114 
ON DISEASES OF THE LUNGS IN HORSES. 
The Causes of Pulmonary Disorders will, in a general 
way, be found in the air horses breathe, and in the work they 
perform: in fact, they may be said to date their origin from the 
time the animal is taken into the stable and made the servant of 
man—in one word, from domestication. 
The Air the horse is compelled to breathe while confined in 
his stable may be cold or heated, moist or dry, pure or impure, 
considered in relation to the atmosphere out of doors. There can 
be no doubt that either excess of temperature—cold or heat— 
must prove excitant to the membrane lining the pulmonary pas¬ 
sages; and yet it is a notorious fact, that horses usually enjoy 
vigorous health in frosty weather. Cold with damp, however, 
has certainly an unfavourable operation. Wet springs and au¬ 
tumns are commonly productive of a good deal of sickness. Is 
this to be ascribed to any direct effect upon the air-passages, or is 
it to be attributed to some operation upon the skin ]—and parti¬ 
cularly since these are the moulting seasons'? In the latter case 
the lungs become secondarily or sympathetically affected. Even 
here, however, we appear to require the presence of some stimu¬ 
lant—such as heat or foul air—before disease will shew itself; 
for horses out in the open air during such insalubrious seasons, 
rarely, if they do at all, contract the prevailing malady. In a 
general way, and in regard to its direct operation upon the bron¬ 
chial membrane, cold must be regarded as a predisponent to dis¬ 
ease ; and not so much cold by itself, as cold with humidity, or 
even a particularly drying cold: the probability being that the 
effects are not owing simply to any sedative operation the cold 
may have on the membrane, but also to the effect produced upon 
it as a surface exhaling and constantly covered with a mucous 
secretion. Cold, then, with more or less moisture than is usually 
contained in the atmosphere, being considered as the predisponent, 
our next inquiry must be after the immediate excitant. The late 
Professor Coleman was in the habit in his Lectures of attributing 
great influence to the foul air engendered in stables by effluvia from 
the dung, urine, and breath; and perhaps, in combination with 
heat, there exists no more fruitful source of disease of the pul¬ 
monary apparatus: but I have my doubts whether foul air without 
heat is often productive of such effects. At the time I did duty 
with the army in the Peninsula, I remember well that most of our 
stables, or places used as stables, were dirty and filthy in the ex¬ 
treme, being either without any pavement at all, or so badly paved, 
that there was nothing like sewers or drains to carry off the 
urine; and that they were in many places all but roofless, and in 
most places in a dilapidated condition. In these situations the 
horses and mules of the army bred farcy and glanders and mange. 
