Heredity / by J. Arthur Thomson.

  • Thomson, J. Arthur (John Arthur), 1861-1933.
Date:
1920
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Heredity / by J. Arthur Thomson. Source: Wellcome Collection.

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    A CONDITION OF E VOL unojy 3 the material on which the many diverse forms of selection and isolation operate. In olden days thoughtful men seemed to see the threads of life within the hands of three sister Fates,—of one who held the distaff, of another who offered flowers, and of a third who bore the abhorred shears of death. So, in Scandinavia, the young child was visited by three sister Norns, who brought characteristic gifts of the past, the present, and the future, which ruled the life to be as surely as did the hands of the three Fates. So, too, in days of scientific enlightenment, we still think of Fates and Norns, though our conceptions and terms are very different. What the living creature is or has to start with in virtue of its hereditary relation ; what it does in the course of its activity ; what surrounding influences play upon it,—these are the three determining factors of life. Heredity, function, and environ¬ ment—famille, travail, lieu—are the three sides of the bio¬ logical prism, by which, scientifically, we seek to analyse the light of life, never forgetting that there may be other components which we cannot deal with scientifically, just as there are rays of light which our eyes can never see. In novels like Zola's Dr. Pascal, in plays like Ibsen's Ghosts, in sermons and newspaper articles, in large books and health lectures, in season and out of season, we have all heard in the last few years much about the importance of heredity ; and though it is to be feared that many widespread impressions on the subject are misleading, the awakening of keen interest is in itself a symptom of progress. What is now required is a serious study of what has been securely established. Otherwise we shall continue to think in platitudes and act on guesses. Practical Importance to Breeders and Cultivators.—And what is important in regard to Man's heredity is even more demonstrably important in regard to his domesticated animals and cultivated plants. What has been achieved in the past m regard to horses and cattle, pigeons and poultry, cereals and