114 The Diseases: of Animals 
the lungs, with a partial closure of the glottis. It 
is an endeavor to remove some irritating substance 
from the lungs or throat. There are two varieties of 
cough commonly recognized by veterinarians. The 
“moist” cough, in which mucus is expelled, accompanies 
an excessive secretion and collection of fluids in the 
air-passages. The “dry” cough is of a hacking nature 
and indicates irritation of the throat or lungs. 
THE MUCOUS MEMBRANE 
The mucous membrane is the soft, smooth, pink 
lining of all the natural openings of the body. It 
lines throughout its length the alimentary canal, and 
all other organs to which the external air may be 
admitted. If any mucous surface is congested and 
red, it shows a general irritated condition of this 
tissue. Such a condition is observed in the disease 
ecmmonly called “pink-eye.” If the mucous mem- 
branes are abnormally pale, it indicates a debilitated 
or anemic condition of the body. A sudden and 
marked pallor of the mucous membranes accompanies 
an excessive loss of blood. If it is blue or slate- 
colored, a lack of oxygen in the blood is indicated. 
A yellow tint in the mucous membrane shows that the 
liver is deranged. 
EXCRETIONS 
The excretions of the body, the feces (dung), 
urine and perspiration, vary, in diseased animals, not 
only in quantity and appearance, but often in com- 
