It has lately been ascertained that, in Prince of Wales's Island, and also in Sumatra, there are trees of a class and order totally different from that above described, which yield a juice similar to this, and applicable to all the same purposes.
254. The CASTOR-OIL PLANT (Ricinus palma christi) is a native both of the East and West Indies, and has a stem from five to fifteen or sixteen feet in height, and large bluish-green leaves, divided into seven lobes, serrated and pointed, the footstalks long, and inserted into the disk.
The flowers are produced in a terminating spike, and the seed-vessels are covered with spines, and contain each three flattish oblong seeds.
It is to the seeds of this plant that we are indebted for the drug called castor-oil. This is sometimes obtained by pressing the seeds, in the same way as is practised with respect to oil of almonds ([152]). But the mode chiefly adopted in the West Indies, whence we principally import it, is first to strip the seeds of their husks or pods, and then to bruise them in a mortar; afterwards they are tied in linen bags, and boiled in water until the oil which they contain rises to the surface; this is carefully skimmed off, strained to free it from any accidental impurities, and bottled for use. The oil which is obtained by boiling is considered more mild than that obtained by pressure, but it sooner becomes rancid. The mildest and finest of the Jamaica castor-oil is limpid, nearly colourless, and has scarcely more taste or smell than good olive-oil.
The uses of castor-oil in medicine are well known.
The plant is sufficiently hardy to grow and ripen its seeds in the open ground of gardens, in the south of England.