Literary Notices. li 



periphery and a simple reflex mechanism be formed with but a single 

 impulse generator in its course; or the fibril might go from ganglion cell 

 to ganglion cell until at last it reached the muscle, closing the circuit. 

 Throughout its entire course the fibril might be tne product of a single 

 nerve cell. Ganglion cells would, then, be, as it were, merely inter- 

 polated in the condcting tract as batteries. Ganglion cells produce 

 that which is to be conducted, the impulse; the nerve cells, that which 

 will conduct, the fibrillae. Such, in brief, is the rather elaborate 

 scheme of the relations of nervous elements which Dr. Apathy pre- 

 sents as the result of his investigations. 



The forms upon which his results were obtained comprise some 

 six genera of the Hirudinea and Lumbricus, and for comparison were 

 investigated Mollusca {Unio, Anodonia), Crustacea {Astacus), and 

 Vertebrata (7>//i?/z, Lophius a.n^ Lepus). The annelids were found 

 most servicable because of the size and isolation of the fibrillae and the 

 ease with which they submitted themselves to the reagents employed, 

 as well as the location and construction of the nervous system. At 

 the other extreme, the vertebrate tissue was most unfavorable. In all 

 of the forms, however, the neurofibrillae were demonstrated, although 

 in the present article attention is largely confined to the annelids. 



These results are, it is almost needless to state, unique. The 

 author recognizes fully the wide divergence of his results from the 

 generally accepted views of nerve development and the relation of 

 nerve cells to each other as based largely on the investigations of His 

 and by means of the chrome-silver impregnation methods. Indeed, a 

 protest is expressed against the ease with which generalizations based 

 on vertebrates alone are made to include lower forms that are simpler 

 and more important from a theoretical point of view. The protest 

 seems to have real application and force. Among others, the results 

 of Kupffer on Am nocoetes and Piatt on Necturus show us that the 

 development of the nerve fiber as an outgrowth of the ganglion cell 

 cannot be accepted as proven even for all vertebrates. Evidence 

 from forms below Reptilia is still needed. A doubt, also, has been 

 expressed by some and probably exists in the minds of others, wheth- 

 er the relation of nerve cell to nerve cell is that of contiguity only and 

 not a continuity of their processes, and if the impregnation methods 

 have not just failed to reveal to us the whole truth. These are sec- 

 ondary considerations which help to make the views of the author 

 more plausible. It is so purely a question of evidence that any dis- 

 cussion at this time is fruitless The comparison with vertebrates is 

 unsatisfactory; however there is promised a second communication 



