6 ORIGINAL ARTICLES 



slow reflex contraction of the whole hind limb. The anterior 

 and posterior columns were inexcitable, and it was proved by a 

 process of division and elimination of the various possible reflex 

 paths for the above reflex movements, that the nerve impulse 

 originated by the stimulus applied to the posterior root or the 

 posterior columns passed outwards to the motor roots partly 

 through the same segment, but largely down the posterior 

 columns and out along several segments below the level stimu- 

 lated ; and that the maximum effect even passed out along the 

 second and third segments below the level stimulated. This 

 result, which has been confirmed in the cervical region by 

 Sherrington, and also by others, seems to the writer to throw a 

 strong side light on the presence and function of some of the 

 fibres in the posterior columns which degenerate downwards. 



DESCENDING DEQENEKATED FIBRES IN THE CERVICAL AND DORSAL 

 REGIONS OF THE SPINAL CORD EXTENDING DOWNWARDS FROM 

 A LESION IN THE THALAMIC REGION. 



About two years ago, at Sir Victor Horsley's suggestion, I 

 did some work for a particular purpose on the thalamic region 

 in several monkeys, etc. ; and twelve months later was not 

 a little surprised to find, on examining a cord stained by the 

 Marchi method, some fibres showing degeneration in the cervical 

 and dorsal regions of the spinal cord of a monkey. On examin- 

 ing other specimens of the above animals, I found one in which 

 there was a definite set of coarse fibres, which had evidently 

 degenerated from a bilateral lesion in the upper part of the mid- 

 brain adjoining the thalamus, and were situated on either side of 

 the middle line, forming a wedge-shaped mass of fibres, with the 

 apex anteriorly, and spreading out loosely towards the periphery 

 behind, the bulk of the fibres being situated slightly posterior to 

 the anterior apex of the columns of Goll. A reference to the 

 adjoining untouched photographs of the actual specimens will 

 show, better than any description can give, their exact situation. 



It will be seen that in the upper cervical region the de- 

 generated fibres occupy a symmetrical position on either side of 

 the postero-median septum. That in section they consist chiefly 

 of coarse fibres, which occupy a wedge-shaped area, with the apex 

 of the wedge slightly behind the anterior angle of the columns of 



