240 



may be i)artifil, involving only one or two coats, and will tben form an 

 aneurism. If complete, it may produce death when it involves a large 

 vessel, especially if it is situated in one of the large cavities permitting 

 an excessive escape of blood. Kupture may be produced by mechanical 

 violence or accident. 



Symptoms. — In fatal rupture associated with profuse bleeding, the 

 animal becomes weak, the visible mucuous membranes become blauclied, 

 the breathing hurried or gasping, pupils dilated, staggering in gait, 

 syncope, death. When the hemorrhage is limited, the symptoms may 

 not become noticeable ; if it is near the surface of the body a round or 

 diffuse swelling or tumor may form, constituting a hygroma. If the 

 rupture is associated with an external wound the bleeding artery should 

 be ligated, or where a bandage is applicable, pressure may be applied 

 by tight bandaging. As a secondary result of rupture of an artery we 

 may have formation of abscess, gangrene of a part, etc. 



Treatment. — When rupture of a deep-seated artery is suspected, large 

 doses of fluid extract of ergot may be given to produce contraction of 

 the blood-vessels. Tannin and iron are also useful. The animal should 

 be allowed to have as much water as he desires. Afterwards stimulants 

 and nourishing food are indicated. 



THROMBUS AND EMBOLISM. 



By thrombosis is generally understood the partial or complete closure 

 of a vessel by a morbid product developed at the site of the obstruc- 

 tion. The coagulum, which is usually fibrinous, is known as a throm- 

 bus. The term embolism designates an obstruction caused by any body 

 detached and transported from the interior of the heart, or of some ves- 

 sel. Thrombi occur as the result of an injury to the wall of tbe vessel, 

 or may follow its compression or dilatation ; they may result from some 

 alteration of the wall of the vessel by disease, or by the retardation of 

 the circulation. These formations may occur during life, in the heart, 

 arteries, veins, or in the i^ortal system. W' hen a portion of fibrin coag- 

 ulates in one of the arteries and is carried along by the circulation, it 

 will be arrested, of course, in the capillaries, if not before ; when in the 

 veins it may not be sto^iped until it reaches the lungs; and when in the 

 portal system the capillaries of the liver will prevent itsfurther progress. 

 The formation of thrombi may act primarily by causing partial or com- 

 l^lete obstruction, and secondarily, either by larger or smaller frag- 

 ments becoming detached from their end, and by being carried along 

 by the circulation of the blood to remote vessels, embolism; or by the 

 coagulum becoming softened and converted into pus, constituting sup- 

 purative phlebitis. These substances occur most frequently in those 

 affections characterized by great exhaustion or debility, as pneumonia, 

 purpura hoemorrhagica, endocarditis, phlebitis, puerpural fever, hem- 

 orrhages, etc. These concretions may form suddenly and produce in- 

 stantaneous death by retarding the blood current, or they may arise 



