50 Journal of Comparative Neurology. 



cess is mostly intensely stained through its entire length. The 

 hiatus between the fiber and its cell is slight but sufficient to 

 cast a doubt on the fact of communication were the conditions 

 not absolutely favorable. With a high power it is possible to 

 see the sheath and the faintly tinged protoplasm so that no 

 doubt is in this case possible. 



It may be noted also that other methods seem to show 

 that it is entirely possible for the protoplasm of a cell to react 

 differently from that of the axis cylinder derived from it. Thus 

 may be explained many of the ambiguous and conflicting re- 

 sults of the applications of the methylene blue process. Fig. 

 33 illustrates the appearance of a section stained with haema- 

 toxylin and picrocarmine, while Fig. 23 is from a methylene blue 

 preparation. Figs. 33-37 are from surface views of the plexus, 

 showing the ganglion cells. Figs. 38 and 39 are from the same 

 region, showing connections with vessels and chromatophores 



(Fig. 3.) 



It will be seen that the fibers of this plexus below the cor- 

 ium are of two sorts. The fine fibers arise, in part at least, in 

 the local ganglion cells and can be traced to the nerve bundles, 

 which they enter and then mingle with the fibers of the larger 

 sort. In the perpendicular sections it is easy to see that a cer- 

 tain number of fibers from the general "mixed" nerves pass 

 without interruption into the skin and so do not participate in 

 the formation of the plexus. Others, on the other hand, divide 

 dichotomously in the level of the plexus and the branches give 

 off "collaterals" that pass through the corium and so reach the 

 epithelial layer. It is not possible to state positively that fibers 

 from the ganglion cells of the plexus give off fibers to the skin, 

 though such certainly is the appearance. After passing through 

 the corium, the fibers do not all at once seek out their definite 

 termini in the cells of the epithelial layer, but they often turn 

 sharply at right angles at the ectal surface of the corium and pass 

 long distances parallel to the surface. This tendency is more 

 marked in some regions than in others. This fact greatly com- 

 plicates the study of the endings. In the case of taste buds and 

 the orrans of the lateral line this is one of the most serious dif- 



