RESTORATION OF CO-ORDINATED MOVEMENTS AFTER NERVE SECTION. 687 



against in judging of the value of early return or of late return of function after section. 

 Thus, where early Teturn of function occurs after nerve section, it is necessary to 

 remember the possibility of a vicarious nerve supply, and where late recovery takes 

 place this is not conclusive evidence in favour of the view of Ranvier, as the reunion of 

 the nerve at first may be inadequate to permit of function being carried on through the 

 segment of reunion. Thus failure of the wound to heal without suppuration will lead to 

 delay or even to failure of reunion. Delay of returning function may, therefore, mean 

 only inadequate reunion of the nerve, and early return may mean vicarious nerve supply. 

 But there are certain cases in which very early return of function occurs after suture, 

 which preclude the possibility of vicarious nerve supply, and which cannot be explained 

 as cases of healing by first intention without degeneration. I refer to cases in which 

 reunion has failed after the section, and in which, after a period of time more or less 

 prolonged, an operation is undertaken for the secondary reunion of the central and 

 peripheral ends. In such cases no vicarious return of function has taken place, and yet, 

 after reunion at the secondary operation, the function, which for a long period of time 

 has been in abeyance, speedily returns. Such return of function can only be explained 

 as due to the restoration by the secondary operation of the conductivity of the nerve, 

 and the speed with which function returns implies the view that the peripheral segment, 

 though separated from its centres, has in the interval formed new fibres in a condition, 

 when united to the central segments, to conduct impulses. But what is remarkable 

 about such cases is that not only does sensation return in the parts which were 

 formerly insensitive, but, though at first indefinite, within a remarkably short period 

 of time localisation becomes perfect. Thus, in cases which I have published # in which 

 the nerves had been completely divided, and had not reunited, and in which a secondary 

 operation was followed by return of sensation in a few days, localisation was found by re- 

 peated examination to be well established by a month. It is easy to understand, on the 

 supposition of independent regeneration of the peripheral segment, how function might 

 return in a very short time after reunion ; but the speedy or even remote perfection 



i of localisation is not what we should expect from our conception of the functional 

 differentiation of the nerve fibres. How is it possible, immediately after division of 



1 a nerve, or more so in a secondary operation for repair of a non-united nerve, in 

 bringing the ends together by suture, that the central ends of the individual nerve fibres 

 can be brought to lie opposite their proper peripheral ends ? We should certainly expect 

 that considerable confusion of localisation of sensation and of co-ordination of move- 

 ments should result from unavoidable imperfect coaptation. This difficulty is common 

 to all the views of repair of divided nerves. In healing by first intention, if it exists, 

 and in healing by regeneration of nerve fibres by independent formation in the peri- 

 pheral segment, it is scarcely possible that the nerve ends will be so accurately coapted 

 that all the corresponding nerve fibre segments will be brought into apposition. In the 

 view of Ranvier the position is no better, for there the sheaths of Schwann of the old 



* Phil Trans., Series B., vol. clxxxviii. (1897), p. 257. 



