RESISTANCE AGAINST BACTERIA. 335 



their resisting power against disease. It is the active, vigorous 

 cow, which produces perhaps but little milk and is not care- 

 fully housed by the farmer, that has the power of resisting 

 disease. At all events this is the most probable explanation 

 of the fact that high-bred cattle seem to yield so much more 

 readily to some diseases than do less valuable animals. In 

 short, the prevalence and the increase of some of the diseases 

 of domestic animals must be attributed, in no inconsiderable 

 measure, to the introduction into our herds of conditions of 

 life which lessen their resisting power, and not wholly to the 

 increasing chances of contagion due to closer contact of animal 

 with animal. That the latter phenomenon is also a factor is, 

 of course, evident. 



These facts are of the utmost importance for the agricul- 

 turist to understand. The conditions of life for his domestic 

 animals are, to a very large degree, under his immediate and 

 perfect control. He can regulate the amount of outdoor life 

 they have, their active or their sedentary life, their food, their 

 drink, and many other factors upon which depends their 

 physical vigor. He may keep his cow housed so that it has 

 little air; he may give it highly stimulating food and prac- 

 tically no chance to use its muscles ; or he can make quite a 

 different animal of it by changing its life and food. He can con- 

 trol the conditions of life among his animals far better than he 

 can, or will, those of his own life. In the conditions of civilized 

 life each individual demands his own personal freedom in regard 

 to all matters regulating the affairs of life, and he absolutely 

 refuses to be guided by rules and regulations, 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 hope to get people to adopt them. But the farmer has 

 absolute control over the life conditions of his cattle. He can 

 regulate their life as suits him, and he can, if he will, work out 

 among animals the problem of health and disease as it cannot 



