264 



between two years and ten years of age should be 

 chosen. 



2. The District in Question. — It seems clear 

 that the comparison of the malaria of widely 

 different regions by means of the percentage of 

 enlarged spleens in the children is not possible. 

 We have, however, found that in Bengal, the 

 parasite rate and the spleen rate in children varied 

 proportionally, the spleen rate was, however, 

 nearly always about double that of the parasite 

 rate. 



3. Time of Year. Seasonal Variations. — We 

 may determine by actual blood examination how 

 many individuals have parasites in the peripheral 

 circulation. By the use of the parasite rate in 

 children up to ten years of age we get a definite 

 and true index of endemicity which may be used 

 in the comparison of one locality with another. 



4. To the last method we would add, as a 

 complimentary one, the determination of the per- 

 centage of infected Anopheles as giving the actual 

 risk of infection in a district. 



The Determination of the Endemic Index of 



A Place 



1. Place a number of cleaned slides in a 

 slide box. Take a straight surgical needle, paper 

 and pencil. 



2. Choose any village or quarter of a town. 

 Get the assistance of a native with local influence, 

 the native magistrate in an Indian bustee, the 

 chief in an African village. Instruct him to 

 muster the children of the village. The free dis- 

 play of ' pice,' half -pence, etc., will greatly aid one, 



