Secondai'y Degeneration following Unilateral Lesions etc. 327 



ration of the ci'iista, and tliat, therefore these cells have some con- 

 nection with the motor tract, l)ut the extent and importance of this 

 connection seems to have been overlooked by most neurologists. 



With regard to the question as to whether fibres from the pyra- 

 midal tract pass directly to the cranial motor nuclei there seems to 

 be much difference of opinion amongst investigators. Melius [14] in 

 monkeys, Romanow [19] in dogs, Hoche [20], and Barnes [21] in the 

 human subject, all using the Marchi method, say that they have been 

 able to trace fibres from the degenerated pyramid to the motor nuc- 

 lei, — most crossing the middle line to the nuclei of the opposite, 

 a few passing to those of the same side. On the other hand, Boyce 

 [13], Dejerine and Long [17] and others expressly state that they 

 have failed to find any fibres passing to these nuclei. In several 

 animals I have made serial sections from the upper limit of the mes- 

 encephalon to the lower limit of the bulb, and in not one have I 

 found degenerated fibres passing to any of the cranial motor nuclei. 

 This is all . the more surprising considering the ease with which such 

 fibres could be traced of the anterior corpora quadrigemina. No fib- 

 res could be seen to pass backwards from the pyramidal tract, with 

 the exception of those to the ant. corp. quad, till the lower levels of 

 the pons were reached, and below this throughout the whole extent of 

 the medulla oblongata, and not alone opposite any particular nuc- 

 leus a very few fibres continued to be given off chiefly from the 

 postero-mesial angle of the degenerated pyramid. Most crossed the 

 middle line at once, disappearing in the formatio reticularis of the 

 opposite side, comparatively few being lost in that of the same side. 

 On comparing some of my sections with the figures given by Mura- 

 toff [18] and by Eomanow [19] in their papers (on which presumably 

 these observers base the statement that fibres from the pyramid pass 

 to the motor nuclei in the medulla and pons) I found that there was 

 a very close resemblance. It will be seen from these figures, three 

 of which I here reproduce, that as in the sections I examined, the 

 fibres in question are not directed towards the grey matter in which 

 the cranial nuclei are situated, but seem, for the short distance to 

 which they can be traced, to pass more lateral-wards towards the 



