246 



the entire circumference of an artery over a short portion of its length, 

 or in a dilatation of only a small portion »f one side of the wall. Aneu- 

 rism may become very large ; as it increases in size it presses uj)on and 

 causes the destruction of neighboring tissues. The cavity of the aneu- 

 rismal sac is filled Avith fluid or clotted blood, or with layers of fibrin 

 which adhere closely to its wall. Death is produced usually by the 

 pressure and interference of the aneurism with adjoining organs, or 

 by rui)ture. In worm aneurism we usually find large thrombi within 

 the aneurismal dilatation of the artery, which sometimes plug the 

 whole vessel or extend into the aorta. Portions of this thrombus or 

 clot may be washed away and produce embolism of a smaller artery. 

 The effect in either case is to produce ana?mia of the intestinal canal, 

 serous or bloodj" exudation in its walls, which leads to paralysis of the 

 intestine and resultant colicky symptoms. 



Treatment. — The only treatment advisable is to extirpate or ligate 

 the tumor above and below. 



RUPTUKE OF AN ARTERY, 



Endarteritis, with its subsequent changes in the walls of arteries, is 

 the primary cause of rupture in the majority of instances. The rup- 

 ture may be partial, involving only one or two coats, and will then 

 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. Rupture may be 

 produced by mechanical violence or accident. 



Symi^toms. — In fatal rupture associated witl^ profuse bleeding, 

 the animal becomes weak, the visible mucous membranes become 

 blanched, the breathing hurried or gasping, j)upils dilated, staggering 

 in gait, syncope, death. When the hemorrhage is limited, the symp- 

 toms may not become noticeable; if it is near the surface of the body 

 a round or diffuse swelling or tumor may form, constituting a 7i?/^roma. 

 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 contrac- 

 tion of the blood-vessels. Tannin and ii'on 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 undei'stood the partial or complete clo- 

 sure of a vessel by a morbid product dcAcloped at the site of the 

 obstruction. The coagulum, which is usually fibi-inous, is known as 

 a thrombus. The term embolism designates an obstruction caused 



