APPLIED SANITATION 15 



of the larger towns in the tropical and subtropical 

 countries there has been a very real diminution of 

 mosquito-carried diseases. For instance, New Orleans 

 was once notorious for its malaria. Endemic malaria 

 now no longer exists in the town. The malaria-carrying 

 mosquito has been driven further and further out, until 

 to-day he only survives along the fringes of the marsh 

 lands outside the city. 



But whilst to general sanitation we must ascribe 

 increased healthiness and a diminution of death and 

 sickness rates and of malaria, nevertheless there is one 

 disease — namely, yellow fever — which persisted, in spite 

 of sanitary reform carried out on the general lines such 

 as are employed in Europe. The town of Rio de 

 Janeiro was an example of this. In spite of the fact that 

 Rio had made immense strides in general sanitation, as 

 disclosed by the annual health returns furnished regu- 

 larly by the medical officer of health, nevertheless it 

 soon became apparent that there was one disease which 

 did not disappear, in spite of the general hygiene — this 

 disease was yellow fever. It was not until special 

 sanitary measures were specifically directed to it that 

 the disease was stopped. Small-pox has furnished a 

 similar example. By means of isolation and general 

 sanitation and disinfection small-pox can be decreased. 

 But the specific method of attack is vaccination. Then, 

 given this specific method of prophylaxis, coupled with 

 provision for isolation and general sanitary reform, 

 the disease disappears. So with yellow fever, general 

 sanitary reform, coupled with the only direct form 

 of attack known to medical science — namely, the 



