724 Growth and Development. 
tions may be ascribed. These characteristics of the lowest forms : 
have had a constant influence upon the subsequent development, 
and vigorously control the evolution of structure in the highest 
animals. But all other organic characteristics must be due to the 
play of the fingers of outer nature upon the whole long line of 
progress. Nature has constantly surrounded and pressed upon | 
the body with her varied energies, inducing responsive motions, 
growths and variations, and influencing every step of evolution. 
The most highly evolved body has been thus formed and molded, 
and possesses hereditary characteristics derived from its whole 
long line of ancestors. The same may be said of ‘its mental 
strain. The mind receives and develops under the force of impres- 
sions received from without. There is no proof that it has any — 
self-power of development. It began in a possibility, which has 
been wrought by outer nature into the existing actuality. 
Each animal, then, has inherent conditions gained during age* 
of development by its ancestors. As an individual it z but 
slightly molded by exterior influences, its internal tendencies be 
ing too vigorous to be easily bent aside. But these w 
cies arose from the action of exterior influences on its long Ti 
parentage. Hence its whole development is virtually a strugg 
between external forces—those which play upon the animal denii 
its short individual life, contending against those which have 
played upon and become inherent in it during its long ar a | 
life. It is as one impression contending against 4 ol 
we can readily understand the stubborn resistance of the 11 
rent organic conditions to external warping influences. ar 
The influence of external contact upon life ang develop 
strikingly seen in certain peculiar phenomena of ae peo : 
world. Vigorous as are the inherited tendencies, yet thee alae 
some cases checked by the action of external conditions which : 
Amphibia, rhe 
t ‘ os 
als, do no The 
pier intoa 
tadpole that is forcibly kept in the wate haa of devel- 
frog. Although inherently tending to attain’ 
of air with 
b 
opment, it seems to need the contact . 
duce- the necessary changes of organization. z odification. 
_ only to water contact nutrition proceeds without it remains i® 
The Axolotl, a gilled salamander, continues ee 
