CH. XV.] 



REGENERATION OF NERVE 



167 



that the new fibres grow from the central stump of the cut nerves 

 has been recently ques- 

 tioned. Some believe that P* " ~^ 



regeneration may occur in 

 the peripheral structures. 

 It certainly is the case that 

 the neurilemmal cells ex- 

 hibit a great deal of activity ; 

 they multiply (fig. 184) ; at 

 a later stage they exhibit a 

 phagocytic action in the 

 removal of the degenerated 

 fat (fig. 185) ; and later still 

 they become elongated and 

 spindle-shaped ; they then 

 join together as though 

 they were forming the basis 

 of new nerve-fibres (fig. 186). 

 But the elongating and 

 apparently contiguous cells 

 are probably only forming 

 a new sheath or basis into 

 which the axis cylinder 

 ultimately grows. Howell and Huber, who have recently investi- 

 gated this question, have arrived at the conclusion that the peri- 



Fio. 184. Single fibre from a degenerating nerve, eight 

 days after the nerve was cut, stained so as to show 

 the division of a neurilemmal nucleus into two. 870 

 diameters. (Mott and Halliburton.) 



FIG. 185. Degenerated nerve, twenty-seven days 

 after the nerve had been cut. /he numerous 



neunlemmal cells, perhaps aided by phagocytes neurilemmal cells to form what look like 



from the exterior contain within them fatty par- fihrp i w^il hnwn ^no rliamptprs 



tides which stain black with osmic acid. They ?Mott and Haufburtor n 



are doubtless active in removing the degenerated 

 myelin. 450 diameters. (Mott and Halliburton.) 



pheral structures are active in preparing the scaffolding, but that 

 the axis cylinder, the essential portion of a nerve-fibre, has an 



