12 
W. ZUILL. 
It is due to a specific poison, which is the direct cause of the 
disease. 
It gains ingress into the system by the lungs, has a period of 
incubation of from ten to one hundred days, and induces compli¬ 
cations in the form of extensive croupous exudation into the 
parenchyma of these organs, and particularly into the lymph 
spaces, also upon the surfaces of the pleura. This finally results 
in consolidation of the lung, occlusion of the tubes, emboli 
of the vessels, and adhesion of the pleural surfaces. 
In some cases destruction of the lung tissue is extensive, rapid, 
and complete, thereby causing death from suffocation ; more 
commonly a lingering character of the disease manifests itself, with 
symptoms of blood poisoning, and great exhaustion from absorp¬ 
tion of the disintegrated pulmonary exudate, and death from 
apneea. 
CLINICAL FACTS CONCERNING PLEURO-PNEUMONIA BASED UPON PER¬ 
SONAL OBSERVATION. 
On the 22d of September, 1883, soon after the present out¬ 
break of contagious pleuro-pneumonia in this State, I visited 
Media for the purpose of investigating, and, if possible, tracing 
the origin of this disease; it having prevailed for several years 
among cattle owned by a Mr. Williamson, breaking out at fre¬ 
quent intervals without giving any evident cause to the attending 
cow leach. After a little questioning, the cause of the disease on 
this farm became so evident as to be scarcely overlooked by a 
most casual observer. 
It was stated that the disease first appeared on this farm two 
or three years prior to the present attack. Of the animals then 
affected one was still retained by him, and she had had a cough 
ever since. She was considered to be the best cow on the farm. 
Other facts elicited in the history show that new outbreaks of 
the disease on this farm have followed the introduction of fresh 
cattle. 
In the present case, four animals were brought on the farm, 
of which one had died of the disease and another was slaughtered 
by the State authorities twenty or thirty days after. 
