Herrick-Coghill, Nerve Endings in the Skin. 49 



rod cells or " Stiftzelle ") is narrower and more deeply stained 

 than the supporting cells and occupies the entire width of the 

 cell. The peripheral part of these cells has not been correctly- 

 described as yet. In reality it consists of a projection of the 

 cell walls to form a narrow tube. These walls are delicate and 

 very thin but easily seen because of the contrast with the proto- 

 plasmic fiber contained in it. The latter structure is delicate 

 but stains a deep red with the picrocarmine, while the walls are 

 not stained by that reagent. (Figs, 26-30.) This axial fiber dif- 

 fers not at all from that seen in the clusters found in the scat- 

 tered sense organs on the head of the tree frog and the frog. 

 (Fig. 32.) The proximal portion of the cell is not as easy to 

 trace, for the corium and often the chromatophores obscure the 

 connections to a degree. Yet it now and then happens that the 

 direct communication with a nerve fiber rising through the 

 corium can be made out. Of course it may be insisted that this 

 connection is only a secondary one, but nothing but evidence 

 from embryology or degeneration experiments will substantiate 

 or refute the claim. So far as the evidence now goes, the scat- 

 tered cells above mentioned and those in the buds stand or fall 

 together, and for the former the evidence of direct continuity 

 between cell and nerve is unimpeachable. 



The Plexus Beneath the Conum. — In portions of the skin 

 stained httra vitani by the methylene blue method and examined 

 at once in glycerine very perfect views of the marvelously elab- 

 orate plexus beneath the corium can be gained. The fibers are 

 of two sorts, the larger being connected with the fibers from the 

 nerve bundles from the central system, while a part at least of 

 the fibers of smaller calibre have a local origin in certain gan- 

 glion cells of this region. These cells were first detected in 

 preparations double-stained with haematoxylin and picrocarmine 

 and were seen in section in a plane parallel to the surface. In 

 the methylene blue preparations they are very conspicuous and 

 surprisingly numerous. The nuclei are large, while the proto- 

 plasm of the cell does not stain or only slightly with the blue. 

 It is an interesting and most instructive fact that the cell body 

 remains transparent, while its own neurite or axis cylinder pro- 



