308 INNERVATION. [CHAP. XI. 



The higher the seat of injury, the more extensive will be the para- 

 lysis. A man who has received extensive injury of the spinal cord 

 in the neck, is like a living head and a dead trunk, dead to its 

 own sensations, and to all voluntary control over its movements. 



Similar remarks may be made respecting those cases in which 

 disease, or compression of the cord by some intra-spinal growth, has 

 interruped its continuity in some region. The extent of the para- 

 lysed parts always affords a correct indication of the seat of the 

 solution of continuity. 



If the spinal cord be divided partially in the transverse direction 

 there will be paralysis of parts on the same side with the injury 

 inflicted. A longitudinal section of the cord along the median line 

 does not cause any paralysis ; a temporary disturbance of its func- 

 tions, however, ensues, which soon subsides. 



So long, then, as the spinal cord and encephalon are continuous 

 and in their normal state, the former organ must be regarded as 

 specially adapted to receive and propagate sensitive impressions 

 from the trunk and extremities, or to convey the stimulus of volition 

 to their muscular nerves. 



There is nothing, however, in these facts to denote that the 

 spinal cord does not share, in some degree, in the function of sensa- 

 tion and voluntary motion. All that we are justified in inferring 

 from them is, that the union of the encephalon with the spinal coi 

 is necessary for voluntary motion and for sensation. 



Indeed, the recent discovery of the amphioxus lanceolatus, a smj 

 fish found in the Archipelago, makes it probable that voluntary me 

 tion and sensation may exist where there is a well-developed spin? 

 cord, the anterior extremity of which tapers to a fine point, and is 

 far from exhibiting the ordinary characteristics even of a brain 

 inferior in organization as that of fishes. 



In most instances where the spinal cord has been divided, whether 

 by design or accident, it has been found that, although the 

 cannot move the paralysed parts, movements do occur in them 

 which the individual is unconscious, and which he is wholly unablt 

 to prevent. These take place sometimes as if spontaneously, 

 other times as the effect of the application of a stimulus to some 

 surface supplied by spinal nerves. The apparently spontaneoi 

 movements frequently resemble voluntary actions so closely, thai 

 it is almost impossible to distinguish them. 



These phenomena occur in all classes of animals, warm-blood< 



* Goodsir, in Ed. Philos. Transactions, and Cyclop, of Anat. vol. iii. p. 615. 



