66 C. WINKLER. THE CENTRAL COURSE 



in the first case, are situated exactly at the same place, where the 

 degenerated fibres in the second case are found , and the non- 

 medullated fibres are corresponding with the non-degenerated. This 

 accordance does not only prove the existence of root-fibres in the 

 systema ventrale , but also puts it beyond doubt that they are 

 situated there in three layers. 



Now , if it were proved , that the Marchi-mcthod demonstrated 

 only root-fibres in degeneration within a fort-night after the root- 

 section ; if it were proved that simultanoiis myelinisation indeed 

 occurred only in fibres of the same system - - then to be sure 

 the conclusion would be justified, that the quantity of root-fibres 

 in the systema-ventrale of the VHP 1 ' nerve was very important. 

 But , because I believe , that even within a fortnight after the root- 

 section , a certain quantity of fibres in the secundary system may 

 degenerate and be demonstrated with Marchi-method , and that a 

 certain quantity of fibres in the secundary system rnyelinisate simul- 

 tanous with the root-fibres, I am not going so far as to declare 

 that all the medullated fibres in the systema ventrale of the new- 

 born rabbit are root-fibres. 



As to the fibres of the secundary octavus-system originating in 

 the ventral nucleus, the tuberculum acusticum and the nuclei 

 supra-olivares , they for the greater part , do certainly not degenerate 

 after root-section , and they have not all a myeline-sheath in the 

 new-born rabbit. 



These fibres are partly mixed between the mednllated fibres (in the 

 strata a, b and d} and partly they are collected in the stratum c. 



The question remains whether it is proved, how many medullated 

 fibres originate in the ventral nucleus and take their course in the 

 systema ventrale. 



If this be the case, such fibres will not be shown by frontal 

 sections through the medulla of the not yet born or new-born rabbit. 



.In such sections there is only seen a field of medullated fibres 

 near the entrance of the auditory roots (Plate XII fig, 17, A, 

 B , C) which , medullated themselves , pass trough the myelinisated 

 corpus trapezoides , to reach the ventral nucleus and the portio 

 interim of the restiform body. I deem it impossible to decide here, 

 whether medullated fibres are root-fibres or fibres from the nucleus 

 ventralis. Even the argument , that there exists a disproportion be- 

 tween the quantity of medullated fibres in the auditory roots and 

 that in the corpus trapezoides , appears more decisive than it really 

 is , as it is not yet proved that the other roots (VII and V) do not 

 at all enter into it. But yet I believe, that a certain quantity of 



