630 ANIMAL PHYSIOLOGY. 
and the food not readily retained in the mouth. Speech is 
affected from paralysis of the lips, ete. 
Secretory fibers proceed (1) to the parotid gland by the super- 
ficial petrosal nerve, thence (2) to the otic ganglion, from which 
the fibers pass by the auriculo-temporal nerve to the gland. 
Gustatory Fibers.— According to some, the chorda tym- 
pani really supplies the fibers to the lingual nerve that are con- 
cerned with taste. 
It will thus be seen that the facial nerve has a great variety 
-of important functions, and that paralysis may be more or less 
serious, according to the number of fibers involved. 
The Trigeminus, Trifacial, or Fifth Nerve.—This nerve has very 
extensive functions. It is the sensory nerve of the face; but, 
as will be seen, it is peculiar, being a combination of the motor 
and sensory, or, in other words, has paths for both afferent and 
efferent impulses. The motor and less extensive division arises 
from a nucleus in the floor of the fourth ventricle. The sen- 
sory, much the larger, seems to have a very wide origin. The 
nerve-fibers may be traced from the pons Varolii through the 
medulla oblongata to the lower boundary of the olivary body 
and to the posterior horn of the spinal cord. This origin sug- 
gests.a resemblance to a spinal nerve, the motor root corre- 
sponding to the anterior, and the sensory to a posterior root, 
the more so as there is a large ganglion connected with the 
sensory part of the nerve within the brain-case. 
Efferent Fibers.—1. Motor.—To certain muscles (1) of mas- 
tication—temporal, masseter, pterygoid, mylohyoid, and the 
anterior part of the digastric. 2. Seeretory.—To the lachrymal 
gland of the ophthalmic division of this nerve. 3. Vaso-motor. 
—Probably to the ocular vessels, those of the mucous mem- 
brane of the cheek and gums, etc. 4. Trophic_——From the re- 
sults ensuing on section of this nerve, it has been maintained 
that it contains special trophic fibers. We have discussed this 
subject in an earlier chapter. 
Afferent Fibers—1. Sensory.—To the entire face. To par- 
ticularize regions: 1. The whole of the skin of the face and 
that of the anterior surface of the external ear. 2. The external 
auditory meatus. 3. The mucous lining of the cheeks, the floor 
of the mouth, and the anterior region of the tongue. 4. The 
teeth and periosteum of the jaws. 5. The lining membrane of 
the entire nasal cavity. 6. The conjunctiva, globe of the eye, 
and orbit. 7. The dura mater throughout. 
Many of these afferent fibers are, of course, intimately con- 
