274 Animal Intelligence 
The evolution of the intellectual and moral nature which 
a higher animal really possesses from the sort of a nature 
which the real activities of the protozoa manifest, is far 
less difficult to explain. 
[ In so far as the higher animal is a collection of original 
éndencies to respond to physical events without and within 
the body, subject to modification by the laws of exercise 
and effect and by these alone, and in so far as the protozoan 
is already possessed of a well-defined repertory of responses 
connected with physical events without and within the 
body in substantially the manner of the higher animal’s 
original tendencies, the problems of the evolution of be- 
havior are definite and in the way of see 
The previous sections gave reason for the belief that the 
higher animals, including man, manifest no behavior 
beyond expectation from the laws of instinct, exercise and 
effect. The human mind was seen to do no more than 
connect in accord with original bonds, use and disuse, and 
the satisfaction and discomfort resulting to the neurones. 
The work of Jennings has shown that the protozoa already 
possess full-fledged instincts, homologous with the instincts 
of man. They too may have specialized receptors, an 
action-system with a well-defined repertory and a connect- 
ing system or means of influencing the bonds between the 
stimuli received and the motor reactions made. The dif- 
ficulties of tracing the possible development of a super-man 
from an infra-animal thus disappear. 
There is, of course, an abundance of bona fide difficulty 
in discovering the unlearned behavior of each group of 
animals and in tracing, throughout the animal series, 
changes in the physical events to which animals are sensi- 
tive so that to each a different response may be attached, 
changes in the movements of which animals are capable, 
