4IO Journal of Coinparathe Ncuroloi^y and Psychology. 



cells of origin for the fila olfactoria. Consequently it must be 

 affirmed that the olfactory nerve has a peripheral origin. This 

 view is supported by observations made by Ehklich,' Retzius,^ 

 Grassi and Castronovo,^ Ramon y Cajal,' Jagodowski'^ and 

 others upon the adult nasal epithelium of mammals and other 

 animals. 



The majority of the cells, therefore, that form the primi- 

 tive cellular anlage of Hi.s and others do not develop into nerve 

 cells. DissE has suggested that they constitute the cellular 

 sheath of the nerve, that is, are comparable to neuroglia cells. 

 Their fate I have not been able to ascertain. The majority of 

 them, however, accumulate in the cap formed over the end of 

 the bulbus. 



His's contention that this cellular anlage constitutes a true 

 ganglion is not supported by my observations. My conclusions 

 on this point harmonize with those of Disse, arrived at for the 

 chick. At most, there is only a partial formation of a ganglion 

 located between the olfactory epithelium and the brain. 



According to this view, the belief that the fibers of the 

 olfactory nerve have the same relation to the olfactory cells as 

 do fibers to sensory cells in the taste buds and tactile corpus- 

 cles is not tenable. The olfactory cells constitute the cell bodies 

 of neurones of the first order. 



^ Ehrlich. Ueber die Methylenblaureaktion dcr Icbendcn Nervensubstanz. 

 Deutsche Med. Wodmischrift, 1886. 



^ Retzu'S. (/. Zur Kentniss der Nervenendipungen in der Riechschleiin- 

 hfiut. Biol. Untersuchtingen, Neue Folge, lid. IV, 1892. 



•^ Grassi and C.vstrdnovo. Beitrag zur Kentniss des Geruchsorgans des 

 Ilundes. Archiv f. 7iiikros. Anatomic., Band XXXIV. 



* Ramon y Cajal. Oiigen y Terminacion de las fibras, nerviosas olfac- 

 lorias. Gazeta sanitaria municipal di Barcelona, Dec, 1890. 



" Jagodowski, K. p. Zur Frage nach der Endigung des Geruchsnerven 

 bei der Knochenfischen. Anat. Am., XIX, pp. 257-267. 



