Palma Christi, _Ricinus communis_, belonging to the natural
order Euphorbiaceae. The botanical name is from Lat. _ricinus_, a tick,
from the form and markings of the seed. The plant is a native of
tropical Africa, but it has been introduced, and is now cultivated in
most tropical and in the warmer temperate countries. In size it varies
from a shrubby plant to a tree of from 30 to 40 ft. in height according
to the climate in which it grows, being arborescent in tropical
latitudes. On account of its very large beautiful palmate-peltate
leaves, which sometimes measure as much as 2 ft. in diameter, it is
cultivated as an ornamental plant. In the south of England, with the
habit of an annual, it ripens its seeds in favourable seasons; and it
has been known to come to maturity as far north as Christiania in
Norway. Plants are readily grown from seed, which should be sown singly
in small pots and placed in heat early in March. The young plants are
kept under glass till early in June when they are hardened and put out.
The fruit consists of a three-celled capsule, covered externally with
soft yielding prickles, and each cell develops a single seed. The seeds
of the different cultivated varieties, of which there are a great
number, differ much in size and in external markings; but average seeds
are of an oval laterally compressed form, with their longest diameter
about four lines. They have a shining, marble-grey and brown, thick,
leathery outer coat, within which is a thin dark-coloured brittle coat.
A large distinct leafy embryo lies in the middle of a dense, oily tissue
(endosperm). The seeds contain a toxic substance, which makes them
actively poisonous; so much so that three have been known to kill an
adult.

The oil is obtained from the seeds by two principal methods--expression
and decoction--the latter process being largely used in India, where the
oil, on account of its cheapness and abundance is extensively employed
for illuminating as well as for other domestic and medicinal purposes.
The oil exported from Calcutta to Europe is prepared by shelling and
crushing the seeds between rollers. The crushed mass is then placed in
hempen cloths and pressed in a screw or hydraulic press. The oil which
exudes is mixed with water and heated till the water boils, and the
mucilaginous matter in the oil separates as a scum. It is next strained,
then bleached in the sunlight, and stored for exportation. A
considerable quantity of ca