THE NERVOUS SYSTEM. 317 



between the facial nerve, 11, and the acoustic nerve, 9. The trigeminus or fifth 

 is still covered entirely by the transverse fibres of the cerebellum. The olivary 

 ganglion, a, is prolonged below the transverse fibres b of the cerebellum ; one 

 part of the transverse fibres of the cerebellum is removed to show the continu- 

 ation of the pyramidal band 1, c, c, which begins to diverge and be reinforced. 

 Outside the optic nerve q, t, v is seen the expansion of the nervous bands, in the 

 inferior convolutions w, w, w of the middle lobe 26, 27. 



A, Left side of the base. A verticle cut of the cerebellum, directed through 

 the entrance of its original bundle e e, and through the middle of its ganglion s, 

 in the direction 92, 28, B, to show the reinforcement of the original bundle in 

 the ganglion, and the ramifications and subdivisions of the nervous chords. All 

 the transverse fibres of the cerebellum which cover the trigeminus k, i, and 

 the prolongation f of the pyramidal bundle 1, c, c, are removed. The pro- 

 longation of the olivary ganglions a, a is still covered by the transverse fibres. 

 The optic nerve is removed from the great fibrous bundle g, and cut at v, q, 

 The pyramidal bundle is seen prolonged from the deeussation 1, to the trans- 

 verse interlacement 35, below the optic nerves. The grey mass 17 has been 

 removed by scraping, to show the two cords of the mammillary bodies 16, 16 ; the 

 one y, towards the transverse interlacement 35, the other, 7, towards the common 

 mass of communication or fornix. The nervous fibres which spread out in the 

 convolutions of the middle lobe, and contribute to its functions, are cut at h, h, k 

 between 35 and 37, on a level with the anterior commissure ; and the middle 

 lobe is entirely removed. The mass of grey substance of the great superior 

 ganglion of the brain, and a part of the convolutions situated below the great 

 fissure, between the middle and anterior lobes, are cut in the same direction. 

 We thus see how this great mass is divided by the nervous bundles S into an 

 inner part I, and an outer part, L L ; how the finest fibres are implanted in the 

 grey substance; how the convolutions 40, 41 are formed by the posterior 

 chords of the great fibrous bundle or crus placed before ' t g, and what are the 

 depth and length of the great fissure 39, 39 between the anterior and middle 

 lobes. By the removal of the middle lobe, the posterior edge of the great 

 cerebral cavity N N becomes visible. This cavity is prolonged inwards and 

 forwards below the great fibrous bundle or crus g. Between 40 and vii. are 

 seen the convolutions situated above the fissura Sylvii between the anterior and 

 middle lobes. The anterior lobe is but slightly cut. 



21. Internal root of the olfactory nerve. 18. Its external root. 23. Its bulb. 

 25, 26. Anterior lobe of the cerebrum. 27. Its middle lobe. 28. Its pos- 

 terior lobe. 20. Optic nerve. 32. Deeussation of the optic nerves, v. Optic 

 nerve after its deeussation. 33. Transverse interlacement of the upper edge of 

 the great commissure of the cerebellum. 34, 34. Transverse interlacement of 

 the great fibrous bundle. 36. Transverse interlacement of the nervous bundles 

 of the middle lobe. 37. Tranverse interlacement of the great superior cerebral 

 ganglion. 38, 38, 38, 38. Situation of the tissue of the two orders of nervous 

 filaments. 13. Pathetic nerve. 6, b. Pons Varolii. 91. Central fissure of the 

 posterior part of the spinal chord. 61. Anterior commissure of the cerebrum. 

 -(Gall.) 



According to Gall c , many primitive bundles of nervous fibres 

 give origin to the cerebrum and cerebellum. The anterior and 

 posterior corpora pyramidalia, bands proceeding immediately from 

 the corpora olivaria, longitudinal bands which contribute to form 

 the fourth ventricle, and many others concealed in the chorda 

 oblongata, to the cerebrum ; the corpora restiformia to the cere- 

 bellum. 



The bands arising from the anterior pyramids are the only ones 



c 1. c. vol. i. 270. sqq. 



