NERVE INJURIES 191 



months, the patient may have some degree of 

 recovery of sensation in the anaesthetic area within 

 a few days after the belated suturing. We know 

 that if the nerve had been restored by primary suture, 

 it would have been months before any recovery 

 could have taken place. The deduction would be 

 that the isolated segment of nerve had regenerated 

 its continuity, and only needed to be put into com- 

 munication with an efficient nerve to become efficient 

 itself. 



One might illustrate the two theories in this way. 

 A telegraph wire near a town A has been cut, and 

 the whole line from A to Z completely destroyed, 

 leaving only the track of the broken poles. Villagers 

 at B, C, D, etc., along the line effect a certain amount 

 of rough repair, and finally restore a continuous 

 \vire from B to Z. After some months, when this 

 has been done, a telegraph operator reunites the 

 wire near A. Communication \vith Z is at once 

 restored. This illustrates the theory of peripheral 

 regeneration. 



But let us vary the process, and suppose that the 

 operator starts from A and unites a new wire to the 

 cut end, and then works slowly through B, C, D, 

 repairing as he goes, until finally he reaches Z. 

 This would illustrate the theory of central regenera- 

 tion. If it be true that communication can be 

 restored within a few hours of the reunion of the 

 wires, it is evident that peripheral regeneration 

 must have taken place. 



It is doubtful, however, whether the chnical obser- 

 vations of inmiediate return of sensation after 



