202 THE OLFACTOKY ORGAN, BY PROFESSOR BABUCHIN. 



the nasal mucous membrane where the olfactory nerves branch 

 and terminate. Were it, however, desired to indicate the pecu- 

 liarity of this spot by a feature characterizing it throughout 

 the whole of the Vertebrata, it would be not so much its colour, 

 but its greater thickness, softness, and, so to speak, greater 

 succulency, as compared with the rest of the membrane. Even 

 this, however, varies in degree in different animals ; for whilst 



Fig. 337. 



Fig. 337. Vertical section of the septum nasi of the Guinea-pig. 

 The specimen was prepared by maceration in solution of chloride of 

 gold, a, Medullary tissue of bone ; 6, osseous lamina ; c, periosteum ; 

 d, gland layer, not filled up, that it may be more distinctly seen ; e, 

 branches of the olfactory nerves ; /, epithelial layer. 



ill Birds, for example, the membrane is tolerably dense at this 

 part, and scarcely presents any peculiarity recognizable to the 

 naked eye, in the Plagiostomata it is so soft as to resemble 

 thick mucus. 



The works of Todd and Bowman (1), Eckhardt (2), Ecker (3), 

 and others, certainly contributed much to our knowledge of the 

 structure of the olfactory region ; but the first really accurate 

 information was furnished by the extremely careful investiga- 

 tions of Schultze, and future research, though it may possibly 

 affect points of detail, will not shake the essential facts that he 

 discovered. Some attempts have, however, been made, with 

 this object in view. 



An idea of the general relations of the olfactory region 

 may best be obtained from fine vertical sections carried 



