OF THE NERVUS OCTAVUS. Ill 



yet it is very easy to trace these fibres to the nucleus of BETTERS 

 when this nucleus is lesioned on purpose. Secondly the now dege- 

 nerated fibres are not the large ones with voluminous black glo- 

 bules, which are characterising the degenerated thick fibres from 

 the large cells of BETTERS. 



Thirdly, they appear abruptly distally from the degenerated corpus 

 trapezoides in the level of the nucleus of the VII th nerve dorsally 

 from it and fourthly they are found on both sides in the symme- 

 trical field, though in lesser quantity on the opposite side. 



More-over the degeneration in the fasc. BETTERS descendens being 

 more intensive, than after rootsection, I therefore believe that from 

 the intermedia! and ventral systema a few degenerate fibres enter 

 in the region dorsally from the facial nucleus, and bend distally 

 in the formatio reticularis, to form a slight degeneration in a 

 descending fasciculus, taking its way in the descendent tract of 

 BETTERS. 



This tract, the existence of which, after rootsection alone, may 

 be doubtful, now appears clearly after section of the ventral -|- the 

 intermedial systema, (though far less extensive as I soon will 

 demonstrate it after section of the dorsal system with injury of 

 BETTERS nucleus). 



And in this way a medial descending spinal tract composed of 

 a few rootfibres and a little more intermediary and ventral secun- 

 dary fibres, may be observed. It exists on both sides, but is 

 much more important at the side of the operation. 



4 The most important descending degeneration however found 

 in this case , is a very marked degenerated area suddenly appearing 

 distally from the corpus trapezoides in the field between the spinal 

 V th root and the facial nucleus. (MoNAKow's aberrirendes Seiten- 

 strangbimdel). 



A retrograde degeneration this cannot be , as it is found a 

 fortnight after the operation. 



In frontal sections it is first seen laterally and ventrally from 

 the facial nucleus (see fig. 22 B and E). More distally it is retiring 

 in a dorsal direction (see fig, 22 E) having now the shape of an 

 equicrural triangle, one of its erect sides along the formatio gelati- 

 nosa , the other touching the lateral side of the nucleus of the 

 lateral column , and its base resting on the periphery of the medulla. 

 It leaves degenerate fibres into the nucleus funiculi lateralis. 



Buring its further course, this tract maintains its situation 

 medially and ventrally from the formatio gelatinosa of the V th root, 

 but the basis of the tract leaves the perifery as the ventral ascen- 



