310 THE HUMAN BODY. 



many actions which are at first only performed with 

 trouble and thought are after a time executed easily and 

 unconsciously. The act of walking is a good instance; each 

 of us in infancy learned to walk with much pains and care, 

 thinking about each step. But the more we walked the 

 closer became ingrained in the nervous system the connec- 

 tion between the stimulation of nerves in the sole when a 

 foot touched the ground, and the sending out by the reflex 

 nerve-centres with which they were in connection, of 

 impulses to those muscles which had to make the next step. 

 At last the contact of the foot with the ground, stimu- 

 lating some sensory nerves, acts so readily on the " nerve- 

 centres of walking" that the cerebral hemispheres need 

 take no heed about it: we walk ahead while thinking 

 of something else. In other words we have acquired a 

 reflex action not born in us. Other instances will readily 

 come to mind: as the difficulty with which AVC learned to 

 ride, or swim, or skate, thinking about and willing each 

 movement; and the ease with which we do all these things 

 after a little practice. The trained lower nerve-centres then 

 do all the co-ordinating work and the Will has no more need 

 to trouble about the matter. A habit simply means that the 

 unconscious parts of the nervous system have been trained 

 to do certain things under given conditions, and can only be 

 restrained from doing them by a special effort of the con- 

 scious Will. A practised rider will keep his seat uncon- 

 sciously under all ordinary circumstances, and can only 

 fall off his horse by taking some trouble to do so, by will- 

 ing it in fact; an unskilled rider, on the other hand, must 

 exert all his attention to avoid falling. So with what in 



Illustrate by the act of walking. Give other examples. What 

 does a " formed habit" really mean? Illustrate. 



