784 



So I have commenced to study other important cortical regions 

 as to differences in cell-lamination and areal limitation, as compared 

 with European brains. 



First of all I examined 



Tlie visual cortex. 



On the cell-lamination of this area I may be brief. The lam. 

 granularis interna — Brodmann's IV^^ layer — is in this area clearly 

 separated into three layers, of Avhich the middle one is rich in fibres 

 and as stria Gknnari can easily be followed np with the unaided eye. 

 The first three layers relatively show a poorer development. 



This situation is very constantly found in many primates. So I 

 was not surprised to find no deviations in the cell-lamination of the 

 iMadurese brains. 



More promising seemed the results of an investigation on the 

 extent of this area — Brodmann's area 17. 



Ellioth Smith has studied this area in a large number of Egyp- 

 tian brains. In the course of his investigations it proved necessary 

 to compare the macroscopical cortical structui-e of a very large 

 number of human and primate brains. The fissures and sulci, to 

 which great importance must always be attached for the orientation 

 and demarcation of areas in the occipital lobe, were determined by 

 him. Now it appeared that the relations of these sulci are not nearly 

 so simple as had always been assumed until now. 



Also Smith points out the necessity of always first considering 

 the configuration of the occipital pole in the light of these com- 

 parative studies, before proceeding to the limitation of a cortical 

 area, especially of area 17. Inversely area 17 helped him to recog- 

 nise atypical sulci. 



The material at Smith's disposal was, apart from its diversity, very 

 large. His publication convinced me that for the limitations of a 

 cortical area in this region nothing could be expected except by 

 using a similar mode of investigation. Now, my limited material 

 precluded any attempt in this direction. 



For this reason I have been obliged to restrict myself to studying 

 the cyto-architectonical deviations from European brains and to 

 mention limitations of cortical areas only when they did not involve 

 accurate knowledge and study of the variations in the configuration 

 of cerebral sulci. This procedure commended itself all the more 

 since on this subject opinions are far from unanimous. 



Also Brodmann (1908) has found in the brains of Hereros and 

 Hottentots relations in the configuration of the sulci such as are 



