It is one happy recommendation of the Natural system of botany, that
many of its orders form groups of plants distinguished not only by the
characteristics of general physiognomy, and the more accurate
differences of structure, but in an especial manner by the medicinal
and economical properties which they possess, and which are indeed
frequently peculiar to the order. Such is the case with the natural
order _Euphorbiaceæ_, or spurge family, to which the tallow-tree of
China belongs. The order includes 2500 species, all of which are more
or less acrid and poisonous, these properties being especially
developed in the milky juices which abound in the plants, and which
are contained, not in its ordinary tissues, but in certain special
vessels. Many important substances are derived from this order,
notwithstanding its acrid and poisonous character. Castor-oil is
obtained from the seeds of _Ricinus communis_; croton-oil, and several
other oleaginous products of importance in medicine and the arts, are
obtained from plants belonging to the order. The root of _Janipha
Manihot_, or Manioc-plant, contains a poisonous substance, supposed to
be hydrocyanic acid, along with which there is a considerable
proportion of starch. The poisonous matter is removed by roasting and
washing, and the starch thus obtained is formed into the cassava-bread
of tropical countries, and is also occasionally imported into Europe
as Brazilian arrow-root.
Many of the important economical productions of China are little known
in this country; we are, however, daily gaining additions to our
knowledge of them; and within the last few years, much valuable
information has been obtained respecting the productive resources of
the Eastern Empire. The grass-cloth of China only became known in
Europe a few years ago, but it now ranks as one of the important
fabrics of British manufacture. Daily discoveries seem to shew that
there are Chinese products of equal importance, as yet unknown to us.
On the present occasion, we call the attention of our readers to a
substance which has been long known, as well as the plant which
produces it, but neither of which has hitherto been prominently
brought into general notice in Britain. For our information respecting
the uses of the tallow-tree, we express our chief obligations to a
paper by Dr D. J. Macgowan, published in the Journal of the
Agricultural and Horticultural Society of India.[1]
The tallow-tree of China is the _Stillingia sebifera_ of botanists; a
plant originally indigenous to China, where it occurs in wet
situations, but which is now somewhat common in various parts of India
and America, chiefly as an ornamental tree. In Roxburgh's time, it was
very common about Calcutta, where, in the course of a few years, it
became one of the most common trees; and it has become almost
naturalised in the maritime parts of South Carolina. In China alone,
however, is it as yet appreciated as an economical plant, and there
alone are its products properly elaborated. It is chiefly prized for
the fatty matter which it yields, and from which it derives its
appropriate name; but it affords other products of value: 'its leaves
are employed as a black dye; its wood being hard and durable, may be
easily used for printing-blocks and various other articles; and,
finally, the refuse of the nut is employed as fuel and manure.... It
grows alike on low alluvial plains and on granite hills, on the rich
mould at the margin of canals, and on the sandy sea-beach. The sandy
estuary of Hangchan yields little else; some of the trees at this
place are known to be several hundred years old, and though
prostrated, still send forth branches and bear fruit.... They are
seldom planted where anything else can be conveniently cultivated--but
in detached places, in corners about houses, roads, canals, and
fields.'
The sebaceous matter, or vegetable tallow, is contained in the
seed-vessels of the _Stillingia_. The processes adopted for
abstracting it are of importance, and meet with due consideration in
Dr Macgowan's valuable paper. The following clear account is given of
the whole process, as practised in China:--'In midwinter, when the
nuts are ripe, they are cut off with their twigs by a sharp
crescentric knife, attached to the extremity of a long pole, which is
held in the hand, and pushed upwards against the twigs, removing at
the same time such as are fruitless. The capsules are gently pounded
in a mortar, to loosen the seeds from their shells, from which they
are separated by sifting. To facilitate the separation of the white
sebaceous matter enveloping the seeds, they are steamed in tubs,
having convex open wicker bottoms, placed over caldrons of boiling
water. When thoroughly heated, they are reduced to a mash in the
mortar, and thence transferred to bamboo sieves, kept at a uniform
temperature over hot ashes. A single operation does not suffice to
deprive them of all their tallow; the steaming and sifting are
therefore repeated. The article thus procured becomes a solid mass on
falling through the sieve; and to purify it, it is melted and formed
into cakes for the press. These receive their form from bamboo hoops,
a foot in diameter, and three inches deep, which are laid on the
ground over a little straw. On being filled with the hot liquid, the
ends of the straw beneath are drawn up and spread over the top; and
when of sufficient consistence, are placed with their rings in the
press. This apparatus, which is of the rudest description, is
constructed of two large beams, placed horizontally so as to form a
trough capable of containing about fifty of the rings with their
sebaceous cakes; at one end it is closed, and at the other adapted for
receiving wedges, which are successively driven into it by ponderous
sledge-hammers, wielded by athletic men. The tallow oozes in a melted
state into a receptacle below, where it cools. It is again melted, and
poured into tubs, smeared with mud, to prevent its adhering. It is now
marketable, in masses of about eighty pounds each--hard, brittle,
white, opaque, tasteless, and without the odour of animal tallow;
under high pressure, it scarcely stains bibulous paper, and it melts
at 104 degrees Fahrenheit. It may be regarded as nearly pure
stearine.... The seeds yield about 8 per cent. of tallow, which sells
for about five cents per pound.'
There is a separate process for pressing the oil, which is carried on
at the same time. The kernels yield about 30 per cent. of oil, which
answers well for lamps. It is also employed for various purposes in
the arts, and has a place in the Chinese pharmacopoeia, because of its
quality of changing gray hair to black, and other imaginary virtues.
The husks are used to feed the furnaces; the residuary tallow-cakes
are also employed for fuel--a small quantity remaining ignited a whole
day. The oil-cake forms a valuable manure, and is of course carefully
used for this purpose in China, where so very great regard is paid to
the collecting of manures. This kind is particularly used for
enriching tobacco-fields, its powerful qualities recommending it for
such a scourging crop.
With regard to the uses of the vegetable tallow, Dr Macgowan observes:
'Artificial illumination in China is generally procured by vegetable
oils, but candles are also employed.... In religious ceremonies, no
other material is used. As no one ventures out after dark without a
lantern, and as the gods cannot be acceptably worshipped without
candles, the quantity consumed is very great. With an unimportant
exception, the candles are always made of what I beg to designate as
vegetable stearine. When the candles, which are made by dipping, are
of the required diameter, they receive a final dip into a mixture of
the same material and insect-wax, by which their consistency is
preserved in the hottest weather. They are generally coloured red,
which is done by throwing a minute quantity of alkanet-root (_Anchusa
tinctoria_), brought from Shan-tung, into the mixture. Verdigris is
sometimes employed to dye them green.' We are not aware that the
vegetable tallow has as yet been imported into Britain to any extent.