S. E. MEZES MAN AND OTHER ANIMALS. 
35 
can use in order to explain what puzzles him. Man has both the expe- 
rience and the idea, and employs the latter to frame conceptions of the 
divine agencies whose purposes find fulfilment in the mysteries of the 
world. 
And now a few words to explain the peculiar efficaciousness of effort; 
for psychology, I venture to think, can make some helpful suggestions 
on that head. First, it is well to hear in mind that effort is a feeling, 
belonging in the same class with anger, hate, revenge, and love, interest, 
enthusiasm. And this will suggest further that effort, too, has a power- 
ful influence over the various bodily movements of strength and skill, 
as other feelings have. Sometimes a man’s interest and enthusiasm 
slip away from him, and then action is hut indifferently performed; 
while if for any reason it returns, action once more becomes full, free 
and strong. And so it is with hate and love and anger and all emotions; 
and, if analogy holds, so should it he with effort. 
But before coming to effort, let us see what physiological psychology 
can do in the way of explaining the motor efficiency of feeling, by 
tracing backward the reasons for movements to their causes in the brain. 
Stated in general terms sufficient for oui purpose, movements depend 
on the contraction of the muscles, these on the excitement of the mus- 
cles by the stimulations brought to bear on them by the motor nerves, 
while the active state of the motor nerves is incited by the active state 
of the portions of the brain with which they are connected. But here 
a difficulty arises. Not every degree of brain excitement stimulates the 
motor nerves; and besides, it is often the case that different portions of 
the brain are active at once, each seeking to effect a movement that the 
other movement, also sought to be effected, blocks. .And this raises the 
question as the characteristics of a brain excitement that gives it power 
for effective stimulation of motor nerves that leads to movement of 
members. 
The question can not be discussed at all adequately, but a few 
specifications may be given. Factors that are known to be im- 
portant are the intensity of the excitement, and the area over 
which it exists. Now, both as psychic experiences, and as physical 
happenings, feelings are at once intense and voluminous. Take the 
following description, epitomized from Montegazza’s account of hatred: 
“Withdrawal of the head backwards, withdrawal of the trunk; projec- 
tions forward of the hands; . . . next, threatening movements, as 
intense frowning, grinding of teeth, etc.; finally, . . . deep inspira- 
tion, general trembling, convulsion of lips and facial muscles, of limbs 
and trunk,” etc., etc. These leading traits! with all detail omitted, will 
serve to suggest that the bodily commotion extends over a wide area and 
exhibits a high degree of intensity. Moreover, these bodily happenings 
