ON THE LUNGS IN BRUTE ANIMALS. 
5 
bones have still less ; while the integument has scarcely any. 
This will materially lessen the comparative quantity. In the 
frame there are various circumstances of retardation ; the vessels 
take a tortuous course—they run in opposite directions —they wan¬ 
der through many a gland, in which the blood is purposely delayed 
for the accomplishment of some important function: but the 
vessels of the lungs take a direct course ; there is nothing to di¬ 
vert or to retard the current, so that a considerable portion of the 
blood which they contain enters the heart at each dilatation of 
the auricle, while a far smaller proportion of the blood of the frame 
generally is then received. That which is deficient in bulk is 
fully supplied by the directness and shortness of the course, and 
the rapidity of the current; beside, the lungs are close to the 
heart; all its power is felt by them, while the blood has begun to 
loiter in its course before it reaches many of the distant portions 
of the frame. 
Transmitting the Whole of the Bloody the Lungs are easily in¬ 
flamed and disorganized, — If, however, it is true that the pul¬ 
monary circulation counterbalances that of the whole frame beside, 
and even of that portion of itself which belongs to the general capil¬ 
lary system, we shall be enabled to account for the prevalence of 
disease in this organ above any other, and especially in that 
shamefully abused animal the horse. When we consider the 
extra labour of these vessels, which is so often required, in order to 
supply the increased consumption of arterialized blood in rapid pro¬ 
gression ; the irritation to which the membrane of the bronchial 
tubes is in some measure exposed, notwithstanding the guard of 
the larynx and the Schneiderian membrane, from contact for so 
many hours with the irritating and empoisoned air of a filthy 
stable; and more especially when we regard all the sympathies 
which such an organ must have with every other, and particularly 
the sympathy which daily experience tells us it has with the 
functions of the skin, and the discharge of the perspiration, sen¬ 
sible and insensible, can it be wondered at that it is so subject to 
inflammation, so difficult to subdue, and often so fatal ? Inflam¬ 
mation is increased action of the capillary vessels; this organ is 
made up of them, and they become engorged, and the substance 
of the lung increases under inflammation with a rapidity un¬ 
equalled in any other part. The walls of these vessels are ex¬ 
ceedingly delicate ; they are of a gossamer structure, in order to 
admit of the escape of the carbon, and the imbibition of the oxy¬ 
gen ; and, when they are distended with blood, it is scarcely 
conceivable how soon it begins to filter thi’ough them. We hear 
it in the very act of filtering, if we apply our ears to the side of 
the animal; and it penetrates into the interstices of the cellular 
