_Semen Cataputiæ majoris_; _Castor Oil Seeds_, _Palma Christi Seeds_;
F. _Semence de Ricin_; G. _Ricinussamen_.
=Botanical Origin=—_Ricinus communis_ L., the castor oil plant, is a
native of India where it bears several ancient Sanskrit names.[2104] By
cultivation, it has been distributed through all the tropical and many
of the temperate countries of the globe. In the regions most favourable
to its growth, it attains a height of 40 feet. In the Azores, and the
warmer Mediterranean countries as Algeria, Egypt, Greece, and the
Riviera, it becomes a small tree, 10 to 15 feet high; while in France,
Germany, and the south of England, it is an annual herb of noble
foliage, growing to a height of 4 or 5 feet. In good summers, it ripens
seeds in England and even as far north as Christiania in Norway.
_Ricinus communis_ exhibits a large number of varieties, several of
which have been described and figured as distinct species. Müller,
after a careful examination of the whole series, maintains them as
a single species, of which he allows 16 forms, more or less well
marked.[2105]
=History=—The castor oil plant was known to Herodotus who calls it
Κίκι, and states that it furnishes an oil much used by the Egyptians,
in whose ancient tombs seeds of Ricinus are, in fact, met with.[2106]
At the period when Herodotus wrote, it would appear to have been
already introduced into Greece, where it is cultivated to the present
day under the same ancient name.[2107] The _Kikajon_ of the Book of
Jonah, rendered by the translators of the English Bible _gourd_, is
believed to be the same plant. Κίκι is also mentioned by Strabo as a
production of Egypt, the oil from which is used for burning in lamps
and for unguents.
[2104] The most ancient and most usual is _Eranda_; this word has
passed into several other Indian languages.
[2105] De Candolle, _Prodr._, xv. sect. 2. 1017.
[2106] _Journ. of Botany_, 1879, 54.
[2107] Heldreich, _Nutzpflanzen Griechenlands_, Athen, 1862. 58.
Theophrastus and Nicander give the castor oil plant the name of Κρότων.
Dioscorides, who calls it Κίκι or Κρότων, describes it as of the
stature of a small fig-tree, with leaves like a plane, and seeds in a
prickly pericarp, observing that the name Κρότων is applied to the seed
on account of its resemblance to an insect [_Ixodes Ricinus_ Latr.],
known by that appellation. He also gives an account of the process for
extracting castor oil (Κίκινον ἔλαιον), which he says is not fit for
food, but is used externally in medicine; he represents the seeds as
extremely purgative. There is a tolerably correct figure of _Ricinus_
in the famous MS. Dioscorides which was executed for the Empress
Juliana Anicia in A.D. 505, and is now preserved in the Imperial
Library at Vienna.
The castor oil plant was cultivated by Albertus Magnus, Bishop of
Ratisbon, in the middle of the 13th century.[2108] It was well known as
a garden plant in the time of Turner (1568), who mentions the oil as
_Oleum cicinum vel ricininum_.[2109] Gerarde, at the end of the same
century, was familiar with it under the name of _Ricinus_ or _Kik_. The
oil he says is called _Oleum cicinum_ or _Oleum de Cherua_,[2110] and
used externally in skin diseases.
After this period the oil seems to have fallen into complete
neglect, and is not even noticed in the comprehensive and accurate
_Pharmacologia_ of Dale (1693). In the time of Hill (1751) and Lewis
(1761) Palma Christi seeds were rarely found in the shops, and the oil
from them was scarcely known.[2111]
In 1764 Peter Canvane, a physician who had practised many years in the
West Indies, published a “_Dissertation on the Oleum Palmæ Christi,
sive Oleum Ricini; or (as it is commonly call’d) Castor Oil_,”[2112]
strongly recommending its use as a gentle purgative. This essay, which
passed through two editions, and was translated into French, was
followed by several others,[2113] thus thoroughly drawing attention to
the value of the oil. Accordingly we find that the seeds of _Ricinus_
were admitted to the London Pharmacopœia of 1788, and directions given
for preparing oil from them. Woodville in his _Medical Botany_ (1790)
speaks of the oil as having “_lately come into frequent use_.”
