484 



DISEASES OF THE CIBOULATOBY SYSTEM. 



ulcerating process starting from a neighboring organ, or from 

 nematode worms contained in the bloodvessels (armed strongyle in 

 the horse — Durieux ; spiroptera in the dog — Morgagni, Mégnin) 

 Animals affected by hypertrophy of the heart are predisposed to 

 vascular lacerations. 



Pathological anatomy. These ruptures have been observed in 

 the posterior vena cava (Page, Scruby, Hertwig), the anterior vena 

 cava (Straub), the pulmonary artery (Hering, Hartmann, Prietsch), 

 upon the aortic trunk, in the neighborhood of the semilunar valves ; 

 here they are the consequence of the atheromatous alteration of the 

 walls of the aorta (Larcher). When the internal and median 

 membranes are torn, the blood accumulates between the adventi- 

 tious layer and the middle tunic of the bloodvessel ; a dissecting 

 aneurism is formed. 



Symptoms. Symptoms of the rupture of a large bloodvessel 

 are those of internal hemorrhage : a sudden appearance of paleness 

 in the mucous membranes ; a filiform pulse, which is imperceptible ; 

 weakness, staggering, dropping, chilled condition of the extremities. 

 Straub has seen epileptiform attacks preceding the laceration of the 

 anterior vena cava ; Hartmann has observed an abundant hemo- 

 ptysis which was produced by the opening of an aneurism of the 

 pulmonary artery into a large bronchial tube. 



It would be of little use to consider the treatment of such acci- 

 dents, which are always followed by the death of the animal 

 within a short time. 



THROMBOSIS OF THE BRANCHES OP THE AORTA. 



THROMBOSIS OF THE ILIAC AND AXILLARY ARTERIES. 



Etiology. Thrombosis of the crural and axillary arteries belongs 

 to the domain of surgery ; lameness of the particular members con- 

 stitutes the principal symptom of it. The causes of these diseases, 

 however, belong to the jurisdiction of internal pathology; they 

 consist in alterations of the large bloodvessels, and we must there- 

 fore consider them here. Its causes are either endarteritis or fibrin- 

 ous clots deposited upon the vascular wall, which has become 

 rugous, or obstruction of the aortic branches, produced by emboli 

 coming from a diseased heart or from an aneurism. 



