452 EQUINE CONTAGIOUS PLEURO-PNEUMONIA 
purulent in character. The pleural cavities generally contain a con- 
siderable quantity of fluid. Dieckerhoff states that from 30-40 liters 
of a serous fluid are occasionally present. The exudate is usually 
turbid and of an orange, grayish-red, brownish-red, or dirty-grayish 
color. It is generally mixed with numerous yellowish colored flakes 
which form a sediment when the liquid is allowed to stand in a glass. 
The pleuritic exudate sometimes consists of pure pus and less fre- 
quently of blood. The pleuritic exudate when present in large 
amount compresses the lungs and pushes them away from the thoracic 
walls. In case of recovery, the pleuritic exudate may become 
organized, binding the lungs to the costal walls and diaphragm. 
Various forms of fibrous, villous growths develop on the pleure. 
The reports show that the other organs of the body are usually in 
a state of parenchymatous inflammation and fatty degeneration. 
The muscular tissue of the heart is, as a rule, brownish-gray in color, 
soft, and suffers from cloudy swelling. In severe cases, it shows 
well-marked fatty degeneration, is of a clay color, and is occasionally 
sprinkled with a large number of small, yellowish-white foci. The 
liver is enlarged, of a clay color or sometimes icteric, and presents 
signs of fatty degeneration. The spleen is flaccid, its pulp increased 
and often sprinkled with hemorrhages. The kidneys may be swollen, 
friable and sometimes show numerous hemorrhagic foci. The lymph 
glands, especially the bronchial and mediastinal glands, are enlarged, 
softened, and exhibit on section a grayish-red color. The muscles of 
the body are soft, and of a yellowish-brown color. Small hemorrhages 
under the serous membranes are frequently reported. Slight endo- 
carditis may occur. The blood suffers less change than any of the 
solid organs. It contains an excess of polynuclear leucocytes. 
The mucous membranes of the stomach and intestines are fre- 
quently hyperemic, swollen, sprinkled with hemorrhages, and some- 
times even ulcerated. The bronchial mucous membrane is swollen 
and inflamed. 
In other cases, the lesions are those of lobar pneumonia, in which 
the stages of hyperemia, red hepatization, gray hepatization and 
resolution (in favorable cases) follow each other in regular order. In 
a fatal case post-mortemed by the writer the right lung was entirely 
involved, the left one being but slightly hyperemic. In non-fatal cases, 
the crisis is reached on the 5th or 6th day, after which resolution begins. 
As already stated the lesions in this disease are so exceedingly 
variable that, in addition to the more typical pneumonia, almost any 
