-58- 

 and do not come so near to the surface as the posterior. 

 The two crescents are united by an anterior white, and a 

 posterior gray, commissure, between wliich is found the 

 central canal. In the gray matter a very fine network of 

 fibres is seen. This is com[)Osed of medullated fibres, 

 liranches of nerve cells, and neuroglia, tissue. The nerve 

 cells are usually found in small groups, those in the ante- 

 rior horn are larger and more numerous. The white mat- 

 ter, stained a l)luish black, surrounds the gray. It is com- 

 posed of medullated nerve fibres seen in cross section. 

 Between these fibres a small amount of neuroglia tissue is 

 observed. Sketch the cord in outline as seen under low 

 l)0wer, and sketch portions of the gray matter of the 

 anterior horn and white matter as seen under high power. 



(c) Cerebellum. 



Small pieces of tliP cerehelliiin were hardeneil in mercuric 

 chh^iiilc, .stained in l^elafield's liaMiiatoxylin, embedded in paralHii, 

 and sectioiKMl at rit^lit angles to tiie small foMs. Fix to the sli<le 

 and iM'iuiit in lialsam. 



Under high ]i()wer the gray matter shows the follow- 

 ing layers in cross-section : — 



( 1 ) An outer molecular layer, composed largely of 

 neuroglial tissue, and containing a few small ganglion cells. 



(2) Between the above stratum and the tliird a single 

 layer of Purkinje's cells is found. From the base of these 

 cells an axis cylinder ])rocess is given otY; from the oppo- 

 site pole one or two ])rotoplasmic processes, these extending 

 into the molecular layer and there dividing and redividiug, 

 until the process has the appearance. of a deer's antlers. 



(3) The granular layer, composed largely of round 

 and spindle-shaped cells possessing comparatively large 

 nuclei, so that in the section very little but the nuclei will 

 be seen. The axis cylinder processes of Purkinje's cells pass 

 through this layer, become medullated, and are lost in the 

 white substance making up the central portion of the fold. 

 Sket(di the cortex under high power. 



(d) Cerebral Cortex. 



Small pieces of cerehral cortex were hardened in niercnric 

 chloride, stained in Delatield's lia;matoxylin, emljedded in jiaratiin, 



