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and four months. A general unthrifty look of the cattle, and a frequent cough, 
especially if the animals are turned out of a warm stable daily into the cool air, 
may be observed. Soon one animal and then another from different parts of the 
same stable droop and show signs of sickness. 
In Europe town dairymen have noticed that their first cases usually occurred 
in fresh cows, often transmitted to markets from healthy districts, but which 
have been confined in railway trucks or in markets in contact with sick cattle. 
These animals, bought at the time of calving, remain healthy until they come 
in season, and immediately after taking the bull show signs of the disease. It 
has been thought by town dairymen that they might prevent the disease if they 
could only prevent the cow going to the bull; and the idea of spaying has been 
entertained, though never adopted to any great extent. The experience of 
town dairymen affords a conclusive proof of the apparent length of the latent 
or incubative stage of the disease, and that experience is supported by numer- 
ous other observations and experiments. 
{ should be disposed to believe that the first changes in the lungs occur as rap- 
idly after ordinary infection as after inoculation, and experiments on this point 
are well worthy of being instituted. The period of incubation in inoculated 
eases may be as short as seven days. It is often nine, and there are eases, of 
which a considerable number have come under my observation, in which the 
local eruptions and swelling have not manifested themselves under twenty or 
thirty days. 
Invasion.—The earliest changes in the lung tissue occur slowly and without 
producing marked general disturbance. In examining infected herds it is 
usual to find animals in apparent health, which on auscultation reveal the ab- 
normal sounds caused by the rush of air through inflamed bronchial tubes. So 
latent is this condition that I have known expert butchers purchase cattle that 
I have ordered to be isolated. They have paid full prices, doubting my 
opinion; and on keeping the animals that they might improve in condition on 
extra keep, the outward symptoms of the disease have appeared in from 
one to three weeks from the date I had condemned them. At this stage there 
is usually a slight elevation of temperature, amounting to one or two degrees. 
Obvious premonitory signs—The obvious premonitory signs are shivering 
fits, as in ordinary fever, but their transient and mild character lead to their 
often being passed unnoticed. The animal’s coat looks dull, staring, and the 
skin is often rigid. An occasional cough of a dry and harsh character is no- 
ticed, and, when inspecting a herd in a field, if the cattle are made to move 
briskly several will be found to cough. For some days the cattle appear to 
thrive well, and milch cows yield a copious amount of milk. It has been re- 
marked that they appear full—indeed fuller in the early morning than other 
animals which, like them, had not fed since the previous evening. The exere- 
ment is dry and urine somewhat scanty. 
An expert dairymaid in the habit of milking cows where the disease prevails 
is apt to notice, as the malady declares itself, that there is some stiffness, and the 
milk is not so freely drawn as usual. The quantity of this secretion then 
diminishes. 
The progress of the malady is then characterized by loss of appetite, altered 
gait, segregation of the sick from the healthy in the field, the sick standing 
with their elbows turned outward, their feet drawn forward, neck and head 
extended, and nostrils somewhat convulsively expanded at each inspiration. 
There is quickness of breathing, especially if the animal is even slightly dis- 
turbed, and on the slightest movement there is an audible grunt. The ex- 
pression of countenance indicates uneasiness or absolute pain, and the eyes are 
prominent and fixed. The pulse rises to 70, 80, and even 100 beats per 
minute. In hot cow sheds the pulse is more frequent than in the open field in 
healthy cattle, and a corresponding increase is seen in this disease under simi- 
