276 MESSRS. F. GOTCH AND V. HORSLEF 



(2.) Relation of the Discharge to Parts of the Body. Localisation of the represen- 

 tation of the gross divisions of the body to certain fields of fibres. (BRISSAUD and 

 others. ) 



D. Spinal Cord. 



It will be scarcely realised, except by those who have made a special study of the 

 literature of the physiology of the spinal cord, how little has been done which would 

 enable us to carry out, strictly speaking, the differentiation of the subject of conduc- 

 tion in tha,t organ, by arranging the facts in the same way as we have just done for 

 the higher parts of the nervous system. So much so is this the case that we do not 

 intend to do more at this stage than indicate what we believe to be a fair estimate of 

 the experimental work already accomplished. In introducing our own work later on, 

 which directly bears on the points at issue, we shall draw attention to many of 

 the more salient details which require attentive discussion. We will, therefore 

 now content ourselves with furnishing a general review of the function of con- 

 duction in the cord. We may note in passing that almost all the literature is to be 

 found in the writings of vox BEZOLD, ECKHAKD, GRUNHAGEN, SCHIFF, IMMANUEL 

 MUNK, and others. We would, in the first place, urge, what we have reason to do 

 with greater weight later, that not one of the foregoing methods, i.e., graphic degene- 

 ration, embryological, &c., is capable of answering the question of conduction or its 

 localisation in an absolute manner. The great difficulty in considering conduction by 

 the cord is the disseverance of the action of the bulbo-spinal centres from that of the 

 nerve fibres which happen to pass through or by them, and this difficulty does not 

 appear to us to have met with the amount of attention that it would naturally seem 

 to deserve. In fact, to our mind the galvanometric method is the only means within 

 our reach at present by which a solution can be arrived at, and even that method 

 requires to be considerably further elaborated. 



Dividing conduction in the spinal cord into the two great classes of 



1. Conduction of impulses downwards ; 



2. Conduction of impulses upwards ; 



we are able to summarise the facts which appear to be thoroughly reliable as follows : 

 (1.) Conduction of Impulses downwards. In Man and the highest Apes direct 

 conduction downwards, i.e., from the cortical centres to the bulbo-spinal system, 

 appears to be provided for in the upper half of the spinal cord by both the anterior 

 column, close to the margin of the anterior fissure, and, speaking roughly, by a 

 triangular area in the posterior part of the lateral column, just external to the 

 posterior horn of grey matter. 



(2.) Conduction of Impulses upwards. There is known to be an entrance from each 

 posterior root into the postero-external column of fibres, which run directly from the 

 ganglion of the posterior root as high as the medulla oblongata. These direct fibres 



