CRITICAL REVIEW OF RECENT PUBLICATIONS OF 

 BETHE AND NISSL. 



By Adolf Meyer, Worcester, Mass. 



Since my "Critical Review of the data, etc. of Modern 

 Neurology" was written, April, 1898, several publications 

 apart from the one of Apathy have appeared which claim a 

 complete change in the current views. Apathy's work deals 

 so exclusively with invertebrate material that I leave its review 

 to one better prepared. The articles here referred to are those 

 of Bethe and Nissl. 



Bethe (i) mentions as the most important findings of Apa- 

 thy the discovery of the numerous fine fibrils in the afferent 

 fibers, and the peculiar origin of the one large fibril of the effer- 

 ent fibers from a net-work around the nucleus of a ganglion 

 cell. This inner net-work anastomoses with a more superficial 

 net-work of finer fibrils which collect there from the splitting 

 up of afferent fibers. 



Bethe's fibril-stain shows clearly the existence of individual 

 fibrils in the nerve fibers of vertebrates, embedded in a homo- 

 geneous substance. At the bifurcation of posterior root-fibers 

 part of the fibrils go into one branch and part into the other. 

 In such bifurcations Bethe has never observed any fibrils passing 

 from one branch into the other, such as is the case in dendrites. 

 It is, moreover, easy in these specimens to say which is the 

 course of a fiber, because the collaterals always leave with the 

 same distal divergence. 



The cell pictures are in many respects the negatives of the 

 Nissl specimens ; but the eagerness with which the nucleus at- 

 tracts the stain makes it difficult to bring out the fibers near the 

 nucleus. In small bipolar cells the fascicles of fibrils pass 

 through from one dendrite to the other, dividing into bundles 



