HABIT. 113 



is repeated, the more easily the movement follows, on account of the 

 increase in permeability of the nerves engaged. 



"But the more easily the movement occurs, the slighter is the 

 stimulus required to set it up ; and the slighter the stimulus is, the 

 more its effect is confined to the fingers alone. 



'' Thus, an impulse which originally spread its effects over the whole 

 body, or at least over many of its movable parts, is gradually deter- 

 mined to a single definite organ, in which it effects the contraction of 

 a few limited muscles. In this change the thoughts and perceptions 

 which start the impulse acquire more and more intimate causal relations 

 with a particular group of motor nerves. 



" To recur to a simile, at least partially apt, imagine the nervous 

 system to i-epresent a drainage-system, inclining, on the whole, toward 

 certain muscles, but with the escape thither somewhat clogged. Then 

 streams of water will, on the whole, tend most to fill the drains that 

 go towards these muscles and to wash out the escape. In case of a 

 sudden ' flushing,' however, the whole system of channels will fill itself, 

 and the water overflow everywhere before it escapes. But a moderate 

 quantity of water invading the system will flow through the proper 

 escape alone. 



" Just so with the piano-player. As soon as his impulse, which has 

 gradually learned to confine itself to single muscles, grows extreme, 

 it overflows into larger muscular regions. He usually plays with his 

 fingers, his body being at rest. But no sooner does he get excited than 

 his whole body becomes 'animated,' and he moves his head and trunk, 

 in particular, as if these also were organs with which he meant to 

 belabor the keys." * 



Man is born with a tendency to do more things than he 

 has ready-made arrangements for in his nerve-centres. 

 Most of the performances of other animals are automatic. 

 But in him the number of them is so enormous, that most 

 of them must be the fruit of painful study. If practice did 

 not make perfect, nor habit economize the expense of ner- 

 vous and muscular energy, he would therefore be in a sorry 

 plight. As Dr. Maudsley says : f 



"If an act became no easier after being done several times, if the 

 careful direction of consciousness were necessary to its accomplishment 

 on each occasion, it is evident that the whole activity of a lifetime might 

 be confined to one or two deeds — that no progress could take place in 

 development. A man might be occupied all day in dressing and un- 



* G. H. Schneider : ' Der menschliche Wille ' (1882). pp. 417-419 (freely 

 translated). For the drain-simile, see also Spencer's 'Psychology,' part 

 V, chap. VIII. 



t Physiology of Mind, p. 155. 



