No. 3.] PERIPHERAL NERVES. 663 



the divided nerve. In Atkinson's case, the impulses were, no 

 doubt, carried along one of the other cutaneous nerves having 

 their distribution in the extremity. The experiments of Vanlair 

 are of interest in this connection. He divided sometimes one, 

 sometimes another, of the nerves in the posterior extremity of 

 dogs, and found that there was very little loss of sensation 

 after section of any one of the nerves. 



A closer study of Landerer's case (No. 8) may also be of 

 interest in this connection. In this case more than six months 

 had elapsed since the radial nerve had been injured, and no 

 regeneration had taken place. Three weeks after implanting 

 a rabbit's sciatic, electrical stimulation above and below the 

 injury excited muscular contraction. He assumes that the 

 implanted segment was at least for a time preserved (erhalten), 

 and conveyed impulses ; later it (the implanted segment) may 

 have been replaced by fibres of the radial. Landerer seems to 

 forget that clinical and experimental evidence would justify 

 the assumption that, in the above case, the peripheral portion 

 of the radial was in a state of complete degeneration at the 

 time of the implantation, so that impulses conveyed through 

 the implanted segment could not have reached the muscles. 

 Then, again, all experiments bearing on this subject, except 

 those reported by Gliick, show that the implanted portion 

 always degenerates, and even more rapidly than does the 

 peripheral end of a divided nerve ; so it could not have carried 

 impulses. Clinical records show that as a rule the return of 

 motion takes place more slowly than the sensory function. 

 Landerer's conclusions would, therefore, hardly stand critical 

 investigation. The muscular contraction observed on electrical 

 stimulation may have been due to a direct stimulation of the 

 muscles, or to stimulation of some of the other nerves in the 

 arm ; any other explanation does not suggest itself to me. 



In a number of cases reported as improved, sensation alone 

 was reestablished ; the cases either having been dismissed 

 before voluntary muscular movement was observed, or no 

 mention is made concerning its return. 



The rapid return of sensation in cases Nos. 7 and 14 would 

 seem to show that the impulses must have been conveyed along 



