THE SURPLUS ENERGY THEORY OP PLAY. 19 



Going on now to the arguments that ground my 

 own opinion, it can very easily be shown that the facts 

 do not point to the universal or essential value of the 

 Schiller-Spencerian principle. Certainly in innumerable 

 cases the superfluity of unemployed energy gives an im- 

 pulse to play, but in many others one is impressed with 

 the fact that instinct is a power in itself which does not 

 need special accumulated stores of energy to bring it 

 into activity. Some examples will make this clear. 

 Notice a kitten when a piece of paper blows past. Will 

 not any observer confirm the statement that just as an 

 old cat must be tired to death or else already filled to 

 satiety if it does not try to seize a mouse running near it, 

 so will the kitten, too, spring after the moving object, 

 even if it has been exercising for hours and its super- 

 fluous energies are entirely disposed of? Or observe the 

 play of young dogs when two of them have raced 

 about the garden until they are obliged to stop from 

 sheer fatigue, and they lie on the ground panting, with 

 tongues hanging out. Now one of them gets up, glances 

 at his companion, and the irresistible power of his in- 

 nate longing for the fray seizes him again. He ap- 

 proaches the other, sniffs lazily about him, and, though 

 he is evidently only half inclined to obey the power- 

 ful impulse, attempts to seize his leg. The one provoked 

 yawns, and in a slow, tired kind of way puts himself on 

 the defensive; but gradually instinct conquers fatigue 

 in him too, and in a few minutes both are tearing madly 

 about in furious rivalry until the want of breath puts 

 an end to the game. And so it goes on with endless 

 repetition, until we get the impression that the dog 

 waits only long enough to collect the needed strength, 

 not till superfluous vigour urges him to activity. I have 

 often noticed that a young dog whom I have taken for 



