46 DARWINISM AND RACE PROGRESS. 



influence upon disease and upon mortality which is 

 unique in the history of humanity. But while the 

 benefit of. our changed and more healthy surround- 

 ings are to the advantage of us all individually, we 

 shall have to consider whether as a people we shall 

 in the long run be the better for this change, or, on 

 the other hand, whether in obtaining this individual 

 advantage we are not imperilling the vigour of the 

 race. 



Micro-organisms of Diseases and their Extermination. 



Nowhere has preventive medicine achieved greater 

 triumph than in the extermination of certain micro- 

 organisms which gain access to the body and cause 

 the febrile class of diseases, such as small-pox, 

 measles, typhoid fever, and very many others. At 

 present none of these micro-organisms can be said to 

 be extinct, but they have in some cases been ban- 

 ished to distant parts of the globe, and in other cases 

 the conditions suitable to their existence, and the 

 means of their propagation are so well understood 

 that their banishment is being systematically and suc- 

 cessfully carried out, so much so that a disease such 

 as small-pox, which at one time headed the list of 

 fatal diseases, does not come in the category of 

 anxieties of the mother of to-day; and pyaemia and 

 puerperal fever, which twenty years ago were at times 



