EVOLUTION IN POSSE 223 



civilised men much more resistance to tuberculosis 

 that is found among savage races, and, again, we find 

 more immunity to malaria among races that have 

 been for long exposed to it. Why such selection 

 should favour men rather that microbes has not 

 been explained. The microbes, which multiply 

 with enormous rapidity, must also undergo a 

 process of stringent selection, and one would 

 think that, century by century, they would become 

 more vigorous and vicious, but this seems not to 

 be the case. The reason probably is that the 

 microbes have not the faculty of variation in so 

 high a degree as the cells of man ; and it is 

 probably just for that reason they have remained 

 microbes, and have not become monkeys or some- 

 thing. It is interesting to think that the final 

 selection of men regarded as physical organisms 

 is being made by these blind, cruel cohorts of 

 death which seem to regard nothing save cellular 

 chemistry, and which may pass by the vicious and 

 the foolish and slay the good and wise. Did not 

 the bacillus of tuberculosis slay Spinoza, and 

 Keats, and Chopin, and R. L. Stevenson ; and how 

 many famous men have died of pneumonia or 

 typhoid ? It seems a process of selection about as 

 sensible as might be made by spinning a coin, 

 and yet no doubt Nature knows what she is about, 

 and perhaps immunity is correlated with most 



