CHAPTER XIII. 



Sense of smell. Olfactory organs. Nose; nasal fossa ; turbinated bones, 

 pituitary membrane. Olfactory nerve. Odoriferous principles; their de- 

 velopment, their action on the nervous system. Smell, its seat; dura- 

 tion of olfactory impressions. Uses, and acuteness of smell. 



Olfactory organs. The smelling apparatus is situated in 

 the middle of the "face, between the orbital cavities and the 

 palatine arch. Placed thus above the organ of taste, which 

 it resembles in many respects, it forms the entrance to the 

 respiratory passages, and controls to a certain extent the 

 purity of the air which enters them. It is composed of the 

 nose and the nasal fossae. 



The nose. Two thin, flattened bones, slightly curved in 

 their breadth, form the superior portion of the nose. They 

 are articulated by their internal border in the median line; 

 at their external border they are united to the ascending 

 processes of the upper jaw, and they are attached at the root 

 of the nose by sutures to the frontal bone. Their inferior 

 borders are attached to the cartilages which complete the 

 nasal walls. The arch formed by the nasal bones is sup- 

 ported by a bony partition, to which is attached a cartila- 

 ginous plate, which divides the nasal cavity into two symmet- 

 rical halves, and separates the nostrils. A delicate skin 

 envelops the nose and covers its little muscles, which are 

 more important from a physiognomical point of view than 

 from their organic functions. 



Nasal fossa. This is the name applied to two irregular 

 cavities which are continuous with the nasal cavities; they 

 rest against each other on the median line, and are bounded 

 below by the palatine arch, and above by the cribriform 



