditis was followed by an embolic 

 closure of arteries of the small intestines, and this led to 

 hemorrhagic infarct of the intestinal "wall. A. Koch and Ijei- 

 benger have each seen a case of aneurysm of the anterior and 

 posterior mesenteric artery in the hog. 



Pathogenesis. The larva? of sclerostoma, according to gen- 

 eral belief, adhere to the intima and even bore into it, after they 

 have gotten into the mesenteric artery; this causes inflammation 



