32 DISEASES OF THE HOBSE. 



of its fluid into the tissues surrounding them, but in passive conges- 

 tion we have a dark, thick blood which has lost its oxygen, instead of 

 the rich, combustible blood rich in oxygen which is found in active 

 congestion. 



The termination of congestion is by resolution or inflammation. In 

 the first case, the choked-up blood vessels find an outlet for the exces- 

 sive quantity of blood and are relieved ; the transuded serum or fluid 

 of the blood is reabsorbed, and the part returns almost to its normal 

 condition, with, however, a tendency to weakness predisposing to 

 future trouble of the same kind. In the other case further altera- 

 tions take place, and we have inflammation. 



INFLAMMATION. 



(Plates I and II.) 



Inflammation is a hypernutrition of a tissue. It is described by 

 Dr. Agnew, the surgeon, as " a double-edged sword, cutting either 

 way for good or for evil." The increased nutrition may be moderate 

 and cause a growth of new tissue, a simple increase of quantity at 

 first ; or it may produce a new growth differing in quality ; or it may 

 be so great that, like luxuriant, overgrown weeds, the elements die 

 from their very haste of growth, and we have immediate destruction 

 of the part. According to the rapidity and intensity of the process 

 of structural changes which takes place in an inflamed tissue, inflam- 

 mation is described as acute or chronic, with a vast number of inter- 

 mediate forms. When the phenomena are marked it is termed 

 sthenic ; when less distinct, as the result of a broken-down and feeble 

 constitution in the animal, it is called asthenic. Certain inflamma- 

 tions are specific, as in strangles, the horsepox, glanders, etc., where a 

 characteristic or specific cause or condition is added to the origin, 

 character of phenomena, or alterations which result from an ordinary 

 inflammation. An inflammation may be circumscribed or limited, 

 as in the abscess on the neck caused by the pressure of a collar, in 

 pneumonia, in glanders, in the small tumors of a splint or a jack; or 

 it may be diffuse, as in severe fistulas of the withers, in an extensive 

 lung fever, in the legs in a case of grease, or in the spavins which 

 affect horses with poorly nourished bones. The causes of inflamma- 

 tion are practically the same as those of congestion, which is the 

 initial step of all inflammation. 



The temperament of a horse predisposes the animal to inflamma- 

 tion of certain organs. A full-blooded animal, whose veins show on 

 the surface of the body, and which has a strong, bounding heart 

 pumping large quantities of blood into the vascular organs like the 

 lungs, the. intestines, and the laminae of the feet, is more liable to have 

 pneumonia, congestive colics, and founder, than lymphatic, cold- 

 blooded animals which have pleurisies, inflammation of the bones. 



