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adult population usually shew no splenic enlargement 

 (Tropical Africa). 



In less malarious regions a certain number of 

 adults will be found with enlarged spleens and malarial 

 infection. The use then of the percentage of adults 

 with enlarged spleens is not a reliable method of 

 determining the real intensity of malaria. 



In the examination of children for splenic en- 

 largement and the presence of parasites in their blood, 

 we found : 



(i) In the early ages, one to two years, the 

 number infected is usually in excess of those shewing 

 splenic enlargement. 



(ii) Above two years, the spleen rate is usually 

 somewhat in excess of the parasite rate. 



(iii) Above ten years, the spleen rate is usually 

 considerably in excess of the parasite rate. 



In the use of a spleen census one should then 

 avoid a mixed adult and child count, and children 

 between two years and ten years of age should be 

 chosen. 



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. 



To the last method we would add, as a 

 complementary one, the determination of the per- 

 centage of infected Anophelines as giving the actual risk 

 of infection in a district. 



THE DETERMINATION OF THE ENDEMIC INDEX 

 OF A PLACE 



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 



