No. 3.] PERIPHERAL NERVES, 697 



surrounded by the proliferated protoplasm ; between these 

 extremes one finds every gradation. The segments are usually 

 surrounded by a layer of myelin varying in thickness, and show- 

 ing a decided difference in the extent to which it is stained 

 with osmic acid. The protoplasm has a homogeneous appear- 

 ance, staining faintly red in safranin. I am unable to state, as 

 a result of the preparations examined, what is the cause of the 

 fragmentation of the myelin and axis cylinder. In the sections 

 at my disposal the degenerative changes were too far advanced 

 to make any observation on this point. It does not, however, 

 seem probable that the fragments of myelin bear any relation 

 to the so-called segments of Lantermann or Schmidt. Their 

 irregular shape and size would exclude such a possibility. The 

 nerve nuclei are found in larger number than in normal fibres, 

 where, as is well known, a single internodal nucleus is present. 

 As a rule they occupy a position in the middle of the fibre 

 between two segments of myelin. It is somewhat difficult to 

 estimate their number, as the nodes of Ranvier cannot be 

 clearly made out at this stage. To some extent, at least, the 

 proliferation of the nuclei would seem to result from karyo- 

 kinetic division of preexisting internodal nuclei ; now and then 

 one is found in the early stages of cell division. I was not 

 fortunate enough, even after looking through a large number of 

 sections, to find a nucleus in the monaster or diaster stage. 

 The nucleus shown in the middle one of the five fibres repro- 

 duced in PI. XXXIV, Fig. i, which represents a portion of a 

 longitudinal section of the implanted segment two days after 

 the operation, presents a structure differing from that of the 

 majority of the nuclei seen. The chromatic filaments (chromo- 

 soma) are clearly discerned, and the nucleoli are wanting, 

 although the nuclear membrane is still present ; while the rest- 

 ing nuclei present a very delicate nuclear network, and usually 

 two, three, or four prominent nucleoli. Now and then one 

 finds a nucleus of hour-glass or dumb-bell shape, which leads 

 one to think that some of the nuclei fragment (amitotic 

 division), and in this way contribute to the proliferation of 

 the nuclei seen. A great number of polynuclear white-blood 

 cells are found in the lymph spaces between the connective 



