488 The Journal 
securing a quicker and surer adjustment 
than would be possible through contact 
and chemical ceptors only.’’ In the 
third class of stimuli the animal as a 
whole responds, whereas responses to 
the contact and chemical stimuli usually 
involve only a part of the organism. 
This does not, however, change the 
essentially mechanical character of the 
occurrence. ‘‘The flight of the giant 
water buffalo at the sight of a lion, or 
the charge of the lion at the sight of its 
prey, is as automatic a reaction as is the 
withdrawal of the limb of a rabbit from 
the sharp prick of a thorn.’ The 
emotions offer good illustrations of this 
third class of stimuli. Fear, for exam- 
ple, is said by Dr. Crile to be intended to 
prepare the body to seek preservation 
by flight. ‘Striking evidence of the 
truth of this assumption is afforded by 
the fact that fear is experienced only 
by animals which depend for self- 
defense and species-preservation upon a 
swift locomotor reaction. The skunk, 
for example, whose chief means of 
protection is its odor; the porcupine, 
defended by its quills; the snake which 
repels its enemies by its venom; the 
turtle which is securely encased in its 
shell; the lion and the elephant secure 
in their superior strength—exhibit little 
fear, if any. On the other hand, the 
rabbit, the bird, the deer, the horse, the 
antelope, the monkey, and man—species 
which have ever had to struggle for 
their existence against stronger or 
swifter enemies—these are the animals 
which preeminently exhibit fear and 
an irrepressible desire to flee from 
danger.” 
The mechanism of fear is further 
discussed, and its effects are declared 
to depend largely on increased activity 
of the thyroid gland, the adrenals, the 
liver, and other glands, the secretions 
of which are either increased or dimin- 
ished. “In the light of this evidence 
many phenomena of fear and of other 
emotions may be explained. It is 
known, for instance, that men and 
animals under the stimulus of strong 
emotion possess an extraordinary 
amount of physical strength. This is 
explained by the fact that fear drives 
certain organs and inhibits others, so 
of Heredity 
that every particle of available energy 
is concentrated upon the fighting mech- 
anism. The advantage that this power 
must have given to prehistoric man in 
his struggles against superior foes in a 
wild environment is apparent to anyone 
who will allow his imagination to revert 
to those days of supreme physical 
contest. But that the tendency should 
persist today, in spite of the disappear- 
ance of most of the stimuli to active 
physical combat, so that, at the slightest 
hint of danger, man’s energies are 
drained, exactly as in the days of 
physical struggle, is one of the mis- 
fortunes of our insufficiently adapted 
state. 
THE EFFECT OF FEAR 
“So strong is the force of these ances- 
tral acts, so firmly established the action 
pattern of muscular response to fear 
stimulus, that now, whether a business 
catastrophe or an attacking enemy 
threaten, fear is expressed in terms of 
the ancestral flight to safety or fight 
for life which took place in the remote 
brute period of human history. In 
spite of the fact that by harnessing the 
forces of nature, and by social coérdina- 
tion, which reduces the number of 
motor reactions, man has progressed 
vastly in his methods of acquiring food 
and avoiding danger, his body still 
responds to the threatened moral or 
financial disaster, as if the old need for 
physical contest r2mained. His heart 
beats wildly; his respirations are quick- 
ened; he trembles and turns cold; his 
knees shake; beads of sweat stand upon 
his brow; he is pale and his mouth is 
dry; he feels faint and he may collapse. 
Whether the cause of fear be moral, 
social, financial or intellectual, the 
result is the same.” 
“As fear activates the body, so all 
emotions and psychic states activate 
the body and exhaust energy in propor- 
tion to the degree in which they repre- 
sent the physical activity attendant 
upon the phylogenetic forms of self- 
defense. As fear recapitulates the an- 
cestral act of flight from the enemy, so 
rage or anger recapitulates the act of 
attack and in like manner activates 
