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diseased tissue. The admissions of air through the air passages into these cavi- 
ties by dissolution of the lung tissue lead to the cavernous sounds which the 
ear can detect .in the living animal, and the broken-up tissue decomposes and 
induces great foetor of the breath. 
One lung may have several points diseased; each lobe may be affected and 
little or no communication between the several parts implicated. The great 
tenacity of a yellowish white deposit around a marked marbled centre of dis- 
ease has been said to indicate a certain tendency to limitation by the formation 
of a capsule, and several encapsulated centres may be found. 
On taking a warm diseased lung, severing the still healthy portions, making 
incisions into the parts solidified, and suspending them so that they may drain, 
a large amount of yellowish serum of a translucent character, almost wholly 
free or more or less tinged with blood, is obtained to the extent of pounds in 
weight. ‘The amount varies with weight of diseased lung drained. 'The quan- 
tity of this and solidified deposit in a diseased lung is so large that from a nor- 
mal weight of four or five pounds, a lung attains to 10, 20, 40, and I have seen 
one as high as 54 pounds in weight. 
Air passages.—The condition of the air passages varies from a condition of 
perfect freedom down to the diseased portions of lung, to a state in which the 
mucous membrane is coated with false membrane or solid exudations of lymph. 
By suitable means it is not difficult to isolate the solid white lymph clogging 
the terminal bronchial tubes and air vesicles in the consolidated tissues, but at a 
distance from these parts it is only in some cases that a kind of croupy compli- 
cation exists. I have seen an animal gasping for breath, with its mouth open, 
nostrils widely expanded, eyes prominent, and visible mucous membranes of a 
bluish red color; on opening the air passages of this cow after death, they 
were found throughout their whole extent nearly filled with a deposit similar to 
that usually found on the surface of the diseased lung. 
There is little necessity for prolonging this description of cadaveric manifes- 
tations. ‘The heart’s sac is sometimes thickened by deposits around it. Not 
unfrequently it contains an excess of serum. The heart itself is contracted and 
pale, containing a little dark blood. ‘The organs of digestion at different stages 
manifest a state of dryness. he third stomach, which is so constantly packed 
with dry food in febrile diseases, is in the same condition in pleuro-pneumonia. 
I have known the mucous layers spotted with irregular or circular congestions 
or blood extravasations, and the membrane softening in these parts has become 
perforated. In advanced cases there is more or less diffuse redness, and even 
blood extravasations in the large intestine with fluid, fetid and sometimes 
slightly blood-stained excrement, such as is discharged during life. 
The anzemia or bloodless condition of other tissues, the dark dry look of the 
meat dressed by the butcher, the yellow color of the fat in some cases, and the 
small quantity of fat left in animals that have succumbed under a chronic attack, 
are all general signs of greater or less value, when taken in conjunction with 
the changes occurring in the chest. 
VI. HISTORY OF THE LUNG PLAGUE. 
It is only necessary for the present purpose to refer briefly to the history of 
contagious pleuro-pneumonia in order to show where and how this disease has 
traveled in the Old World ; its importation into America, and the alarming char- 
acter of its present existence at remote parts of this continent. 
History abroad—The contagious pleuro-pneumonia of cattle is a disease 
doubtless of the greatest antiquity. All reliable records point to the simple 
truth that has to be told of many contagious disorders, that it has travelled 
from the east westwards. Older writers confound it with rinderpest, and a host 
of other maladies. It was only towards the end of the last century that the 
