388 
DISEASES OF THE RESPIRATORY ORGANS. 
disturbance, while a third condition, that cannot be defined, 
will lead to the production of occasional noises or sounds 
made only under peculiar circumstances; to these may be 
added certain other sounds, which are the result of habit, or 
under the influence of the animaFs will. 
Under the comprehensive classification of cc abnormal 
sounds in respiration,” we have, therefore, to notice four 
distinct divisions, which will include—1, animals suffering 
from recent disease of the respiratory organs, causing certain 
sounds during respiration under exertion; 2, animals whose 
breathing is attended with unnatural noise only upon occa¬ 
sions or under certain conditions; 3, animals whose respi¬ 
ration under exertion is invariably attended with abnormal 
sounds, consequent upon permanent organic derangement; 
and, 4, animals that make certain noises in respiration as 
the result of habit, or in the exercise of their volition. These 
divisions will probably include all the peculiarities of sound 
met with in the examination of the respiratory capabilities of 
the horse, in reference to which the most rigid scrutiny is 
usually required. The separate consideration of each section 
may assist in the establishment of what is much needed—a 
uniform method of examination and classification. 
TEMPORARY NOISES RESULTING FROM RECENT DISEASE. 
Depending upon the extent of the attack and its acuteness, 
will be the nature of the sound emitted during respiration. 
We shall, at different times, observe all possible variations, 
from the crowing respiration, resulting from laryngeal ob¬ 
struction, down to the slight whistle observed commonly when 
the horse is exerted while affected with a simple cold. 
So long as any decided noise is made in the act of breathing 
while the animal is at rest, it is evident enough that an acute 
cause is present, and any question of soundness does not 
occur; but in numerous instances, where the breathing at 
rest is perfectly natural, the slightest exertion will be followed 
by the occurrence of abnormal sound, either whistling or 
roaring, but most frequently the former. Sometimes it will 
be apparent in the trot, sometimes a canter will be necessary 
to elicit it, and even it may be a sharp gallop. During the 
exertion the animal may cough, or the subsequent examina¬ 
tion may detect soreness of throat, and at once afford an 
explanation of the unsoundness. Technically, it certainly is 
important to distinguish between such a case and one where 
the absence of all evidence of recent disease renders it 
probable that the animal is permanently unsound. In com- 
