522 



CEEEBRLM. 



stem of the laminae, whence they radiate into the cortex. They disappear 

 in the granule layer, and are commonly believed to be continuous ^^ith 



the outer processes of the 

 Fig- 367. corpuscles of Purkinje, but 



some consider that they 

 arise, in part at least, by 

 the union of the fine fibres 

 of the plexus in which the 

 granules of the outer layer 

 are embedded. 



Fig. 367. — From the Outer Later 

 OF THE Cerebellum (from a 

 drawing by Mr. H. R. 0. Sankey). 

 Processes op the Corpuscles 

 OF Purkinje, connected, by 



THEIR FINER BRANCHES, WITH 



THE Corpuscles of the Outer 

 Layer. (Highly magnified. ) 



The structure of the cor- 

 pus dentatum resembles tliat 

 of the olivary body. Stel- 

 late cells, x-sVo^l^ to Woo^'l 

 inch in size, lie in several 

 layers, among a plexus of 

 finer nerve fibres, passing in 

 variousdirections, but chiefly 

 from without inwards. 



THE CEKEBRUM. 



The cerebrum, oi- brain proper, constitutes the highest and much the 

 largest portion of the encephalon. It consists of the following parts, 

 viz., the peduncular masses of the crura cerebri and processus a 

 cerebello ad cerebrum ; the series of eminences or cerebral centres or 

 ganglia concealed from view, named corpora quadrigemina, optic 

 thalami and corpora striata ; the cerebral hemispheres, which are by far 

 the most bulky part of the cerebrum ; various commissural structures 

 including the corpus callosum and fornix; and lastly some smaller 

 structures, viz., the j)ineal and the pituitary bodies, and the olfactory 

 bulbs. 



EXTERIOK OF a?HE CEEEBRUM. 



The cerehral hemispheres together form an ovoid mass, flattened on 

 its under side, and placed in the cranium with its smaller end forwards, 

 its greatest width being opposite to the parietal eminences. They 

 are separated in the greater part of their extent by the great longitu- 

 dinal fissure. 



Each cerebral hemisphere has an outer, convex surface, in contact 

 with the vault of the cranium ; an inner or median, flat surface, which 

 forms one side of the longitudinal fissm-e ; and an irregular under 

 surface, in which is a deep cleft, the fissure of Sylvius. In front of this 



