THE COMBAT AGAINST BOVINE TUBERCULOSIS 2Q1 
resist it. This side of the question is too commonly neglected, 
and nearly all of the attempts made to combat the disease have 
been directed solely toward devising measures for preventing the 
distribution of the bacillus. It is, however, impossible absolutely 
to prevent the bacillus from being distributed by diseased ani- 
mals, and occasional infection will occur in spite of all preventive 
measures. Without some efforts directed toward producing a 
healthy herd of resisting animals, it is quite certain that the 
endeavor to prevent the distribution of the disease will be unsatis- 
factory. 
It is doubtless much more easy to give the farmer directions 
looking toward the prevention of the spread of the bacillus, than 
it is to instruct him how he may increase the resisting power of 
his animals. But nevertheless some suggestions may be made 
which, if carried out, will certainly improve the conditions and 
induce better health and, hence, greater resisting powers. There 
is little doubt that in a majority of cases the cattle need more air. 
Too many are crowded together in a small space in the winter sea- 
son and there is too little ventilation of the cow stalls. In the 
attempt to keep animals warm, they have been too closely shut 
up in badly ventilated rooms, and they breathe the warm air over 
and over again. Such a condition, wholly independent of the 
tubercle bacilli which might be present, has a debilitating effect 
upon cattle, just as it does on men. Too frequently, even on the 
better farms, the cattle are shut up in the stalls early in the fall, are 
not allowed to go out during the long months of the winter, and 
never get a breath of fresh air. Sometimes the case is even worse 
than this, for many cows are thus shut up as soon as they begin to 
produce milk, and, winter and summer alike, remain in close, 
poorly ventilated rooms. To protect his cattle from cold the 
farmer makes his cow barn too warm and allows it too little air. 
To save trouble he keeps the cows housed all the time, with no out- 
of-door air; and to save expense he crowds them together in the 
smallest amount of space. ‘These facts show why so many animals 
