EVOLUTION AGAINST DISEASE 151 



yet no reason to doubt that the bacillus of the disease is in 

 both instances alike, but this is a matter which it would be 

 interesting to have settled by direct observation. 



250. " The conditions under which the individuals live are 

 in both cases practically the same. The difference, there- 

 fore, does not appear to arise from any factor acting immedi- 

 ately and directly on the individuals, but to be connected 

 with something more remote. To me there appears to be but 

 one solution of the matter ; the peculiarity depends on inherited 

 differences, in fact on racial characteristics." l 



251. I have been unable to gather anything very definite 

 concerning the Chinese in their relation to tuberculosis; 

 but considering how large and numerous their cities are, 

 how ancient their civilization, how filthy their habits, 

 and how crowded their dwellings, especially the sleeping 

 apartments, they should be of all races of the world the most 

 resistant, if not to tuberculosis, which infests in particular 

 houses of the European type, yet against many other non- 

 malarial zymotic diseases. 



252. Measles, whooping-cough and small-pox fall with such 

 frightful severity on races which have had little or no previous 

 experience of them, that it is clear that the resisting power 

 of such races is very low. It is difficult, however, to draw 

 exact comparisons. As in the case of other diseases, the 

 problem has not been studied hitherto from a biological 

 standpoint. No works on the subject have been compiled, 

 and one is able to form an opinion only on isolated references 

 scattered through medical literature. The problem is compli- 

 cated, moreover, by the fact that in countries new to them air- 

 borne diseases usually prevail in an epidemic form when first 

 introduced. So large a part of the community is stricken 

 down, that the sick are apt to receive insufficient attention. 

 The death-rate becomes high even out of proportion to the 

 relative weakness of the resisting power. Nevertheless, 

 though epidemics of air-borne diseases occasionally occur in 

 the Eastern Hemisphere of such severity that almost every 

 member of the community is attacked, yet the mortality 

 never reaches the enormous proportions it does in the Western 

 World. * We know the story of measles in Fiji, how in 1876 

 it swept away forty thousand out of the population of one 

 hundred and fifty thousand. Measles when it attacks the 

 Polynesians is no longer the infantile malady we know of. 

 It becomes a devastating plague. The Tongans with the 

 experience of Fiji in their memories, took, it is true, some 



1 Grieve, British Gumna Medical Annual, March 1, 1890. 



