ACQUIRED RESISTANCE. 257 
of life among animals far better than we can, or will, those of our 
own life. In the conditions of civilized life each individual de- 
mands his personal freedom in regard to matters regulating his own 
affairs, and he absolutely refuses to be guided by rules and regula- 
tions, even though he may know them to be for his best physical 
good. No matter how good rules for living our physiologists may 
make, they cannot force people to adopt them. But the farmer has 
absolute control over the life conditions of his stock. He can 
regulate their life as suits him, and he can, if he will, work out among 
cattle the problem of health and disease as it cannot be worked out 
among men. He may, by breeding, produce animals with some 
valuable feature most extremely developed, but in so doing he 
must remember that he is producing abnormal animals that are 
likely to have little resisting power against disease. He may feed 
them with stimulating food and force them in lines which suit him; 
but he must bear in mind that there is a limit to the possibilities, 
since all of these methods of treatment lead to abnormal conditions 
and to greater liability to disease. 
The adoption of precautions for preventing the distribution of 
disease germs is doubtless a matter of very great significance; but of 
more significance still is the endeavor so to modify the conditions of 
life as to increase their resisting power against these bacteria. In 
every case, doubtless, the plan adopted will be by the way of com- 
promise, and will be such as to give the greatest amount of physi- 
cal vigor consistent with the ends which the farmer has in view in 
his use of the animals. To turn them out into the fields with no 
attempt to produce special types, and with no high feeding, would 
doubtless produce a vigorous breed, but it would not produce milk. 
ACQUIRED RESISTANCE. 
Some species have a perfect resistance to the diseases that other 
species will take, a condition called race immunity. Some individuals 
will resist a disease that others of the same species cannot resist, and 
this is individual immunity. An individual may also develop a 
resistance to a disease which he did not at first possess. This is 
