42 CHARLES F. W. MC CLUEE, 



These fine neuroglia fibrils ^) have been noticed by Rohde, whose 

 interpretation concerning their character I cannot accept. In my 

 estimation, they represent prolongations of the primitive axis-cylinder 

 fibrils which extend into the neuroglia, and are connected with the 

 transmission of nervous impulses. Of these two double stains, the 

 safranin-light green combination is by far the best for bringing out 

 the fibrils in the axis-cylinder process (Fig. 6). 



Fibrils of the Cell Body. 



Thin sections of nerve cells {Helix and Ärion\ which have been 

 fixed in Flemming's or sublimate solutions, and stained by the pro- 

 gressive iron-alum-haeraatoxylin method, show, in addition to the gra- 

 nules, the presence of fine fibrils in the cell body. 



In my preliminary paper, I refrained from expressing any definite 

 views concerning the mode of distribution of these fibrils in the cell 

 body, beyond the statement that, in all probability, it corresponds to 

 that of the granular rows. After a more extended investigation on 

 this subject, I am now convinced that this, in part, is really the case 

 for reasons stated below. 



These structures, which I have described as fibrils in the cell 

 body, possess a diameter much smaller than that of the small chromo- 

 philous granules and, when differentiated, give up their stain more 

 readily than the latter. Thus, in a properly differentiated section, 

 they appear as delicate lines, which are more darkly stained than the 

 ground-substance of the cell, and more lightly stained than the chromo- 

 philous granules (Figs. 11 — 16 inch). In these respects they agree 

 with the fibrils found in the axis-cylinder processes. 



The appearance presented by these fine fibrils in the cell body 

 is as follows: 



1) Certain fibrils appear to have no connection with granules. 

 These are found chiefly in the semilunar area at the axis-cylinder pole, 

 and in the ectoplasmatic area of the cell body. This ectoplasmatic area 

 is not always free of granules. In some cells, however, it is quite free of 

 granules, and in this case the fibrils are plainly seen. Fibrils free of 

 granules are also met with within the granular area of the cell body 

 (endoplasmatic area). 



2) When the small, chromophilous granules appear to be arranged 

 into well defined rows, one can often see, in properly differentiated 



1) These fine fibrils were found to stain slightly darker than those 

 in the axis-cylinder process. 



