INFLAMMATION OF THE LUNGS. 
235 
organized, impervious, hepatized. By careful examination with 
the ear, you will be enabled to get at this also. Where the lung 
is impervious—where no air passes—no sound will be heard, not 
even the natural murmur. Around it the murmur will be heard, 
and louder ; it will be a kind of rushing sound ; for the same 
quantity of blood must be arterialized, and the air must rush 
more rapidly and forcibly through the remaining tubes: and if 
there is considerable inflammation or tendency to congestion, 
the crepitating crackling sound will be recognized, and in pro¬ 
portion to the intensity of the inflammation. Gentlemen, I do 
not overrate the advantages to be derived from the study of aus¬ 
cultation. It was strong language lately applied by an able critic 
to the use of the stethoscope by the human practitioner; I would 
literally apply it to the use of immediate auscultation, that ‘Gt 
converts the organ of hearing into an organ of vision, enabling 
the listener to observe, with the clearness of ocular demonstration, 
the ravages which disease occasionally commits in the very centre 
of the ribbed-cased cavity of the body.” 
A horse with any portion of the lungs hepatized cannot be 
sound. He cannot be capable of continued extra-exertion; his 
imperfect and mutilated lung cannot supply the arterialized blood 
which rapid progression long continued requires, and that portion 
wdiich is compelled to do the work of the whole lung must be 
exposed to injury and inflammation from many a cause that would 
otherwise be harmless. Here are several specimens of hepati¬ 
zation. 
Tubercles .—Another consequence of inflammation of the sub¬ 
stance of the lungs is the formation of tubercles. There is a great 
deal of mystery, and there has been some acrimo’nious dispute, 
about this. It would seem that at first there are a greater or 
smaller number of little distinct cysts, cells into which some fluid 
is poured in the progress of inflammation : the cells become 
gorged, distended, and occupy a space varying from a pin’s point 
to a large egg. Here is a beautiful specimen of tubercles of the 
lung, each nearly the size of a filbert. Here is another in w’hich 
they are more numerous, but not so large as the smallest millet- 
seed. This last belonged to a glandered horse. 
By degrees the fluid becomes concrete; the little tumour is 
much harder than the surrounding substance, and so it continues 
for a while—the consequence and the source of inflammation. 
It occupies a space that should be employed in the function of 
respiration, and by its pressure it irritates the neighbouring parts, 
and exposes them to inflammation. 
By and by commences another process, never sufficiently ex¬ 
plained. The tubercle begins to soften at its centre,—^a process 
