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112 parasite in Melanesia, confirmed as they have been by English observers in India and Africa, have definitely settled the matter. The mortality in native children from malaria is very great; but it would appear that a relative tolerance is soon acquired, for although the negro child may have a rich infection of parasites in its blood, possibly in consequence partly of increasing immunity, partly of some racial and inherited quality, it may exhibit a remarkable tolerance of the malaria toxins. It has often been remarked that these dark-skinned children, with enormous spleens and a rich stock of malaria parasites in the blood, run about fever-free, and apparently in rude health. It would seem that certain races of men react to the malaria parasite much in the same way as the Texan cattle react to Babesia, or as the large game animals of Africa react to Trypanosoma brucei; repeated infection in early youth, if it does not quickly prove fatal, creates immunity. Race may have something to do with the tolerance of the infection; but it is not everything, for the negro from a non-malarial country on becoming infected in a malarial country suffers almost as severely as the European.