7 
NASAL CAVITY IN THE HOUSE, &C. 
them communicate together, and are lined and externally wrapped 
together by the same membrane, the whole assuming a pear-like 
shape, attached by its base or greater extremity ; decreasing in 
size as it proceeds downward; the cells becoming fewer; and ter¬ 
minating at length in one cell, a kind of pedicle or stalk, and 
which passes under the superior turbinated bone, and communi¬ 
cates with the central meatus, and forms a kind of valve over the 
opening between the nasal cavity &nd the maxillary sinuses. 
Then if you add that the olfactory or first pair of nerves abuts 
upon these cribriform plates, and passes through their minute 
openings, and spreads itself over every one of these cells, but 
thicker and more evident to the eye near the cribriform plate, you 
have a tolerably correct picture of this portion of the sethmoid 
bone. 
This bone has different degrees of development in different ani¬ 
mals, in proportion to their acuteness of smell. The ox is not so 
domesticated an animal as the horse. He has more occasion for 
acuteness of smell than the horse, and particularly in the early 
part of the spring, when the plants are young, and have not ac¬ 
quired their peculiar scent, therefore this portion of the sethmoid 
bone is much larger in him than in the horse. In the sheep it is 
large, and seems to fill the superior portion of the nasal cavity. 
It is even more developed in the swine than in the horse; but in 
the dog it seems to occupy the cavity almost to the exclusion of 
the turbinated bones. Being nearer to the cribriform plate than 
they are, it is probably most concerned in the sense of smell, and 
therefore larger where acuteness of smell, is required, and in pro¬ 
portion as it is required. It is much more fragile in the dog 
than in the ox, and the plates have a considerably thinner struc¬ 
ture. The sethmoid bone of the horse or the ox may be removed 
from its situation with little injury, but that of the dog can scarcely 
be meddled with without fracture. 
The turbinated Bones. —Below the sethmoid are the two turbi¬ 
nated bones. The superior turbinated bone in the horse seems to 
be almost a continuance of the sethmoid. It is oblong and con¬ 
voluted, and thence its name, turbinated or turban-shaped. The 
French call these bones comets , from their convolutions. It pre¬ 
sents a labyrinth of cavities, divided into cells by curious thin 
septa, and all of them communicating with each other; and the 
parietes being thin, porous, elastic, in the living animal, and ex¬ 
ceedingly brittle in the dead one. 
It is so placed as to form a division between the nasal cavity 
and the maxillary sinuses. It is that which renders them sepa¬ 
rate cavities, and there is a communication between, as l have 
