INFECTION FROM CHILDREN 



267 



2. Segregation of Europeans from Natives. 

 This method is strongly advocated by the members 

 of the Nigeria Expedition of the Liverpool School 

 (1900). The distance of removal to half a mile is 

 considered sufficient: ' ' Considerable evidence has 

 now been accumulated to prove that the distance 

 which is traversed by a mosquito is never very 

 great, and extremely rarely reaches so much as 

 half a mile." The arguments in favour of this 

 method of "segregation" are of so great interest 

 that they must be put here at some length. The 

 drawback is that the method cannot be followed 

 everywhere to its logical issue without some risk 

 of giving offence, of seeming to abandon the native, 

 of damaging commerce, and so forth. But, short 

 of this, much might be done for the protection of 

 Europeans in Africa : — 



"This method is a corollary of the discovery 

 that native children in Africa practically all contain 

 the malaria parasite, and are the source from which 

 Europeans derive malaria. Koch showed in New 

 Guinea that in most places infection was very 

 prevalent in native children, so much so that in 

 some villages 100 per cent, of those examined con- 

 tained parasites. He also showed that, as the 

 children increased in age, immunity was produced, 

 so that in the case of adults a marked immunity 

 was present, and malarial infection was absent. 

 The Malaria Commission showed, independently, 

 that a condition of universal infection existed 

 among the children of tropical Africa, associated 

 with an immunity of the adults. This infection in 

 children had many remarkable characteristics. The 



