780 

 Heschi/s convolution{s) and the first temporal convolution. 



In the literature I found publications on this subject by Hammar- 

 BERG (1895), Campbell (1905), Ramon y Cajal (1906), Rosenberg (1908), 

 Brodmann (1909;, and. Droogleever Fortuyn (1911). 



All these authors see in Heschl's convolution and the first tem- 

 poral convolution two different areas. Brodmann restricts himself to 

 the demarcation of the two areas and gives no description of them. 

 The areal limits, according to him, do not as a rule coincide 

 precisely with the anatomical bordeis of the cortical parts. Heschl's 

 convolutions are divided by him into two architectonically different areas 

 41 and 42. In this he stands alone. No more than other investigators 

 have 1 been able to confirm this view. As a general characteristic of 

 the temporal lobe he mentions a relatively strong development of 

 the IVth, Vth and Vlth layers. 



Campbell illustrates his accurate descriptions by clear drawings. 



Droogleever Fortuyn entirely agrees with Campbell. The area 

 (41 -|- 42) — following Brodmann's nomenclature 1 shall retain 

 these figures — occupying the Heschl convolutions, is, according to 

 them, characterised by the occurrence of large cells in the Hid layer, 

 the lamina pyramidalis. These cells which differ from the pyramidal 

 cells in shape as well as by their size, are at once recognised as 

 a special type. Therefore Campbell and Droogleever Fortuyn thought 

 it best to denote them by the name of giant cells, differing 

 herein from Marinesco and Goldstein (1910), who assign to these 

 cells the confusing and little characteristic name "large pyramidal cells". 



Also in the first temporal convolution — pretty well the same as 

 Brodma.sln's area 22 — these giant cells occur, but in so much 

 smaller number that according to Campbell it is easy to distinguish 

 these two areas by this alone. Besides by the number of giant cells 

 however area 22 can be distinguished from area (41 -{- 42) by the 

 much greater richness in large pyramidal cells in the lam. pyramidalis. 



Cajal and Rosenberg in their study of these areas give descriptions 

 of the different cellular shapes in each separate layer. As for the 

 present purpose this seemed superfluous, 1 have refrained from this. 



The distinction between areas (41 + 42) and 22 Rosenberg 

 sought in quite a different manner than Campbell and Droogleever 

 Fortuyn. However, he also makes mention of the occurrence of giant 

 cells, especially again in the HESCHL-convolutions. By measurements 

 of the cortical layers Rosenberg arrived at the conclusion that the 

 ratio of the layers I, II, and HI to IV, V and VI, differs in these 

 areas. In area (41 -j- 42) the three upper layers only occupy 7, of 



