OF THE NERVUS OCTAVUS. 1 1 5 



from the same-sided nucleus trapezoides (?) and from the same-sided 

 nucleus lateralis lemnisci. 



Now from the degenerated fibres composing here the fillet, by 

 far the larger portion is due to MONAKOW'S fibres. 



MONAKOW has proved evidently with GUDDKN'S method, that, in 

 the dog, after a section of the lateral fillet at one side, fibres are 

 lost in the opposite stria acustica medullaris, together with a loss 

 of nearly all the large pyramidal cells in the tuberculum acusticum. 



He also distinguishes several layers in the lateral fillet, according 

 to their origin from the opposite tuberc. acusticum, the dorsal 

 border of the same-sided oliva, the nucleus ventralis lemnisci and 

 the ,,aberrirendes Seitenstrangbimdel." 



Now it cannot be doubted that after a section through the 

 dorsal system - - including the stria medullaris - - in the neigh- 

 bourhood of the tuberculum acusticum, all the large cells in this 

 nucleus are found in chromatolysis 5 days afterwards, whereas in 

 the cells of the nucleus ventralis N. octavi (if it be spared) the 

 chromatolysis is not so intensive. Three months after ablation of the 

 tuberc. acusticum, there has remained nothing of it. 



But it is very interesting to verify, to what extent GUDDEN'S 

 atrophy six months after the ablation of this nucleus, confirms 

 the results of MAiicm-method. In the case here mentioned (Plate 

 XXI and Plate XXII fig. 28 A F) the ablation of the tuber- 

 cnlum was nearly a total one (fig. 28 A, B, C, D) from the 

 ventral nucleus a ventro-distal end has been left (see fig. 28 B). 



Consequently the same-sided corpus trapezoides has lost the 

 greater part of its fibres (see fig. 28 D) at the operated side, 

 only in the distal part fibres have remained. 



The same-sided oliva has lost a large numbre of fibres in its 

 dorsal and ventral layer. At the contra-lateral side the dorsal layer 

 of the oliva superior has lost many fibres and on both sides the so 

 called trunk of the olivary bodies is very clearly to be seen, (see 

 Plate XXII fig. 28 G). As it has already been memorated the 

 crossing fibres through the raphe do not form a very sharply 

 defined bundle. Nevertheless from the stria medullaris originates 

 (Plate XXII fig. 28 E) a large bundle and passes through the 

 issuing facial root, which does not exist on the operated side. It 

 enters into the formatio reticularis, where more transverse fibres 

 are found than on the operated side. 



Now on the contra-lateral side, the dorsal surroundings of the 

 oliva superior are joined to the surroundings of the nucleus 

 ventralis lemnisci. These surroundings have lost a great many fibres 



8* 



