SEGREGATION 51 



nature of their occupation necessarily exposes them 

 to infection on all sides. The answer to this is the risk 

 of infection can be greatly diminished by the use of in- 

 telligence and the carrying out at any rate of some (if it 

 is not possible to carry out all) of the precautions which 

 modern discoveries have placed in our hands. If health 

 is worth preserving, then it is business to diminish risks 

 or to take no risks at all. This is absolutely feasible, 

 and has succeeded on innumerable occasions ; just as the 

 •" don't care " policy has meant prolonged sickness or 

 even death. 



1. Measures to avoid the human reservoirs. — It 



having been incontestably proved that the indigenous 



inhabitants of tropical countries nearly all harbour in 



their blood the parasites of malaria, and that they 



have to a great degree become accustomed or inured 



to their presence, so that they can go about their 



daily work with little inconvenience, it stands to 



reason, given the presence of the anopheles mosquito, 



that the new-comer would be running an unnecessary 



risk did he not try to avoid living in close quarters 



with the infected. The new arrival is in no sense 



immunised in the same degree as the indigenous 



inhabitant, and by taking risks he puts himself at a 



very great disadvantage compared to the native. 



Curiously enough, precisely the same argument holds 



good with the locally and partially immunised native 



himself, for it is well known that the native of one 



country who is through long infection more or less 



immune to the malaria of his native land, yet readily 



succumbs to an invasion of the malarial parasites of 



