74 
CORRESPONDENCE. 
contagious pleuro-pneuraonia was not in existence, and we so re¬ 
ported. Our report, at that time in the minority, has been re¬ 
inforced by the post mortem and microscopic examination of 
sections of the lungs taken, and lately by a letter to Prof. Smith, 
of Toronto Yet. College, from Prof. Williams, of the Edinburgh 
Veterinary College, who witnessed one hundred post mortems of 
the American cattle slaughtered in Liverpool, said to be suffering 
from contagious pleuro-pneumonia. Williams reports that they 
suffered from simple pleuro-pneumonia, which was non-con¬ 
tagious. 
In my experience the incubative stage does not extend from 
one to sixteen weeks. During an enzootic of pleuro-pneumonia 
confined to the lower part of Westchester County, in the years 
1875—’76, I received and treated 360. In some cases in cattle the 
incubative stage was short. On one farm, in a dairy of 80 cows, 
three days after purchasing some cows from a drover, the inva¬ 
sion of the disease occurred, ushered in by a chill (rigors); eleva¬ 
tion of temperature, thermometer registering 102° to 104° F.; 
respiration increased in frecpiency and became spasmodic in 
character and abdominal; nostrils abnormally dilated; visible 
mucous membranes infected; suppressed cough ; loss of appetite; 
the flow of milk arrested, and, in the majority of cases, entirely 
suspended until convalescent. Auscultation and percussion re¬ 
veal abnormal sounds peculiar to disease of the respiratory 
organs. Convalescence sets in on the seventh or eighth day, 
and is completed in a majority of the cases on the twenty-first 
day. Under appropriate treatment 85 per cent recover. Such is 
my record ; and in my opinion cattle that have passed through 
an attack are better suited for dairy purposes in an infected dis¬ 
trict than fresh stock. In experimenting with milk of diseased 
cows fed to calves, I have failed to produce positive results. At 
Blissville the mortality from the disease was slight. The major¬ 
ity of the animals were slaughtered, and sold in the market as 
beef. This is not in keeping with a malignant disease theory. 
Again, in conversing and corresponding with veterinary surgeons 
and stockraisers, in various parts of the country, I have as yet 
failed to discover the innumerable quantities of animals affected, 
