400 
MR. YOUATT’S VETERINARY LECTURES, 
DELIVERED AT THE UNIVERSITY OF LONDON. 
LECTURE XVI. 
The Velum Palati, and Os Hyoides . 
Now, gentlemen, proceeding beyond the simple cavity of the 
nose, I must entreat your attention to a little anatomical detail : 
it shall be short, strictly confined to physiology or to practice ; for 
I have too much to do in this short course, embracing the dis¬ 
eases of so many kinds of patients, to indulge in any inquiry, 
however otherwise interesting, which has no practice for its scope 
and object. 
Attached to the crescent-shaped border of the palatine bone, 
you perceive a dense membranous curtain, a duplicature of mem¬ 
brane with interposed cellular and glandular and muscular sub¬ 
stance. Its superior face is a continuation of the lining membrane of 
the nose ; its inferior one that of the palate. It is called the 
velum palati, the veil of the- palate : it hangs as a curtain or veil 
at the back of the palate. 
It is attached to the whole of the crescentic border of the 
palatine bone, and also to the sides of the ductus communis 
narium , and likewise, a3 you will perceive, to the side even of the 
dorsum of the tongue ; and it extends backward as far as the 
larynx, and lies upon, and in contact with, the dorsum of the 
epiglottis. So that you plainly see, in its natural loose pendant 
state, it is a perfect veil, or curtain, interposed between the cavity 
of the nose and the mouth, and cutting off all communication. 
The Horse breathes only through the Nose. —The portion which 
lies upon the epiglottis is, to a certain degree, loose; but so tied 
down by this long attachment, which you trace anteriorly, and 
also by muscles which I shall presently describe, that it will open 
but a little way, and in one direction only : it will open to let the 
pellet of food pass into the oesophagus, and it will close when any 
pressure is made upon it from behind: so that two singular facts 
necessarily follow. The first is, that the horse breathes through his 
nose alone ; and this will account for the complicated mechanism 
of muscle, and elastic cartilage and membrane, which we have 
already described, around the nostril, and which so beautifully 
expands it when, in rapid progression, a larger supply of air is 
required ; and also the adaptation of the construction of the nostril 
to the different purposes for which the different breeds of horses 
are intended. If the nostrils are the only apertures through 
which the air can be admitted, they must be capacious, and easily 
