DERIVATION.--A mixture of hydrocarbons, chiefly of the methane series,
obtained by distilling off the lighter and more volatile portions from
petroleum and purifying the residue.
PROPERTIES.--A white, unctuous mass, of about the consistency of an
ointment, transparent in thin layers, completely amorphous; without odor
or taste. Otherwise it resembles, in solubility, petrolatum.
ACTION.--All preparations of petrolatum are valuable emollients. They
soothe, protect and soften parts to which they are applied and are
superior to animal or vegetable fats or oils in not becoming rancid.
USES.--Petrolatum may be used alone, or as an excipient in the
preparation of ointments, but does not aid the absorption of drugs (as
do alcohol, glycerine, chloroform, animal oils and fats), for it is not
itself absorbed even when administered internally. Petrolatum exerts a
demulcent action upon the mucous membrane of the alimentary tract, and
may be prescribed in electuary or capsule in inflammation thereof.
Liquid petrolatum is useful given internally in piles (dogs one-half
ounce twice daily) to soften the feces. It is also very serviceable with
menthol and camphor (equal parts, fifteen grains to one ounce) dropped
in the nostrils (with a medicine dropper) for dogs with acute nasal
catarrh. Petrolatum is sold universally under the proprietary names of
vaseline and cosmoline, and is often combined with antiseptics for
medical and surgical purposes in skin diseases and upon inflamed mucous
membranes, blisters and abraded surfaces and sores. It is one of the
most useful agents in lubricating instruments, protecting metal from
rust, and is sometimes employed as a vehicle for electuaries. It should
not be used as a base for blisters or other ointments where absorption
is desired.