82 DISEASES OF CATTLE. 



ANEURISM. 



A circumscribed dilatation of an artery, constituting a tumor which 

 pulsates synchronously with the beats of the heart, is called aneurism. 

 It is due to disease and rupture of one or two of the arterial coats. 

 The true aneurism communicates with the interior of the artery and 

 contains coagulated blood. They are so deeply seated in cattle that 

 treatment is out of the question. These abnormalities are due to 

 severe exertion, to old age, to fatty or calcareous degeneration, or to 

 parasites in the blood vessels. Death is sudden when due to the rup- 

 ture of an aneurism of a large artery, owing to internal hemorrhage. 

 Sometimes spontaneous recovery occurs. As a rule no symptoms are 

 caused in cattle by the presence of deep-seated aneurisms, and their 

 presence is not suspected until after death. 



A false aneurism results from blood escaping from a wounded artery 

 into the adjacent tissue, where it clots, and the wound, remaining 

 open in the artery, causes pulsation in the tumor. 



THROMBOSIS (OBSTRUCTION) OF THE ARTERIES. 



Arteries become obstructed as a result of wounds and other injuries 

 to them, as those resulting from the formation of an abscess or the 

 extension of inflammation from surrounding structures to the coats 

 of an artery. Arteries are also obstructed by the breaking off of par- 

 ticles of a plug or clot, partly obstructing the aorta or other large 

 artery. These small pieces (emboli) are floated to an artery that is 

 too small to permit them to pass and are there securely held, produc- 

 ing obstruction. Such obstructions are shown by loss of power in the 

 muscles supplied by the obstructed artery and by excitation of the 

 heart and respiration after exercise. The loss of power may not come 

 into evidence until after exercise. 



Symptoms. — While standing still or when walking slowly the ani- 

 mal may appear to be normal, but after more active exercise a group 

 of muscles, a leg, or both hind legs, may be handled with difliculty, 

 causing lameness, and later there is practically a local paralysis. 

 These symptoms disappear with rest. In some cases the collateral cir- 

 culation develops in time, so that the parts receive sufficient blood 

 and the symptoms disappear. 



INFLAMMATION OF VEINS (PHLEBITIS). 



When bleeding is performed without proper care or with unclean 

 fleam or lancet, inflammation of the vein may result, or it may be 

 caused by the animal rubbing the wound against some object. When 

 inflammation follows the operation, the coats of the vein become 

 enlarged; so much so that the vessel may be felt hard and knotted 

 beneath the skin, and when pressed on pain is evinced. A thin, watery 

 discharge, tinged with blood, issues from the wound. When the pin 



