126 Lijf and Letters of Francis Galton 



already leaving the 'town' schools, while they appear to be still coming to 

 the ' country ' schools. The former ure doubtless going out into business 

 and other occupations, and the boys that leave earliest will, as a rule, be 

 those most fully developed. Galton has clubbed together his .schools so that 

 we cannot separate them out, but one would anticipate that Liverpool 

 College, if it draws from Lancashire, would racially have a low stature. 

 Here again Galton reachetl a right conclusion, if tlie data on which he bases 

 it are open to criticism. If we take, as the Galton Laboratory has done, 

 adjacent rural and urban districts in Worcestershire or Staffordshire and com- 

 pare the children of like Jiges in the jiriinary schools, then the balance of 

 physique is in favour of the rural. In doing this we work within the same 

 social class, we attempt to get the same local race, but we caimot Ije certain 

 that the town occupations have not attracted the less physically fit jwirenta. 



D. HEHEDITY IX TWINS 



It seems best to consider here two papers on the subject of twins, because 

 although they to some extent were associated with Galton's ideas on heredity, 

 yet they sprung, I think, from his work on the influence of environment. 

 The first paper is entitled "The History of Twins, as a Criterion of the 

 Relative Powers of Nature and Nurture'." Among the claims which twins 

 have to attention, Galton tells us, is the fact that : 



"their history affords means of distinguishing between the effects of tendencies received at 

 birth, and of those that were imposed by the circumstancc-K of their after livtw; in other words, 

 between the effect* of nature and of nurture. This is a subjeet of especial iriiptjrtance in its 

 bearings on invc  into m<-^ ility, and I, for my part, have keenly felt the 



difficulty of dra« i .n-oessary o; n whenever I attempted to eHtiinate the degree in 



wliicli mental ability was, on the average, inherit*?*]. The objection to statistical evidence in 

 proof of its inheritance has always been: 'The jierBons whom j'ou compare may have lived 

 under similar social conditions and have had similar advantages of education, but such pro> 

 minent conditions are only a small ]iart of those that determine the future of each man's life. 

 It is to trifling accidental circumstances that the bent of his disposition and his success are 

 mainly due, and these you leave wholly out of account — in fact they do not admit of being 

 tabulated, and therefore your .statistics, however plausible at first sight, are really of verj* little 

 use,' No method of inquiry which I have Jjeen able to carry out — and I have tried very many 

 methods — is wholly free from this objection." (p. 391'.) 



Accordingly Galton turns to try and appreciate what relative effect 

 nature and nurture have. Galton's scheme was to consider twins who were 

 closely alike in youth and whether after l>eing separated they grew unlike, 

 and again whetner twins who being unlike in childhood were subjected to 

 the same nurture grew more alike. Galton collected his material by circu- 



.' Frtuer'i Magazin*;, Nov. 1875, issued with revision and additions in Jcmnud of the Royal 

 Anthropoloifical InttituO- (\»lt>), Vol. v, pp. .391-406, 1H76. 



* The passage is clearly written before the idea of correlation had reached Galton's mind. 

 The (rue test is whether the degree of association in mental characters lietweeu relatives is the 

 suae as that between physical characters. If it be, then it is exceedingly imjirobable that 

 nurture on the ooe hand should have produced exactly the same quantitative association as 

 nature on the other, for we can always select physical characters which are not materially 

 influenced by nurture. 



