696 HUDER. [Vol. XL 



Other nuclei, of a safranin color, the protoplasm a faint red. 

 In case the safranin stain is extracted too much the blue stain 

 will predominate in the section. Yellow elastic tissue will 

 sometimes stain very much like an axis cylinder, but the defi- 

 nite outline of the elastic fibres, and their relation to other 

 structures, will make it possible to obviate any misinterpreta- 

 tion. In a number of experiments, especially those in which 

 the earlier degenerative changes of myelin and the behavior of 

 the nerve nuclei were made the subject of study, the nerves 

 were hardened in Flemming's solution (extension being main- 

 tained in the manner described for Miiller's fluid-hardened 

 nerves), imbedded in paraffin, sectioned and fixed to the cover 

 glass, and doubly stained with safranin and licht griin, after 

 Benda's method. 



In making teased preparations it was found quite helpful to 

 cut sections twenty to thirty mikrons thick, remove the paraffin, 

 stain in anilin blue and safranin, or safranin and licht griin, 

 and then tease these stained sections in oil of bergamot, and 

 mount in balsam. Sections, especially such as contain much 

 fibrous tissue, can thus be easily teased, and the nerve fibres 

 are, as a rule, not so liable to be broken up as when teased in 

 the usual way. 



{a) Degeneration and Regeneration after Implantation of a 



Nerve Segmejit. 



The degenerative changes which befall the implanted seg- 

 ment do not differ materially from this process as observed in 

 peripheral nerves after severance from its center, except that 

 the changes take place more rapidly. 



By the end of the second day the myelin and axis cylinders of 

 the nerves of the implanted segment are found to be broken up 

 into larger and smaller fragments, and there is already an 

 increase of the protoplasm within the sheath of Schwann. At 

 this stage the segments of myelin vary largely in size and 

 shape : some are long, and entirely fill the sheath of Schwann 

 in that portion of the degenerating fibres in which they are 

 found ; others are in the form of small, round, or oval balls. 



