82 DISEASES OF THE HORSE. 
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 lamine 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, 
