44 CHARLES F. W. MC CLUßE, 



In substantiation of the view that the granules in the cell body 

 are isolated structures, and not varicose thickenings of fibrils, the 

 following evidence is presented: 



1) The granules stain so differently from that of the fibrils, that 

 it seems quite improbable that they can be an organic part of the 

 fibrils. 



2) As already stated, fibrils are met with in the cell body which 

 have no connection with granules. 



3) It is generally conceded that the chromophilous substance in 

 the nerve cells of Vertebrates, with which that of the nerve cells of 

 Invertebrates is unquestionably homologous, is a substance organically 

 independent of the fibrils, and not, in Pflücke's sense, varicose 

 thickenings of the same. 



4) When nerve cells are stimulated by electricity, it has been 

 shown that granules may migrate from one region of the cell to 

 another. An explanation of this pheaomenon is easy, if we regard 

 the granules as isolated structures lying in a semi-fluid ground-sub- 

 stance, and capable of moving in the same when currents are set up 

 in the latter. I refer to the investigations of Hodge, Vas, Mann. 



The appearance presented by fibrillar structures in nerve cells, 

 which have been stained by the methylen blue-eosin and safranin-light 

 green combinations, is by no means distinct. This is undoubtedly 

 due to the fact that in each case the fibrils are stained by the same 

 dye (eosin or light green) as the ground - substance , a circumstance 

 which naturally prevents a clear definition being made between 

 the two. 



I have observed, however, in these sections, between the granules 

 of the granular rows, the presence of delicate lines which stain slightly 

 darker than the ground-substance, and which in position and size, so 

 closely resemble the fibrils brought out by other methods, that I am 

 inclined to regard them as such. 



On account of the difficulty experienced in differentiating the 

 fibrils from the ground-substance, neither of these two methods has 

 proved of any great value in determining the course of individual 

 fibrils in the cell body. These methods have proved of special value, 

 however, in determining the topographical arrangement of fibrillar and 

 granular areas in the cell. 



fibrils coarser than those of Helix and Arion. I reserve my figures 

 and a detailed account of the nerve cells of Astacus for a future paper. 



