This position soon became itself not only suggestive to the child of sleep, but sometimes necessary to sleep, even when she was laid across the nurse's lap in what seemed to be an uncomfortable position.
This case illustrates what may be called Physiological Suggestion.

It shows the law of physiological habit as it borders on the conscious.
The same sort of phenomena appear also in adult life.

Positions given to the limbs of a sleeper lead to movements ordinarily associated with these positions.

The sleeper defends himself, withdraws himself from cold, etc.

Children learn gradually to react upon conditions of position, lack of support, etc., of the body, with those actions necessary to keep from falling, which adults have so perfectly.