Sense of smell. Olfactory organs.—Nose; nasal fossa, turbinated bones, pituitary membrane.—Olfactory nerve.—Odoriferous principles; their development, their action on the nervous system.—Smell,—its seat; duration of olfactory impressions.—Uses, and acutencss of smell.
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 fossæ.
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 supported by a bony partition, to which is attached a cartilaginous plate, which divides the nasal cavity into two symmetrical 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.