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 gpod 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 



