Eugenics and environment / by C. Lloyd Morgan.

  • C. Lloyd Morgan
Date:
1919
Catalogue details

Licence: In copyright

Credit: Eugenics and environment / by C. Lloyd Morgan. Source: Wellcome Collection.

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    act, are just tliose which are admittedly susceptible of improvement Ijy training and education. One would therefore expect that, if what is acquired indueuces the determinants in the germ-cells, there would be a note¬ worthy difference in the co-efficient of correlation in the case of these mental characters from that which holdb good for physical characters. But there is no suds difference. And this, by the way, so far ***him Nurture.** the view that mental characters are correlated with physical characters in the brain. Galton was firmly convinced that nature is far stronger than nurture. Further statistical evidence confirms this opinion, and renders it probable that the results of nurture are confined to the individual and are, in the great majority of cases, not transmitted. I think one may say that current Mendelian treat¬ ment is wholly founded on the assumption that all the phenomena discussed are explicable on the basis of cellular-filiation; and the validity of this assumption seems to stand the test of appeal to observable facts. There are, of course, some people who urge that con¬ clusions reached by the study of peas or other plants, of rabbits and fowls or other animals, have no bearing on heredity in mankind. But, so far as they go, statis¬ tics seem to be against this view, and in favour of the view’ that the prol^lem of heredity is a biological one. On this latter view the chief advantage of studying lower forms of life lies in the diminished complexity of the problem in these more simple forms. In any case, as I have said something on IMendel’s peas, I will here add a few words on .Tohannson’s beans. Johannsen’s aim was to get, by careful selection, “ pure lines ” of descent. Choosing, for example, the weight of bean-seeds on