--1. By boiling in water. 2. By
expression. 3. Extraction by alcohol. In the first the seeds are
slightly roasted to coagulate the albumen, cleaned of the integuments,
bruised in a mortar, and the paste boiled in pure water. The oil which
rises on the surface is removed, and treated with an additional
quantity of fresh water; 10,000 parts of clean seed give by this
process (in Jamaica) 3,250 of oil, of good quality, though
amber-colored. 2. Expression is the simplest and most usually adopted
process; the cleaned kernels are well bruised, placed in cloth bags,
and compressed in a powerful lever and screw press. A thick oil is
obtained, which must be filtered through cloth and paper to separate
the mucilage. In Bengal the manufacturers boil the oil water, which
coagulates some albumen, and they subsequently filter through cloth,
charcoal, and paper. 3. The extraction by alcohol is practised by some
druggists. Each pound of paste is triturated with four pounds of
alcohol, specific gravity 8.350, and the mixture subjected to
pressure. The oil dissolved by the alcohol escapes very freely: one
half is recovered by the distillation of the spirit, the residue of
the distillation is boiled in a large quantity of water. The oil
separates and is removed, and gently heated to expel any adherent
moisture; then filtered at the temperature of 90 deg. Fahrenheit;
1,000 parts of the paste have by this process given 625 of colorless
and exceedingly sweet oil.

The cultivation of the _Palma christi_, and the manufacture of castor
oil, is extensively carried on in some parts of the United States, and
continues on the increase. A single firm at St. Louis has worked up
18,500 bushels of beans in four months, producing 17,750 gallons of
oil, and it is stated that 800 barrels have been sold, at 50 dollars
per barrel. The oil may be prepared for burning, for machinery, soap,
&c., and is also convertible into stearine. It is more soluble in
alcohol than lard-oil.

American castor oil is imported for the most part from New York and
New Orleans, but some comes from our own possessions in North America.
In the United States, according to the "American Dispensatory," the
cleansed seeds are gently heated in a shallow iron reservoir, to
render the oil liquid for easy expression, and then compressed in a
powerful screw press, by which a whitish oily liquid is obtained,
which is boiled with water in clean iron boilers, and the impurities
skimmed off