56 C. WINKLER. THE CENTRAL COURSE 



2 e . The principal portion of the degenerated fibres of the ventral 

 root passes straight forward between the oval area of the corpus 

 restiforme and the spinal root N. V to reach the portio interim 

 corporis restiformis (corpus juxta-restiformis). There they occupy 

 the medio-ventral part , resting upon the dorsal surface of the spinal 

 root N. V. Immediately after their entrance they change abruptly 

 their direction. The larger number of fibres turns downward (dib- 

 tally) - - the radix descendens nervi octavi (see Plate V fig. 9) - 

 and in a smaller quantity they turn upward (proximally) the 

 radix ascendens nervi octavi (Plate IV fig. 8 , as well as Plate IX, 

 X, XI, fig. 16 A N). 



For this reason their course is better studied in horizontal series 

 of sections (Plate IX, X, XI fig. 16) than in frontal ones (Plate 

 VIII and IX, fig. 15). 



These are the medial root-fibres of the ventral root, forming the 

 important medial trunk of the ventral root. 



Many authors think that all the fibres found between area ovalis 

 and spinal quintus root are ventral rootfibres. Marchi-degeneration 

 has shown us in the preceding paragraph , that in the distal region a 

 small portion of dorsal root-fibres take their course in the medial trunk. 



Many authors also are of opinion, that all the ventral root-fibres 

 may be continued among the here described fibres and that none 

 of them take another way. But this certainly is not the case. 



3 e . Moreover an important number of ventral rootfibres passes in 

 the stratum latero-dorsale corporis restiformis. 



The capital situated part of this layer is nearly totally formed 

 by ventral root-fibres. As we have seen in the preceding paragraph, 

 a large number of dorsal root-fibres are also found in this layer, 

 but in the dorsal and capital regions there always remain normal 

 fibres (after removal of the cochlea) lying closely to the area ovalis. 

 These fibres now degenerate after the section of the auditory nerve. 



They turn in a curvature round the oval area of the restiform 

 body, always touching it (see fig. 4 on Plate IV). On this way a 

 part of them reaches the latero-dorsal part of the portio interna cor- 

 poris restiformis, another part, perforating the oval area, and run- 

 ning transversally through it, also enters the portio interna. As 

 soon as (in series of frontal sections) the oval area enters the cere- 

 bellum as its pedunculus inferior in the most proximal regions 

 of the octavus-entrance - - the stratum latero-dorsale has disappeared 

 and the medial root-fibres are the only remaining fibres or better 

 the latero-dorsal and the medial trunk of root-fibres fall together, 

 and there are no longer two trunks. 



