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In the earliest stages of pleuro-pneumonia the deposit of lymph on the serous 
covering of the ribs and lungs produces a leathery friction sound, and as liquid 
aceumulates in one or both cavities of the chest the respiratory murmur is lost 
towards the lower part of the affected side or sides, and it is alone distinct over 
the upper portions of pervious lung tissue. 
A careful examination of the chest reveals day by day the progress of the 
disease. When one lung is affected an animal is much more likely to recover 
than when both are diseased. Portions of the diseased lung tissue are apt to 
die, and becoming detached or softened, producing cavities on the lungs, which 
are indicated by a cavernous rile or sound somewhat similar to that produced 
by blowing air in the hollow of the hands when closed against each other. 
By parerul auscultation the cases that tend to don veleseeee may be dis- 
tinguished by less marked roughness in the inspirations, and a gradual though 
slow return of the respiratory murmur, with increased mobility of the ribs and 
easier movement of the flanks. 
Termination.——Cases of lung diseases in cattle end in partial or complete res- 
toration to health or death by prostration, suffocation, purulent fever, or hectic. 
As a rule, when a herd of cattle has suffered from the contagious pleuro-pneu- 
monia, the surviving animals whenever slaughtered show old adhesions, partial 
collapse of the lung tissue, atrophy or wasting, of the lung, thickness of the 
heart’s covering or pericardium, and sometimes chronic abscess. Complete 
-recovery without leaving the slightest traces of pre-existing lesion occurs. It 
has been noticed that cattle that have once had pleuro-pneumonia fatten more 
readily than others. 
Death supervenes during the acute attacks of the disease from shock, prostra- 
ition, or gradual suffocation. When animals linger on for some time in the blood- 
less state peculiar to this disease,and which is mainly due to the great drain on 
the system by the immense discharge which occurs in the substance of the lung 
and cavities of the chest, a permanent impairment of the functions of nutrition 
‘or assimilation occurs, and although the appetite may be partially restored, emaci- 
ation advances, and the animal sinks. A terrible diarrhoea or dysentery usually 
accompanies this form of disease. 
In other cases abscesses form in and around the lungs and in other parts of the 
body, and the animals die of purulent infection. Occasionaliy a cavity formed 
by the breaking up of diseased lung tissue communicates with the pleural sac or 
cavity of the chest, and a condition known to pathologists as empyema results 
to the certain destruction of the animal. 
‘Duration of the disease.—Aftected animals usually pass through an incuba- 
tive stage varying from 20 to 80 days, and usually averaging from 25 to 40 
days. The acute stage of the disorder varies from 7 to 21 days. Convalescence 
extends over.a period of one, two, and even three months, during the greater 
part of which the convalescent animal is often capable of infecting healthy 
cattle. 
The mortality varies from 1 to 90 per cent. of the affected animals. When 
a first case is isolated early all the remaining animals may continue to enjoy 
health. As arule in mild outbreaks the mortality obtains 25 per cent., and in 
severe cases 60, 70, 80, and even 100 per cent. 
In England the lung disease bas doubled the usual cattle mortality of the 
country, and during many years 50 per cent. of the cattle that have died of 
disease have died of the contagious lung disease. 
Latent form—lt is necessary that I should draw special attention to the large 
number of cases which run an insidious course and pass unobserved. These 
are the most dangerous, as less care is paid to their isolation. 
Relapsing form.—An animal affected with contagious pleuro-pneumonia may 
to all appearances recover, the affected lung becomes limited by a capsule of 
solid lymph, and convalescence may apparently advance for some days, or even 
