A MANUAL OF PHYSIOLOGY 







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FIG. 356. CELL-LAMINATION OF GYRUS POST- 

 CENTRALIS (CAMPBELL). 



A, just behind upper end of fissure of Ro- 

 lando ; B, from the posterior edge of the gyrus 

 (intermediate postcentral area of Campbell). 



' ganglionic ' layer, con- 

 taining the largest pyra- 

 midal cells (deep large 

 pyramids] ; (6) a layer 

 (lamina multiformis] of 

 spindle-shaped or polymor- 

 phous cells. These layers 

 vary in their structural 

 details, and especially in 

 their relative development 

 in animals of different rank 

 in the mammalian scale, in 

 one and the same animal 

 at different periods in its 

 embryonic and extra-uter- 

 ine growth, and also in 

 different parts of the cortex 

 in an adult animal of given 

 species. The region in 

 front of the central sulcus 

 (fissure of Rolando), e.g., is 

 characterized by the pres- 

 ence of the giant pyramids 

 of Betz, which give origin 

 to the pyramidal fibres 

 going to the trunk and 

 limbs (Fig. 357). 





FlG. 357,-^CELL-LAMINATION OF 

 GYRUS PRECENTRALIS (CAMPBELL). 



From the portion of the gyrus im- 

 mediately in front of the central 

 sulcus (Campbell's precentral area 

 in Figs. 359, 360). 



VJ7 



FIG. 358- CELL - LAMINATION OF 

 GYRUS PRECENTRALIS (CAMPBELL). 

 From anterior part of the gyrus (Camp- 

 bell's intermediate precentral area hi 

 Figs. 359. 36o). 



Although the results are less definite, the work of Flechsig on 

 the time of development of the medullary sheath of the fibres m t 

 various cerebral convolutions has also contributed to our knowledge 



