ON THE CAUSES OF DISEASE. 25 



Aeta \s, also, sometimes caused by inoculation ; is frequently pro- 

 duced in healthy subjects by mismanagement, as by insufficient 

 food, want of shelter, and overwork; and often supervenes on 

 bad attacks of influenza, strangles, diabetes, and other diseasea 

 which debilitate the system, or impair the integrity of any of its 

 more important parts. These causes appear to possess the power 

 of engendering in the constitution of a horse a peculiar poison, 

 which, as it reproduces itself, and spreads to all parts of the body, 

 gives rise to the characteristic symptoms of glanders, causing, 

 sooner or later, a breaking up of the system, and a fatal prostra- 

 tion of the vital powers. This poison produces in the blood ab- 

 normal changes, which vitiate that fluid, and unfit it for healthy 

 nutrition.* From the irritant action of the morbid fluids j)assing 

 through them, the lymphatic glands and vessels become inflamed, 

 and lymph is deposited. This, however, being of an unhealthy 

 nature, soon runs on to softening, which extends to the ikin over- 

 lying the part, and ulcerating farcy-buds are formed. On the 

 surface of the more vascular mucous membranes eflusions of tu- 

 bercular matter are also poured out ; these take on an unhealthy 

 inflammation, and degenerate into chancrous ulcers, which may 

 generally be seen on the mucous membrane of the nostrils in most 

 bad cases of glanders. 



" These are the most common scrofulous diseases of horses; but 

 an animal of the scrofulous diathesis, besides being specially sub- 

 ject to these, is little able to withstand ordinary morbific causes, 

 and hence is also unusually liable to many ordinary diseases; in 

 such a subject, too, disease is very apt to be severe and complicated, 

 and to be acted on tardily and imperfectly by all remedies." 



Having now furnished the reader with a few valuable facta 

 bearing on hereditary predisposition, we shall briefly discourse 



• " A comparison of the two subjoined analyses will jhoT Ihe great diflferenct 

 iB composition between the blood of healthy and of gluoderous horses — a difFe»> 

 •Boe consisting chieily in a diminution of the red corprsoules, and a propof* 

 Uonal increase of the tibriuc and albumen. 



Blood of Uealthy Horse. Tlod of ^arJeront flocM. 



A. «. 



WaU<r „ 804.76 «. . 842. ». »5» 



Pibnne - 2*1 _.......>. t-C . ..._...........« 8.7 



Blood corpuscHlea — . 117.13 _ 68 90..^................. 44.21 



Albnmen 67.86; tb»>....^ w.« 



Bolubte sa'ts 6.82 ... e.6r„..... ....>. _ 6.sa 



£tmon't Animal Ckf»^fi- m Dl. Tw, »0« •* t»^J>.- 