At this period and for several years subsequently, the small supplies
of the seeds and oil required for European medicine were obtained from
Jamaica.[2114] This oil was gradually displaced in the market by that
produced in the East Indies: the rapidity with which the consumption
increased may be inferred from the following figures, representing
the value of the Castor Oil shipped to Great Britain from Bengal in
three several years, namely 1813-14, £610; 1815-16, £1269; 1819-20,
£7102.[2115]
[2108] _De Vegetabilibus_, ed. Jessen, 1867. 347.
[2109] Turner’s _Herbal_, pt. ii. 116.
[2110] From the Arabic _khirva_, _i.e._ Palma Christi.
[2111] Hill, _Hist. of the Mat. Med._, Lond. 1751. 537.—Lewis, _Hist.
of the Mat. Med._, Lond. 1761. 468.
[2112] The word _castor_ in connection with the seeds and oil of
_Ricinus_ has come to us from Jamaica, in which island, by some strange
mistake, the plant was once called _Agnus Castus_. The true Agnus
Castus (_Vitex Agnus castus_ L.) is a native of the Mediterranean
countries and not of the West Indies.
[2113] For a list of which consult Mérat et De Lens, _Dict. de Mat.
Méd._ vi. (1834) 95.
[2114] How small was the traffic in Castor Oil in those days, may be
judged from the fact that the stock in 1777 of a London wholesale
druggist (Joseph Gurney Bevan, predecessor of Allen and Hanburys) was
2 Bottles (1 Bottle = 18 to 20 ounces) valued at 8_s._ per bottle. The
accounts of the same house show at stocktaking in 1782, 23 Bottles of
the oil, which had cost 10_s._ per bottle. In 1799 Jamaica exported 236
Casks of Castor Oil and 10 Casks of seeds (Renny, _Hist. of Jamaica_,
1807. 235).
[2115] H. H. Wilson, _Review of the External Commerce of Bengal from
1813 to 1828_, Calcutta, 1830, tables pp. 14-15.
=Description=—The fruit of _Ricinus_ is a tricoccous capsule, usually
provided with weak prickles, containing one seed in each of its three
cells. The seeds attain a length of ³/₁₀ to ⁶/₁₀, and a maximum breadth
of ⁴/₁₀ of an inch, and are of a compressed ellipsoid form. The apex of
the seed is prolonged into a short beak, on the inner side of which
is a large tumid caruncle: from this latter proceeds the raphe as far
as the lower end of the ventral surface, where it forks, its point of
disappearance through the testa being marked by a minute protuberance.
If the caruncle is broken off, a black scar, formed of two little
depressions, remains.
The shining grey epidermis is beautifully marked with brownish bands
and spots, and in this respect exhibits a great variety of colours and
markings. It cannot be rubbed off, but may after maceration be peeled
off in leathery strips. The black testa, grey within, is not thicker
than in croton seed, but is much more brittle. The kernel or nucleus
fills the testa completely, and is easily separated, still covered by
the soft white inner membrane.
The kernel in respect to structure and situation of the embryo, agrees
exactly with that of _Croton Tiglium_ (p. 565), excepting that the
somewhat gaping cotyledons of _Ricinus_ are proportionately broader,
and have their thick midrib provided with 2 or 3 pairs of lateral
veins. If not rancid, the kernel has a bland taste, with but very
slight acridity.
=Microscopic Structure=—The thin epidermis consists of pentagonal or
hexagonal porous tabular cells, the walls of which are penetrated
in certain spots by brownish colouring matter, whence the singular
markings on the seed. It is these cells only that become blackened when
a thin tangential slice is saturated with a solution of ferric chloride
in alcohol.
Beneath these tabular cells there is found in the unripe seed[2116] a
row of encrusted colourless cells, deposited in a radial direction on
the testa. In the mature seed this layer of cells is not perceptible,
and therefore appears to perish as the seed ripens. The testa itself is
built up of cylindrical, densely packed cells, 300 to 320 mkm. long,
and 6 to 10 mkm. in diameter. The kernel shares the structure of that
of _C. Tiglium_, but is devoid of crystals of oxalate of calcium. If
the endopleura of _Ricinus_ is moistened with dilute sulphuric acid,
acicular crystals of sulphate of calcium separate from it after a few
hours.
