Olfactory x4.pparatiis in Dog, Cat and Man 31 



opening into the nose^ any movement of the air back and forth through 

 the narrow outlet would be likely to bring the odorous particles in 

 contact with the olfactory epithelium. There is a variation of opinion 

 concerning the extent of the olfactory area in man. According to 

 Scarpa, this is very extended. It includes the entire area of the upper 

 turbinated zones (a few filaments going to the inferior turbinal). Some 

 of the nerves of the septum are pictured as reaching the floor of the 

 nasal cavity (Fig. 10). Sappey's pictures show a less extended distribu- 

 tion of these nerves a little less than lA of the septum; the superior i^ 

 of the middle turbinated bones. According to von Brunn only a small 

 portion of the superior turbinals and a corresponding area of the 

 septum are olfactory in function (Figs. 28, 29). My results are mid- 

 way between those of Sappey and von Brunn. Figs. 30, 31 were made 

 from dissections and show that the olfactory nerves reach nearly to the 

 free edge of the superior turbinated bone and about % the width of the 

 lateral wall and occupy about ^/g of the septum. 



Tpie Histological Structure of the Olfactory Epithelium. 



The epithelium of the olfactory region consists of three kinds of 

 cells : the supporting or sustentacula! cells, the olfactory cells and the 

 small stellate basal cells (Figs. 39, 42). In the sub mucosa serous 

 glands are found; these are known as Bowman's glands and are well 

 pictured in all the books. The ducts of these glands are stained by the 

 Golgi method and pictured in Fig. 41. 



The supporting cells are elongated and cylindrical; they have an 

 oval nucleus and a thin cuticular border (Figs. 40, 42). The central 

 end has wing-like processes, often irregular in outline, which project 

 toward the basement meml)rane between the olfactory cells. This cell 

 was distinguished from the olfactory cell by Eckhard in 1855; but he 

 and other early writers were doubtful as to its true nature. These cells 

 occupy the superficial border of the epithelium and contain pigment. 

 Stellate cells lie near the basement membrane among the processes of 

 the epithelial cells. 



The olfactory cells have been studied by four different methods : the 

 Golgi, gold chloride, methylene blue, and dissociation (Figs. 32-38). In 

 all, their position appeared the same. They lie in the middle and 

 deeper layers of the epithelium and send their process between the 

 supporting cells. They are fusiform in shape, with a spherical nucleus 



