THE NERVOUS SYSTEM 



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lobe, the upper part of which is the superior vermis, and two 

 lateral lobes, each with a secondary small lobe, the flocculus. 

 Its surface is raised into long ridge-like folds running in the 

 horizontal plane, and is covered over with grey matter, the 

 cortex. In the substance of the white matter forming the 

 centre of the organ are two masses of grey matter on each 

 side 1, the roof nucleus; and 2, the dentate nucleus 

 (Fig. 86, R.N. and Dent.). 



The cortex may be divided into an outer somewhat homo- 

 geneous layer (the molecular layer, Fig. 87, G.L.) and an inner 



FIG. 87. Diagram of the Arrangement of Fibres and Cells in the Cortex of the 

 Cerebellum. G.L., Molecular Layer; N.L., Nuclear Layer; P., Purkinje's 

 Cells. (After RAMON Y CAJAL. ) 



layer studded with cells (the nuclear layer, N.L.). Between 

 these is a layer of large cells the cells of Purkinje (P.). 



By Golgi's method the arrangement of fibres and cells in 

 the cerebellum has been shown to be as follows : 



Fibres coming into the cortex from the white matter end 

 either in synapses round cells in the nuclear layer, or proceed 

 at once to the outer layer (Fig. 87). From the cells in the 

 nuclear layer processes pass to the outer layer and there form 

 synapses with other cells. From these, processes pass to 

 the cells of Purkinje, round which they arborise, and from 



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