When thin slices of the kernel are examined under concentrated
glycerin, no drops of oil are visible, notwithstanding the abundance
of this latter; and it becomes conspicuous only by addition of much
water. Hence it is probable that the oil exists in the seed as a kind
of compound with its albuminoid contents.[2117] As to the latter,
they partly form in the albumen of _Ricinus_ beautiful octohedra or
tetrahedra, which are also found in many other seeds.[2118]
[2116] Gris, _Annales des Sciences Nat._, Bot., xv. (1861) 5-9.
[2117] Sachs, _Lehrbuch der Botanik_, 1874. 54.
[2118] For further particulars, see Trécul, _Ann. des Sc. Nat._, Bot.,
x.,(1858) 355; Radlkofer, _Krystalle proteinartiger Körper_, Leipzig,
1859. 61. and tab. 2 fig. 10; Pfeffer, _Proteïnkörner_ in Pringsheim’s
_Jahrbücher für wissenschaftliche Botanik_, viii. (1872) 429. 464.
=Chemical Composition=—The most important constituent of the seed is
the fixed oil, called _Castor Oil_, of which the peeled kernels afford
at most half of their weight.
The oil, if most carefully prepared from peeled and winnowed seeds by
pressure without heat, has but a slightly acrid taste, and contains
only a very small proportion of the still unknown drastic constituent
of the seeds. Hence the seeds themselves, or an emulsion prepared with
them, act much more strongly than a corresponding quantity of oil.
Castor oil, extracted by absolute alcohol or by bisulphide of carbon,
likewise purges much more vehemently than the pressed oil.
The castor oil of commerce has a sp. gr. of about 0·96, usually a pale
yellow tint, a viscid consistence, and a very slight yet rather mawkish
odour and taste. Exposed to cold, it does not in general entirely
solidify until the temperature reaches -18° C. In thin layers it dries
up to varnish-like film.
Castor oil is distinguished by its power of mixing in all proportions
with glacial acetic acid or absolute alcohol. It is even soluble in
four parts of spirit of wine (·838) at 15° C., and mixes without
turbidity with an equal weight of the same solvent at 25° C. The
commercial varieties of the oil however differ considerably in these as
well as in some other respects.
The optical properties of the oil demand further investigation, as we
have found that some samples deviate the ray of polarized light to the
right and others to the left.
By saponification castor oil yields several fatty acids, one of which
appears to be _Palmitic Acid_. The prevailing acid (peculiar to the
oil) is _Ricinoleic Acid_, C₁₈H₃₄O₃; it is solid below 0° C., does
not solidify in contact with the air by absorption of oxygen, and is
not homologous with oleic or linoleic acid, neither of which is found
in castor oil. Castor oil is nevertheless thickened if 6 parts of it
are warmed with 1 part of starch and 5 of nitric acid (sp. gr. 1·25),
_Ricinelaïdin_ being thus formed. From this _Ricinelaïdic Acid_ may
easily be obtained in brilliant crystals.
As to the albuminoid matter of the seed, Fleury (1865) obtained 3·23
per cent. of nitrogen which would answer to about 20 per cent. of such
substances. The same chemist further extracted 46·6 per cent. of fixed
oil, 2·2 of sugar and mucilage, besides 18 per cent. of cellulose.
Tuson in 1864, by exhausting castor oil seeds with boiling water,
obtained from them an alkaloid which he named _Ricinine_. He states
that it crystallizes in rectangular prisms and tables, which when
heated fuse, and upon cooling solidify as a crystalline mass; the
crystals may even be sublimed. Ricinine dissolves readily in water or
alcohol, less freely in ether or benzol. With mercuric chloride, it
combines to form tufts of silky crystals, soluble in water or alcohol.
