LAUGHING AND CRYING 
What Is Their Use?—Probably Safety Valve for the Body When It Is Affected by 
Emotions—Their Evolutionary Origin 
HY do you laugh when a man 
\ \ / slips on a banana-peel? 
Great philosophers have pon- 
dered on the problem. Spencer 
and Bergson have tried to explain it. 
The latest discussion, and one of 
interest and lucidity, is that of Dr. 
George W. Crile.1 He starts with the 
assumption that the habit of laughing 
must be of some use to the race, and 
then he undertakes to show what this 
use is. 
As a preliminary, we must understand 
just what we mean, physiologically, by 
laughter. It is ‘‘an involuntary rhyth- 
mic contraction of certain respiratory 
muscles, usually accompanied by certain 
vocal sounds. It is a motor act of 
the respiratory apparatus primarily, al- 
though if intense it may involve not 
only the extraordinary muscles of res- 
piration, but most of the muscles of the 
body. There are many degrees of laugh- 
ter, from the mere brightening of the 
eyes, a fleeting smile, tittering and 
gigeling, to hysteric and convulsive 
laughter. Under certain circumstances, 
laughter may be so intense and so long- 
continued that it leads to considerable 
exhaustion.” 
“What causes laughter? Good news, 
high spirits, tickling, hearing and seeing 
others laugh; droll ‘stories; flashes of 
wit; passages of humor; averted injury; 
threatened breach of the conventions; 
and numerous other causes might be 
added. It is obvious that laughter 
may be produced by diverse influences, 
many of which are so unlike each other 
that it would seem at first sight improb- 
able that a single general principle 
underlies all.” 
If we are to find a general principle, 
we must proceed from some elementary 
1 Crile, George W., “‘The Origin and Nature of the Emotions.”’ 
Go;, 1915: 
facts: Mane Dr, .Crile”. telilss is. 1s 
“essentially a motor being.’’ He is 
organized for action. The sight of a 
mad dog, let us say, tends to produce 
action in the beholder; the body auto- 
matically gets ready to run or to fight. 
These various responses of the body to 
this situation probably occur before the 
man himself has realized the situation, 
and the emotion of fear which is aroused 
in him results, it is supposed, from the 
activities of the body in preparing for 
retreat or defense. 
Not only are the brain-cells stimulated 
by the sight of the mad dog, but the 
ductless glands at once set to work to 
pour into the circulation their energizing 
secretions, thus putting the body in a 
position to meet the unusual demands 
made on it. In other words, an 
emotion (say, fear) 1s accompanied, or 
perhaps the result of, the preparation 
of the body for unusual action. If the 
action takes place, the fuel which has 
been released, the sources of energy 
which have been made available,” are 
used up, and the body returns to its 
normal condition. 
NECESSITY FOR ACTION 
But suppose that no action follows the 
emotion—what happens? The blood is 
full of ‘‘emergency rations,” which are 
not needed and which therefore have 
to be eliminated as waste products, 
thus putting atax onthe system. That 
is why emotion unaccompanied by 
muscular action, is more injurious to 
the body than is muscular action alone. 
Suppose, then, that one were so 
impelled to anger that he got in fighting 
mood, and wanted to hit somebody. 
He might pursue three courses: 
1. He might perform no physical act, 
Philadelphia, W. B. Saunders 
2“Eninephrin, thyroid and hypophyseal secretions are thrown into the blood streams, while 
that most available fuel, glycogen, is also mobilized in the blood.” 
281 
