128 C. WINKLER. THE CENTRAL COURSE 



tract begins the formation of the restiform body, the area must 

 leave the peripherical margin. At the end of the oblongata it has 

 the shape of an equal-sided spherical triangle. Its top is lying in the 

 formatio reticularis lateralis medullae, one of its sides borders the 

 formatio gelatinosa of the posterior cornu, the other borders the 

 nucleus funiculi lateralis. (Plate XVIII fig. 22 H). 



In the medulla the degenerated field preserves ist place, with 

 the top in the formatio reticularis and resting upon the formatio 

 gelatinosa cornu posterioris, bordered ventrally by the pyramidal 

 tract in the lateral column, and laterally by FLECHSIG'S Kleinhirn- 

 Seitenstrangbahn (the dorsal ascending spino-cerebellar tract). This 

 position (Plate XVII fig. 21 C <i) it retains, until the sacral part. 

 It also has a tendency to reach the peripherical margin of the 

 postero-lateral column, and in the middle of the thoracic part of 

 the cord (Plate XVII fig. 21 D 4) the whole peripherical margin 

 of the colunma laterales et anteriores, may be formed by a small 

 degenerated band, composed of fibres of our three descending tracts. 



I believe this descendent tract for the greater part issued from 

 the ventral nucleus n. octavi, because I have not foumj it dege- 

 nerated in such an extensive degree after dorsal section as after 

 section of the ventral systema. 



It is found chiefly degenerated at the operated side, but slightly 

 degenerated is also its contra-lateral partner in all cases. 



But here a difficulty arises. The way traced out is the way of 

 the descendent path in MONAKOW'S ,,aberrirendes Seitenstrangbundel," 

 which according to PAWLOW and VAN GEHUCHTEN might be a 

 rubro-spinal path. 



Certain it is, that in none of my cases the nucleus ruber is 

 lesioned. But it is questionable whether by the dorsal section, the 

 tract in its course from the contra-lateral nucleus ruber, crossing 

 in the ventral decussatio tegmenti and reaching in such a way the 

 ,,aberirrendes Seitenstrangsbiindel" may be divided. 



This rubro-spinal path exists, I do not doubt it, but the aber- 

 rirende Seitenstrangbundel reaches also the lateral fillet (Plate XXII 

 fig. 28 E and F). There, lying still more medial than the medial 

 bundle of this fillet, it is not only formed by the crossed fibres 

 of the rubro-spinal tract, but it reaches probably much farther. 



In the section of the dorsal system of fig. 20 (Plate XVI fig. 20 D) 

 the lateral fillet in its dorsal regions has been touched, but in the 

 section of the lateral trunk of the ventral system (Plate XVIII 

 fig. 22 B) it is not, and in the double-sided lesion (Plate XX 

 fig. 25 C H) equally the fillet is intact. In the dorsal section of 



