298 GENETICS 



man by long, patient, and devious processes when poor 

 eyes are made good almost instantly by a visit to the 

 oculist. She has long since given up providing natu- 

 ral weapons of defense for those who have the wits to 

 supply themselves more efficiently with artificial means 

 of self-preservation, and she no longer attempts to 

 improve the natural powers of locomotion of those 

 who are able to tame a horse to ride upon, or who 

 build steamships, railroads, automobiles and aero- 

 planes, thus accomplishing at once what would require 

 ages at least to evolve. 



Neither does the law of the survival of the fittest in 

 its original sense apply equally to man and to other 

 organisms. Human society to-day protects its unfit 

 in hospitals, asylums, and through various philan- 

 thropies, while physicians devote themselves to the art 

 of prolonging life beyond the period of usefulness. 



We do not desire these results of our modern 

 civilization to be otherwise, but the fact remains that 

 some of the most inflexible and universal "natural 

 laws" are ineffective in the case of man, and it is profit- 

 able to bear this in mind when applying the laws of 

 genetics to man. 



The laboratory for human heredity is the wide 

 world, and it is obvious that the experimental method 

 which has proven so effective in studying the heredity 

 of animals and plants is impracticable in the case of 

 man. The consideration of human heredity, therefore, 

 must always be largely from the statistical side, con- 

 sisting in an analysis of experiments already performed 

 rather than in arbitrarily initiating new experiments. 



Such institutions as insane asylums, prisons, sani- 



