486 Veterinary Medicine. , 



But the heart is not always the primary soixrce of such clots. 

 Virchow and others have demonstrated, by post mortem examina- 

 tions in cases of plugging, and by a number of experiments on 

 the lower animals, not only that such clots may have their place 

 of nativity in some distant and diseased part of the body and 

 proceed in the veins to the heart, and thence through the arteries 

 to other distant parts of the body where they plug the vessels 

 and induce a train of morbid changes ; but that such embolism, 

 arteritis and abscesses can be produced at will by the introduction 

 into the circulation of solid and insoluble (infecting) bodies. 

 Fragments of decaying and suppurating tissue and the elements 

 of tubercle and cancer may be thus equally carried onward in the 

 current of the circulation, and reproduce themselves at those 

 points where their course is arrested. This is a mode in which 

 secondary deposits of these morbid matters are determined. 

 Embolism and arteritis in the body and limbs, occurring in this 

 way, necessarily have their point of departure in pre-existing 

 disease of the lungs. The clots, loosened from the capillaries or 

 veins of the lungs, are carried through the left side of the heart 

 into the arteries of the body at large to be arrested in some of the 

 smaller vessels. I have seen plugging of the digital arteries of 

 the hind limbs, to occur in this way in a horse that had been 

 suffering from inflamed lungs. 



Microbes and toxins may pass harmlessly through healthy parts, 

 including the pulmonic circulation, to establish colonies and 

 embolism beyond where the tissues have become debilitated. 

 Thus Gamgee records a case of embolism of the anterior mesen- 

 teric, right external iliac and right femoral arteries, supervening 

 on an attack of strangles. 



Symptoms of acute arteritis. These consist largely in impaired 

 muscular power in the part which the artery supplied, indications 

 of acute local suffering, such as trembling and tenderness to the 

 touch, if the obstructed vessel lies within reach, it can be felt as 

 an exquisitely tender cord-like mass, and the limb on the distal 

 side of the embolism and dependent on the diseased vessel for its 

 blood supply is anaemic and cold. In the distal portion of 

 the embolic artery and its branches pulsation has ceased. If 

 the lesion is extensive there may be more or less fever, but 

 a limited arteritis in a small vessel may escape this complica- 



