404 Obstruction of the Mesenteric Arteries. 



iiig each other. It occurs occasionally that a thrombus is not 

 found on postmortem examination as it existed during- life, be- 

 cause a movable occluding portion of the thrombus may have 

 been moved by section of the affected vessel from the opening 

 which it closed during life. The obstructed vessel, particularly 

 often the anterior mesenteric or the arteria ileo-coecocolica 

 shows chronic arteritis with thrombosis and usually also aneu- 

 rysmatic dilation. The blood coagulum usually contains the 

 sclerostoma larvae, sometimes 100 to 300 individuals, especially 

 in younger animals, while thrombi in older animals contain few 

 or even no larvae at all. Sclerostoma larvae are usually less 

 numerous in citv horses than in horses recentlv pastured 

 (Wall). 



Contrary to the view of Sticker that one finds larvaj in different stages of devel- 

 opment according to the season in which the postmortem examination is made, 

 Glage has shown that larva^ and mature worms may lie found at all seasons in the 

 intestines or in the mesenteric arteries of the horse. 



Symptoms. The disease sets in suddenly with symptoms 

 of colic without any discoverable external circumstances ; the 

 animals may be at a meal, at work or at rest. The authors' nu- 

 merous observations, however, seem to indicate that the disease 

 makes its onset more frequently during work than at other 

 times. This may be caused by the fact that the blood circula- 

 tion is more active during work and hence the detachment of 

 pieces of a thrombus may more easily occur. The s}^nptoms of 

 colic are either intense from the start, manifesting themselves 

 in reckless rolling and throwing, or the^^ are at first mild and 

 reach a higher intensity later on, or the great restlessness first 

 shown later yields to a more quiet behavior. The attacks of 

 pain occur after shorter or longer, sometimes after very long, 

 intervals. The other s^anptoms vary according to whether 

 compensation is established within a certain time, or whether 

 this is impossible. One may distinguish clinically a mild and 

 a severe type, depending upon this circumstance. 



In the mild type, aside from the attacks of restlessness oc- 

 curring at unequal intervals, a variable intensification of the 

 intestinal sounds is observed in certain regions, sometimes over 

 a large portion of the abdomen, and frequent defecation. The 

 feces are normal except for their generally softened consistency. 



Eectal exploration may reveal a pulsating dilatation or a 

 trembling of the wall of the anterior mesentery artery or of one 

 of its branches, occasionally also of the posterior mesenteric 

 artery; the condition of the intestines and of the other a1)dom- 

 inal organs is normal. 



Pulse and respiration do not show any deviation in fre- 

 quency and quality, the sensorium of the patients is perfectly 

 normal in the intervals between the attacks of pain. 



The restlessness becomes diminished, usually after a short 

 time, always during the course of the first day and recovery oc- 



