586 PSYCHOLOGY. 



The same principles also apply to the relations of K 

 and M. M, lying in the forward direction, drains K, and the 

 path KM, even though it be no primary or connate path, 

 becomes a secondary or habitual one. Hereafter K may be 

 aroused in any way whatsoever (not as before from S or 

 from without) and still it will tend to discharge into M ; or, 

 to express it again in psychic terms, the idea of the move- 

 ment M/'s sensory effects ivill have become an immediately ante- 

 cedent condition to the production of the movement itself. 



Here, then, we have the answer to our original question 

 of how a sensory process which, the first time it occurred, 

 was the effect of a movement, can later figure as the move- 

 ment's cause. 



It is obvious on this scheme that the cell which we have 

 marked K may stand for the seat of either a resident or 

 a remote sensation occasioned by the motor discharge. 

 It may indifferently be a tactile, a visual, or an auditory cell. 

 The idea of how the arm feels when raised may cause it to 

 rise ; but no less may the idea of some sound which it makes 

 in rising, or of some optical impression which it produces. 

 Thus we see that the ' mental cue ' may belong to either of 

 various senses ; and that what our diagrams lead us to 

 infer is what really happens ; namely, that in our move- 

 ments, such as that of speech, for example, in some of us 

 it is the tactile, in others the acoustic, Effectshild, or memory- 

 image, which seems most concerned in starting the articula- 

 tion (Vol. I. pp, 54-5). The primitive ' starters,' however, of 

 all our movements are not Effectshilder at all, but sensations, 

 and objects, i^nd subsequently ideas derived therefrom. 



Let us now turn to the more complex and serially con- 

 catenated movements which ofteuest meet us in real life. 

 The object of our will is seldom a single muscular contrac- 

 tion ; it is almost always an orderly sequence of contractions, 

 ending with a sensation which tells us that the goal is. 

 reached. But the several contractions of the sequence are 

 not each distinctly willed ; each earlier one seems rather, 

 by the sensation it produces, to call its follower up, after 

 the fashion described in Chapter VI, where we spoke of 



