ON THE FUNCTIONS OF THE CEREBRUM 305 



mental method, which was responsible for the non-recognition of 

 an important contribution to our knowledge, was also the method 

 which first supplied evidence of its truth. 



With the exception of the elaborate cell and lamination studies 

 of Hammarberg, which were published posthumously in 1895, and 

 of a paper by Schlapp in 1898 on the cortex of the ape, no con- 

 tributions of direct interest appeared until the year 1900, when 

 the present writer communicated his paper on the exact histo- 

 logical localisation of the visual area of the human cerebral 

 cortex. 



In this paper the exact limits of the human " visuo-sensory 

 area " were mapped out in six hemispheres derived from persons 

 with normal vision and from cases of long-standing and congenital 

 blindness, and the surrounding zone of cortex, the lamination of 

 which was unaffected by the absence of vision, was described 

 under the term " visuo-psychic." 



The limits given to the former area indicated the approximate 

 truth of the opinion at this time held by Henschen and supported 

 by the embryological researches of Flechsig and the clinico-patho- 

 logical investigations of Seguin, Vialet, and others ; and their 

 correctness has since been confirmed by Campbell, Brodmann, 

 Elliot Smith, and many other investigators. 



Since this paper was published, numerous contributions have 

 appeared on the subject of cortical localisation by the histological 

 method. 



Of these the chief are by Brodmann (1902-1907), Campbell (1905), 

 W. Kolmer (1901), Hermanides and Koppen (1903), Koppen and 

 Lowenstein (1905), Elliott Smith (1904-1907), 0. Vogt (1906), Mott 

 (1907), G. A. Watson (1907), and Mott and Kelley (1908). 



In these papers the whole cortex 'in many orders of mammals 

 has been mapped out into various histologically different regions, 

 but, except in the case of the psychomotor and visuo-sensory 

 areas, experimental or histo-pathological proof of the function of 

 these regions is not yet complete. 



The most elaborate of these researches are those of Brodmann 

 and of Campbell. These authors have independently mapped out 

 into histologically different areas the whole human cortex cerebri, 

 as well as the cortex cerebri of many orders of mammals. Owing 



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