CONTAGIOUS PLEURO-PNEUMONIA. 
499 
Animals have been known to carry the disease in their systems 
for long periods, ranging from three to fourteen months, without 
evincing any outward symptoms that could be detected by the 
veterinarian, and were only discovered after they had infected 
other animals with which they came in contact, and with them 
were slaughtered. 
Again, the disease may verge into the chronic stage, and the 
diseased portion of the lung become encysted, or enclosed in a 
cyst or sac; it is said so long as this remains intact they are 
harmless, but let it once break down and the diseased portion 
become liquified and pass into the bronchial tubes, the contagion 
is thrown off with the breath and impregnates all the animals that 
are in immediate contact. 
That this theory is not generally accepted by those interested 
in the eradication of the disease in this country, I am well aware, 
and I have taken great pains to fortify myself with the results of 
the experience of some of the most practical workers and eminent 
scientists that have given attention to the symptoms and rages of 
pleuro-pneumonia. 
In Pennsylvania, the State that I have the honor to represent, 
Dr. Francis Bridge has possibly had as large an experience in this 
disease as any person in the United States. In frequent con¬ 
versations, and in several letters hereto appended, he states most 
unqualifiedly that the disease can only be communicated by con¬ 
tact with the living diseased animal. 
In his experience as an inspector for over seven years he has 
seen numerous instances in which healthy animals have been 
placed on farms and in buildings from which diseased animals had 
recently been removed to other quarters, or for slaughter, without 
any disinfection or purifying process being used, but buildings 
and litter allowed to remain just as they were when the diseased 
animals were taken out. 
He cites one instance where, by accident, healthy animals 
during the night broke into an enclosure where the carcass of an 
animal affected with pleuro-pneumonia that had been killed, was 
allowed to remain unburied, and came into direct contact with 
