CoGHiLL, Structure of the Netvc Cell. 173 



continuous with those of the axone, but none of them anastomose. 

 They follow an undulating or somewhat spiral course through the cell 

 body, with a tendency to be more nearly parallel in the peripheral 

 zone. The interfibrillar substance is homogeneous. 



But the fibrils of this net, it is important to notice, are to Holm- 

 gren the neurofibrillae. In both vertebrates and invertebrates they 

 may enter or leave the neurone at any point in the periphery of the 

 perikaryon or of the processes. Furthermore, Holmgren says, "die 

 wabige, pseudowabige oder spongioplasmatische Structur, wie man sie 

 auch uennen will, die ich bei Lophius, die Ram6n-y-Cajal, Lenhos- 

 s:6k, van Gehuchten u. A. beschrieben haben, nur einem accidentellen 

 Aussehen der resp. Zellen entspricht, im besten Falle durch einen 

 gewissen physiologischen Zustand hervorgerufen." That is to say, 

 the "filare Substanz" of Flemming is resolved by Holmgren into the 

 neurofibrillae of Apathy and Bethe, and the structural parts of the 

 ground substance, such as granules, trabeculae etc., of many authors 

 are interpreted as functional or artificial modifications of Flemming's 

 amorphous "interfilare Substanz." 



Kolster's monograph upon the nerve cell of Feiroi/iyzon con- 

 tains an interesting demonstration of certain features of the ground 

 substance. Kolster has made an exhaustive study of unstained 

 preparations of the nerve cell mounted' in media of various refractive 

 indices, and also of unstained osmic acid preparations. In none of 

 his mounts made by these methods has he found anything akin to a 

 fibrillar or reticular structure. But in cells preserved in Flemming's 

 solution for several mouths or even for more than a year, and subse- 

 quently stained in saffranin and differentiated in a 20% tannin solu- 

 tion followed by absolute alcohol, he discovers very fine lines running 

 through all the cytoplasm. These lines are made up of a single row 

 of dark red granules which the author treats as microsomes. In some 

 of his figures these lines seem to form a net with relatively large, ir- 

 regularly shaped meshes, but the author believes that anastomoses be- 

 tween the lines are relatively rare. In thick sections these granules 

 appear large, but thinner sections show that these relatively large 

 granules are made up of short rows of exceedingly small granules run- 

 ning in all directions. The whole structure, then, is resolved into a 

 network of microsomes in linear arrangement. Furthermore, Kolster 

 demonstrates that this net is concentrated into a dense granular mass 

 directly around the centrosphere, where a granular effect is_ given in 

 unstained preparations. From this central mass rather thick rays ex- 

 tend in different directions, and these fray out into the fine lines of 



