Olfactory Apparatus in Dog, Cat and Man 19 



frequently copied into text-books (E. G. Barker's Laboratory Manual 

 of Anatomy, 1904; Quain's Organs of the Senses, 1906) and represeiit 

 pictorially the opinion of anatomists as to the true relation. 



Instead of a plexus of the olfactory nerves I have found that the 

 nerves extend in non-anastomosing bundles to the olfactory bulb. All 

 appearance of anastomosis being due (a) to a crossing of the bundle 

 of nerves or (6) to a net-like arrangement of the connective tissue or 

 blood vessels. 



5-6. The position of the vomeronasal organ and its innervation by 

 the olfactory and 5th nerves have been shown in gross preparations of 

 dog and cat. In histological preparations the sensory cells of this organ 

 with their nerves have been demonstrated in the cat and mouse. 

 Branches of the anterior ethmoidal nerve have been traced among the 

 olfactory nerves of the conchfe in dog and cat ; their terminations among 

 the folds were not found in gross specimens. 



The naso-palatine nerve was found on the septum in all gross prepa- 

 rations. Kerves with free terminations were seen in histological speci- 

 mens, both on the nasal septum and in the concha; it is thought that 

 these are the endings of the 5th nerve. 



These facts are in agreement with the results of other workers. 



Historical Summary. 



The olfactory region has been a subject of special investigation for 

 many years. Various opinions concerning the endings of the olfactory 

 nerves have been published. Some views have been disproven, but as 

 early as 1856 Max Schultze had established with considerable certainty 

 the true conditions of the endings of the olfactory nerves in the nasal 

 mucosa. A review of the literature will give the present standpoint. 



Eclvhard, 1855, found that the olfactory epithelium of the frog was 

 formed of two kinds of cells, a cylindrical cell and a fusiform cell. 

 These were morphologically and physiologically distinct. The cylindrical 

 cell, an epithelial cell, had a central bifurcating end which terminated 

 in the subjacent layer. The fusiform cell was entirely different from 

 the epithelial cell. He suspected a difference in function, and thought, 

 without doubt, that one was the true termination of a nerve fibril; but 

 he did not say which one. 



Eclcer, 1855, published his observations on the olfactory mucosa of 

 man and some mammals. He saw two kinds of cells, a cylindrical cell 



