1 26 
MR. YOUATT S VETERINARY LECTURES. 
sometimes a few of them may be traced down to the lower 
lip. 
The third Branchy in the order of its being given off, is the den¬ 
tal nerve . This is generally considered as the continuation of 
the main trunk of the nerve. It passes across the pterigoideus, 
and enters a canal, the dental canal, on the inner face of the 
lower jaw-bone, near the upper edge, and at the bending or angle 
of the jaw. It takes its course along the interior of the bone, 
close to the roots of the teeth, and gives branches to each of 
them as it passes. Emerging through the lower maxillary fora¬ 
men, it divides into two branches, one of which is spent in nu¬ 
merous ramifications on the outside of the lower lip, and the 
other in fewer ramifications on the inside of the lip. These are 
evidently sensitive fibrils, and the power of motion is derived from 
the seventh pair. 
The fourth Branch in point of order, but which does not enter 
into the dental canal, is the gustatory or lingual nerve , and 
it is the largest of the four. It is singularly fiat, like a little 
riband. It runs along the inside of the lower jaw, and a portion 
of it enters a foramen in the jaw to supply the roots of the inci¬ 
sor teeth with nervous influence ; but the main nerve, proceeding 
obliquely downward, gives fibrils to the submaxillary glands, 
and to the glands and muscles at the base of the mouth gene¬ 
rally. These fibres form true plexuses about the salivary glands 
and the muscles of the tongue ; they anastomose freely with the 
twelfth pair (the linguales or motor nerve of the tongue), as this 
nerve had previously done with the seventh pair (the portio 
dura). The gustatory branch penetrates the substance of the 
tongue, between the stylo and genio-glossal muscles ; it passes 
obliquely to the surface of the tongue, and terminates in the pa¬ 
pillae ; and these papillae, thus endowed with nervous influence, 
are the seat of the sense of taste. 
Theffth a Compound Nerve. —It appears then that the fifth 
nerve has a double origin and a double function; —the larger por¬ 
tion, and that which passes through a ganglion, is derived from the 
superior surface of the supposed prolongation of the spinal chord ; 
and the smaller, and the ganglionless, springs from the inferior 
sinj ace. The portion with the ganglion is devoted to sensation ; 
that ivhich afterwards joins it is connected with motion; and 
thus the same sheath contains sensitive and motor fibrils, and the 
;nerve is devoted to the double purpose of sensation and voluntary 
motion. The sensitive root, however, is so much larger than the 
other, and the sensitive fibrils so much more numerous, that it may 
still be called the sensitive nerve of the face ; and upon mature 
examination we are assured that it is the only nerve of the brain 
