PHYSICAL DETERIORATION. 57 



numbers of the phthisical type that would have been 

 born with each generation. 



If we stamp out Infectious Diseases we perpetuate 

 Poor Types. 



It is a hard saying, but none the less a true one, 

 that the bacillus tuberculosus is a friend of the race, 

 for it attacks no healthy man or woman, but only the 

 feeble. It is like the bacillus of leprosy in this 

 respect, but in this respect only, for leprosy attacks 

 anyone living under certain unhygienic conditions. 

 Remove these conditions as we have done long 

 ago and the bacillus of leprosy disappears ; its 

 duties are over, like those of the extinct plants and 

 fishes in the rocks. 



The tubercle bacillus on the other hand attacks a 

 type to be found not only in the poor, ill-fed, and ill- 

 conditioned, but also those who live well. It is a disease 

 of all classes, and those who live in well-ventilated 

 rooms, and who conform to every sanitary regula- 

 tion, may still belong to the type who fall a prey to 

 it. It is certain, therefore, that, improve the external 

 conditions of life how you will, this type will remain. 

 It is also as certain that in giving the type a better 

 chance than it has already, by preventing infection or 

 by delaying the disease, the type will be more and 

 more prevalent as each generation comes to life. 



