REGENEEATION OF PERIPHERAL NERVES 511 



22. Thus in the operated ammal in which the fibers of both 

 the control and operated nerves are all diminished in total area, 

 the axis-sheath relation is such that in all three localities the 

 area of the axis is relatively less than in the fibers from the 

 normal animal. 



23. This deviation from the normal in the case of the control 

 nerves and the proximal end of the operated nerves represents an 

 alteration in existing structures while in the fibers distal to the 

 lesion, it appears in structures which have been newly formed. 



CONCLUSIONS 



The relation of the more important results here given to pre- 

 vious information is as follows: 



The observations that meduUated nerve fibers branch in their 

 course and in a gjven nerve increase in number for a time, with 

 age, is in accord with the findings of all the authors who have 

 studied these matters. Also, in agreement with others is the 

 fact that the number of fibers on the two sides of the same ani- 

 mal is similar. In agreement with Schwalbe ('82) and Dunn 

 ('02) it is found that the largest fibers in the peroneal nerve 

 undergo a conical diminution. 



The fact that in the operated animals the number of fibers is 

 diminished on the control side has been reported by Dunn ('09) 

 for the frog. The observations that the fibers of the control 

 side are greatly diminished in diameter and that the area rela- 

 tion of the axis and sheath is modified — also that the same is 

 true for the fibers in the proximal portion of the operated nerve, 

 are all new. 



The results on the area relation of the axis-sheath in the fibers 

 of the normal nerve agree in general with the observations of 

 Donaldson and Hoke ('05), but the determinations of this rela- 

 tion in the newly formed fibers on the distal side of the lesion 

 has not been previously made. 



The observations of Perroncito ('06), Osborne and Kilvington 

 ('08-'09) and the study of neuromata all indicate a tendency to 

 branching in the regenerating fiber. Our observations give pre- 

 cise information as to the amount of this branching, the general 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 23, NO. 5 



