59 



and sectioned at right angles to the surface. Fix and mount in 

 balsam. 



Under high power the following structure will be 

 seen : 



(1) The outer or molecular layer, composed largely 

 of neuroglial tissue. In it are a few small nerve cells and 

 a thin stratum of fine medullated fibres, running parallel 

 to the surface just under the pia mater. 



(2 and 3) Layer of small and large pyramidal cells. 

 In the former layer the cells are small and close together; 

 in the latter they are larger and farther apart. There is, 

 however, no distinct boundary line between the two layers. 



(4) A layer of small cells, some of which are pyram- 

 idal, others spindle-shaped, still others multipolar. 



Sketch a portion of the cortex under high power. 



(e) Cerebral Cortex Stained with Weigert's Haem- 

 atoxylin. 



Small pieces of the human cortex were hardened in Muller' s 

 fluid, embedded in celloidin, sectioned at right angles to the surface, 

 stained in Weitrert's hsematoxylin, dehydrated, and cleared in 

 carbol-xylol. Wipe away excess of clearing fluid, and mount in 

 balsam. The nerve fibres are stained a bluish-black, all other 

 elements (except the red blood cells) a yellowish brown. 



Study under low power. "The nerve fibres entering 

 the gray cortex are arranged in bundles, from which arise 

 networks variously arranged and situated. The radiating 

 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." (Piersol.) Sketch a portion 

 of the cortex as seen under low power. 





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