324 RESEARCHES ON CORTICAL LOCALISATION AND 



not fundamentally but in detail on every occasion on which they 

 are evolved or employed. 



Words may arise into consciousness through any of the 

 four language spheres. When, however, they are voluntarily and 

 silently reproduced, i.e. thought of, words are invariably awakened 

 through the articulatory word-centre under normal conditions. 

 .Further, this reproduction requires a muscular effort, and cannot 

 take place without a definite articulatory attempt, usually, but 

 not necessarily accompanied by a slight expiration. Again, words 

 cannot be voluntarily repeated in thought by means of the cheiro- 

 graphic centre if the hand is not actually moved, unless such hand- 

 movements are replaced by slight movements of the head, or even 

 of the lower jaw or the eyes, through the agency of their respective 

 motor spheres. Such observations as have just been indicated 

 are valuable because they render it probable that the important 

 factors in the reproduction are not the muscular movements but 

 the sensorial impulses derived from these ; otherwise there is no 

 reason why such muscular movements should not be imagined 

 without any attempt at their actual performance. If words should 

 spontaneously arise in the visual or the auditory word-centre, the 

 condition is so abnormal as to constitute a hallucination, which 

 the subject may or may not be able to distinguish from a true 

 visual or auditory sensation. A homologous phenomenon to such 

 a hallucination may be observed during the stimulation of the 

 psychomotor area of a monkey which has recovered from anaesthesia. 

 Such an animal regards the movement, say of the arm, with great 

 surprise, and at once performs a voluntary and opposite movement, 

 exactly as if the limb had been moved by an external agency. 



There is thus reason to consider that words invariably arise 

 into consciousness by sensorial or sensori-memorial, and not by 

 psychomotor, means ; and the observation that normally they are 

 voluntarily awakened by the preliminary aid of the psychomotor 

 area is of significance with regard to the thesis that the frontal 

 lobes are concerned with psychic function from the higher asso- 

 ciational and also the motor aspect, and the remainder of the 

 cerebrum from the sensorial, sensori-memorial, and lower associa- 

 . v tional. 



However they arise into consciousness, words naturally 

 possess very different symbolic values. Articles, pronouns, pre- 

 positions, conjunctions, interjections, and the simpler adjectives, 



