152 ANTHROPOLOGY. 
deeply grooved by three fossz, 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 ¢nferior 
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 infundibulum, 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 medtus. Hach 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 
lined 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. Ifthe breath be held, no perception of odor takes place, and if a piece 
of camphor be held in the closed month 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. 
Pl. 182, fig. 27 a, a portion of the Schneiderian membrane with its nerves 
of natural size; jig: 27, 6, the same magnified three diameters: a, 6, dura 
mater; c—/f, section of the Schneiderian membrane; g, g, section of the 
eribriform plate of the ethmoid bone; h, /, foramina in it for the transmis- 
sion of nervous filaments; 7, branch of the olfactory nerve, cut off to show 
the following branch % with the manner of its escape from the dura mater 
1, and the passage of the nerve through the bone m; n, 0, p, arteries of the 
Schneiderian membrane. /g. 26,-distribution of the olfactory nerve on 
the septum of the nose: a, b, c, d, nerves of the olfactory; e, nervous branch 
from the fifth pair; f, g, superior posterior nasal nerves from the second 
branch of the fifth pair; h, superior cutaneous nasal nerve, from the infra- 
orbital nerve; 7, &, apparent boundary of the branches of the olfactory 
nerve. Fg. 28, nervous plexus of the linmg membrane of the nose: *~, 
basal extremities of the first eight cerebral nerves; a—d, olfactory bulbs 
with their threads, ****, passing through the ecribriform plate; °®”, larger 
portion of the fifth pair of nerves; e, fg, first branch of the fifth pair. 
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