OF THE NERVUS OCTAVUS. 127 



rior root, it has a position in the colnmna anterior, between the 

 anterior horn and the fissura anterior medullae. It rests upon the 

 commissure anterior, and following the medial border of the horn, 

 it is laterally limited by the most medial issuing rootlet. 



This situation the degenerated field preserves in its course through 

 the cervical medulla, giving fibres into the anterior horn. (Plate XXI 

 fig. 25 N and 0). 



If one-sided section through the dorsal systema is made it pre- 

 vails very much upon the operated side (Plate XVII fig. 2 1 C 4 ). 



As it reaches the cervical intumescentia, it retires from the com- 

 missura and from the horn, takes a position at the peripheric mar- 

 gin of the cord along the fissura anterior and at the anterior 

 margin. Extending more laterally, it soon touches the medial end 

 of the tractus DEITERS descendens and together these two tracts 

 now form a long peripherically situated degenerate small band, 

 beginning at the commissura anterior, along the fissura anterior 

 and the antero-lateral margin, untill the middle of the lateral column 

 (Plate XVII fig. 21 C 7). 



To reach the grey matter, their fibres often bend abruptly into 

 a medial direction, crossing obliquely the columna. 



This is the second long descendent tract, which unites the pri- 

 mary octavus-nuclei with the motor columns of the spine. Together 

 they may be traced unto the sacral part of the cord (Plate XVII 

 fig. 21 S 3 ). Thus it is found degenerated as well after section of 

 the lateral trunk of the ventral system, (Plate XVIII fig. 22 H). 

 as after section of the dorsal system (Plate XVII fig. 20 and 

 fig. 21. Plate XXI fig. 25 M O) and after section on both sides. 



Through the existence of contra-lateral symmetrical tracts may 

 not be denied, those on the same side are much more volumi- 

 nous, as the intensy of their degeneration shows evidently. 



There still remains to discuss the third long descendent path 

 towards the spinal. cord. 



I already described its degeneration after the section of the late- 

 ral trunk of the ventral systema. 



I saw it very intensely degenerated after the section of the dorsal 

 systema (Plate XVII fig. 20 F and fig. 21 C 2 S 3 ) and in a less 

 intense way after the double-section (fig. 25 M. N. O.) 



It appears in the oblongata as soon as the voluminous degene- 

 ration of the corpus trapezoides has ended, as a degenerated area 

 between the fifth root and the facial nucleus, extending ventrally 

 of this nucleus at the peripherical margin. As GOWERS tract, with 

 which its fibres are mixed, slightly bends medially and FLECHSIG'S 



