DISEASES OB^ THE HORSE. 241 



cause may be, often leads to veiy serious results in the development 

 of secondai\v changes in their walls. Arteritis may be acute, sub- 

 -acute, or chronic; when the inner coat alone is affected it is known as 

 endarteritis. 



Symptoms. — Arteritis is characterized by a painful swelling along 

 the inflamed vessel, throbbing pulse, coldness of the parts supplied by 

 the inflamed vessel, sometimes the formation of gangrenous sloughs, 

 suppuration, abscess, etc. In an inflammation of the iliac arteries we 

 find coldness and excessive lameness or paralysis of one or both hind 

 limbs. 



Pathology. — In acute arteritis we find swelling along the vessel, loss 

 of elasticity, friability, and thickening of the walls; a roughness and 

 loss of gloss of the inner coat, with the formation of coagula or pus in 

 the vessel. Subacute or chronic arteritis may afl'ect onl}^ the outer 

 coat {periarteritis)., both the outer and middle coat, or the inner coat 

 alone {endarteritis)', and by weakening the respective coats leads to 

 rupture, aneurism, or to degenerations, such as bony, calcareous, fatty, 

 atheromatous, etc. It ma}^ also lead to sclerosis or increase of fibrous 

 tissue, especially in the kidne3^s, when it may result in the condition 

 known as arterlo-capUlary fihrosls. Chronic endarteritis is fruitful in 

 the production of thrombus and atheroma. Arteritis 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 degenei-ated tissue, and the 

 formation of erosions or ulcer-like 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 sur- 

 face of the inner coat or upon the surface of the erosions. 



Fatt}' degeneration and calcification of the middle and outer coats 

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

 thrombi may form or maj^ 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 potassa in 1-dram doses, to be given in 4 

 ounces liquor acetate of ammonia every six hours; scalded bran suffi- 

 cient to produce loosening of the bowels, and complete rest; exter- 

 nall}', 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 



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