PLEURO-PNEUMON1A IN AUSTRALIA. 
173 
eases. Pleurisy, asthma, consumption, haemoptysis, tuber¬ 
cles, pneumonia, sporadic or malignantly epidemic, rank on 
the lists. Tubercular formations are extensively found in 
Victorian cattle, and are common enough in many of the 
New South Wales districts. These previous formations 
would doubtless accelerate the finale of pneumonia. Irri¬ 
tations of texture cause inflammations; serous membranes, 
like the pleura, produce adhesive lymph; this brings on con¬ 
gestions in the lungs; congestions preclude access of fresh 
air, and animals die of asphyxia. One of the most adverse 
conditions of this disease is the extreme debility which 
very soon is observable. So sudden a prostration of strength 
renders prescriptions of medicines exceedingly uncertain, and 
the quadruple stomachs of cattle make their effective ad¬ 
ministrations very doubtful, and the drugs too often inope¬ 
rative until too late. 
This pleura (commonly called skirts) is a serous mem¬ 
brane, which envelopes the lungs, and lines the cavities of 
the chest. 
The pleura costalis, or rib lining, is a fine sheet of elastic 
cellular tissue, attached to the sides. The pleura pulmonalis 
is placed on the exterior of the lobes of the lungs, and is 
believed to afford important aids to expiration. 
These two portions are continuous, and have a sac into 
which a small quantity of serous fluid is constantly secreted, 
which moistens the opposite superficies of the lungs, and at 
every expansion by inspiration of air causes them to play 
easily on one another; meaning the lungs, on the smooth 
pleuritic membranes. And it is here worthy of notice, that 
this pleura, and the peritoneum or enveloping membrane of 
the intestines and abdominal cavity, are both serous; and 
that whereas the first is ultimately severely inflamed in pleuro¬ 
pneumonia, so also is the other in Cumberland enteritis, thus 
showing their susceptibility to inflammatory diathesis. 
Inflammation of the pleura is always accompanied by ex¬ 
travasations on its internal surface, being coagulating lymph 
or serous purulency. 
This matter is partly absorbed, leaving often a dangerous 
coating. In course of time, adhesions ensue, and lung and 
pleura become united—a condition very common in the 
human subject. Whatever the causes, serous membranes 
seem very prone to inflammation, even more than the 
mucous. 
Pleuro-pneumonia is both infectious and contagious at 
certain periods and seasons. It may for a time assume a 
chronic type, and again burst forth with all the virulence of a 
plague. Certain states of the atmosphere which call into 
