RECENT RESEARCHES ON CORTICAL LOCALI- 

 SATION AND ON THE FUNCTIONS OF THE 

 CEREBRUM 



BY JOSEPH SHAW BOLTON 



INTRODUCTION 



THE experimental study of the functions of the cerebrum, after a 

 period of activity lasting through three decades, reached its acme 

 in an important research (Sherrington and Griinbaum), which 

 resulted in the belated recognition of the histological investigation 

 of Bevan Lewis and Henry Clarke (1878) on the cortical localisa- 

 tion of the motor area of the brain. Of late years the histological 

 has largely replaced the experimental method, and the study of 

 cortical localisation, although still in its infancy, may now fairly 

 claim to be regarded as a branch ot exact science. 



Owing to the far-reaching importance of the controversy regard- 

 ing the neurone theory, the majority of the numerous recent 

 publications on the anatomy and histology of the nervous system 

 deal with the finer histology of nerve cells and fibres. Of 711 

 contributions, for example, which appeared during the years 1905 

 and 1906, and which were critically abstracted and reviewed by 

 Edinger and Wallenberg in their last report, over 300 papers 

 were concerned with this subject, and few of the remainder were 

 of direct physiological significance. It is not the purpose of this 

 article to deal with purely histological investigations which have 

 no immediate bearing on cortical localisation, and therefore no 

 reference will be made to such contributions beyond the remark 

 that, of those by English writers, the papers of John Turner are 

 especially worthy of attention. 



During the past eight years numerous publications have 

 appeared on the subject of cortical localisation by the histological 

 method. In these several contributions the mode of evolution 

 and the functional significance of the different cell layers of the 

 cortex cerebri have been considered from both the ontogenetic 



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