Page:Popular Science Monthly Volume 48.djvu/534

492 of "sports" which, if useful, are seized upon and perpetuated by selection.

He says that a sport is a substantial change of type effected by a number of small changes of typical center, each more or less stable, and each being in its turn favored and established by natural selection to the exclusion of its competitors.

"The distinction between a mere variety and a sport is real and fundamental."

This generalization, based upon definite numerical data, is so fundamental and far-reaching that a critical discussion of the evidence is most important.



URING the past dozen years scientific writers, American as well as European, have given a certain amount of attention to the part played in human life by imitation, with especial reference to the conditions under which children acquire from parents and associates the salient characters of individual and social habit. But the examples drawn upon for illustration have been narrow in their range, while the analogous process of assimilation among the lower animals and in the realm of the inorganic has received but scant recognition. It is proposed in the present article to connect the three classes of phenomena by formulating a general law which may serve, provisionally at any rate, to cover them all, and then to group the phenomena in their various natural divisions.

Without taking note of its unimportant and obvious qualifications, the statement may be made that all things free to move, capable of becoming closely associated, and impelled to movement by the system to which they belong, tend to come together when they are likes, and to be separated when they are unlikes. If we regard this tendency from the point of view of the movement, we shall say that likeness of things involves association of them in the degree of their likeness, and that unlikeness of them involves dissociation of them in the degree of their unlikeness; while, if we regard the tendency from the point of view of the things themselves, we shall say that association of things involves likeness of them in the degree of the association, while dissociation of things involves or implies unlikeness of them in the degree of the dissociation. These truths may be expressed in a more general way by saying that in systems the association of likes involves the least degree of resistance among them, while 