MAN 
pleased, or when tickled. 
IS NOT THE ONLY PRIMATE WHO LAUGHS 
Darwin long ago pointed out that the great apes shared with man the habit of laughing when 
The photograph above, from Underwood and Underwood, 
shows Mike, the clever chimpanzee in the London zoo; Dr. Crile considers that he is 
laughing although, according to Darwin, the chimpanzee does not ordinarily put so much 
heart in it, but contents himself with grins and chuckles. 
but merely give expression to the emo- 
tion of anger. This would, for the 
reasons pointed out above, be distinctly 
injurious to him. 
2. He might hand his coat to the 
nearest innocent bystander, roll up his 
sleeves, and “let go’’ with the result, 
if the other man were not too big, that 
he would completely satisfy his anger 
and return to normal. 
3. He might immediately turn and 
run around the block, or engage in some 
other violent exercise. This would 
consume all the motor-producing ele- 
ments mobilized by the body and, again, 
would leave him normal. 
It is not proposed, from these state- 
ments, to insist on the moral that you 
should fight every time you get hot 
129 
(Fig. 19.) 
under the collar, but merely to point 
out that when a strong emotion is not 
followed by some physical action, the 
body suffers. 
Now laughter consists of physical 
action, of muscular exertion. It serves, 
Dr. Crile says, “precisely such clarifying 
purposes as would be served by the 
gymnastic exercises of an angry man. 
As it seems to me, the muscular action 
of laughter clears the system of the 
energizing substances which have been 
mobilized in various parts of the body 
for the performance of other actions. 
“If this be true, the first question 
that presents itself is, “Why “Is the 
respiratory system utilized for such a 
clarifying purpose? Why do we not 
laugh with our hands and feet as well?’ ”’ 
