xxii Journal of Comparative Neurology. 



others, abundantly confirmed Max Schultze's theoretical condition. 

 Previous workers had, however, attacked the problem experimentally. 

 C. K. Hoffmann operated on frogs and mammals finding, as resulting 

 therefrom, what appeared to him to be a fatty degeneration of the 

 peripheral nerve and of the cells of the nasal epithelium. These re- 

 sults, however, in the opinion of Neuberger, will not permit of close 

 scrutiny, and, moreover, have been rendered of doubtful value by the 

 counter-researches of Schiff on young dogs and Colasanti on frogs, 

 neither of whom found any such degenerative change. So again, 

 Exner and Lustig thought they had found an atrophy, as well as the 

 entire loss of cilia, as the result of similar extirpation in frogs (they 

 failed completely in the same with rabbits); but these conclusions also 

 seem to be not well substantiated because of faulty observation. The 

 work of B. Baginsky on rabbits was supposed to have been conclusive 

 since he made sections through the entire membrane ; but his observa- 

 tions are rendered untrustworthy by his own admission of important 

 collateral injuries in performing the extirpation. In view of these con- 

 tradictory conclusions arrived at by so many different investigators, 

 Neuberger, at the suggestion of Dr. R. Krause, decided to study the 

 duck, an exceptionally good subject for the extirpation because of the 

 long fila olfadoria. He employed every means to avoid the mistakes 

 of previous researches, using a variety of methods and subjects. The 

 results of his investigations, taken in connection with the work of 

 Schiff and Colasanti, serve to confute the conclusions of the other in- 

 vestigators to whom reference has been made. In concluding, he sum- 

 marizes by saying that the cross-section of the olfactory nerve in the 

 duck results in a quite noticeable atrophy caudad of the point of opera- 

 tion in the corresponding brain centre, but that the olfactory mucous 

 membrane in both the duck and the frog exhibits no alteration resulting 

 therefrom. This conclusion furnishes, he says, a new link in the chain 

 of evidence for the new conception of the morphology of the nasal 

 epithelium, viz. that the olfactory cells really are nothing more nor less 

 than modified ganglion cells lying in the peripheral epithelium, which 

 is thus the real originating centre of the olfactory tract. This view is 

 important in that it contradicts the prevailing opinion that the olfactory 

 nerve differs fundamentally from the other cranial nerves, and in 

 throwing additional light on the newer view, advocated also by the 

 editor of this journal, that it simply exhibits an arrested stage of devel- 

 opment which is the priniitive condition of every sensory nerve, and 

 thus is of fundamental importance in understanding the formation of 

 central neural connections. The directions given for the proper man- 



