450 EQUINE CONTAGIOUS PLEURO-PNEUMONIA 
increased but later becomes slower. There is general depression, 
usually loss of appetite and muscular weakness; the conjunctive and 
other visible mucous membranes become congested. There may be 
from the beginning marked indications of localized lesions in the lungs, 
or the general symptoms may continue without evidence of pronounced 
lung disturbance. Many symptoms may be exhibited, corresponding 
to the variations in the morbid processes. If the heart, digestive 
tract, liver, kidneys or brain become the localized seat of the disease, 
symptoms referable to impaired functions of these organs are in 
evidence. The septicemic form has been described as being followed 
by localized suppurative lesions. G 
The duration of the disease varies. The high temperature lasts for 
from five to eight days in the typical cases. The convalescence 
requires from two tofour weeks. If there are complications the course 
may be much longer. 
The mortality is often very high. The literature shows it to vary 
from one to thirty per cent. It frequently leaves animals practically 
worthless because of pleural adhesions and other complications. 
Morbid anatomy. The morbid changes in the tissues and organs 
vary according to the course of the disease, which is exceedingly 
irregular. There may be a regular form of lobar pneumonia, or the 
disease may run an atypical, complicated, acute, chronic, and not 
infrequently an abortive course. Further, authorities agree that 
many complications may arise modifying or changing completely the 
morbid anatomy of the disease from the conditions found in the more 
typical cases. In the few cases examined post-mortem by the writer, 
the gross lesions were restricted to the lungs. These were either in a 
state of congestion, or exhibited changes of fibrinous pneumonia in the 
cephalic (anterior) portions of one or both lungs. Pneumonia is the 
most common localized lesion. Several quite distinct forms of lung 
disturbances are described. ; 
According to Gaffky and Lithrs, “the local changes in the lungs 
begin in the finest branches of the air passages. In the beginning 
of the disease there is secreted a glassy, transparent, slightly gela- 
tinous, yellowish material. This is surrounded by a thick layer of 
cells and a serous infiltration. In the region of the affected bronchi 
the alveoli are filled with a fluid rich in cells. 
“In those places where the disease foci are near the pleura there 
is an infiltration of the subpleural tissue with a transparent, yellow- 
