382 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1915. 



parent, and no normal has been known to pass on the condition. 

 Such an example well serves to illustrate the fixity of the rules of 

 descent. Similar instances might be recited relating to a great 

 variety of other conditions, some trivial, others grave. 



At various times it has been declared that men are born equal and 

 that the inequality is brought about by unequal opportunities. Ac- 

 quaintance with the pedigrees of disease soon shows the fatuity of 

 such fancies. The same conclusion, we may be sure, would result 

 from the true representation of the descent of any human faculty. 

 Never since Galton's publications can the matter have been in any 

 doubt. At the time he began to study family histories even the broad 

 significance of heredity w^as frequently denied, and resemblances to 

 j)arents or ancestors were looked on as interesting curiosities. In- 

 veighing against hereditary political institutions, Tom Paine remarks 

 that the idea is as absurd as that of an " hereditary Avise man," or 

 an " hereditary mathematician," and to this day I suppose many 

 people are not aware that he is sajdng anything more than commonly 

 foolish. We, on the contrary, would feel it something of a puzzle if 

 two parents, both mathematically gifted, had any children not mathe- 

 maticians. Galton first demonstrated the overwhelming importance 

 of these considerations, and had he not been misled, partly by the 

 theory of pangenesis, but more by his mathematical instincts and 

 training, which prompted him to apply statistical treatment rather 

 than qualitative analysis, he might, not improbably, have discovered 

 the essential facts of JMendelism. 



It happens rarely that science has anj-thing to offer to the common 

 stock of ideas at once so comprehensive and so simple that the courses 

 of our thoughts are changed. Contributions to the material progress 

 of mankind are comparatively frequent. They result at once in 

 application. Transit is quickened; communication is made easier; 

 the food supply is increased and population multiplied. By direct 

 application to the breeding of animals and plants such results must 

 even flow from Mendel's work. But I imagine the greatest practical 

 change likely to ensue from modern genetic discovery Avill be a quick- 

 ening of interest in the true nature of man and in the biology of 

 races. I have spoken cautiously as to the evidence for the operation 

 of any simple Mendelian system in the descent of human faculty ; yet 

 the certainty that systems which differ from the simpler schemes only 

 in degree of complexity are at work in the distribution of characters 

 among the human population can not fail to influence our concep- 

 tions of life and of ethics, leading perhaps ultimately to modification 

 of social usage. That change can not but be in the main one of 

 simplification. The eighteenth century made great pretense of a 

 return to nature, but it did not occur to those philosophers first to 

 inquire what nature is; and perhaps not even the patristic writings 



