OP THE NEEVUS OCTAVUS. 161 



used to argue that variations either in the motion or in the pres- 

 sion of the endolymph may be stimuli adaequate to the ciliated 

 cells upon the cristae ampullarum. Here again motor innervations 

 may follow these stimuli after their being changed in nerve-impulses, 

 conducted by octavus-fibres. Here again no single argument is 

 delivered to prove that the changes in motility following them , 

 should be produced consequent to an altered perception. For my 

 purpose, that does not regard the modus of stimulation within the 

 labyrinth adaequate to the there found nerve-endings, rotation- 

 experiments are lying beyond the limits of my researches. 



The adaequate stimuli cause the afferent impulses. These are 

 given to octavus-fibres and bound to their central course. 



Therefore the study of the central distribution of the N. octavus 

 touches the questions mentioned above, but it remains within its 

 own limits. 



Now this study offers, as I have tried to demonstrate, no facts 

 arguing a distinct separation in the way followed by the two 

 octavus-roots. 



On the contrary my researches in rabbits teach, that each of 

 them, the cochlear as well as the vestibular root, after having entered 

 the medulla, divides in three trunks of rootfibres (pag. 53 57). 



The dorsal trunk (the stratum latero-dorsale C. R.) though com- 

 posed for far the larger part , of dorsal rootfibres , receives a 

 considerable number of ventral or vestibular-fibres. (The ramus 

 intermedius N. octavi). The medial trunk , though composed nearly 

 totally of ventral rootfibres, receives a few fibres from the dorsal 

 root or cochlear-fibres. Both roots participate* nearly equally to 

 the ventral trunk (the corpus trapezoides). 



From these trunks originate the rootfibres in the three important 

 octavus-systems , and rootfibres together with fibres of secundary 

 systems are constituating the dorsal , intermediary and ventral systems 

 of the N. octavus. 



After rootsection , the roots and the trunks of root-fibres , atrophy 

 totally. Not so the systemata. They only partly - - as far as root- 

 fibres are contained therein - - degenerate and their atrophy never 

 is a total one (page 59 and 67). 



With the roots and trunks however a great many of small cells 

 atrophy or rather disappear. 



They are found along the dorsal trunk (in the nucleus proprius 

 of the dorsal root . in the disto-ventral portion and round the 

 ventral octavus-nucleus , in the stratum latero-dorsale , in the 

 deep layers of the tuberculurn and in the lateral part of the dorsal 



Verhand. der Kon. Akad. v. Wetensch. (Tweede Sectie.) Dl. XIV. 11 



