THE 
VETERINARIAN. 
VOL. XII, No. 136.] APRIL 1839. [New Series, No. 76. 
HIPPO-PATHOLOGY. 
Diseases of the Air-Passages. 
By Wm. PERCIVALL, Esq. M.R.C.S., V. S. 1st Life Guards. 
THE conduits for the air into and out of the lungs are the 
chambers of the nose, the larynx, and the windpipe and its ramifi- 
cations, the bronchial tubes : altogether, these parts are comprised 
under the appellation of the air-passages. Similar parts, similarly 
connected, constitute the air-passages in man ; but between man and 
horse there is this difference — that the one is able to respire both 
through his mouth and nose, while the other can breathe but through 
his nose alone : the communication between the cavity of the mouth 
and the orifice of the windpipe being occluded by the soft palate, 
which in the horse is of extraordinary dimensions. To this fact, 
familiar as it is, I should say by no means sufficient importance 
had been attached in the consideration of the pathology of the air- 
passages. In consequence of the want of another outlet or entrance 
for the air, the nasal passages are in the horse made large and capa- 
cious, and from the circumstance of all the air respired having to 
pass through them, these passages necessarily become more under 
the influence of the aerial current — more obnoxious to any effluvia 
contained in that current — than the same parts are in man. Hence 
it is that catarrhal affections in the horse have their seat in the 
chambers of the nose in particular, and not in the mouth and throat, 
as in man ; hence it is, also, that glanders is (or rather used to be) 
a common disease in the former, while in man, unless it happen by 
inoculation, the disorder is unknown. 
The same difference of structure will, in a measure, serve to 
account for the extreme proneness of the horse to pulmonary af- 
fections. The nostrils being large and widely open for the admis- 
sion of air, the membrane lining the nose becomes so much the 
more exposed and subject to changes of temperature and to noxious 
effluvia in the air, whence it follows that inflammation is likely to 
be set up in some part of the nasal membrane, and from that 
part creep down the windpipe and settle upon the lungs. 
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