576 ON PERIPNEUMONIA IN CATTLE. 
We have found a well-defined line of separation between 
such parts of the lung as remained sound and such parts as had 
become diseased. The former yielded to atmospheric pressure 
and to that of the finger, and was quite light, owing to the 
quantity of air it still contained. 
By the sides of the sound lobules were others of a deeper 
colour, which somewhat resisted pressure ; these contained 
new blood and less air. Oftentimes we found them surrounded 
by a liquid of a bright yellow colour, which was contained 
within the cellular tissue separating each lobule from the sur- 
rounding ones. These constituted the recent changes. 
In other lobules the disease appeared of older date. These 
lobules were much redder, some even black, and were more 
solid than those which were yet but slightly reddened. Around 
them were some septa, whitish-yellow fencings formed of the 
interlobular parenchymatous tissue, containing but a very little 
fluid. 
Lastly, in the advanced stage of the disease (but animals 
often die before they arrive at this stage) the pulmonary lobules 
become soft and lose much of their deep tinge; and sometimes 
the places where they were, become filled with a liquid, 
greyish, odourless matter. At this time, nothing is left of the 
anatomical element of the lung save the interlobular cellular 
tissue, now become thickened and substantial. When these 
lobules come to be washed, or even when we wash the portions 
of lung in which collections of matter appear in their places, the 
cases in which the lobules are contained become apparent. In 
these are to be seen perforations like those of a large sponge. 
The entire of the proper tissue of the lung has vanished — all 
that served to bring the blood under the influence of atmo- 
spheric air. Nothing remains but the cellular envelope, and 
that is thickened, hardened, and diseased. 
The same changes which pervade the cells of the interlobular 
reticular tissue are to be found in the cellular tissue attaching 
the pleura to the lungs. 
The pleura becomes involved in disease before, during, or 
after the lungs become so. A quantity of serosity may be 
found in its cavity, and, swimming in the fluid, masses of 
yellow substances, readily broken to pieces. Flocculi of the 
same substance are attached to the surfaces of the lungs. 
Bands and bridles of it are to be seen running between the 
pleura (costalis) and the lung, and the latter and the diaphragm. 
Instead of being loose within the cavity, the lung is attached to 
its walls. 
The serous membrane of the pericardium at times contains a 
much larger quantity of liquid than is found in a state of 
