Progress, Its Law and Cause

Every child has made the attempt to hold the foot still while it is tickled. And has failed; and probably there is scarcely any one who has not vainly tried to avoid wink ing when a hand has been suddenly passed before the eyes. These examples of museu lar movements which occur independently of the will. Or in spite of it, illustrate what physiologists call re?ex action; as likewise do sneezing and coughing. To this class of cases, in which involuntary motions are ao companied by sensations, has to be added another class of cases, in which involuntary motions are unaccompanied by sensations: instance the pulsations of the heart; the contractions of the stomach during digestion. Further, the great mass of seemingly volun~ tary acts in such creatures as insects, worms, For numerous illustrations see essay on The Origin and Function of Music.

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