RECENT RESEARCHES i'sr. 



and the phylogenetic aspects ; and the whole cortex cerebri in 

 many orders of mammals (including man) has been mapped out 

 into various histologically different regions. 



Of these regions, experimental or histo-pathological proof of 

 the functions of the precisely-defined psychomotor and visuo- 

 sensory areas is complete. In the case of the prefrontal region, 

 which is the latest evolved, the most variable, and the most com- 

 plexly constructed portion of the human cerebreum, histo-patho- 

 logical evidence of its functional significance has been derived from 

 the examination of cases of mental disease, which method consti- 

 tutes an advance on the time-honoured study of cases of gross 

 lesion of the brain. 



Finally, with regard to the localisation of the language centres, 

 important papers by Marie and by Monakow, and a lengthy volume 

 by Moutier, have been published ; and the existence of Broca's 

 speech area has thereby been seriously threatened if not ren- 

 dered entirely doubtful. Articles on the psychological experiences 

 connected with the different parts of speech, on the language 

 mechanism and its psycho-physiology with regard to the functions 

 of the cerebrum, and on the subject of sense-deprivation, have also 

 been recently published. 



In the course of the present article, the lamination of the cortex 

 cerebri and the functional significance of its several layers will 

 first be considered. The subject of cortical localisation by means 

 of the histological method will then be detailed. This description 

 will be followed by remarks on the mode of evolution of the 

 cerebral functions. The higher functions of the human brain will 

 afterwards be dealt with, and in connection with this matter the 

 psycho-physiology of the language mechanism will be discussed. 

 The subject of sense-deprivation will next receive attention, as 

 a preliminary to the consideration of the recent researches on 

 aphasia. The article will be concluded by references to certain 

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

 and to a number of recent publications of importance, which 

 could not be conveniently included in the general text. 



LAMINATION OF THE CORTEX CEREBRI 



Since the year 1872, when Meynert published a description of 

 the structure of the cortex cerebri which, from the general aspect, 



