332 AGRICULTURAL BACTERIOLOGY. 



times an individual shows a great tendency to develop boils or 

 abscesses, and but little power of healing them. We say his 

 " blood is in bad condition." By this is really meant that his 

 body activities are so repressed that he is unable to resist the 

 invasion of some of the common bacteria which are present on 

 every hand, and which an individual in vigorous condition 

 easily repels. If his physical vigor can be restored the 

 troubles will disappear, although the bacteria which produce 

 the boils and abscesses are just as abundant around him as be- 

 fore. The same principle may be applied to all attacks of 

 parasitic bacteria. Physical vigor is the best protection against 

 the invasion of parasitic bacteria, and a weakened physical con- 

 dition invites attack. 



This matter is emphasized here because it is too generally 

 lost sight of in the combat against infectious diseases. During 

 the past two decades there has been a very general tendency, 

 in the attempt to avoid diseases, to place the whole emphasis 

 upon the methods of avoiding bacteria. This has been very 

 natural since the demonstration of the causal connection of 

 bacteria and disease. If a disease is produced by a bacterium, 

 what more natural method could be suggested for avoiding it 

 than to avoid the bacterium ? In accordance with this idea 

 there has developed, on all sides, a long series of rules and 

 regulations suggested by bacteriologists and adopted by health 

 boards, all designed for the prevention of the distribution of 

 disease germs. This is indeed the foundation of modern sani- 

 tation. 



At the present time there is a manifest reaction against this 

 one-sided attitude. No one fails to see the importance of this 

 attempt to prevent the distribution of bacteria by any practical 

 means, but there is to-day a growing recognition that there is 

 another side of the question. The strengthening of personal 

 vigor is of no less importance, many believe it is of more 

 importance, than the prevention of the distribution of bacteria. 



