THE SCHNEIDERIAN MEMBRANE. 37 
sinuosities of the passages, and the air lingering in them, the 
sense of smell is possibly more acute and faithful. 
These are mucous membranes. Then their first and distin¬ 
guishing characteristic under inflammation is, increased mucous 
secretion, and that often assuming a purulent form. This in¬ 
creased secretion, under inflammation, is a beautiful provision of 
nature: it warns us of the presence of the evil, it relieves the 
engorged vessels, and it covers and defends them from those 
painful impressions to which their increased sensibility would ex¬ 
pose them. 
The mucous membrane of the nose, although smooth and soft, 
is covered by innumerable papillae. On the superior portion 
of the nasal cavity, both on the septum and the aethmoid bone, 
they are particularly evident. These have nothing to do with 
secretion or exhalation; they are connected with the sensation of 
the part; they are the terminations of the nerves, whether of pe¬ 
culiar or common sensation. These papillae are smaller than, in 
most mucous surfaces—small indeed when compared with those 
on the tongue. Continually exposed to rapid currents of air, 
and to the influence of pungent gases, and to extreme variations 
of temperature, little common sensibility was wanted, it was only 
needed that the sense of smell should be acute in a degree cor¬ 
responding with the situation and habits of the animal. If the 
papillse, however, are not large, they are more numerous than on 
other membranes, the olfactory nerve is more spread over the sur¬ 
face than terminating in fibriculi. 
The nasal cavity is plentifully supplied with bloodvessels, and 
particularly from the lateral nasal branch of the internal maxil¬ 
lary artery, which enters through the eethmoidal cells, to be dis¬ 
tributed chiefly over the membrane of the septum. Other branches 
ramify on the sethmoid and turbinated bones ; and the lower part 
of the nostrils is indebted to the facial artery and to the palato 
maxillary. 
The Schneiderian Membrane , as indicating Inflammatory 
Action in the Respiratory Passages. —The mucous membrane of 
the nose is distinguished from other mucous surfaces, not only by 
its thickness, but its vascularity. The bloodvessels are likewise 
superficial ; they are not covered even by integument, but merely 
by an unsubstantial mucous coat. They are deeper seated, in¬ 
deed, than in the human being, and they are more protected from 
injury; and, therefore, there is far less haemorrhage from the 
nostril of the horse than from that of the human being, whether 
spontaneous or accidental. Lying immediately under the mucous 
coat, these vessels give a peculiar, and, to us, a most important 
tinge to the membrane, and particularly observable on the sep- 
