SPACE 13 



air the numeral 3 : you will get two numerals in their correct 

 position . Now quickly give to both hands simultaneously the 

 order to write a 3, and instead of 3 3 you will get £ 3, i.e. two 

 numerals, of which one is the mirror-image of the other. 

 This is not surprising, since the muscles of the two arms, 

 although alike, are arranged mirror-wise with relation to one 

 another. The experiment merely shows that the nerve 

 impulse is divided between the two arms to carry out the 

 same movement, and that the movement is performed without 

 reference to the different arrangement in the left arm. 



Every muscular action is connected with a direction-sign. 

 For the right hand we have learnt by now to make the impulses 

 succeed one another in such a way that the direction-signs 

 thereby sounding produce the numeral 3. When we initiate 

 the same series of muscular actions in the left arm, the mirror- 

 image of the numeral 3 must result. 



Nevertheless we are somewhat surprised, because we get 

 none of the effects we expected from the left arm. Before 

 the act of writing, we picture to ourselves more or less clearly 

 the numerals 3 3, and we find now that the result does not 

 correspond with this preconceived image. We should feel 

 the same astonishment, if, when we wanted to play a familiar 

 tune on a piano, we found that the strings of the piano were 

 arranged in reversed sequence. 



From this experiment we may infer that the preconceived 

 image, however exactly formed, does not directly innervate 

 the muscles of the left arm. The preconceived image consists, 

 in the best instances, of carefully ordered memory-signs 

 which are arranged extensively like the actual direction-signs. 

 In contrast to this, the innervation that initiates the move- 

 ment consists of separate impulses which follow one another 

 in time. For the arrangement in time of different factors we 

 shall employ the current term for a succession of sounds — 

 " melody." 



