264 DISEASES OF THE HORSE. 



increase of fibrous tissue, especially in the kidneys, when it may result 

 in the condition known as arterio-capillary fibrosis. Chronic endar- 

 teritis is fruitful in the production of thrombus and atheroma. Ar- 

 teritis may be limited to single trunks or it may affect, more or less, 

 all the arteries of the body. Arteries which are at the seat of chronic 

 endarteritis are liable to suffer degenerative changes, consisting 

 chiefly of fatty degeneration, calcification, or the breaking down of 

 the degenerated tissue, and the formation of erosions or ulcerlike 

 openings in the inner coat. These erosions are frequently called 

 atheromatous ulcers, and fragments of tissue from these ulcers may 

 be carried into the circulation, forming emboli. Fibrinous thrombi 

 are apt to form upon the roughened surface of the inner coat or upon 

 the surface of the erosions. 



Fatty degeneration and calcification of the middle and outer coats 

 may occur, and large, hard, calcareous plates project inward, upon 

 which thrombi may form or may exist in connection with atheroma 

 of the inner coat. When there is much thickening and increase of 

 new tissue in the wall of the affected artery it may encroach upon the 

 capacity of the vessel, "and even lead to obliteration. This is often 

 associated with interstitial inflammation of glandular organs. 



Treatment. — Carbonate of potassium in 1-dram doses, to be given 

 in 4 ounces liquor acetate of ammonia every six hours ; scalded bran 

 sufficient to produce loosening of the bowels, and complete rest; 

 externally, applications of hot water or hot hop infusion. 



ATHEROMA. 



Atheroma is a direct result of an existing chronic endarteritis, the 

 lining membrane of the vessels being invariably involved to a greater 

 or less degree. It is most frequently found in the arteries, although 

 the veins may develop an atheromatous condition when exposed to 

 any source of prolonged irritation. Atheroma may affect arteries in 

 any part of the body; in some instances almost every vessel is dis- 

 eased, in others only a few, or even parts of one vessel. It is a very 

 common result of endocarditis extending into the aorta, which we 

 find perhaps the most frequent seat of atheroma. As a result of this 

 condition the affected vessel becomes impaired in its contractile 

 power, loses its natural strength, and, in consequence of its inability 

 to sustain its accustomed internal pressure, undergoes in many cases 

 dilatation at the seat of disease, constituting aneurism. In an 

 atheromatous vessel, calcareous deposits soon occur, which render it 

 rigid, brittle, and subject to ulceration or rupture. In such vessels 

 the conti-actility is destroyed, the middle coat atrophied and beyond 

 repair. Atheroma in the vessels of the brain is a frequent cause of 

 cerebral apoplexy. No symptoms are manifested by which we can 

 recognize this condition during life. 



