Ribot, the French authority on heredity, alleges two causes as among the chief at work in cases where the law of transmission does not obviously manifest itself. The first is the disproportion of an initiatory force to the amount of energy it may liberate or direct, as in the slight agencies by which fires are lit or explosions set off. The accidental surroundings of a mother before the birth of her child may affect it for life in a way altogether disproportioned to the forces at work. The military excitements in which Madame Bonaparte lived just prior to Napoleon's birth are well known. Anxiety, grief, elation, an unusual degree of physical health or debility at such times are productive of very striking effects, quite capable of masking the likeness between parent and child in form and disposition. The Greeks believed so strongly in the potency of prenatal conditions that they not only guarded mothers who were bearing with the kindest care, but used even to surround them with beautiful works of art, that imagination might act a favorable part.
The second cause which Ribot thinks often tends to obscure the evidence of heredity is the transformation in development of characteristics which are the same at root. Thus a consumptive father has a son who suffers from rheumatism or paralysis. Here the transmission has simply been that of a feeble constitution, which gives way in the first circumstances of severe trial—those favoring rheumatism, paralysis, or other disease. The crystal of life, to use Galton's figure, is disturbed, and reposes on a new facet. In cases where talent appears conspicuously in a family, it may be that energy and patience, productive of but ordinary results in a father, are directed by his son to supplying some new public want, or filling 'a position created by some sudden national emergency. The constructive powers of Stephenson were less remarkable than his dogged perseverance; and when the world needed steam locomotion he was the man to give it, and surmount the immense difficulties in the way. His strong will is not a rare trait of character, but, joined to his ingenuity, it won him success in his great opportunity. Had Charles I. been a good king, Cromwell would probably have died a brewer. Unbending will was also his chief characteristic, but at Huntingdon it could have enjoyed but narrow play.
Readers of the Monthly may remember Galton's paper on "Twins," published in January, 1876. In that paper, based on wide and carefully made comparisons, it was proved that in the production of character original constitution is a much more important factor than either education or surroundings. The resemblance of twins when it occurs, as it frequently does very strongly, continues through life in a large proportion of cases. The same author has confirmed his opinion that Nature is more powerful than nurture in moulding men, by collecting elaborate testimony from all the illustrious Englishmen of science now living, who say for the most part that their tastes were either innate or manifested themselves very early under the influence of training, and in
