96 CONSCIOUSNESS AND SENSATION. 



be so to account for reflex actions, but it cannot 

 in any part of its course, pass through a fibre com- 

 mon to it and another spot of the periphery, 

 without the consciousness being bereft of all means 

 of distinguishing the one spot from the other. 

 But all that we know of the structure of the cord 

 notoriously contradicts the notion of such an ar- 

 rangement an arrangement which would involve 

 the continual accumulation of additional sensory 

 tracts in the cord from its lower to its upper 

 extremity. Moreover, it appears certain from the 

 experiments of Dr. Brown-Sequard that the greater 

 'part of the conducting material of the cord, its 

 white matter, may be divided, and, provided the 

 grey matter is left intact, sensation in the parts 

 beyond the lesion remains unimpaired. Thus, the 

 routes of communication between the brain and 

 nearly the whole surface of the body are known to 

 pass through the extremely limited area exhibited 

 by a transverse section of the grey matter of the 

 cord, and probably more than half that area is 

 occupied with binding tissue which has nothing to 

 do with nervous conduction, while of the nerve-fibres 

 which traverse it, a number are motor, and accord- 

 ing to the theory some must be devoted entirely to 

 impressions from internal parts of the body, even 

 though such impressions are principally patho- 



