342 RESEARCHES ON CORTICAL LOCALISATION AND 



a mass of evidence which confirms the correctness of the obser- 

 vations with regard to cortical localisation and cerebral function 

 which have been recorded during recent years. These observations 

 are difficult to correlate with in fact, they are in many respects 

 opposed to the hitherto current doctrines with regard to aphasia ; 

 but they have received confirmation and derived illumination from 

 the researches of Marie. 



The attention of the reader will finally be drawn to certain 

 matters of interest with regard to the functions of the cerebrum, 

 and to a number of recent publications, the consideration of which 

 could not be conveniently introduced into the general text of this 

 article without interference with its continuity. 



The first subject which will be briefly indicated is termed 

 " alteration of personality." This may be conveniently defined 

 as a mental state in which the higher cerebral functions are 

 exercised, not over psychic processes founded on such recently 

 acquired time-related portions of the content of mind as con- 

 stitute the normal personality, but over psychic processes founded 

 on complex and time -related portions of the subconscious content 

 of mind, which exhibit such abnormal prominence as to entirely 

 replace for the time those recent experiences on which normal 

 cerebral activity depends. In such cases not only one, but several 

 such time-related portions of former experience, may separately 

 and at different times acquire abnormal prominence, and thereby 

 give rise to the phenomena of multiple personality. In the normal 

 individual, on the other hand, the recent time-related personality 

 cannot be voluntarily subordinated, and all that is possible in this 

 direction is the occurrence of some degree of associational elabora- 

 tion of former sensori-memorial images, which is always imperfect 

 and often incorrect. To test the truth of this statement, the 

 reader needs only to endeavour to recall, in a time-related manner, 

 the events of yesterday. 



This " alteration of personality " or switching on of a former 

 period of cerebral activity, with temporary obliteration of later 

 experience, is common in hysteria, epilepsy, and hypnotic states. 

 The phenomenon is of importance in that it proves that, whilst 

 the exercise of the cerebral functions is an active process which 

 derives its pabulum from both the past and the present, the whole 

 of the psychic life is nevertheless recorded in the cerebrum in a 



