7V//: CEREIIRUM. 



689 



with tin- crura ccrebclli, and on the other terminate in the cells of the grey 

 nbetanoe. 



In the grey spot that forms the corpus rhomboidoum, is a great number of 

 largo nerve-cells. 



With regard to structure, the grey matter of the cere- pig. 328. 

 belliun may be decomposed into two layers ; the super- 

 ficial is very rich in blood-vessels, has a greyish tint, and 

 is composed of largo nerve-cells and smaller rounded ele- 

 ments ; the deep layer is of a yellow colour, and also 

 contains nerve-cells and round elements, though the latter 

 are smaller than in the other layer, and have been sometimes 

 mistaken for simple nuclei. 



DIFFERENTIAL CHARACTERS OF THE CEREBELLUM IK OTHER THAN 

 SOLI 1'l.D ANIMALS. 



The external and internal conformation of the cerehellum oners 

 the closett analogies in the donuMttoated mammifers. In all, its 

 volume, compared with that of the other encephalic lobes, is not 

 inviiriiiMr. Thus, while the relation between the weight of the cere- 

 Ix-lliiiu and that of the brain of the Horse is as 1 to 7 ; with the Ox 

 it is as 1 to 9; with the Dog 1 to 8 ; with the Cat 1 to 6; and with 

 the Sheep 1 to 3. These are the only differences to be noted. 



COMPAHI8OK OF THE CEREBELLUM OF MAN WITH THAT OF ANIMALS. 



In Mini, the encephalic mass being enormous, the cerebellum 

 is absolutely more considerable in volume than in the larger domesti- 

 cated animals ; though, in proportion to the cerebral hemispheres, it 

 is smaller than in the Ox, its relation to the latter lobes being as 

 1 to 8. 



It is \\ i.ler than it is long, and projects much beyond the medulla 

 oblongata. It lias three lobes; but these are only visible on its 

 low, i n the opposite face, the median lobe is depressed and 



iled til-math the lateral lobes, which are so large that they 8ECTION 

 have been named the crrfbeUiir hemitphenf. The inferior veimis 

 forms a free projection in which is the fourth ventricle; this is 

 termed the a ruin <>i tin < n-lidlum. The uvula is connected at each 

 side with the valves of Tarin: lamina- of nerve-substance lodged for 

 the most part in the fourth ventricle, and hidden by the lower face 

 of the cereliellar hemispheres. The latter constitute, on the 

 the medulla uhlonguta, two prominences .situated one below the other, 

 the crnni cerelx-lli; the first is dcMghatcd the amygdala or 

 -.Mid the /Hi' nmoijiiftrir. limle (or flocculus}. 



ARTICLE IV. THE CEBEDRUM. 



Tlio cwlintm, the principal portion of the encephalon, 

 comprises the two anterior lotas or kemitpkent of that 

 appsiratus: enlargements which are elongatl in tin- direc- 

 tion of the great diameter of the head and cranial cavity, 

 -idi- i arh other on the middle line, and are unite. I 

 at their central }>art by a transverse eoniniissiire, and by 

 the eiirephalic isthmus, whose anterior xtn inity j'eiietrati >. inf. riorly, 

 into their substance. (See Fig. 8'2'J for a ^.od id, a ( ,f this p.-netra- 



OF THE 

 CORTICAL SUB- 

 STANCE OF Till: 



Ci.KI T.IXLUM. 



Medullary sub- 

 stance, showing 

 its lilires; 6,Sub- 

 stantia fernnri- 

 nea, composed of 

 fibres and <v!l- 

 nuclei ; c, Grey 

 siirtac.', sjraini- 

 Inr at the sur- 

 face, and cont a in- 

 ini; large mul- 

 tipolar Itraucli- 

 iiiL, r cells near 

 tii.- sttbstautia 

 ferruginea. 



.; two lobes together represent an ovoid masfi, having its thick 

 inity adjacent to the cerebellum; it is depress, d from ahu\v to belou, 

 . 'livi.li .1 above, in front, and behind bv u median autcm-jntM 



J t 



