71 8 HUBER. [Vol. XL 



nective tissue layer. From one side of this bulb there extends 

 into the connective tissue below the bulb, a small bundle 

 of nerve fibres about i mm. in thickness, composed largely 

 of new axis cylinders, some of which are surrounded by 

 a thin layer of myelin. For a distance of about Yt, ctm. the 

 fibres constituting the above bundle have nearly a straight 

 course, and are parallel to a line uniting the central and 

 peripheral parts of the resected nerve. Just below this point 

 the nerve bundle would seem to split up, brush-like, into larger 

 and smaller groups of fibres ; these, for the greater part, now 

 have a very irregular course. In cross and longitudinal sections 

 of the cicatricial tissue i to 2 ctm. below the central bulb only 

 scattered nerve fibres and small bundles of fibres are met with. 



In the connective tissue just above the central end of the 

 peripheral portion of the resected nerve, I was not able to find 

 any axis cylinders. Sections made from different parts of the 

 external and internal popliteal show these to be completely 

 degenerated ; only the collapsed sheath of Schwann containing 

 a nucleated band of protoplasm, with here and there a fragment 

 of unabsorbed myelin, were seen. 



In Exp. 32, of 130 days' duration, where the sciatic 

 was resected 5 ctm. and a tubular suture made, there was 

 no return of functional activity to the peripheral end, as 

 tested with electrical and mechanical stimulation. Histolog- 

 ical examination, however, revealed the presence of new axis 

 cylinders in the connective tissue between the central and 

 peripheral parts of the sciatic, to a point just above the periph- 

 eral wound. From the lower end of the bulb, in which the 

 central stump terminated, bundles of small nerve fibres, some 

 naked, others possessing thin medullary sheaths, could be 

 traced into the connective tissue below the bulb. At first 

 these bundles have a regular, straight, or slightly wavy course. 

 This regular arrangement is lost about i ctm. from the end of 

 the central sciatic, and below this point the connective tissue 

 contains small bundles of nerve fibres running in every direc- 

 tion, the nerve fibres becoming less numerous as the peripheral 

 wound is reached, where they are entirely wanting. The 

 popliteal branches were completely degenerated. 



