ON THE FUNCTIONS OF THE CEREBRUM 319 



of the functions of which are derived from the various motor 

 exhibitions which are presented by its possessor. 



In the lower animals these are of two kinds, evidences of feeling 

 or emotion, and evidences of intelligent (instinctive or acquired) 

 activity ; and either of these may be partly indicated by means of 

 articulatory exhibitions. 



The same evidences of cerebral activity are presented by man, 

 in whom, however, the indications of emotion are more numerous 

 and complex, and the evidences of psychomotor activity are in- 

 finitely more elaborate. The latter, apart from the ordinary motor 

 indications of intelligence, consist of gestures and of spoken and 

 written language. 



Any discussion of the theory of the emotions would be out of 

 place in this article, but it may be indicated in passing that they 

 are probably evolved from the lower or instinctive plane of motor 

 exhibition. This is suggested by the common observation that 

 very young infants " make faces " indicative of various emotions 

 under the influence of gastrointestinal irritation, long before they 

 present evidence of intelligent motor activity, and still longer 

 before they are able to articulate a word. Further, objective in- 

 dications of probably experienced emotions become well-developed 

 in infants at a time when the ordinary motor indications of intelli- 

 gence are still highly inco-ordinate. 



Of the indications of human psychic activity, the most im- 

 portant, namely, language, will now be considered. 



The elements on which cerebral activity is based are the various 

 sensory impressions which arrive at the cortex and which are con- 

 served there as sensori-memorial images. These elements form 

 the raw material of the psychic processes and are spoken of as 

 sensations. To be understood, sensations require localisation in 

 space and reference to the objects from which they arise. The 

 cerebral process involved in the preliminary fusion of sensations 

 is spoken of as perception. For example, the sound of a clock 

 ticking results in the localisation of the sensation in a certain 

 direction and to a particular object, the clock. Not only, however, 

 does the process of perception involve the fusion of direct sen- 

 sations, but it also necessitates the awakening and fusion with 

 these of sensori-memorial images of former sensations. In the act 

 of identifying an object, e.g. a locomotive, the various sensations 

 arising from it awaken a variable number of sensori-memorial 



