A New Disease of Cattle. 
241 
Treatment and prevention . — According to all the experience 
hitherto gained, Johne’s Disease is invariably fatal. The 
diarrhoea may be temporarily checked, but the loss of condition 
continues, and in the end the animal becomes so weak that it 
is unable to rise. The duration of the illness is variable. In 
one of the cases examined post mortem during the past year, 
the animal had survived for nearly a year after the onset of 
distinct symptoms, but sometimes the loss of condition is much 
more rapid, and death may occur in two or three months. 
At the present moment it is impossible to say what period 
usually elapses between time of infection and the onset of 
distinct symptoms, but in all probability the period of incuba- 
tion is often a long one, extending possibly to many months. 
Some precise information with regard to this point will pro- 
bably be gained in the future by experiment. Unfortunately, 
there is reason to fear that animals may be capable of spreading 
the infection some considerable time before they themselves 
show any decided symptoms. 
The disease being in the present state of our knowledge 
incurable, and affected animals being a source of danger to 
others kept in the same premises or pasture, it follows that the 
best course to adopt when the disease has been certainly 
diagnosed is to have the animal or animals promptly slaughtered. 
The manure of such animals ought either to be destroyed or 
spread on land that is going to be ploughed down. Unfortu- 
nately, on some farms the disease appears to have established 
a firm footing, owing to the fact that cases have occurred for 
years past, and that no measures have been taken to prevent 
the spread of the disease or the infection of the pastures. 
Any field that is specially infected might be used exclusively 
for grazing sheep or horses, as there is reason to believe that 
animals of these two species are not susceptible to the disease. 
Probably little or no benefit is to be expected from the applica- 
tion of lime or any other dressing to the pasture. 
J. McFadyean. 
Royal Veterinary College, London, N.W. 
VOL. (17. 
K 
