NORMAL HISTOLOGY. 



14 fj. in diameter ; among the smaller elements a few larger pyramidal 

 cells are often encountered, as well as radiating bundles of med- 

 ullated nerve-fibres. The cells of this layer resemble those of 

 the second, since their axis-cylinder processes are confined to the 



gray matter, the elements be- 



FIG. 343. ing, therefore, cells of the 



second type. 



5. The fifth layer indicates 

 the proximity of the white 

 matter by the large areas occu- 

 pied by bundles of radiating 

 nerve-fibres directly contin- 

 uous with the medullary tracts ; 

 within the interspaces between 

 the nerve-bundles lie the small 

 and medium - sized cells, 

 spindle to pyramidal in form, 

 which characterize this layer. 

 While these cells are arranged 

 generally parallel with the fibre- 

 bundles, sometimes, especially 

 at the bottom of the fissures, 

 they are placed at right angles 

 thereto, in the latter case as- 

 suming a pronounced spindle 

 type. 



The nerve-fibres enter- 

 ing the gray cortex are ar- 

 ranged in bundles, from which 

 arise net - works variously 

 situated and arranged. The 

 radial bundles proceed as 

 such through about half the 

 entire thickness of the cortex ; 

 beyond this level they rapidly 

 separate into the component 

 fibres which take their way 

 between the ganglion - cells. 

 The fibres given off during the 

 course of the bundles form net- 

 works at all depths occupying the interfascicular portions of the 

 layers traversed ; within the deepest part of the fourth layer, how- 

 ever, the nervous fibrillae are especially numerous, and constitute 

 a conspicuous reticulum in preparations stained by Weigert's 



Section of human cerebral cortex stained by 

 Weigert's method, exhibiting groups of nerve-fibres ; 

 part of white matter and inner layers of gray sub- 

 stance shown : F, white matter from which radiating 

 bundles of nerve-fibres () extend into gray matter ; 

 C, D, and E, third, fourth, and fifth zones of gray 

 matter : cells are faintly stained. 



