152 ANTHROPOLOGY. 



deeply grooved by three fossoe, the superior, middle, and inferior meatus ; 

 these are situated between the spongy bones, the middle being the widest. 

 The nasal or lachrymal duct opens into the anterior third of the inferior 

 meatus, the Eustachian tube behind. Into the middle meatus the antrum 

 maxillare opens by a small oblique slit, in front of which is a groove named 

 the infundibulura, leading from the frontal sinus ; into this groove the ante- 

 rior ethmoidal cells open. The posterior ethmoidal cells and the sphenoid 

 sinuses open into the upper meatus. Each naris opens posteriorly into the 

 pharynx above the velum, by an oblong oval opening, separated from each 

 other by the vomer. 



All the internal surface of the nose and of the communicating sinuses is 

 Kned by a soft, vascular, and highly sensitive mucous membrane ; this is 

 the pituitary or Schneiderian membrane. The olfactory nerves are distributed 

 to it on the septum and ethmoidal region in the form of numerous plexuses ; 

 it is also supplied on each side and on the septum with branches from the 

 ophthalmic and superior maxillary divisions of the fifth pair. The olfactory 

 or first pair of nerves endow the superior portion of this membrane with its 

 peculiar sense or power of smelling; while its general acute sensibility 

 depends on the fifth pair, the general nerve of feeling of the head. 



Such bodies can alone be considered as capable of imparting the sensation 

 of smell as are capable of being vaporized or dissolved in the atmosphere. 

 The essential conditions of smell, however, are not yet satisfactorily ascer- 

 tained ; so much is certain, that the odorous particles must come in contact 

 with the nerves, and especially by being inhaled in ordinary nasal respira- 

 tion. If the breath be held, no perception of odor takes place, and if a piece 

 of camphor be held in the closed mouth during nasal exhalation, compara- 

 tively little odor will be perceived. The particles of matter, nevertheless, 

 do not come into immediate contact with the nerves, since the mucus of the 

 nose is interposed, together with the basement membrane of the Schneide- 

 rian. It may be that solution in the mucus is necessary to this sense, as 

 when the nasal passages are dry it is much enfeebled. 



PI. 182, fig. 27 a, a portion of the Schneiderian membrane with its nerves 

 of natural size ; fig. 27, Z>, the same magnified three diameters : a, 6, dura 

 mater ; c — ^ section of the Schneiderian membrane ; g, g, section of the 

 cribriform plate of the ethmoid bone ; h, h, foramina in it for the transmis- 

 sion of nervous filaments ; i, branch of the olfactory nerve, cut off to show 

 the following branch h with the manner of its escape from the dura mater 

 Z, and the passage of the nerve through the bone m ; n, o, p, arteries of the 

 Schneiderian membrane. Fig. 26, distribution of the olfactory nerve on 

 the septum of the nose : o, h, c, d, nerves of the olfactory ; e, nervous branch 

 from the fifth pair ; / g, superior posterior nasal nerves from the second 

 branch of the fifth pair ; h, superior cutaneous nasal nerve, from the infra- 

 orbital nerve ; i, k, apparent boundary of the branches of the olfactory 

 nerve. Fig. 28, nervous plexus of the lining membrane of the nose : '"*, 

 basal extremities of the first eight cerebral nerves ; a — d, olfactory bulbs 

 with their threads, "• ", passing through the cribriform plate; ""''', larger 

 portion of the fifth pair of nerves ; e, f, g, first branch of the fifth pair. 

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