208 LAUGHTER 



F.R.S., recognising him among the crowd in front of their 

 cage when he was still far off. And I have often made 

 chimpanzees laugh " roar with laughter," and roll over 

 in excitement by tickling them under the arms. The 

 saying of Aristotle (inscribed over the curtain of the Palais 

 Royal Theatre in Paris) that "laughter is better than tears, 

 because laughter is the speciality of man," is not true. Not 

 only do the higher apes and some of the smaller monkeys 

 laugh, but dogs also laugh, although they do not make 

 sounds whilst indulging in "spasms of laughter." But their 

 distant cousin, the hyena, does laugh aloud, and its laugh- 

 ter agrees with that of the dog and with the laughter of 

 children and grown men in simpler moods in that it is 

 caused by the pleasurable emotion set up by the imminent 

 gratification of a healthy desire. The hyena laughs, the 

 dog grins and bounds, the child laughs and jumps for joy 

 at the approach of something good to eat. But it is a 

 curious fact that the whole attitude is changed when the 

 food is within reach, and the serious business of consuming 

 it has commenced! Nor, indeed, is the satisfaction which 

 is felt after the gratification of appetite accompanied by 

 laughter. It seems that the display of the teeth by drawing 

 back the corners of the mouth, which is called a "grin," 

 and is associated in many dogs with short, sharp, demon- 

 strative barks, and in mankind with the cackle we call a 

 "laugh," is a retention, a survival, of the playful, good- 

 natured movement of gently biting or pulling a companion 

 with the teeth used by our animal ancestors to draw 

 attention to their joy and to communicate it to others. 

 Gradually it has lost the actual character of a friendly bite; 

 the fore-feet or hands pull instead of the teeth ; the sound 

 emitted has become further differentiated from other 

 sounds made by the animal. But the movement for the 

 display of the teeth, though no longer needed as a part of 

 the act of gripping, remains as an understood and universal 



