274 COMPARATIVE ANATOMY AND PATHOLOGY. 
which result from the convolutions ; but, even there, the parietes 
are of wondrous thinness. They are elastic in the living animal, 
but exceedingly brittle in the dead one. 
This bone is so placed as to form a division between the nasal 
cavity and the maxillary sinuses, and to render them distinct 
cavities ; and, probably, distinct in their office, and as well in 
their situation. There is a communication between them under 
the valve-like prolongation of the lower cell of the superior turbi- 
nated bone. 
The Cavities communicating with the Nose. — This, perhaps, 
may be the proper place to hint, that I believe, with Sir Busick 
Harwood, that the sinuses which surround the internal nares, the 
maxillary, the sphenoidal, and the frontal have nothing to do with 
the sense of smell. No prolongation of the olfactory nerve has 
been traced into one of these cavities. Each of them communicates 
with the nostril by a single aperture, and by that alone. A free 
current of air is evidently necessary for the perception of scent, which 
we occasionally prove, when, half-sickened by some nauseous 
stench, we close the nostrils, continuing to breathe through the 
mouth, and the posterior communication between the nose and the 
mouth remaining open. No smell is then perceived, and, indeed, 
it is difficult to conceive that a stream of air, diverted from its 
natural course, should make a circuit of such cavities, at the same 
instant passing and repassing in opposite directions through the 
narrow channel*. 
The inferior Turbinated Bone . — This is more porous than the 
superior one ; and, although simple — compared with that of carni- 
vorous animals — is far more convoluted and complicated than the 
superior one. It is farther removed from the origin of the nerve, 
and therefore a greater extent of surface is contrived, in order that 
the impression may still be lively and distinct. The gauze-like 
perforated structure of this bone is deserving of notice. Being 
somewhat more exposed to danger than the upper turbinator, 
peculiar means are taken for its security. The lower portion of 
the upper turbinated bone hangs comparatively loose in the nasal 
cavity, but the inferior turbinated bone is attached to the superior 
maxillary bone, as well as to the nasal. Neither of them, how- 
ever, can be separated from the bony parietes of the cavity by 
maceration, but they are too readily broken off in our dry pre- 
parations. 
There is a singular prolongation of this bone over the inner ala 
of the false nostril, and which may be readily seen by lifting the 
nostril. It is a hollow bony pedicle, which has more than once 
* Sir B. Harwood’s Comparative Anatomy, p. 15. 
