DEGENERATION AND REGENERATION OF NERVES 79 



logical grounds, has met the objections of his opponents in a 

 most creditable manner by repeated experiments and new evi- 

 dence which appear irrefutable. Langley and Anderson ('04), 

 Lugaro ('05) and j\Iott, HaUiburton and Edmonds ('04) have 

 repeated many of Bethe's experiments but oppose rather than 

 support him in his contention for auto-regeneration in the periph- 

 eral stump. Langley and Anderson ('04) admit that the periph- 

 eral stump, after a sufficient length of time has elapsed, may be 

 found capable of conducting impulses even when union with the 

 central stump is successfully prevented. The}' explain this ap- 

 parent auto-regeneration by an ingrowth of nerve fibers from 

 the surrounding tissues. In every case where the peripheral 

 stump became capable of conducting impulses, strong evidence 

 was obtained to show that an ingrowth of fibers into it from other 

 neighboring nerves had taken place. Mott, Halliburton and 

 Edmonds ('04) have confirmed this finding and have found that 

 in a piece of medullated nerve transplanted in the same animal 

 in such a manner that an ingrowth of fibers from other nerves 

 is prevented, regeneration fails to take place. They ha\e further 

 shown that in a regenerating nerve the medullary sheath ''appears 

 earliest at situations near the point where the ends of a nerve 

 have been joined together, and reaches the distal portions later." 

 Bethe ('07) has again repeated these experiments but can find 

 no reason to abandon his former strong conviction that auto- 

 regeneration takes place in the peripheral portion of a divided 

 medullary nerve. The experimental work of Ballance and Purves 

 Stewart ('01) lead them to declare for auto-regeneration, and 

 Van Gehuchten ('04) has confirmed Bethe's results. Wilson ('09) 

 after repeating some of Bethe's work, draws no specific conclusion 

 regarding auto-regeneration of divided meduUai*}' nerves. 



In short the main contention of the advocates of auto-regen- 

 eration hangs on whether there may be no ingrowth of foreign 

 fibers from neighboring nerves into the peripheral portion of a 

 divided nerve. This at bottom is the point in dispute between 

 a class of able workers who hold to auto-regeneration and a 

 group of equally acute observers who advocate the outgrowth 

 of the axis cylinder from the central stump. So long as so cap- 



