TASTE AND SMELL 



97 



to the mucous membrane of the nasal passages (Fig. 56), 

 where the fine filaments of the nerve end in delicate 



rod - shaped cells 

 crowded in among 

 the columnar cells 

 of the epithelium 

 lining the nasal 

 passages (Fig. 57). 



Fig. 56. - Section of nose, showing outer wall Fl f 57 ~ Cells from ol- 



of right nasal cavity factor y membrane, 



a, 6, c, d interior of nose. -# epithelial cell. 



K olfactory bulb, below which are seen the nerve W nerve cell, 

 fibers spreading out in the mucous membrane. 



127. An Olfactory Impression. Odors are usually car- 

 ried to the membrane of the nose by means of the atmos- 

 phere, but they must be dissolved or suspended in liquid 

 before they can affect the end organs for smell. Hence 

 the glands of the olfactory membrane lining the nasal 

 passages, whose secretions keep the surface always moist, 

 are important subsidiary organs. As the air is brought 

 to the membrane in ordinary breathing, one is able to 

 perceive various odors when moderately strong. By 

 what is called " sniffing " the air is drawn into the upper 

 as well as the lower nasal chambers, and more of the 

 MACY'S PHYS. 7 



