INFLAMMATION. 41 



External inflammation most frequently proceeds from wounds, or 

 bruises, or other accidents to which cattle are liable. These produce 

 different degrees of disease, according to the severity of the injury; 

 and when the inflammation runs high, or continues long, it atTects 

 the whole system, and brings on fever; or, in other words, a certain 

 degree of inflammatory action pervades the entire frame. 



External inflammation sometimes results from causes which affect 

 the whole system, but the chief mischief of which is determined to 

 particular parts, from previous weakness in them, or disposition to 

 take on inflammation. Tiiis is the case with inflammation of the 

 udder of cows, or the joints of young cattle. The whole frame had 

 been exposed to cold ; but the udder of the cow that had lately calved 

 was very much disposed to inflammation, and the joints of young 

 cattle had not acquired their full strength. In inflammatory fever, 

 also, the inflammation will settle in particular parts, from causes 

 which it is impossible to explain, as in the tongue in blain, and in 

 the limbs in quarter evil. 



The swelling of the inflamed part is principally to be ascribed to 

 the increased quantity of blood passing through it. Every little vessel 

 is distended by the additional fluid it is compelled to carry ; and there 

 is likewise a greater deposition of fluid and solid matter in the cellu- 

 lar texture of the inflamed part: for every secretory vessel is doing 

 increased duty in proportion to the blood with which it is supplied. 



In the minute ramifications of the vessels, the blood is changed 

 from arterial to venous ; and it is while this change is efiecting that 

 animal heat is extricated or produced. In inflammation, a great deal 

 more than the natural quantity of blood is passing through tiiese 

 vessels : a great deal more is changed from arterial to venous ; and a 

 great deal more heat must necessarily be evolved. 



The tenderness is caused by the unnatural distension of the vessels, 

 and by their pressure on the neighbouring parts, and also the pressure 

 of the natural deposit produced by inflammation. The nerves of sen- 

 sibility likewise unite very freely w ith the nerves of another order 

 that supply the capillaries; and when the nerves of the capillaries 

 are initated, those of sensibility will become irritable too, and the 

 part will become so tender as not to be touched without extreme pain. 



Internal Injlammation. 



Internal inflammation is characterised by other and often more in- 

 distinct symptoms. We can here seldom ascertain tiie heat or ten- 

 derness or swelling of the part, and can usually only judge of the 

 complaint by the effect which it produces on the system. Every in- 

 ternal inflammation does, however, soon affect the system. There is 

 no inflammation of any important internal part that is not quickly 

 accompanied by fever; and that fever and the degree of it are easily 

 ascertained, by the heat of the breath and the mouth and the base of 

 the horn, by the redness of the eye, and the frequency and hardness 

 4* 



