OF THE NERVUS OCTAVUS. 59 



always crossing queer this body. It is not necessary to study younger 

 foetus of rabbits in order to demonstrate , that fibres in important 

 quantity are going from the ventral towards the dorsal root , and from 

 the ventral root queer through the area ovalis towards the stratum 

 latero-dorsale of the restiform body. Therefore I can only conclude 

 that the fibres of the latero-dorsal layer, terminating as well in 

 the ventral auditory nucleus as in the tuberculum acusticum , are 

 originating of both roots of the VHP' 1 nerve. 



The myelinisation-method at the same time confirms the opinion 

 that rootfibres of the ventral root penetrate transversally through 

 the oval area to reach the stratum latero-dorsale. Degenerate 

 fibres after sectioning the VHP' 1 nerve, demonstrated with Marchi- 

 method in the preceding paragraph (to compare Plate IV fig. 4, 

 Plate VIII fig. 15 N. 7 and 8 with Plate XIII fig. 18 C and D) 

 may also be traced transversally through the oval area. There is 

 shown , that they are not found after the removal of the cochlea. 



Therefore, I think it evident, that the myelinisation-method sup- 

 ports in every way the supposition that the stratum-latero-dorsale 

 and the ,,sy sterna dorsale nervi octavi" contain root-Jibres of both 

 auditory roots. 



But there is more. In the new-born rabbit and better still in 

 younger foetus , it may be seen , that the niyelinisated corpus tra- 

 pezoides receives its fibres not only from the nucleus ventralis N. 

 VIII (Plate XIII fig. 18 B) but from both roots (Plate VI fig. 

 19 B). Rootfibres pass directly into it. 



This is so evident, that I also think it demonstrated by the 

 myelinisation-method , that the ,,systema ventrale nervi octavi" 

 contains root-Jibres of both auditory roots as well as fibres of the 

 secundary system. 



d. The supposition that both roots send t//eir fibres in the corpus 

 Irnpezoidcs is also confirmed by GUDDEN'S method. The tuberculum 

 acusticum and ventral auditory nucleus being removed in the young born 

 aimal, without grave lesion of the auditory roots, the corpus trape- 

 zoides having lost its secundary only contains rootfibres. 



VAN GEHUCHTEN, who has published many excellent articles on 

 the central course of the cerebral nerves , has in a recent paper revi- 

 ded the views previously originated in his laboratory as results of 

 the researches of his disciple TIUCOMI-ALLEGRA. 



The isolated removal of the cochlea in two guinea-pigs caused 

 MAiicni-degeneration only in the dorsal root, which was only to 

 be traced in the ventral auditory nucleus and the tuberculum 



