402 MR. youatt’s veterinary lectures. 
ble to force it by a single effort, or even perfectly by the double 
effort that characterizes broken wind. The structure of the lung, 
and the discharge of function, and the treatment, too, being so 
different, these diseases require separate consideration. 
Thick Wind. 
Hepatization. —When speaking of pneumonia T observed, that 
not only are the vessels which ramify over the delicate membrane 
of the air-cells gorged with blood, but they are sometimes rup¬ 
tured, and the cells are filled with blood. The black, softened, 
pulpy appearance of the lung thus produced, is the rottenness of 
the groom and farrier, proving equally the intensity of the in¬ 
flammation, and that it is of recent date. If the horse is not 
speedily destroyed by this lesion of the substance of the lungs, 
the serohs portion of the effused blood is absorbed, and the solid 
becomes organized. The cells are obliterated, and the lung is 
hepatized, or its structure bears considerable resemblance to the 
parenchyma of the liver. This may occur in patches, or it may 
involve a considerable portion of the lung. 
Effect of this on liespiration. —Now the horse has no lung to 
spare in the performance even of the ordinary service we require 
from him, much less under the cruel tasks which we sometimes 
impose upon him. If, therefore, a portion of the lung is thus 
rendered impervious, the remainder will have additional work to 
perform. The same quantity of blood must be supplied ; and if 
the working part of the machine is diminished, it must move 
with greater velocity as well as force,—the respiration must be 
quicker and more laborious. This quick and laboured breathing 
can be detected even when the animal is at rest, and it is indi¬ 
cated plainly enough by his sad distress when he is urged to 
unusual or continued speed. The inspirations as well as the 
expirations are shorter, as well as more violent; the air must be 
more rapidly admitted and more thoroughly pressed out; and 
this is accompanied by a peculiar sound. I have called it a 
half-roaring, that can rarely be mistaken. 
Vomicw. —The healthy structure of the lung is rarely or never 
restored when the air-cells have been once filled with, and obli¬ 
terated by, this organized deposit. The hepatization, however, 
does not always remain, for the organization is not complete; it 
does not perfectly resist various and perhaps slight causes of de¬ 
composition, and a softening process usually commences. This 
deposit, or some portion of it, begins to dissolve. I know not 
how we are to ascertain the commencement of this change, or to 
take advantage of it if we could discover it: the membfane has 
