8 Life and Letters of Francis Gallon 



"separates under two distinct heads the innumerable elements of 

 which personality is composed"-? He noted that twins are of two 

 kinds those born physically and mentally alike, and those born as 

 unlike as ordinary brothers and sisters. He proceeded to determine 

 how far like twins were differentiated by unlike environments, and 

 how far unlike twins were rendered like by their common nurture. 

 He discovered that whatever the environment like twins remained 

 alike and unlike twins remained unlike, even as they were born. Thus 

 he sums up his History of Twins, as a Criterion of the Relative POWITX 

 of Nature and Nurture : 



"There is no escape from the conclusion that nature prevails enormously over 

 nurture when the differences of nurture do not exceed what is commonly to be found 

 among persons of the same rank of society in the same country. My only fear is that 

 my evidence seems to prove too much, and may be discredited on that account, as it 

 seems contrary to all expectation that nurture should go for so little. But experience is 

 often fallacious in ascribing great effects to trifling circumstances. Many a person has 

 amused himself by throwing bits of stick into a tiny brook and watching their progress ; 

 how they are arrested, first by one chance obstacle, then by another ; and again, how 

 their onward course is facilitated by a combination of circumstances. He might 

 ascribe much importance to each of these events, and think how largely the destiny of 

 the stick has been governed by a series of trifling accidents. Nevertheless all the sticks 

 succeed in passing down the current, and they travel, in the long run, at nearly the same 

 rate. So it is with life, in respect to the several accidents which seem to have had a great 

 effect upon our careers. The one element, which varies in different individuals, but is 

 constant for each of them is the natural tendency ; it corresponds to the current in 

 the stream, and inevitably asserts itself." (Journal of the Anthropological Institute, 

 1875, p. 391, etc.) 



Such work as the Gal ton Laboratory has done was to give quanti- 

 tative definiteness to this conclusion of its founder. And, in view of 

 it, would it not be idle in this biography to pass over the nature the 

 ancestral factor and spend our time chiefly on the nurture of Francis 

 Gal ton ? To those of us who believe in alternative inheritance, to 

 those again who favour its more fashionable Mendelian phases, there is 

 nothing marvellous in transcendent intellectual power being associated 

 with one member of a Darwin or with one member of a Galton 

 fraternity. To those who put their faith in nurture as the controller 

 of mental characters, it must be a standing miracle that brothers 

 reared under identical environment should fail to show the same 

 ability, or showing the same ability should be so diverse in their 

 physical attributes or in other mental characters ! 



