THE NOSE OR ORGAN OF SMELL. 383 



The inferior meatus lias the nasal duct opening into its 

 anterior portion while the Eustachian tube is seen behind 

 on a level with the inferior spongy bone. 



These different meatuses constitute so many channels, 

 extending from before backward, in the nasal fossce, which 

 with the spongy bones, present a large amount of surface 

 covered by mucous membrane, upon which the air in pass- 

 ing along, makes odorous impressions. 



The mucous membrane lining the nasal-fossae is called 

 the pituitary or Sclmeiderian membrane. It is attached to 

 the internal surface of the bones of the nose, lines the si- 

 nuses, is traced into the wthmoid and sphenoid cells, passes 

 through the nasal duct } and is continuous with the tunica 

 conjunctiva of the eye. Backward through the posterior 

 nares, it becomes continuous with the mucous membrane of 

 the mouth and pharynx, and consequently with the great 

 gastro-pulmonary division. In some parts it is very vascu- 

 lar, soft, and thick, as on the turbinated bones and septum. 

 In other places it adheres strongly to the periosteum. It is 

 pale and thin in the sinuses. It is constantly moistened 

 with mucus, and, like mucous membranes elsewhere, has 

 its surface covered with an epithelium. This epithelium is 

 of the columnar form, except in the sinuses where it is 

 found to have more of the squamous character. It is every 

 where observed to bo furnished with cilia, whose vibratile 

 motions, it is believed, have an important influence in 

 directing the mucus towards the various openings by 

 which it is discharged. 



Blood-vessels of the Nose. The terminating branches of 

 the facial artery supply the external nose, while the 'an- 

 terior and posterior wthmoidal of the ophthalmic, with the 

 splieno-palatine and pterygo-palatine of the internal maxil- 

 lary, supply the nasal fossse or internal nose. 



Nerves. The olfactory or first pair, (Fig. 110,) are the 

 special nerves of the nose and of the sense of smell ; their 

 development being always found in the lower animals in 

 proportion to the acuteness and development of this sense. 



They come from the brain through the foramina in the 



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