RESTORATION OF CO-ORDINATED MOVEMENTS AFTER NERVE SECTION. 693 



Improvement in the muscular power and control advanced, and on the eleventh day 

 the dog was able to run about freely on the leg, only occasionally getting on to the 

 dorsal surface of the paw, and then voluntarily readjusting the position after one or two 

 steps. There was distinct evidence of returning sensation, as, when pricked over the 

 formerly anaesthetic region of the paw and leg, the animal whined and withdrew the 

 limb. When pricked on the paw, while standing, it at once withdrew the leg with 

 flexion at the tibio-tarsal joint. 



The dog by the fourteenth day was running about apparently quite recovered, and 

 never treading on the dorsal surface of the paw. The only differences to be found in 

 the two legs were the less keen sensation and the slight atrophy of the muscles. 



On the forty-ninth day, all improvement having been maintained, the animal was 

 killed, and the seat of section having been exposed, the nerve was found united, a 

 neuroma having been developed at the seat of section. Stimulation with a weak 

 current above, below, and on the seat of section caused muscular contraction. The 

 muscles were apparently normal, though somewhat less bulky than those of the 

 opposite limb. 



Comparison of Experiments. 



The conditions of these three experiments coincided so closely that a comparison 

 between them is justifiable. All the dogs were of the same kind, and all were young. 

 The same nerve in all was divided at the same point, and the healing of tbe wound in 

 all was satisfactory, in no case becoming septic. In Experiments I. and II., however, 

 the peripheral was sutured to the central segment after having been rotated on its long 

 axis to the extent of a semicircle, while in Experiment III. the reunion was made in the 

 normal position. The last was thus a control experiment, intended to ascertain if any 

 important differences could be detected in the course of recovery of function in the two 

 cases, viz. : in the case in which the corresponding central and peripheral segments of 

 each of the nerve fibres were brought to lie as closely as possible opposite each other, 

 and in that in which these two segments were displaced from each other as far as 

 compatible with suture of the nerve stem. 



During the first six days the course was the same in all three. Thus, after a day 

 or two, the dogs were up and walking about on their splints, but with no return of 

 function, the paw being simply dragged along the ground dorsal surface down. 



In all three the seventh day brought the first improvement ; for on this day all 

 were able to walk with the plantar surface down. In all the dogs the paw was on 

 this day frequently turned over while walking, bringing the dorsal surface into contact 

 with the ground ; but in Exp. I. and II. the animal had the power voluntarily to 

 readjust the abnormal position of the paw, and again place it plantar surface down, 

 while in Exp. III. no voluntary power in this respect was shown, and the foot 



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



