362 



THE SENSES 



the so-called olfactory hairs, extending out into the moisture of the 

 nasal cavities. Sustaining these cells in place are long columnar epithe- 

 lial cells branched toward the basement-membrane. Among the branches 

 of these are other cells, broad below and with processes above, resting 

 on the membrane, which are of unknown use. Round about in places 

 are the serous glands of Bowman or olfactory glands, whose cells contain 

 the brownish or yellow pigment of the olfactory region. 



THE REGIO OLFACTORIA in man on each side of the body consists 

 of an area of ("Schneiderian") mucous membrane, folded in the middle, 

 and about 2 cm. long by 1 cm. wide. One sq. cm. of the area is on the 



FIG. 214 



Tentative scheme of the principal neurone-systems of the olfactory conduction-path. 



(Barker.) 



inside surface of the upper part of the middle of the superior turbinated 

 bone and the other sq. cm. is directly opposite on the nasal septum 

 (von Brunn). Sometimes minute islands of the olfactory mucosa are 

 to be found adjacent to this tract. In these areas alone are the olfactory 

 cells to be found. The region is in color a brownish yellow. It is 

 placed high enough on the superior turbinated bone and nasal septum 

 to be out of the direct current of inspired air and especially of expired 

 air, yet it is sufficiently near the incoming air-stream to be continually 

 bathed in a slow current, and this is the condition best adapted to easiest 

 smelling. In sniffing, the in-rush of air is more sudden and probably 

 reaches directly the olfactory mucosa. 



