728 HUBER. [Vol. XI. 



ulnar segment did not follow the course of the reflected flap, 

 but were lost in the connective tissue surrounding the peripheral 

 end of the central stump. 



In the experiments of 147 days' duration (Nos. 47 and 48) 

 the appearances presented on microscopical examination were 

 essentially the same as those described for Exp. 46. The 

 central segment presents a slight enlargement, beyond which 

 extends a bundle of nerve fibres, some of which are medullated, 

 while others are not. At a point about 4 ctm. below the 

 enlargement this bundle breaks up, and the nerve fibres assume 

 a very irregular course, running in all directions, and are finally 

 lost in the connective tissue. In Exp. 47 a few small bun- 

 dles of nerve fibres were observed in the neighborhood of 

 the peripheral wound, but could not be traced through the 

 wound into the peripheral ulnar segment. In the above exper- 

 iments sections were made from the different parts of the 

 ulnar below the place of resection, but no regenerated fibres 

 were found. The conclusions reached may be summarized in 

 the following statements : — 



I. The nerve flap, whether it be made from the central or 

 peripheral stump of a resected nerve, degenerates throughout 

 its whole extent. The entire peripheral segment likewise 

 degenerates. 



II. In that part of the central stump from which the nerve 

 flap was made many degenerated fibres are found, a result of 

 the traumatism incurred while forming the flap. 



III. The junction of the flap with the peripheral end of the 

 central stump is not of such a nature as would offer favorable 

 mechanical conditions, such as would best guide the down- 

 growing axis cylinders of the central stump to the peripheral 

 part of the resected nerve. The experiments show that the 

 budding axis cylinders are lost in the connective tissue surround- 

 ing the peripheral end of the central segment. 



{e-f) Nerve Grafting and Cross- Suturing and G^'afting. 



The microscopical examination of the nerves involved in 

 Exps. 49 and 50 corroborate in every way the results ob- 

 tained at the physiological examination of the nerves involved 



