ORGANS OF THE SENSES. 501 



in connection with the ordinary sebaceous glands of the hair 

 follicles. 



Higher up the mucous membrane of the nose, losing its 

 papillae and scaly epithelium, becomes thick and soft, and 

 presents more completely the ordinary appearances of a 

 mucous membrane ; imbedded in its substance are numerous 

 mucous follicles of large size, having but small apertures, 

 which are best seen thickly studding the surface of the mem- 

 brane after slight maceration and the removal of the epithe- 

 lium. Between and around these the blood-vessels are dis- 

 posed, the veins being particularly large, and forming a very 

 evident plexus, each mesh of which corresponds with a follicle. 

 (See Plate LXIX.y^. 2.) 



The large size and considerable numbers of the mucous 

 follicles explain the copious secretion which proceeds from 

 this portion of the mucous membrane, when suffering from 

 irritation, while the venous plexuses sufficiently account for 

 the disposition of this part to hemorrhage. 



This is by far the largest of the three nasal regions, and 

 may be denominated the pituatory ; the epithelium which 

 clothes it is of the ciliated kind, and several of the cavities 

 in connection with the meatuses are invested by a similar 

 epithelium, as the fontal and sphenoidal sinuses, the antrum 

 maxillare, and the Eustachian tubes. In the sinuses, how- 

 ever, the mucous membrane, losing its follicles, becomes much 

 reduced in thickness, and presents the characters of a fibrous 

 rather than of a mucous structure. 



Still higher up in the nose we come upon the third region, 

 which has been particularly defined and described by the 

 authors of the Physiological Anatomy as follows under the 

 name of the olfactory region : 



" The olfactory region is situated at the top of the nose, 

 immediately below the cribriform plate of the ethmoid bone, 

 through which the olfactory nerves reach the membrane ; 

 and it extends about one third or one fourth downwards on the 

 septum, and over the superior and part of the middle spongy 

 bones of the ethmoid. Its limits are distinctly marked by a 

 more or less rich sienna-brown tint of the epithelium, and by 



