6 MR. youatt’s veterinary lecturer. 
of the mischief, by cutting off all communication with the neigh¬ 
bouring parts; and also to preserve one nostril pervious, when 
the other is diseased or obstructed. It would appear as if there 
were design in this—as if that dreadful malady, which our absurd 
management of this noble quadruped has entailed upon him, had 
been foreseen, and in some degree provided against. The horse 
and the ass alone are subject to glanders, and in them alone is 
the division between the nostrils perfect. From the separation of 
the vomer from the palate there is a communication between the 
cavities far below the crescental border in cattle and sheep , while 
in the hog the perfect division scarcely extends more than half 
way along the nostril. There is a sufficient division to cut off 
the communication of inflammation or other disease from one 
nostril to another under ordinary circumstances; and where this 
pest of the equine race is concerned, the division is perfect. 
Where it is left imperfect by the separation of the vomer from the 
floor, and the consequent impairment of strength, there is provi¬ 
sion made for the security of the part in the broad expanse of the 
forehead in the ox and the sheep, and on which the blow would 
be more likely to fall than on the nasals; and in the form and the 
nature of the connexion of the nasals with the neighbouring 
bones, and also in the strength of those bones in the hog and the 
d°g- 
The Mthmoid Bones. —We arrive at length at the contents of 
the nasal cavity. • Posteriorly and superiorly, on each side, in 
the common duct, but scarcely reaching into the closedv nostril, 
is the mthmoid bone, or that portion of it which may be termed 
the (ethmoidal cells. On the upper and anterior part of the mth¬ 
moid bone in the horse there is a somewhat curved projection or 
eminence, possessing no indistinct resemblance to the forepart of 
the comb of a cock, and hence called the crista galli. It sup¬ 
ports the perpendicular plate of the skull before, and the falciform 
process of the dura mater behind: on either side of it, and sup¬ 
ported by it, are two thin plates of bone pierced with innumera¬ 
ble holes—the cribriform plates of the mthmoid bone—and 
through which pass the pulpy filaments of the olfactory nerve. 
From the bony arch which surrounds this plate, arises a pear- 
shaped collection of thin, porous, bony cells. I feel some diffi¬ 
culty in describing them. Conceive a great number of little hol¬ 
low pedicles proceeding from, and forming around, the cribriform 
plate. As they move downward they belly out into distinct vesi¬ 
cles or cavities ; smaller and more numerous behind ; fewer in 
number, and larger in front, and each of them, not a simple ca¬ 
vity, but more or less convoluted; while the bony walls of these 
cells is of gossamer thinness, and porous as any gauze. All of 
