The function of this secretion is to preserve the brilliancy of the eye.
The tears are spread over this organ by the reflex movement of the
eyelid, called winking, and then collected in the _puncta lachrymalia_
and discharged into the nasal passage. This process is constant during
life. The effect of its repression is seen in the dim appearance of the
eye after death. Grief or excessive laughter usually excite these glands
until there is an overflow.

SEBACEOUS MATTER. Three varieties of this secretion are found in the
body. A product of the sebaceous glands of the skin is found in those
parts of the body which are covered with hairs; also, on the face and
the external surface of the organs of generation. The _sebaceous glands_
consist of a group of flask-shaped cavities, opening into a common
excretory duct. Their secretion serves to lubricate the hair and soften
the skin. The _ceruminous glands_ of the _external auditory meatus_, or
outer opening of the ear, are long tubes terminating in a glandular
coil, within which is secreted the glutinous matter of the ear. This
secretion serves the double purpose of moistening the outer surface of
the membrana tympani, or ear-drum, and, by its strong odor, of
preventing the intrusion of insects. The _Meibomian glands_ are arranged
in the form of clusters along the excretory duct, which opens just
behind the roots of the eyelashes. The oily nature of this secretion
prevents the tears, when not stimulated by emotion, from overflowing the
lachrymal canal.

MUCUS. The mucous membranes are provided with minute glands which
secrete a viscid, gelatinous matter, called _mucus_. The peculiar animal
matter which it contains is termed _mucosin_. These glands are most
numerous in the Pharynx, Esophagus, Trachea, Bronchia, Vagina and
Urethra. They consist of a group of secreting sacs, terminating at one