OF THE NE'RVUS OCTAVUS. 181 



Fig. 14 A E. A series of horizontal sections, a fortnight after 

 rootsection of the nervus octavns, through the central 

 system of a rabbit. (MAiicm-preparation). 



The abbreviations as in the proceeding drawings. 

 PLATE XIV. 



Fig. 14 A. The section falls through the radix descendens radicis ventralis N. VIII 

 and the gemi of the N. VII. It demonstrates the degeneration of root- 

 fibres in the ascending DEITEIIS tract, in the fasciculis long, posterior, 

 in both fasciculi spino-cerebellares ventrales ascendentes , and round both 

 nuclei ventrales lemnisci laterales. Still better it is demonstrated in. 



Fig. 14 B. A horizontal section falling somewhat more dorsally. 



Fig. 14 c. A horizontal section at the level of the tuberculnm acusticnm shows at 

 the left side the union of the two bundles of the lateral fillet. The one, 

 the fasciculus spino-cerebellaris ventralis ascendens , and the other the 

 lemniscus ad corp. quadrigeminuni posticmn. At the right this union has 

 not yet taken place. 

 PLATE XV. 



Fig. 14 D and E Horizontal sections through the nuclei tecti cerebelli, demon- 

 strate, the distal end of the fasciculus spino-cerebellaris ventralis ascen- 

 dens on both sides , their deviation into the nuclei tecti and their decussatio 

 in the corpus medullare cerebelli. 



PLATE XVI and PLATE XVII. 



Fig. 20 A F, Fig. 21. A series of horizontal sections through 

 the brain and a series of frontal sections through the 

 medulla of a rabbit ten days after a proximal section 

 through the corpus juxtarestiforme. 



The injury is found in fig. 20 A D in x. Its most 

 dorsal white surroundings are found in fig. 20 A. The 

 incision enters medio-ventrally from the tuberculum acus- 

 ticum in the nucleus of BETTERS, and from the IV th ven- 

 tricle it goes proximally and laterally from the IV th nucleus 

 in fig. 20 B. 



The largest extension of the injury is found in fig. 20 c, 

 where it nearly reaches the lateral fillet, and in fig. 20 D 

 where it divides the Bracchium conjunctivum pedunculi 

 cerebelli superioris, causing its centripetal degeneration. 

 It touches the ventral part of the lateral fillet with its 

 most ventral end in fig. 20 F. 



From this injury many secundary degenerations exit. 



Fig. 20 A. The root of the IV th nerve is sectioned. The decussatio and the opposite 

 root of the nervus trochlearis is degenerated. The fasciculus spino- ventralis 

 ascendens is degenerated on both sides. 



Fi"- 20 B. A horizontal section through the tuberc. acusticum. This is degenerated in 



O CT 



all its layers. (The superficial as intensive as in the deep layers.) Both 

 trochlearis nuclei are degenerated. 



Fig. 20 c. A horizontal section somewhat more venfrally , demonstrating the dege- 

 neration in the tractns DEITEUS ascendens. 



