322 GALL'S ANATOMY. 



as intended to increase the formative fibres of the cerebellum, and 

 therefore he terms it the ganglion of the cerebellum. (Cut, p. 311. 

 No. 7*.; p. 312. No. 9.) One of the principal bands which proceed 

 from this advances towards the median line, and with its fellow 

 becomes a long rounded eminence, or ridge, rising from before 

 backwards, and usually called the vermiform process, but by Gall 

 the fundamental part of the cerebellum^ because it is always found 

 in animals which have a cerebellum. (Cut, p. 313. No. 8.) The 

 other bands from the ganglion proceed upwards, downwards, 

 backwards, and outwards, disposed in thin horizontal layers ; 

 those which are nearest the middle being the longest, and those 

 nearest the spot where the original bundles enter the ganglia the 

 shortest. Their extremity distant from the middle is covered 

 with cineritious pulpy substance. A vertical cut exhibits the 

 white layers as branches and twigs, each being surrounded by 

 cineritious substance ; the twigs so surrounded resemble leaflets ; 

 and the whole is known by the name of arbor vitae. (Cut, p. 312, 

 313. 316.) 



Besides these diverging fibres, there are, as in the cerebrum, 

 converging fibres, having no immediate connection with the pri- 

 mitive bundle, with the chorda oblongata, or with the ganglion. 

 These arise from the pulpy substance, and proceed in different 

 directions among the diverging fibres towards the external an- 

 terior part, where those from each side, under the name of crura 

 cerebelli, unite together and form the mesocephalon, or, more 

 properly, the large commissure of the cerebellum. (Cut, p. 304. 

 No. 13. ; p. 311. No. 9. ; p. 313. No. 27. ; p. 316. b.) The size of 

 this is in direct proportion to the size of the hemispheres of the 

 cerebellum, just as the corpus restiforme, ganglion, and cerebel- 

 lum, are all proportionate to each other. Another cerebellic 

 commissure exists at the vermiform process, by means of the 

 soft delicate layers of transverse fibres of its superior and in- 

 ferior part. A layer of fibres, under the name, according to 

 Reil, of inferior medullary veil, or commonly of valve of Vieus- 

 sens and processus a cerebello ad testes, or, according to Gall, 

 of mass of connection between the primitive part of the cerebellum 

 and the corpora quadrigemina, establishes a commissure between 

 the cerebellum and the corpora quadrigemina : and another layer, 

 termed by Reil the superior medullary veil, establishes a commis- 

 sure between the lower portion of the fundamental part or ver- 

 miform process and the posterior pyramidal bodies of the chorda 

 oblongata. (Cut, p. 313.) The fourth ventricle is a mere space 



