

OF 111E 



sides the cartilage which forms the septum erf the nose, two 

 others of an elastic nature constitute the wings ; and as they 



admit of motion, several muscles are attached 

 order to regulate the external orifices in accordance with 

 different conditions of respiration, and also to enable us to 

 exercise the sense of smell with greater effect, when we wish 

 voluntarily to employ that function. 



3. The membrane which lines the nasal fossae, resembles 

 the mucous membranes generally, and adheres firmly to the 

 bones and cartilages which it covers. Externally, this mem- 

 brane is continuous with the common integuments, and pos- 

 teriorly with the lining membrane of the throat. It varies 

 somewhat in appearance in different situations. In the 

 sinuses, it is thin, pale, and of a smooth surface ; but where 

 it constitutes the immediate seat of smell, it is thicker, more 

 vascular, and of a redder colour than mucous membrane in 

 other situations. It is studded with mucous follicles, which 

 yield the secretion with which it is moistened ; though it is 

 also bathed with the tears that spread out upon it, after 

 having been conveyed from the eye through the nasal ducts. 

 The nasal mucus seems as essential to the sense of smell, as 

 the secretion from the mucous membrane of the mouth to 

 that of taste. In those who use tobacco in the form of 

 snuff, this secretion often becomes so scanty or so changed 

 in quality, that the smell is much impaired, and sometimes 

 entirely lost : the voice also is seriously injured by the same 

 practice. 



4. |The olfactory, or first nerve, is the sense of smell. This 

 is spread out on the thick vascular portion of membrane just 

 described. 'Twigs from the first and second branches of the 

 fifth, are plentifully ramified over the whole surface of the 

 pituitary membrane, imparting to it common sensibility. 

 The nose is also supplied with branches from the facial to 

 regulate the action of the muscles. Dr. Majendie says, that 

 the organ of smell ought to be described as a sort of sieve, 

 placed in the passage of the air, as it is introduced into the 



