110 Dynamic Theory. 



winter of 1854-55 destroyed four-fifths of the birds in his grounds. 

 The winter of 1880-81 was as destructive as that upon the antelope in 

 Dakota, the snow being too deep to allow them to graze. 



All this struggling, whether it be against the elements of nature or 

 against other organisms, is certain to have a selective tendency. In a 

 contest between two, the strongest is generally the victor and secures the 

 spoils of the victory ; and these spoils are generally of some advantage 

 to the victor and by so much a loss to the conquered. Where plants 

 crowd and smother each other, those having the most vigorous growth 

 monopolize the light and air with their spreading leaves and the juices 

 of the soil by their spreading roots, and they become more vigorous by 

 their accession, and what is very much to the point, transmit this su- 

 perior vigor to their successors. The feeble plants, on the other hand, by 

 being compelled to put up with what is left, which may be insufficient 

 for their needs, become still more stinted and feeble and transmit a re- 

 duced constitution to their posterity. It is easy to see how in a few 

 generations this process might cause one class to become greatly im- 

 proved and the other to be exterminated. But the conquered generally 

 have another alternative presented to them and that is a modification 

 which amounts to a structural or habitual difference, which may or ma}' 

 not be an elevation of the type, but must at all events be a better 

 adaptation to circumstances. The North American Indians have in 

 some cases saved themselves from extermination by the whites by adopt- 

 ing civilized modes of life and each contenting himself with a quarter 

 section of land, whereas in a state of barbarism he required several 

 square miles. His resources are reduced on one side, but on the other 

 he has adopted such a modification of habits as more than compensates 

 for his losses, so that on the whole he is better off than before. But the 

 Digger Indian of the Pacific Slope, who used to live in good houses and 

 raise corn and weave blankets, when defeated and plundered on all sides 

 by rapacious and vigorous savages, at last obtained immunity by the 

 adoption of a vagabond life and a poverty too abject to excite the cupid- 

 ity of even a savage. * This selection is the rule in civilized life as well 

 as savage. To save himself from starvation a man will change his oc- 

 cupation from one thing to another, and if disappointment follows him 

 too persistently he may change his habits of industry into those of va- 

 grancy, and become a tramp or a thief. Or if he be unduly prosperous 

 new habits of vicious idleness and a pampered way of life may be fast- 

 ened on him. And whatever change of habit or characteristic is ef- 

 fected in one generation it is certain to affect and differentiate the suc- 

 ceeding generation. Whether a temporary habit or new anatomical con- 

 dition which is transmitted by heredity shall become a fixed character- 

 * The Digger is said to be a degenerate relative of the Civilized Aztecs. 



