EVOLUTION AGAINST DISEASE 137 



appears. Had the habits and customs of the Europeans been 

 the same as those of the Asiatics and Negroes, without doubt 

 their death-rate would have been higher than it was, as may 

 be judged by the following extract : 



" It has been stated over and over again that Negroes and 

 natives of the countries where malarial fevers are endemic 

 are themselves immune to the poison of malaria. 



" This is too sweeping a statement to make, certainly as 

 far as regards British Guiana, and I believe other tropical 

 countries as well. 



" It is quite true, that the Negroes and Creoles of this 

 colony do not suffer to nearly so great an extent as foreigners, 

 a very marked difference in this respect being evidently notice- 

 able in the numbers of the coolies attacked compared with 

 those of the Negroes and Creoles. Coolies all suffer to a very 

 great degree, and are probably the class of foreigners most 

 subject to malarial poison. 



" On the other hand, we must take into account in dealing 

 with the question of immunity in the natives of tropical 

 countries the various conditions under which they live as 

 compared with those of foreigners. Now, unfortunately, the 

 natives of this country live under the most insanitary con- 

 ditions conditions which would soon be fatal to Europeans 

 unaccustomed to tropical life. Yet their death-rate would 

 probably compare very favourably with that of foreigners. 



" Again, the reason why the coolie suffers so terribly from 

 malaria as compared with other foreigners is obviously due 

 to the conditions under which he lives, and doubtless partly 

 also to his occupation. The coolies, as we know, live in huts 

 built on the ground, in many cases no attempt being made 

 to raise the floor, the latter as often as not being mother 

 earth ; so that they may be said to be literally grovelling in 

 malarial dust. Their occupation being mainly that of agri- 

 culturalists again only serves to keep them saturated with 

 earth poison. 1 



" It would not have been unreasonable to suppose that the 

 coolies, coming from an evidently malarious country, would 

 have acquired a high degree of immunity to the malarial 

 poison ; unfortunately such is very far from being the case, 

 and that this is true is entirely due to the causes men- 

 tioned above. Were the coolies to live under conditions 

 more sanitary than the present one, it is probable that they 

 would show a certain amount of immunity. There can, I 



1 In other words, the coolies are particularly exposed to tlie attacks 

 of the mosquito. 



