The development—or the destruction—of man’s body and mind depends upon external stimuli. Unless one is very careful, and unless one sees to it that the intensity of the stimuli is gradually increased, one will find too late that the body, or the mind, has atrophied. According to doctors, there is nothing that requires more attention than the human stomach. Give it nothing but gruel, and you will apparently find one day that it has lost the power to digest anything else.
