110 C. WINKLER. THE CENTEAL COURSE 



in ventral direction they reach the fasc. praedorsalis in their distal 

 course. They are found at both sides of the raphe. 



At the same time, the intermedia! transverse fibres, now inten- 

 sively degenerated, send, near their passage through the raphe, a 

 not unimportant number of fibres distally in the praedorsal tracts 

 on both sides, but more in the homolateral than in the opposite side. 



At the level of the facial nucleus (Plate XVIII fig. 22 C and 

 D) the degenerated fibres (root-fibres) in the fasc. long. post, are 

 separated from those (secundary fibres) in the fasc. praedorsalis. 

 The two separated tracts unite more distally and at the level of 

 the inferior olivary body, they have become one, along the raphe, 

 dorsally from the stratum intra-olivare (medial fillet). The tracts 

 may be traced dorso-laterally from the decussatio pyramidum, into 

 the anterior columns of the spinal cord, where we afterwards will 

 meet them again. But distal wards the degeneration in the opposite 

 tract is found gradually diminishing and in the most distal sections 

 (Plate XVIII fig. 22 F and H.) the homo-lateral tract is by far 

 the most degenerate one. 



Here for the first time a degenerated tract descending to the 

 spinal cord is stated beyond doubt. It is composed , for the greater 

 part, of secundary fibres from the transverse fibres of the 

 intermedio-ventral system - - for the lesser part of rootfibres -- from 

 the dorsal transverse fibres. 



It is a medial or anterior descending spinal tract from the 

 octavus-system. 



But it is also remarkable, that there now are found degenerate 

 fibres dorsally from the nucleus N. VII in the field, where the 

 tractus DEITERS descendens is localised. As the degeneration in the 

 transverse dorsal fibres does not much exceed that after rootsection , 

 it is not very probable, that the degenerated fibres now found there 

 in a number, sufficient to exclude every doubt as to their forming 

 a slight tract, are all rootfibres. For, as is clearly shown by com- 

 parison with frontal sections after rootsection, the degenerate fibres 

 in the region of the so-called fasc. DEITERS descendens (fasc. ves- 

 tibulo-spinalis) are now increased in an abundant manner. 



The first presumption presenting itself, when we try to explain 

 this fact, may be: the nucleus of DEITERS, lying close to the sur- 

 roundings of the incision, and being perhaps accidently injured, 

 is sending degenerated fibres to this region. 



But this presumption seems to be erronous. Firstly there is seen 

 no lesion of the nucleus, and there are found no degenerated 

 fibres issuing from it in the direction of the degenerated field 



