Psychical Processes 169 



A healthy infant will lie for hours moving his 

 limbs about in an aimless manner. These 

 movements, however, tend to promote the 

 growth, not only of the child's bones and 

 muscles, but also of the nervous substance of 

 his cerebral hemispheres, because the constant 

 movements bring numerous muscular sense- 

 organs into action, thus leading to a discharge 

 of energy which passes to sensori-motor centres, 

 and by exercising their elements promotes their 

 organisation and also that of the cerebral cortex 

 as a whole. That this is the case is shown by 

 the fact, that an infant four or five months 

 old not infrequently ceases crying to be fed 

 when he hears his nurse's voice, showing that 

 he has come to associate the sound of her voice 

 with the relief of the cause of his distress. 1 



Infants when about six months old, as a rule, 

 make persistent but ill-directed efforts with 

 their arms and hands to reach any near object, 

 especially if it happens to be of a bright colour ; 

 movements such as these depend to a large ex- 

 tent on reflex automatic action. When a child 

 is a little older he guides his hands so as to seize 



1 Instinct and Experience, by C. Lloyd Morgan, pp. 20, 33. 



