Secoiidai-y Degeneration following Unihitenil Lesions etc. 329 



side of the substantia g'elatinosa. Traced upwards tliese fibres — wliicli 

 correspond to what is usually known as Pick's bundle — become rapidly 

 diffused and lost in the region of the nucleus ambig-uus, not a single 

 fibre being visible in this region at the lowest pontine level, and none 

 of them can be seen to cross the middle line. Traced downwards 

 towards the pyramidal decussation these fibres retain their position 

 but increase in number and compactness, lying close to the ventro- 

 lateral aspect of the posterior horn at its junction with the substantia 

 gelatinosa in the upper part of the first cervical segment. Here the 



Raphe 



T^- A Degenerated fibre represen- 



to' ted as passing from pyra- 



mid to Hijpogìossaì Nu- 

 Photograph of drawing illustrating Ro- cieus of opposite side 



manow's paper. 



degenerated bundle appears to gradually merge into the degenerated 

 crossed pyramid which lies immediately adjacent to it. . . ." He comes 

 to the conclusion that "it is probably an ascending tract which arises 

 from the crossed pyramid at the decussation, and forms at least part 

 of the pyramidal supply of the nucleus ambigims; it is fairly fre- 

 quently degenerated in cases of hemiplegia". So far it has only been 

 referred to in the human subject. 



Pyramidal degeneration in both lateral columns of the spinal cord, 

 as the result of a unilateral motor cortical lesion, was first recorded 

 by Schäfer [23] in a dog in 1883, and also the probable source of 

 the homolateral fibres was first indicated by him, viz: — an incom- 

 plete crossing at the pyramidal decussation. In 1884 it was observ- 



