MALARIAL PROPHYLAXIS— SEGREGATION 
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We have said before that Anopheles are only capable of giving rise to malaria 
when they have previously fed upon blood containing malarial parasites, but a curious 
fact, and one of great importance, may be here noted. Anopheles are mainly to be 
found in association with native dwellings. One has not long to do with Anopheles 
without finding that they are hardly ever really abundant, except ill native communities. 
Whenever in any place we wished to collect large numbers, OUr invariable practice 
was to proceed to the native quarter, and there we could collect Anopheles generally 
without difficulty. It was otherwise elsewhere, and in remote marshes occasional 
specimens (most frequently of a ' wild ' species) only were caught in our tents. So 
fir as appears at present, the majority of Anopheles in Africa haunt native villages. 
It is, perhaps, almost permissible to say that about five per cent, of all the Anopheles 
of tropical Africa are infected with malaria, and infected solely because they have 
derived the infection from latent native malaria. 
In nearly every hut, then, of the millions scattered over the jungle lands of 
Africa, and of those forming the densely crowded towns of West Africa, we have 
children with parasites in their blood, and Anopheles to disseminate these. 
The Consequent Infection of Europeans 
The condition of extreme unhealthiness found, par excellence, in West Africa 
is not determined by the ' climate.' The reason is largely to be found in the con- 
ditions under which Europeans at present live in Africa. Even on general grounds 
it would be well to avoid native huts and hovels, with all their dirt and insanitary 
surroundings, conditions which may be likened to those in the worst slums of our large 
towns. When, however, we realize that these huts are veritable hotbeds of malaria, 
it is evident that the very first sanitary law for Europeans in Africa is to avoid their 
neighbourhood. It is, however, a striking, but most deplorable feature, that in Africa 
hardly ever do we find a European bungalow or dwelling place built with this end in 
view. European houses are often situated among the huts of the natives ill towns, as 
in Freetown, Sierra Leone, or they have a cluster of hovels or huts close at hand. In 
one instance we saw a new settlement being built on the very fringe of a native 
village. It was not a question of necessity, as land free from villages or huts was 
available all around, nor was there any reason of policy, the Europeans being employed 
on the railway, and having no relation with the villagers. The choice of such a site 
sufficient in itself to ensure the settlement being a very deadly one, as indeed was 
later the case, could only be deplored. To sum up, then, we can say that with 
certain notable exceptions, to be mentioned later, the European on the West Coast of 
Afr.ca is living in the midst of native huts, and is consequently daily exposed to the 
bites of infected Anopheles. The actual conditions are described in greater detail in 
the following section dealing with prophylaxis. 
