332 Prof. R. Kennedy. Restoration of Paralysed 



cortical representation in the case of the hind limb, as in the dog this is 

 represented by a single centre. 



The author has performed five experiments in dogs on the right fore-limb, 

 which has the advantage, in the first place, that section of the nerves above 

 the elbow paralyses the limb in such a way that it is impossible for the 

 animal to use it for walking until recovery of co-ordinated movements 

 occurs. This is then a very severe test. In the second place, the fore-limb 

 of the dog is represented by two separate and distinct centres, one for flexion 

 and one for extension, which are only exceptionally defective. 



The experiments are of two kinds, but are the same in so far that in all 

 the musculo-cutaneous, median, ulnar, and musculo-spiral nerves were each 

 divided above the elbow, and the limb thus completely paralysed below the 

 elbow. Then the four distal segments were united to the proximal end of 

 the musculo-spiral nerve, and the three remaining proximal ends left 

 ununited ; or, on the other hand, the four distal segments were united to the 

 proximal ends of the musculo-cutaneous, median, and ulnar, and the one 

 remaining proximal end (musculo-spiral) left ununited. The limb was fixed 

 in plaster of Paris as long as necessary. 



The following results were obtained : — 



A. Where the central supply was that proper to the flexor muscles 

 (musculo-cutaneous, median, and ulnar), the first sign of recovery of the 

 muscles was shown at 96 and 93 days respectively after the operation, and 

 a satisfactory recovery, enabling the dog to run about, and in one case to be 

 taken for exercise into the streets, was reached at 126 and 123 days respec- 

 tively. In the first case no interruption of the excellent recovery occurred 

 as long as the animal was allowed to live, namely, 225 days, but in the latter 

 case there was some trouble by the development of a slight flexor contracture 

 which hindered the recovery up till the animal was killed at 187 days. 



B. Where the central supply was that proper to the extensor muscles 

 (musculo-spiral), the first sign of recovery was at 81 and 59 days respectively 

 in the two which showed recovery. In the first case a pressure sore inter- 

 fered with further progress, but in the second case at 79 days the animal ran 

 about normally, and was able to be taken out for exercise in the streets 

 without any fear of attracting notice. It may be noted that although in this 

 form of experiment the muscles of the limb were supplied by the lesser 

 number of nerve fibres, namely, those contained in the musculo-spiral, the 

 recovery commenced earlier than when the three nerves normally supplying 

 flexors formed the sole central supply, although in that case the greater 

 number of nerve fibres were available for the supply. This is explained as 

 due probably to the earlier recovery of the extensors when the musculo-spiral 



