Page:The American Cyclopædia (1879) Volume XII.djvu/530

 516 NOSE the third the duct of the nasal canal which conveys the tears from the eyes to the nose ; from the last also the Eustachian tube, by which the tympanic cavity of the ear communicates with the throat, may be most easily entered, as is frequently necessary in aural surgery ; the septum or inner wall is a thin vertical partition situated upon the median line, and separating the nasal passages on the right side from those on the left. The suture of the nasal bones in man remains ununited generally until very late in life, in this differing from the condi- tion in the highest apes, in which they are very early consolidated into a single bone with hardly a trace of suture 5 their inner border is also elevated, so that the depressed nose of the negro has never the flatness of that of the go- rilla and chimpanzee. The external prominent part of the nose, which gives the character to the feature, is composed of several cartilages, connected to the bones and to each other by strong fibrous tissue, sufficiently firm to pre- serve the shape of the organ, and so elastic and flexible as to permit the expansion and contrac- tion of the nostrils in respiration; at the tip of most noses, on the median line, may be felt a fossa or depression bounded on each side by the lateral cartilages, which, with the absence of rigidity, some ethnologists have made char- acteristic of certain human races, like the Ma- lay and negro. The varying expression given to the face by the movements of the nose depends on the action of its muscles, attached to the cartilages, skin, and upper lip ; most of the expressions arising from these movements are disagreeable, indicating either contempt, anger, fear, or pain. The openings of the nose are provided with stiff curved hairs, which prevent the entrance of many particles floating in the air. The mucous membrane lining the nasal passages is of two kinds, viz. : the Schnei- derian membrane, occupying the lower portion, FIG. 1. Olfactory Membrane of the Sheep, in vertical section. a. Epithelium. &, &. Fibres of the olfactory nerve, c. Mu- cous follicle, d. Orifice of the mucous follicle. and the olfactory membrane, occupying the upper portion. The Schneiderian membrane is covered with ciliated epithelium, is provided with compound mucous glandules, and supplied with nerves of ordinary sensibility from the nasal branch of the ophthalmic division of the fifth pair; it is to be considered as forming a part of the respiratory surfaces. The olfactory membrane is covered with non-ciliated epithe- lium, provided with simple, nearly straight mucous follicles, and supplied with filaments from the olfactory nerve; it constitutes the organ of the special sense of smell. The soft FIG. 2. Profile View of the Nasal Passages. a. Superior turbinated bone, covered by its mucous mem- brane, b. Middle do. c. Inferior -do. d. Horizontal or hard palate. olfactory nerves or nerves of smell arise from the olfactory lobules, which rest, in the inte- rior of the cranium, upon the cribriform plate of the ethmoid bone; the nerves then pierce the ethmoid bone and reach the nasal cavities, FIG. 3. Transverse Section of the Nasal Passages. Or. Cribriform plate of the ethmoid bone, upon which rest the olfactory lobules and through which pass the fila- ments of the olfactory nerves. 8. T. Superior turbinated bone. M. T. Middle turbinated bone. / T. Inferior tur- binated bone. An. Antrum of the superior maxillary bone. Sp. Septum of the nares. PL Hard palate. being finally distributed to the olfactory mem- brane upon the upper part of the septum, and upon the superior and middle turbinated bones. The nose forms one of the characteristic fea- tures of the human face, and by physiogno- mists has been regarded as a faithful index of character. The sense of smell is less developed than that of sight in man, and in comparison with that of some other animals is very feeble, and the more so in proportion to the elevation of the race in the scale of civilization ; the blind have a more acute sense of smell to compen- sate for the deficiency of sight ; the Mongolian,