RESTORATION OF CO-OB DIN ATED MOVEMENTS AFTER NERVE SECTION. 701 



characters, and of supplying the required nervous impulses in perfect co-ordination. 

 This hypothesis implies a capacity of the organism to undergo a profound change in the 

 functions of the central nervous system. It implies that the centres controlling 

 different groups of muscles can interchange their functions, and carry on co-ordinated 

 movements as before. This question has frequently been tested by means of nerve 

 crossing, or the division of two neighbouring nerves and cross union of the ends by 

 suture, to ascertain if under the new conditions the animal would regain its lost functions. 

 A review of the literature of this subject shows that opinions as to the possibility differ. 

 Thus, of the more recent contributors to this subject, Rawa,* STEFANi,t and 

 Cunningham,| the first two affirm the possibility, while the last named denies it. I 

 have conducted some experiments of this kind, and the results, although not yet ready 

 for publication, lead me to adopt the views of Rawa and of Stefani. The microscopic 

 appearances, as already mentioned, from the extreme degree of convolution of the fibres 

 in the nerve cicatrix, do not give a satisfactory answer to this question, all that can be 

 taken as evidence being that the appearances are much the same, whether accurate union 

 was effected or union after twisting of the peripheral segment. Seeing that function 

 was restored as soon in the one case as in the other, whatever the explanation may be, 

 it may be taken as a practical result of the experiments that in reuniting a divided nerve, 

 it is not necessary to take care that the two segments are brought together in their old 

 relationship, but only to see that the two segments are brought into apposition, no 

 matter in what relationship. 



I conclude from the results recorded : — 



1st. That after section and immediate coaptation of a nerve, restoration of con- 

 ductivity and of voluntary function may be effected in a few days. 



2nd. That this early restoration of conductivity need not be the result of 

 reunion of the old nerve fibres, i.e., reunion by so-called first intention or without 

 Wallerian degeneration, but may be the result of regeneration of young nerve fibres in 

 the peripheral segment. 



3rd. That voluntary co-ordinated movements are regained equally soon, whether 

 the two ends of the divided nerve are united as accurately as possible, so as to bring the 

 corresponding ends of the nerve fibres into contact as nearly as possible, or whether 

 previous to reunion the peripheral segment is twisted so that, when united to the 

 central segment, non-corresponding ends of the nerve fibres are brought into contact. 



4th. That in the latter case the microscopic examination of the seat of reunion 

 leaves it doubtful whether the restoration of function is due to the re-establishment of 

 the old paths by decussation in the nerve cicatrix, or to the reunion of ends of nerve 

 fibres which do not correspond, but which happen to be brought into apposition. 



5th. That in suturing a divided nerve no trouble need be taken to secure that 



* Archivfiir Physiologie, 1885, S. 296. 

 f Archivfiir Physiologie, 1886, S. 488. 

 X American Journal of Physiology, vol. i., 1898, p. 239. 

 VOL. XXXIX. PART III. (NO. 27). 5 Q 



