608 



THE NERVOUS SYSTEM 



into two coarse branches, which each divides dichotomously into a suc- 

 cession of increasingly more delicate branches forming peripherally a 

 dendronic field of extreme profusion of non-anastomosing fibrils. The 

 > dendron viewed as a whole constitutes a fan- 

 JK S \ slinpcd stniHure. Its expansion is in a 



^^^^^^^ \s^ plane at right angles to the long axis of the 

 >, :; ffijr convolution. In sections parallel with the 



/ long axis of the convolution the dendronic 



field is very narrow, and never wider than 

 the diameter of the cell-body. 



The basket-cells, or large cortical cells, 

 are multipolar elements with relatively 

 short robust branching dendrons, and a 

 long axon which passes horizontally in the 

 same plane in which the dendronic expan- 

 sion of the Purkinje cells are placed. Along 

 its course it gives off five or six collaterals 

 which, as also the post-collateral portion 

 of the axon itself, pass centrally toward the 

 Purkinje cells where each breaks up into a 

 profuse terminal arborization which invests 

 the cell-body in the manner of a 'basket.' 

 The basket cells occupy the middle and 

 outer portions of the molecular layer; they 

 are apparently of the nature of association 

 neurons, perbaps coordinating the function 

 of a number of Purkinje cells. 



The small cortical cells are distributed 

 throughout the molecular layer but are more 

 abundant in the outer half. They are mul- 

 tipolar and vary considerably in size, some 

 being almost as large as the basket cells. 

 They possess from two to five delicate den- 

 drons distributed for the most part in the 

 same plane as those of the Purkinje cells. 

 Their short slender axon, which is horizon- 

 tally placed, is frequently characteristically 

 looped. The axon of some of these cells has numerous collat- 

 erals. 



The nuclear or granular layer also contains three distinct types 



FIG. 526. A PURKINJE CELL 

 FROM THE CEREBELLAR 

 CORTEX OF THE RABBIT. 



Highly magnified. 

 Nissl.) 



(After 



