712 HUBER. [Vol. XL 



trical stimulation of the ulnar at the wrist excited distinct move- 

 ments of the digits ; and microscopical examination of the 

 nerve in this region revealed the presence of regenerated fibres. 

 PI. XXXV, Fig. 19, shows the extent of regeneration at the 

 wrist 182 days after implantation. It will be seen that many 

 of the fibres possess axis cylinders, and some of the fibres {a) 

 present the structural appearance of a normal nerve. 



Only one experiment of secondary implantation of a nerve 

 was made. The right ulnar of a dog was resected 6 ctm., and 

 without suturing the ends of the nerve the wound was closed. 

 After a period of forty-one days the nerve was again exposed. 

 At this time the end of the central ulnar segment was much 

 enlarged, and seemed very sensitive. The ulnar was redivided 

 just above the bulb, and after vivifying the central end of the 

 peripheral ulnar a segment of cat's sciatic was implanted. 

 Sections of the portion removed from the peripheral stump of 

 ulnar showed that the nerve fibres had undergone complete 

 degeneration. 



Sections of the bulb (Stumpfneurome, amputations or Durch- 

 schneidungsneurome) removed from the central ulnar stump 

 present the appearance so often described for such structures. 

 Kolliker states that the bulbs must be looked upon as express- 

 ing the regenerative energy of the nerve, an hypothesis which, 

 no doubt, expresses correctly the existing conditions. Struc- 

 turally this bulb consisted largely of small groups of new nerve 

 fibres very complexly interwoven between bundles of fibrous 

 tissue. Such neuromes would seem to develop from the 

 degenerated part of the central stump and the connective 

 tissue surrounding its end. Above the bulb the fibres of the 

 ulnar presented a normal appearance. 



The dog was killed 155 days after the second operation. 

 The results of the physiological and histological examination of 

 the nerve involved in this experiment are so similar to the ones 

 obtained in experiments of primary implantation of about 120 

 days' duration, which have already been recorded, that a detailed 

 description of them at this stage would only be a repetition of 

 observations already given. 



I have purposely avoided making any mention of the develop- 



