828 
PLEUROPNEUMONIA. 
character. In the history of the malady many titles occur, 
but, singularly, none of them distinguish the disease, which 
is so unlike any other disease of the respiratory organs, from 
ordinary inflammation. The expression which is now in use, 
pleropneumonia, is by common consent made to mean inflam- 
mation of the lungs and pleura in all animals except the ox, 
but when applied to him it refers to an affection which is not 
inflammatory in any of its stages, and never presents any of 
the phenomena which are associated with inflammation. Of 
all the expressions which have been employed, exudative 
pneumonia , although not strictly correct, conveys the most 
exact idea of the peculiar character of the lesions which are 
distinctive of the disease ; the exudation of fibrinous material 
into the fibrous or connective tissue which exist between the 
small, many-sided masses (lobules), that make up the sub- 
stances of the lungs. The various local terms, lung disease, 
“ lung pest,” “ distemper,” “ murrain,” “pleuro,” are scarcely 
more objectionable than the professional term pleuropneu- 
monia; indeed they may be said to share with it the objec- 
tion that they are indefinite even when they are not abso- 
lutely inapplicable. It is, however, too late to attempt to 
get rid of the word pleuropneumonia as applied to the epi- 
zootic of cattle, and it becomes, therefore, necessary to insist 
upon its restriction to the particular disease in cattle to which 
it is constantly, but not invariably, applied. In reference to 
inflammation of the lungs of other animals the word will 
continue, as a matter of course, to be used, but considering 
the comparatively rare occurrence of ordinary inflammation 
of the lungs of the ox tribe, pleuropneumonia may, without 
inconvenience, be adopted exclusively as the title of the 
epizootic disease, which is always distinguished by inter- 
lobular exudation. 
Pleuropneumonia is essentially determination of blood to 
the lungs, and exudation of liquor sanguinis, that is to say, 
blood deprived of its red particles into the connective tissue 
which is everywhere distributed throughout the lung struc- 
ture, existing abundantly between the lobules and on the 
surface of the lungs under the pleural membrane. Exudation 
occurs also on the surface of the pleura, but the chief deposit 
takes place under it, and causes its elevation from the lung 
tissue just as the exudation between the lobules causes them 
to separate from each other. 
At the commencement of the local disturbance a portion 
of one lung will be found to present the appearance of con- 
gestion, not to any great extent, but sufficiently to render 
that part of the organ quite distinct from all other parts ; the 
