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SCIENCE 



[N. S. Vol. XL. No. 1027 



he is saying 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 mathematicians. Galton first demon- 

 stated 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 qualita- 

 tive analysis, he might, not improbably, 

 have discovered the essential facts of 

 Mendelism. 



It happens rarely that science has any- 

 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 applica- 

 tion. Transit is quickened; communica- 

 tion is made easier; the food-supply is in- 

 creased and population multiplied. By 

 direct application to the breeding of ani- 

 mals and plants such results must even 

 flow from Mendel's work. But I imagine 

 the greatest practical change likely to ensue 

 from modem genetic discovery will be a 

 quickening 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 com- 

 plexity are at work in the distribution of 

 characters among the human population 

 can not fail to influence our conceptions of 

 life and of ethics, leading perhaps ulti- 

 mately to modification of social usage. 

 That change can not but be in the main 

 one of simplification. The eighteenth cen- 

 tury made great pretence of a return to 

 nature, but it did not occur to those philos- 



ophers first to inquire what nature is ; and 

 perhaps not even the patristic writings 

 contain fantasies much further from 

 physiological truth than those which the 

 rationalists of the "Encyclopedia" adopted 

 as the basis of their social schemes. For 

 men are so far from being born equal or 

 similar that to the naturalist they stand as 

 the very type of a polymorphic species. 

 Even most of our local races consist of 

 many distinct strains and individual types. 

 From the population of any ordinary 

 English town as many distinct human 

 breeds could in a few generations be iso- 

 lated as there are now breeds of dogs, and 

 indeed such a population in its present 

 state is much what the dogs of Europe 

 would be in ten years' time but for the 

 interference of the fanciers. Even as at 

 present constituted, owing to the isolating 

 effects of instinct, fashion, occupation and 

 social class, many incipient strains already 

 exist. 



In one respect civilized man differs from 

 all other species of animal or plant in that, 

 having prodigious and ever-increasing 

 power over nature, he invokes these powers 

 for the preservation and maintenance of 

 many of the inferior and all the defective 

 members of his species. The inferior freely 

 multiply, and the defective, if their defects 

 be not so grave as to lead to their detention 

 in prisons or asylums, multiply also with- 

 out restraint. Heredity being strict in its 

 action, the consequences are in civilized 

 countries much what they would be in the 

 kennels of the dog-breeder who continued 

 to preserve all his puppies, good and bad: 

 the proportion of defectives increases. The 

 increase is so considerable that outside 

 every great city there is a smaller town 

 inhabited by defectives and those who wait 

 on them. Round London we have a ring 

 of such towns with some 30,000 inhabit- 

 ants, of whom about 28,000 are defective, 



