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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 Anofthelines 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 
