228 THE BIOLOGY OF THE SEASONS 



who played best when young, worked best, lived best, 

 perhaps loved best when they grew up, and thus through 

 the long ages the play-instinct has been fostered. It is 

 interesting, also, to notice that the animals which man has 

 succeeded in domesticating are notably playing animals. 



If Groos's theory of animal play is biologically sound, as 

 it seems to us to be, it must apply also to human-kind. 

 Children's games are natural safety-valves, to close which 

 must mean disaster ; they are opportunities for the free 

 play of individuality, originality, idiosyncrasy variations, 

 in short, more or less sheltered from selection ; they are 

 necessary to the perfecting of powers physical, emotional, 

 and intellectual which are afterwards of critical moment. 

 Play is thus a rehearsal without responsibilities, a pre- 

 liminary canter before the real race, a sham-fight before the 

 real battle, a joyous apprenticeship to the business of life. 

 Thus our study of animals playing in the Summer sunshine 

 gives a deeper meaning to the familiar saying, " All work 

 and no play makes Jack a 'dull boy." May we not twist 

 an old precept a little, and say, " Let us play while we can, 

 so that we may work when we will " ? 



