LAUGHTER AND WEEPING. 315 



laughter in them would have to be relegated to some other 

 category than human laughter. In studying this subject of 

 the physical manifestations in other animals comparable to 

 laughter in man, I applied in the first place to two expe- 

 rienced comparative anatomists, enquiring whether and how 

 far the lower animals, or certain of them, possess the various 

 muscles concerned in laughter that is, physical apparatus 

 for its exhibition. 



These authorities were Professor Macalister, of the Uni- 

 versity of Dublin, and Professor Morrison Watson, of the 

 Owens College, Manchester. The replies received from 

 both left me in no doubt that various animals do possess 

 such muscular apparatus, and that, so far a,s it is concerned, 

 there is no reason why certain of them should not laugh as 

 well as smile, grin, or grimace. Macalister, for instance, 

 demonstrates the presence of the facial muscles of laughter 

 in the gorilla, while Darwin had previously pointed out 

 that various monkeys possess the same facial muscles which 

 in man are engaged in laughter. It is well known that all 

 the Mammalia, in common with man, have a diaphragm 

 capable of rapid alternations of contraction and relaxation, as 

 well as of spasmodic or convulsive action. 



In other animals, as in man, the physical phenomena of 

 laughter include 



1. Certain changes in facial expression. 



2. Certain voice or other sounds ; and 



3. Certain convulsive or other movements of the chest 

 or other parts of the body. 



Changes in facial expression, of a kind comparable with 

 those that occur and are characteristic of laughter, are met 

 with also in smiles, grins, and grimaces in certain ani- 

 mals. Some monkeys and apes such as the chimpanzee 

 smile (Darwin, Pierquin). The smile of the titi is described 

 as a 'playful' one (Cassell). Smiling in the dog has been 

 represented as occurring from the very different feelings of 

 hypocrisy and ggod-nature. Grins and grimaces, again, are 

 common among monkeys and apes, but are described also 

 as occurring in the dog under the influence of pleasure or 

 affection (Darwin). That 'broad grin' which is usually 



