292 TUBERCULOSIS 
yield to tuberculosis in the colder countries. Warm rooms anda 
close crowding of the animals may result in a saving of food, but it 
invites the spread of tuberculosis if it once gains access to a single 
animal. In the human race it is well known that the best pro- 
tection against the disease, and the best remedy for it after it has 
once started, is out-of-door life. Doubtless the same is true of 
cattle, but this fact has been almost forgotten in the attempt to 
produce the most milk possible at the smallest expense. The 
farmer may perhaps insist that such crowded conditions are nec- 
essary and unavoidable in the modern farm, but he must also re- 
member that, whether necessary or not, they are certainly inviting 
tuberculosis and bringing his animals into a condition where they 
are sure to yield to the infection the first time that chance brings 
the bacillus in their vicinity. More outdoor life and more air 
are the prerequisites for a healthy herd. 
Anything which will induce a vigorous life will decrease the 
tendency to the disease. Proper food is an important factor in 
determining health. It may be difficult under the conditions of 
modern farming to allow the cattle to have proper exercise in the 
winter, but the lack of it is certainly one of the factors tending to 
increase the liability to tuberculosis. Too great attention paid 
to the increase in the yield of milk lessens the resisting power of 
cattle. Our agriculturists, by overfeeding with certain kinds of 
food, and by special high breeding for the purpose of increasing the 
yield of milk, are trying to turn an animal into a milking machine. 
The highly bred animals are, of course, useful for the purpose for 
which they are bred; but the agriculturist must remember that he 
cannot turn his cow into a simple milking machine without suffer- 
ing some evil results from the change in her nature. In short, if 
the cattle owner will learn that cattle are animals and not machines 
and that they need something besides food and water to keep them 
active, he will probably soon find the tendency to tuberculosis 
becoming less. 
