0$ THE NERVUS OCTAVUS. 83 



with a few fibres from the internal layer of rootfibres , which leave 

 the intermedial tract , they enter among the fibres of the descen- 

 ding ventral root. 



The latter two systems will be studied afterwards, because they 

 may better be demonstrated after section of the nervus octavus. 



But after removal of the cochlea there is found an important 

 degeneration in the dorsal systema , that in this way is composed of 

 the following layers. 



l e . rootfibres to the ventral nucleus. 



2 e . rootfibres to the tuberculum acusticuin. 



3 e . rootfibres which reach more proximally and go , & to the 

 lateral-cells of the dorsal nucleus , /3 between dorsal nucleus and 

 portio interna to become transverse dorsal fibres that will be des- 

 cribed afterwards, y penetrating into the portio interna to the 

 descending and ascending octavus-roots to be described afterwards. 



4 e . fibres, emanating from the ventral nucleus and the tuberculum 

 acusticum. 



5. rootfibres forming the already demonstrated intermedial system. 



The three last named fibres form together the layer at the dorsal 

 border of the area ovalis, described by v. MONAKOVV as stria acustica . 

 It is increased by new fibres originating in the cerebellum and 

 they all participate in the structure of the dorsal systema of the 

 nervus octavus. 



m. The results of the secundary atrophy, as far as it may be applied 

 to this question, allow the same views as those, which are defen- 

 ded in the preceedent paragraph , and the myelinisation-mcthod 

 also confirms the description given t/iere of the achitecture of the 

 systema dorsalis nervi octavi. 



I have demonstrated, that MARcm-method allowed a division of 

 the stratum latero-dorsale in several layers. Degenerated rootfibres 

 formed an internal and an external layer , holding between them 

 the non degenerate fibres of a secundary system (fig. \a on Plate 

 I by |3). The secundary atrophy within the stratum latero-dorsale 

 some, months after the root-section in a young born animal enables 

 to isolate therein all fibres that are no root-fibres. 



For instance in fig. 3 arid in fig. 13# on Plate III the atrophy 

 in the distal end of the stratum latero-dorsale was drawn a year 

 after the root-section in the young-born animal. In this case the 

 two nerve-roots of the n. octavus have completely disappeared and 

 as the comparison with the non-operated-side of the medulla demon- 



6* 



