CHAP. XXX.] HIGHER CEREBRAL FUNCTIONS. 679 



Broadbent says: "In its first attempts to talk the child 

 is influenced by imitation and guided by the ear ; that is, 

 as the grouping of the motor cells of the cord is effected 

 through the sensory cells, by cell processes passing from 

 the posterior to the anterior nerve nuclei, so the grouping 

 of the cells in the corpus striatum will be effected through 

 the cells of the auditory perceptive centre by means of the 

 fibres connecting together the two. . . . And, as the 

 motor nuclei of the cord can still be employed in reflex 

 action through the sensory nuclei, as well as in voluntary 

 motion by means of descending fibres from the corpus 

 striatum, so may the word groups in the corpus striatum 

 be reached imitatively through the auditory perceptive 

 centre, as well as through the third frontal gyrus." Con- 

 sequently he assumes that there is a double action of a 

 consensual character from both Auditory Centres, and that. 

 in the early ' imitative ' Speech-processes these parts would 

 both react upon their respective Corpora Striata. There 

 is also, as he thinks, a higher or volitional unilateral 

 action through the left third frontal gyrus an action 

 which is unilateral because, as he puts it, " The left 

 hemisphere alone is educated for intellectual expression." 



But, Sensori-motor and Ideo-motor acts of Speech are 

 dependent upon processes occurring (in a slightly different 

 manner) in identically the same cerebral regions and these 

 would correspond with Broadbent's ' imitative ' modes of 

 Speech. Yet, as the writer has previously endeavoured to 

 show (pp. 550-557), no valid demarcation can be estab- 

 lished between Ideo-motor and Voluntary acts of Speech, 

 and the distinction conferred upon the latter by the 

 addition of an ' emotion of desire ' does not make it the 

 less necessary for the outgoing stimulus primarily to 

 pass off from the Auditory Centre ; nor, on the other 

 hand, is there any distinct evidence to show that the 



