92 POPULAR SCIENCE MONTHLY. 



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 pa- 

 tience. To select for posterity those individuals which best meet our 

 needs or please our fancy, and to destroy those with unfavorable qual- 

 ities, 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 selec- 

 tion, 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 improve- 

 ment. The first of these meanings is entirely distinct from the other. 

 The results of training and education lie outside the scope of the pres- 

 ent 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 effective- 

 ness. 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, edu- 

 cation 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 de- 

 cadence of France. It is claimed that the birth-rate is falling off in 



