OF THE NEKVUS OCTAVUS. 67 



secundary fibres from the ventral nucleus towards the corpus tra- 

 pezoides are myelinised in the new-born rabbit, because in sagittal 

 sections indeed images may be seen (Plate XII fig. 18 B, Plate 

 VI fig. 19 B) allowing the interpretation of a direct transition 

 of medullated fibres from the ventral nucleus in the ventral system 

 on one side , as well as on the other side of a transit of root-fibres in it. 

 But the accordance between the results of the myelinisation of 

 the root-fibres, and their degeneration after root-section may be 

 sufficient, to elucidate the situation of the root-fibres in the systema 

 ventrale N. VIII, and to establish that, in rabbits their number 

 is more important , than is thought generally. 



g. The sccnndary atrophy also confirms the existence of transversal 

 foot-fibres in the systema ventrale of the VIII* h nerve. 



If really the systema ventrale nervi octavi contains so many 

 rootfibres as is affirmed here, a long controversed question in the 

 central course of the nervus octavus ought to be settled. It is the 

 question , whether the corpus trapezoides does undergo an atrophy 

 or not , after the removal of the labyrinth in the young born 

 animal. 



The first investigators on this subject, FOKEL and ONUFKOWICZ , 

 supposed that the removal of the labyrinth in young rabbit was 

 not followed by any atrophy , worth mentioning , in the corpus 

 trapezoides. BAGINSKY, on the other hand, repeating the experiments, 

 defended the view that the atrophy of this body , after three months, 

 was important enough. 



As to my experience , the opinion of BAGINSKY is right , and the 

 reason of the discordance between his results and those of ONUFROWIOZ 

 may easily be understood. 



For , it must be kept in mind , that the spiral and the vesti- 

 bnlar are intercalated between the perifical labyrinth and the roots, 

 that the spiral ganglion is necessarily removed with the cochlea, 

 and that the vestibular ganglion remains untouched (unless its 

 removal be intended for) when the contents of the vestibuluin only 

 are withdrawn. 



Now ONUFROWICZ has not completely removed the contents of the 

 vestibulum. He describes clearly enough, that the typical attitude 

 of the operated rabbits was not obtained immediately, but weeks 

 afther the operation , owing to a secundary lesion of the vestibulum. 

 His drawings also demonstrate, that the ventral root was very 

 little atrophied , instead of having disappeared. 



5* 



