18 C. WINKLEE. THE CENTRAL COURSE 



is obtained of the interior of the 4 th ventricle , bordered by the inferior 

 peduncle of the cerebellum. On both sides the interior part of the 

 corpus restiforrne appears as protruding edges, that may be easily 

 reeogni/ed. The interior part of the corpus restiforrne may now be 

 incised and with the corpus restiforme the stria acustica may be 

 sectioned transversally at different places. 



This may be done: 



l ly more distally. The thin knife is introduced through the most 

 lateral portion of the dorsal octavus-nucleus into the interior part 

 of the corpus restiforme, cutting this in latero-distal direction, pas- 

 sing farther through the oval area of the corpus restiforme and the 

 nucleus ventralis N. VIII and reaching the surface of the oblon- 

 gata dorsal from the place of entry of the octavus-roots. If the 

 operation is well done, the tuberculum acusticurn and the nucleus 

 ventralis N. VIII are separated from the medulla, the oval area 

 of the corpus restiforme is sectioned but the two roots of the 

 nervus octavus are often very slightly injured. 



If the attempt be made imperfectly, the point of the knife remains 

 within the juxtarestiform body. 



2 ly more proximally. Again the knife is introduced in lateral 

 direction in the most lateral portion of the dorsal octavus-nucleus; 

 but now it is turned somewhat more cranial , and is cleaving more 

 cranialward the ped. cerebelli superior, reaching the lateral surface 

 of the brain, a little above the pons in the lateral fillet. 



Whilst by the former operation through the pedunculus cerebelli 

 inferior, the stria medullaris was cut transversally in its more distal 

 part, the cranial rest of the stria did remain uninjured. 



This cranial rest, to be sure, is cut transversally in the second 

 operation. But in the mean time this latter involves the section of 

 the pedunculus cerebelli superior. 



Both these operations are likewise necessary, in order to obtain 

 orientation about the course of the secundary octavus-tracts. They 

 must be repeated several times before their influence upon secun- 

 dary degeneration may produce a uniform result. 



2. The acute motor-troubles arising after one-sided 

 removal of the labyrinth. 



When, operating on rabbits in the above described manner, the 

 cavum tympani has been opened, the bony wall of the promon- 

 torium removed, the spiral convolutions of the (thus opened) cochlea 

 destroyed, the vestibulum having next been entered into and sac- 



