442 THE POPULAR SCIENCE MONTHLY. 



which lie had lived during that earlier time, and to which his steps 

 from the school had then habitually led. We all of us have a definite 

 routine manner of performing certain daily offices connected with the 

 toilet, with the opening and shutting of familiar cupboards, and the 

 like. Our lower centers know the order of these movements, and 

 show their knowledge by their " surprise " if the objects are altered 

 so as to oblige the movement to be made in a different way. But our 

 higher thought-centers know hardly anything about the matter. Few 

 men can tell off-hand which sock, shoe, or trousers-leg they put on first. 

 They must first mentally rehearse the action ; and even that is often 

 insufficient — the action must be perforyned. So of the questions, 

 "Which valve of my double door opens first ? Which way does my door 

 swing? etc. I can not tell the answer ; yet my hand never makes a 

 mistake. No one can describe the order in which he brushes his hair 

 or teeth; yet it is likely that the order is a pretty fixed one in all of us. 



These results may be expressed as follows : 



In actions become habitual, what instigates each new muscular 

 contraction to take place in its appointed order is not a thought or a 

 perception, but the sensation occasioned by the muscular contraction 

 just finished. A strictly voluntary action has to be guided by idea, 

 perception, and volition, throughout its course. In a secondarily auto- 

 matic or habitual action, mere sensation is a sufficient guide, and the 

 upper regions of brain and mind are set comparatively free. A dia- 

 gram will make the matter clear : 



Let A, B, C, D, E, F, G represent an habitual chain of muscular 

 contractions, and let a, b, c, d, e,f, g stand for the respective sensations 

 which these contractions excite in us when they are successively per- 

 formed. Such sensations will usually be in the muscles, skin, or joints 

 of the parts moved, but they may also be effects of the movement 

 upon the eye or ear. Through them, and through them alone, we 

 are made aware whether the contraction has or has not occurred. 

 When the series, A, B, C, D, E, F, G, is being learned, each of these 

 sensations becomes the object of a separate perception by the mind. 

 By it we test each movement, to sec if it be right before advancing to 

 the next. We hesitate, compare, choose, revoke, reject, etc., by intel- 

 lectual means ; and the order by which the next movement is dis- 



