ain
a clear, insipid liquid; afterwards it becomes milky and sweet,
and changes by degrees until it becomes hard as ivory. Animals eat
the fruit in its young green state; a sweet oily pulp incloses the
seeds, and is collected and sold in the markets under the name of
Pipa de Jagua. Vegetable ivory may be distinguished from animal
ivory by means of sulphuric acid, which gives a bright red color
with the vegetable ivory, but none with the animal ivory.

342. PICRASMA EXCELSA.--This yields the bitter wood known as Jamaica
Quassia. The tree is common in Jamaica, where it attains the
height of 50 feet. The wood is of a whitish or yellow color, and
has an intensely bitter taste. Although it is used as a medicine
in cases of weak digestion, it acts as a narcotic poison on some
animals, and the tincture is used as fly poison. Cups made of this
wood, when filled with water and allowed to remain for some time,
will impart tonic properties to the water.

343. PINCKNEYA PUBENS.--This cinchonaceous plant is a native of the
Southern States and has a reputation as an antiperiodic. It is
stated that incomplete examinations have detected _cinchonine_ in
the bark. It has been used successfully as a substitute for
quinine. A thorough examination of this plant seems desirable so
that its exact medical value may be ascertained.

344. PIPER BETEL.--This plant belongs to the _Piperaceae_. Immense
quantities of the leaves of this plant are chewed by the Malays.
It tinges the saliva a bright red and acts as a powerful stimulant
to the digestive organs and salivary glands; when swallowed it
causes giddiness and other unpleasant symptoms in persons
unaccustomed to its use.

345. PIPER NIGRUM.--This twining shrub yields the pepper of commerce.
It is cultivated in the East and West Indies, Java, etc., the
Malabar being held in the highest esteem. The fruit when ripe is
of a red color, but it is gathered before being fully ripe and
dried in the sun, when it becomes black and shriveled. White
pepper is the same fruit with the skin removed. When analyzed,
pepper is found to contain a hot acrid resin and a volatile oil,
as well as a crystalline substance called _piperin_, which has
been recommended as a substitute for quinine.

346. PISTACIA LENTISCUS.--