BOVINE TUBERCULOSIS. 
365 
This would tend to show that direct transmission ol tuber¬ 
culosis from parent to offspring- is rare. As a rule, the off¬ 
spring of tuberculous parents is weak and predisposed to 
disease in consequence of the want of constitutional vigor to 
resist it. In the majority of cases tuberculosis is not directly 
transmitted; there is simply a constitutional weakness and 
predisposition, perhaps not especially to tuberculosis but to 
disease in general. 
Among the many predisposing causes of tuberculosis I 
would class anything that lowers or tends to lower the vital¬ 
ity of the system; anything that decreases or tends to de¬ 
crease the disease-resisting powers which all animals possess 
to a high degree ; and hereditary predisposition is probably 
one of the foremost of these causes, because for generations 
cattle have been bred for their milk supply, with a total and 
suicidal disregard for the general health and strength of the 
animal. 
Among the causes that have tended to produce this pecu¬ 
liar constitutional predisposition of dairy cattle probably the 
most important are confinement and want of exercise, poor 
ventilation and bad sanitary condition generally, with injudi¬ 
cious feeding and breeding. 
A German journal states “that in Canton Freiburg in 
1890, out of 14,142 housed animals there were 249 deaths, 
and 8.7 of these deaths were due to tuberculosis, while in the 
district in which the cattle were fed out of doors, the deaths 
from tuberculosis amounted to only three per cent, of the 
total losses; that is to say in the districts where the animals 
were almost constantly housed and fed unnaturally, the deaths 
were two and one-half times greater than where the animals 
were kept out of doors and fed naturally.” 
This is only what one would expect, as it is in close, ill- 
ventilated barns that the bacilli would naturally collect; and 
apparently no better proof of this could be found than the re¬ 
markable results obtained through improvement in ventila¬ 
tion in the French cavalry stables. 
After sanitary measures were adopted, cases in glanders 
in the cavalry horses fell from 23.32 per 1,000 in 1847-52 to 
