277 
Pneumonia — St. Pancras School. 
\^Extracts, GleaningSy and ReminiscencesJ\ 
About thirty years ago this disease was not understood, 
although it is one of the most frequent that occurs. Farriers 
called it the yellows ; they scarcely knew what the lungs meant. 
This disease kills more horses than all the other disorders put 
together. 1 hope I have sufficiently informed you of the nature 
of the lungs. I have told you that they are composed of cells 
very similar to an honeycomb; have either a direct or indirect 
communication one with the other, and also with the windpipe 
by means of the bronchial tubes, and thence to the nose; and 
that these cells are for the purpose of receiving atmospheric air; 
and that the blood in passing through the lungs undergoes an 
important change. 
When a horse is attacked with this disease, he is said to have 
caught a cold. That horses, from being exposed to wet and cold 
air, may not catch this disease, I am not prepared to say; but if 
they do, it is a most uncommon case. Sir James McGregor, 
principal surgeon to the army during the campaign with the 
Duke of Wellington, says, that all that part of the army who 
were encamped on the mountains were, to his suprise, in perfect 
health, for from the severity of the season he expected to have 
a great many pneumonic patients. But the great majority of 
those who were comfortably situated, and w'ho had warm beds 
and good living, were attacked with catarrh and inflamed lungs. 
In the human subject, exposure to colds and cough tends to 
produce the disease; but it is not the cause of it. It makes them 
more susceptible of heat: cold of itself is a strong sedative. If 
you look around you, you will see many hundreds of persons who 
are exposed to low temperature, and never become thus diseased. 
But let them be exposed to hot air, and that has been breathed 
again and again, and it is this that does the mischief and injures 
the windpipe and lungs, and will produce inflammation of the 
lungs. 
This, however, is not the only cause : any thing that excites a 
greater degree of action of the heart and arteries, as violent 
exertion, will produce this disease. This is by no means a frequent 
case in man; for in him it is almost always caused by a poisoned 
atmosphere ; but the horse is almost the only animal in whom in¬ 
creased exertion produces it, and for the most obvious of all 
reasons, because he is the only animal that can be compelled to 
move when distressed in his breathing. The ox, ass, or even dog 
is suffered to be at comparative rest; but the poor horse, in his 
VOL. VI. ^ n 
