4 ORIGINAL ARTICLES 



subject. A little later (in 1899), Dejerine (20), who had pub- 

 lished several accounts of similar descending fibres, published in 

 conjunction with The'ohari (21) a masterly summary of our 

 knowledge of these fibres up to that time. They described and 

 figured as a result of compression at various levels in the spinal 

 cord, not only descending degeneration in the comma tract area 

 and immediately adjoining portions of the postero-external 

 columns, but also similarly affected fibres occupying the super- 

 ficial area described by Hoche in the dorsal region, the oval 

 field of Flechsig in the lumbar region, and the triangular area 

 of Gombault and Philippe in the sacral region. A reference to 

 Fig. ii., PI. 3, which is a reproduction of some of their diagrams, 

 be of interest. 



According to investigations carried out more recently (1902) 

 by Marburg (22), traces of the posterior cervical roots may be 

 followed as low down as the dorse-median sacral bundle ; from 

 the cervical region descending fibres can be traced into the upper 

 sacral region along the lateral part of the posterior columns. 

 These fibres undergo a " ventral thickening " at the neck of the 

 posterior horns, and a " dorsal thickening " in the postero- 

 external portions of the postero-external columns. According 

 to Marburg some fibres also pass in continuity from the dorsal 

 thickening to the posterior para-median septum, and thence 

 along the postero-median septum down into the lowest sacral 

 region. In agreement with many others, he describes some of 

 these fibres as arising in the cells of the neck and apex of the 

 posterior horns (therefore endogenous) and ending at various 

 levels lower down in cells in the same regions (also Hoche). 



However, van Gehuchten (23), after section of the first and 

 second posterior cervical roots in rabbits, could not trace by the 

 Marchi method degenerated fibres lower down than three spinal 

 segments, whereas after similar section of the eighth cervical 

 and first dorsal posterior roots he could by the same method 

 trace descending degeneration for eight spinal segments. It is 

 interesting to remember that Flatau (17) in the dog, on section 

 of the same roots, obtained the same extent of degeneration, and 

 that Margulies (24) in the monkey obtained on cutting a pos- 

 terior root, descending degeneration over nine spinal segments, 

 in each case in the comma tract area. Farquhar Buzzard (25) 

 has also published a case of division of the third lumbar pos- 



