524 DISEASES OF THE HORSE. 
The lesions of the lungs may be scattered throughout both lungs, 
involving numerous small areas, or they may be confined to and more 
or less fully occupy one or two lobes. Occasionally there is a general 
involvement of both lungs. The body temperature has now reached 
104° or 105° F., or in extreme cases even a degree higher. The de- 
bility of the animal is great without the stupefaction or evidence of 
cerebral trouble, which is constant with such grave constitutional 
phenomena in influenza or severe pneumonia. The animal is sub- 
ject to occasional chills, and staggers in its gait. The yellow colora- 
tion of the visible mucous membrane is rendered pale by infiltra- 
tion of the liquid of the blood into the tissues; the pulse may become 
so soft as to be almost imperceptible, the heart movement and sounds 
being at the same time exaggerated. The animal loses flesh rapidly, 
and dropsies of the extremities, of the under surface of the belly, or 
of the internal organs may show themselves. 
Terminations —These symptoms may gradually subside after five 
to eight days, with an improved appetite the inanition may cease and 
the animal commence to nourish its impoverished blood and tissues; 
the pulse becomes stronger and the heart more regular and less 
tumultuous; the mucous membranes assume a brighter and more 
distinct color; the difficulty of respiration is removed, and the ani- 
mal may make a recovery. When death occurs it is usually directly 
due to heart failure; in some cases it is caused by asphyxia, owing to 
the great amount of exudation into the lung tissue, rendering its 
further function impossible. 
Complications —The pulmonary complications of infectious pneu- 
monia are secondary inflammatory or necrotic changes in the lungs 
themselves. Suppuration at times takes place in the bronchi and 
may extend to the lung tissue. In this case mucous rales develop 
which are most distinctly heard over the trachea and on the sides of 
the chest directly behind the shoulders. With the development of 
the mucous rales, to be heard on auscultation, we have a more puru- 
lent discharge from the nostrils, similar to that of a chronic or sub- 
acute bronchitis. If the inflammation has been of some standing, 
cavernous rales may be heard, indicating the destruction of a con- 
siderable portion of lung tissue and the formation of a cavity. The 
effects of this more acute inflammatory process are not appreciable in 
the general condition of the animal, except to weaken it still further 
and add to its debilitated and emaciated cachexia. Gangrene some- 
times occurs. A sudden rise of the body temperature of 1° or 2°, 
with a more enfeebled pulse and a still more tumultous heart, develop 
simultaneously with the appearance of a discharge from the nostrils. 
This discharge is gray in color, serous or watery in consistency, 
mixed with the detritus of broken-down lung tissue, and sometimes 
contains clots of blood, or in more serious cases may be marked by 
