Royal Mierosco2)ical Society. 3 



nerve fibres are seen crossing in various directions ; the terminal 

 ramifications of which form an imperfect network. The meshes 

 of this network, measuring about ^^ mm. in width, extend into 

 the granular substance to a depth of ^V mm., and are gradually 

 lost in the fine terminal nervous network, already mentioned. A 

 considerable number of free nuclei, surrounded by pigment granules, 

 are distributed throughout the stratum to a depth of t^o^ mm. 

 Advancing farther, we now meet with the first ganglionic bodies, 

 forming a layer of about f¥o mni- in depth. The direction of the 

 processes of these bodies is various and indefinite, as some pursue a 

 vertical and oblique course, while others run in an opposite direc- 

 tion. Their further connection is difficult to discover, as they can 

 only exceptionally be traced to a greater distance than yw n^iii. 

 From certain observations, I suppose that those fine dark-bordered 

 nerve fibres on the surface, above mentioned, as well as others of 

 the same kind, running horizontally in the iuterior, are derived 

 from them. I doubt not but that these small ganghonic bodies also 

 send a nerve fibre to the white substance. The transition of the 

 ramifications of some of their processes into the terminal network 

 can always be seen. 



About tA iiim. from the surface of the cortical layer, the 

 ganghonic bodies commence to change their form by the lengthening 

 of their pointed process, and thus approach the above - described 

 pyramidal type. Gradually increasing in size, they attain, about 

 -nrW nun. deeper, their maximum, with a length of from yio to 

 -^ mm. These bodies, the most perfectly developed, and repre- 

 senting the type, form a layer of about -^^ mm. in thickness. 

 Advancing still deeper, they diminish again in size, and become, to 

 a certain degree, though not without exception, more spiudle- 

 shaped, in which form they extend to the white substance. At the 

 same time they decrease in number, so that in the lowermost layer 

 of the cortical substance the fibrous element already predominates. 

 The decrease m size of the ganghonic bodies in approaching the 

 white substance, however, is not so considerable as might be sup- 

 posed, for they still attain a length of about too mm. or more; 

 their pointed process, however, is proportionately thinner. 



3. The Cortical Layer of the Cerebellum. — This consists of 

 the true cortex or so-called grey layer, and of the reddish-grey 

 nucleated layer. In the latter, the transition of the grey matter 

 into the white, composed of nerve fibres, takes place. 



The grey layer is about -^^^ mm. thick, and consists of gan- 

 ghonic bodies and free nuclei, imbedded in a fine granular substance 

 through which a terminal nervous network extends. The principal 

 ganghonic bodies are those of Purhinje, well known by their pecu- 

 Har form. They are found at the inferior margin of the grey layer, 

 whence they extend their enormous antler-shaped processes with 



B 2 



