ORGANS OF SENSE. 151 



The Nose is essentially formed of cartilages ; one occupies the median 

 line or septum, the others are placed on each side and form the alae. They 

 are continuous laterally with the superior maxillary, and superiorly with 

 the margin of the nasal bones ; inferiorly they bound two oval openings, 

 tlie nostrils. Each nostril has its long axis, antero-posterior, and is partly 

 surrounded by stiff hairs {vihriU.ai\ which bend across it and instantaneously 

 give notice of the entrance of foreign particles. The skin covering the tip 

 of the nose is thickened, and furnished with numerous sebaceous follicles, 

 the mouths of which frequently appear like black dots, owing to the adhe- 

 sion of extraneous particles. The secretion of these folhcles may often be 

 forced out in fine long tlii-eads like small worms. 



The cartilages of the nose or fibro-cartilages are five in number, one in 

 the centre, one at each side, and one inferiorly in each ala. The septal or 

 median cartilage is a true cartilage of considerable strength ; it not only 

 separates the nostrils, but also the anterior portions of the nasal fossae. It 

 is inclosed in thick mucous membrane, and is not always vertical, but may 

 project to one side. 



The lateral nasal cartilages are two on each side, superior and inferior. 

 The superior lateral is attached externally and posteriorly to the nasal pro- 

 cess of the superior maxillary bone and to the inferior margin of the nasal ; 

 anteriorly and internally to the opposite one and to the septal cartilage, and 

 inferiorly by fibrous tissue to the inferior cartilages. The inferior lateral or 

 alar cartilages form the upper part of each ala, the tip or lobe and the 

 boundary of the nasal openings. All the lateral cartilages are readily acted 

 on by the superimposed muscles, which can move the whole organ, or alter 

 the shape of the openings, but cannot perfectly close them. 



PL 132, fig. 29, left side of the nose of an adult, the cuticle supposed to 

 be removed for the purpose of more clearly exhibiting the openings of the 

 sebaceous follicles. Fig. 30, lateral view of the bones and cartilages of the 

 nose : a, a, skin of the nose ; 6, left nasal bone ; c, left superior lateral car- 

 tilage ; d^ left alar cartilage with its three appendages, e, / ^, which are 

 attached to each other by the ligaments /?, /, h. Fig. 31, anterior view of 

 the nasal cartilages : a, i, nasal bones ; c, o?, superior lateral cartilages ; e, 

 septum ; fi / small cartilages proceeding from it ; g-o^ alar cartilages with 

 their three appendages. Fig.^ 32, outline view of the preceding figure. 

 Fig. 33, inferior view of the nasal cartilages : a, 6, c, d, outline of the nose ; 

 e, septal or median cartilage; / extremity of the upper jaw to which it is 

 attached ; g-k, alar cartilage of the left side with its three appendages ; ?-o, 

 do. of the right side. Fig. 34, superior lateral cartilage of the nose. Fi<]. 

 35, septal cartilage of the nose. Fig. 36, left alar cartilage. Fig. 37, do. 

 with its three appendages (from without). Fig. 38, do. from within. Figs. 

 39 and 40, the three small cartilaginous appendages, without and within. 



The Nasal Foss^ are bounded by several bones which are covered by 

 a very delicate periosteum ; to the anterior part of the bones of the nose 

 are attached the cartilages already described. These several bones are the 

 nasal, frontal, ethmoid, sphenoid, superior maxillary, palatine, unguis, 

 spongy, pterygoid, and vomerine bones. The external wall of each naris is 



857 



