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-Séquard 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- 
