THE CEREBELLAR CORTEX 35 



the branches of the Purkinje cells, without becoming tortuous. All the dendrites of the 

 Purkinje cells end in free terminations, as is well shown in the plates. The majority of the 

 branches extend quite to the superficial margin of the convolution. 



The neuraxon of the Purkinje cell, well shown in the plate, enters the granular layer 

 from the side or base of the cell, and passes through it to enter the white matter. In its 

 passage it gives off several collaterals, which turn backward and ascend into the molecular 

 layer, where they become longitudinal in their direction, branch, and interlace with the 

 dendritic branches of the cell. Cajal supposes that by means of these collaterals the inter- 

 action of numerous cells is secured. The neuraxons of the Purkinje cells form the chief 

 constituents of the white tracts of the cerebellum which issue from the cortex. They pass in 

 various directions which will be described later. 



To the right of the plate a horizontal fibre is to be seen in the molecular layer, giving 

 off a branch which in turn divides into several branches. This is one of the so-called 

 baskets of the cerebellum a brush-like or basket-like mass of fibres which surrounds the 

 body of the Purkinje cell. These are also shown in Plate XVIII. 



Plate XV. shows another Purkinje cell of the adult human brain with its arborization. 

 The gemmules upon the dendrites are well shown in this plate. The size of the cell is 

 70 p.. This plate displays the wonderful manner in which the dendrites divide and subdivide 

 until the final terminal filaments are reached. The body of this cell is distinctly pear- 

 shaped, and the neuraxon is clearly seen coming out of the base on one side, but can only 

 be traced a short distance. It has recently been affirmed by Semi Meyer ' that the gemmules 

 are artifacts of the Golgi method, he having failed to demonstrate their existence by the methylin 

 blue method of staining. This assertion appears to be inconsistent with the uniformity of their 

 appearance in all specimens and with the regularity of their arrangement, both on the dendrites 

 of the Purkinje cells and on the dendrites of the pyramidal cells of the cerebral cortex. They 

 must be considered as actual structures. 



1 Arch, fur Micro. Anat., Oct. 1895. 