Werner (1869) on repeating Tuson’s process on 30 lb. of Italian castor
oil seeds, also obtained a crop of crystals, which in appearance
and solubility had many of the characters ascribed to ricinine, but
differed in the essential point that when incinerated they left a
residuum of magnesia. Werner regarded them as the magnesium salt of a
new acid. Tuson[2119] repudiates the suspicion that ricinine may be
identical with Werner’s magnesium compound. E. S. Wayne of Cincinnati
(1874) found in the leaves of _Ricinus_ a substance apparently
identical with Tuson’s ricinine; but he considers that it has no claim
to be called an alkaloid.
[2119] _Chemical News_, xxii. (1870) 229.
The testa of castor oil seeds afforded us 10·7 per cent. of ash, one
tenth of which we found to consist of silica. The ash of the kernel
previously dried at 100 C. amounts to only 3·5 per cent.
=Production and Commerce=—Castor oil is most extensively produced in
India, where two varieties of the seeds, the large and the small, are
distinguished, the latter being considered to yield the better product.
In manufacturing the oil, the seeds are gentry crushed between rollers,
and freed by hand from husks and unsound grains. At Calcutta, 100 parts
of seed yield on an average 70 parts of cleaned kernels, which by the
hydraulic press afford 46 to 51 per cent. of their weight of oil; the
oil is afterwards subjected to a very imperfect process of purification
by heating it with water.[2120]
The exports of castor oil from Calcutta[2121] in the year 1870-71
amounted to 654,917 gallons, of which 214,959 gallons were shipped to
the United Kingdom. The total imports of castor oil into the United
Kingdom[2122] in the year 1870 were returned as 36,986 cwt. (about
416,000 gallons), valued at £82,490. Of this quantity, British India
(chiefly Bengal) furnished about two-thirds; and Italy 11,856 cwt.
(about 133,000 gallons), while a small remainder is entered as from
“other parts.” In 1876 the imports were 79,677 cwt., valued at £133,838.
_Italian Castor Oil_, which has of late risen into some celebrity, is
pressed from the seed of plants grown chiefly about Verona and Legnago,
in the north of Italy. The manufactory of Mr. Bellino Valeri at the
latter town produced in the year 1873, 1200 quintals of castor oil,
entirely from Italian seed. Two varieties of _Ricinus_ are cultivated
in these localities, the black-seeded Egyptian and the red-seeded
American; the latter yields the larger percentage, but the oil is not
so pale in colour. The seeds are very carefully deprived of their
integuments, and having been crushed, are submitted to pressure in
powerful hydraulic presses, placed in a room which in winter is heated
to about 21° C. The outflow of oil is further promoted by plates of
iron warmed to 32-38° C. being placed between the press-bags. The
peeled seeds yield about 40 per cent. of oil.[2123]
All the castor oil pressed in Italy is not pressed from Italian seed.
By an official return[2124] it appears that in the year 1872-73 there
were exported from Bombay to Genoa 1350 cwt. of castor oil seeds,
besides 2452 gallons of castor oil. There are no data to show what was
exported from the other presidencies of India in that year.
=Uses=—Castor oil is much valued as a mild and safe purgative; while
the commoner qualities are used in soap-making, and in India for
burning in lamps. The seeds are not now administered. The _leaves_ of
the plant applied in decoction to the breasts of women are said to
promote or even to occasion the secretion of milk. This property, which
has long been known to the inhabitants of the Cape Verd Islands,[2125]
was particularly observed by Dr. M’William about the year 1850. It has
even been found that the galactagogue powers of the plant are exerted
when the leaves are administered internally.
[2120] _Madras Exhibition of Raw Products, etc. of Southern
India_,—Reports by the Juries, Madras, 1856. 28.
[2121] _Annual Volume of Trade and Navigation for the Bengal Presidency
for 1870-71_, Calcutta, 1871. 119.
[2122] _Annual Statement of the Trade, etc. of the U.K. for 1870._—No
later returns.
[2123] H. Groves, _Pharm. Journ._ viii (1867) 250.
[2124] _Annual Statement of the Trade and Navigation of the Presidency
of Bombay for 1872-73_, part ii. 87. 88.
[2125] Frezier, _Voyage to the South Seas_, Lond. 1717. p. 13.—Turner
in his Herbal (1568) gives the plant an opposite character, for the
bruised leaves, says he, “swage the brestes or pappes swellinge wyth to
muche plenty of milke.”