The lower an animal is in the scale of development, the more are its adaptation to nature and all its activities controlled by instinctive and reflex action mechanisms. The famous social organizations of some insects are created entirely by instincts. On the other hand, the higher an animal is in the scale of development, the more flexibility of action pattern and the less completeness of structural adjustment do we find at birth. This development reaches its peak with man. He is the most helpless of all animals at birth. His adaptation to nature is based essentially on the process of
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