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Chapter XXI 
To Make a Malarial Survey 
Endemic Malaria 
The clue to the epidemiology of malaria in the 
tropics is to be found in the infection of the native 
population of a country. The malaria of Europeans 
is merely the result of their exposure to infection from 
this source. Investigation into the natural history 
of malaria, therefore, resolves itself largely into the 
study of native or endemic malaria. It has always 
been recognised that in a particular country certain 
districts are more malarial than others. It was not, 
however, till Koch used the percentage of infected 
children as the test of the malarial intensity of a place 
that accurate measurement of this became possible. 
To Investigate the Endemic Malaria of a 
District 
(A) T he Breeding-Places of Anophelines — 
It is the case in India, and almost certainly will be 
found to be so in other countries, that certain kinds 
of breeding-places are preferred by certain species.* 
A collection of larvae made from shallow puddles will 
be found to yield quite a different set of species to one 
made from a streamlet or pool full of vegetation, even 
though close to the puddles (Fig. 68). 
i. Examine all collections of water within half 
a mile. Stir up the mud of small puddles, and use a 
dipper where the water is weedy or difficult of access. 
Examine wells, £ chatties,’ streams, and swamps, as 
* Thus M. lutzi is said to breed only in the water collected in the leaves of 
the parasitic Bromeliaceae , and N. annulipes is said to breedrin the sea. - 
