OF THE NEEVUS OCTAVUS. 109 



ration much more intensive than after root-section and therefore 

 contains a secundary system, as well as all the other layers. It is 

 however no longer differentiated from the ventral secundary system. 

 The transverse fibres are so intermingled that it exists no longer as 

 a system separated from the systema ventrale. 



In this way it may be demonstrated, that a very important number 

 of secundary fibres enters in the systema ventrale, from the ventral 

 nucleus, and along the intermedia! system, and that there still are 

 found non-desrenerate fibres originating in the oliva, leaving it through 



O O O ' **J 



the medial hilus and going to the opposite side (the lateral fillet). 

 2. There is also found now a degeneration more intensive than 

 after root-section in the region between the spinal root of the V th 

 nerve and the oliva superior. Not only at the operated side but 

 also on the opposite side, and like the root-fibres (there are root- 

 fibres among them), the now degenerated fibres may be traced into 

 the two formerly described ascending tracts; 



a. as to the ventral ascending spino-cerebellar tract, now also 

 the homolateral degeneration is more intensive (Plate XVIII fig. 

 22 B) than that in the opposite bundle; 



b. as to the degenerated fibres to the corp. quadrigeminum posti- 

 cum through the lateral fillet, now again, like after root-section, 

 the degeneration in the opposite tract is more important than that 

 in the homolateral. 



Though the number of degenerate fibres is now very (Plate 

 XVIII fig. 22 A) much increased I was not able to trace them 

 beyond the corp. quadr. posticum into its bracchium to the nucleus 

 geniculatus medialis. 



But in the here described case, there was found a thin bundle 

 of degenerate fibres, forming a specimen of a commissural bundle 

 between the two degenerated lemnisci, passing ventrally from the 

 nucleus of the IV th nerve. 



These fibres are probably the same commissural fibres seen also 

 by PROBST in fillet-degeneration and that have been described as 

 the bundle of PROBST (Plate XVIII fig. 22 A). 



3. In the dorsal systema there also is found a degeneration, which 

 as I have remarked, does not exceed very much that, found after 

 rootsection. Yet, the two roots and the ventral end of the stratum 

 latero-dorsale being sectioned, it may to a slight degree be increased. 



In the fasciculus longitudinalis posterior therefore are found, 

 rootfibres from the degenerated transverse dorsal fibres, going l e 

 to the motor nuclei of the eye 2 e going distally. 



These latter fibres do not remain there, but slightly deviating 



