Page:Popular Science Monthly Volume 59.djvu/102

92 a herd descended from the best. It is said that when the short-homed Durham cattle first attracted attention in England, the long-horns, which preceded them, inferior for beef or milk, vanished as if smitten by a pestilence.' The fact was that, being less valuable, their owners chose to destroy them rather than the finer Durhams. Thus the new stock came from the better Durham parentage. If conditions should ever be reversed, and the Durhams were chosen for destruction, then the long-horns might again appear, swelling in numbers as if by magic, unless all traces of the breed had in the meantime been annihilated.

VII. In selective breeding with any domesticated animal or plant, it is possible, with a little attention, to produce wonderful changes for the better. Almost anything may be accomplished with time and patience. To select for posterity those individuals which best meet our needs or please our fancy, and to destroy those with unfavorable qualities, is the function of artificial selection. Add to this the occasional crossing of unlike forms to promote new and desirable variations, and we have the whole secret of selective breeding. This process Youatt calls the 'magician's wand' by which man may summon up and bring into existence any form of animal or plant useful to him or pleasing to his fancy.

VIII. In the animal world progress comes mainly through selection, natural or artificial, the survival of the fittest to become the parent of the new generation. In the world of man similar causes produce similar results. The word progress is, however, used with a double meaning, including the advance of civilization, as well as race improvement. The first of these meanings is entirely distinct from the other. The results of training and education lie outside the scope of the present discussion. By training the force of the individual man is increased. Education gives him access to the accumulated stores of wisdom built up from the experience of ages. The trained man is placed in a class relatively higher than the one to which he would belong on the score of heredity alone. Heredity carries with it possibilities for effectiveness. Training makes these possibilities actual. Civilization has been defined as 'the sum total of those agencies and conditions by which a race may advance independently of heredity.' But while education and civilization may greatly change the life of individuals, and through them that of the nation, these influences are spent on the individual and the social system of which he is a part. So far as science knows, education and training play no part in heredity. The change in the blood which is the essence of race-progress, as distinguished from progress in civilization, finds its cause in selection only.

IX. To apply to nations the principles known to be valid in cattle-breeding, we may take a concrete example—that of the alleged decadence of France. It is claimed that the birth-rate is falling off in