ART. IV.-Uses of the Stillingia sebifera or Tallow Tree, with a notice of the Pe-la, an Insect-wax of China :* By J. D. MACGOWAN, M.D.

THE botanical characters of this member of the Euphorbiacæ are too well known to require description; but hitherto no accurate account has been published of its varied uses, and although it has become a common tree in some parts of India and America, its value is appreciated only in China, where alone its products are properly elaborated. In the American Encyclopedia it is stated that this tree is almost naturalized in the maritime parts of South Carolina, and that its capsules and seeds are crushed together and boiled, the fatty matter being skimmed as it rises, hardening when cool.

Dr. Roxburgh in his excellent Flora Indica, says: "It is now very common about Calcutta, where in the course of a few years, it has become one of the most common trees. It is in flower and fruit most parts of the year. In Bengal, it is considered only an ornamental tree; the sebaceous produce of its seeds is not sufficient in quantity, nor its qualities so valuable, as to render it an object worthy of cultivation. It is only in very cold weather that this substance becomes firm; at all other times it is in a thick brownish fluid state, and soon becomes rancid: such is my opinion of the famous vegetable tallow of China."

Dr. Roxburgh was evidently misled in his experiments by pursuing a course similar to that which is described in the Encyclopedia Americana, (and in many other works,) or he would have formed a very different opinion of this curious material.

Analytical chemistry shows animal tallow to consist of two proximate principles-stearine and elaine. Now what renders the fruit of this tree peculiarly interesting is the fact that both these principles exist in it separately, in nearly a pure state. By the above named process, stearine and elaine are obtained in a mixed state, and consequently presents the appearance described by Dr. Roxburgh.

Nor is the tree prized merely for the stearine and elaine it yields, though these products constitute its chief 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. The Stillingia sebifera is chiefly cultivated in the provinces. of Kiangsi, Kougnam, and Chehkiang. In one district, near Haugchan, the inhabitants defray all their taxes with its produce. It grows alike on low alluvial plains and on granite hills, on the

* Drawn up for the Agricultural and Horticultural Society of India. SECOND SERIES, Vol. XII, No. 34-July, 1851.

rich mould at the margin of canals, and on the sandy sea beach. The sandy estuary of Haugchan 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. Some are made to fall over rivulets, forming convenient bridges. They are seldom planted where any thing else can be conveniently cultivated-in detached places, in corners about houses, roads, canals, and fields. Grafting is performed at the close of March, or early in April, when the trees are about three inches in diameter, and also when they attain their growth. The Fragrant Herbal recommends for trial the practice of an old gardener, who instead of grafting, preferred breaking the small branches and twigs, taking care not to tear or wound the bark.

In mid-winter, when the nuts are ripe, they are cut off with their twigs, by a sharp cres-centric kuife, attached to the extremity of a long pole, which is held in the hands, 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 strained in tubs, having convex, open wicket bottoms placed over cauldrons of boiling water. When thoroughly heated they are reduced to a mash in the mortar, and thence transferred to bamboo sieves, kept at an uniform temperature over hot ashes. A single operation does not suffice to deprive them of all their tallow, and the steaming and sifting is 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, and constructed of two large beams placed horizontally so as to form a trough, is 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 about 80 pounds each-hard, brittle, white, opake, without taste, and without the odor of animal tallow; under high pressure it scarcely stains bibulous paper; melts at 104° Fahrenheit. It may be regarded as nearly pure stearine, the slight difference is doubtless owing to the admixture of oil expressed from the seed in the process just described. The seeds

yield about eight per cent. of this vegetable stearine, which sells for about five cents per pound.

The process for pressing the oil, which is carried on at the same time, remains to be noticed; it is contained in the kernel of the nut, the sebaceous matter which lies between the shell and husk having been separated in the manner described. The kernel and the husk covering it are ground between two stones, which are heated to prevent clogging from the sebaceous matter still adhering. The mass is then placed in a winnowing machine, precisely like those in common use in other countries. The chaff being separated exposes the white oleaginous kernels, which after being steamed are placed in a mill to be mashed. This machine is formed of a circular stone groove, twelve feet in diameter, three inches deep and about as many wide, into which a thick solid stone wheel, eight feet in diameter, tapering at the edge, is made to revolve perpendicularly by an ox harnessed to the outer end of its axle, the inner turning on a pivot in the centre of the machine. Under this ponderous weight the seeds are reduced to a mealy state; they are then steamed in the tubs, formed into cakes, and pressed by wedges in the manner above described, the process of mashing, steaming, and pressing being repeated with the kernels likewise. The kernels yield above thirty per cent of oil, and it sells for a little more than three cents per pound. It is called Tsing-yu, and answers well for lamps, though inferior for this purpose to some other vegetable oils in use. It is also employed for various purposes in the arts, and has a place in the Chinese Pharmacopia, because of its quality of changing grey hair black, and other imaginary virtues. The husk which envelops the kernel, and the shell which encloses them with their sebaceous covering, are used to feed the furnaces, scarcely any other fuel being needed for this purpose. The residuary tallow cakes are also employed. for fuel, as a small quantity of it remains ignited a whole day. It is in great demand for chafing dishes in the cold weather. And finally, the cakes which remain after the oil has been pressed out are much valued as a manure, particularly for tobacco fields, the soil of which is rapidly impoverished by the Virginia weed. Artificial illumination is generally procured in China by vegetable oils, but candles are also employed by those who can afford it, and for lanterns. 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 also 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 colored red, which is done by throwing a minute quan

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tity of Alkanet root (Anchusa tinctoria), brought from Shangtung, into the mixture, which forms the coating of the candle; Verdigris is sometimes employed to dye them green. The wicks are made of rush, coiled round a stem of coarse grass, the lower part of which is slit to receive the pin of the candlestick, which is more economical than if put into a socket. Tested in the mode recommended by Count Rumford, these candles compare favorably with those made from spermaceti, but not when the clumsy wick of the Chinese is used. They cost about eight cents per pound.

Prior to the thirteenth century, beeswax was employed as a coating for candles; but about that period the white insect-war was discovered, since which time that article has been wholly superseded by the more costly but incomparably superior product of this insect. It has been described by the Abbé Grassier, Sir George Staunton, and others; but these accounts differ so widely among themselves, as well as from that given by native authors, as to render further inquiry desirable.

From the description given by Grassier, entomologists have supposed the insect which yields the Pe-la, or white wax, to be a species of Coccus. Staunton on the contrary describes it as a species of Cicada (Flata limbata). As described by Chinese writers, however, it is evidently an apterous insect, hence the inference, either that there are two distinct species that produce white wax, or that the insect Staunton saw was falsely represented as the elaborator of this beautiful material. This like many other interesting questions in the natural history of this portion of the globe must remain unsolved, until restrictions on foreign intercourse are greatly relaxed, or wholly removed. In the mean time, native writers may be consulted with advantage; and from the chief of these the Pun-tsau and Kiunfangpú, two herbals of high authority, the subjoined account has been principally derived. The animal feeds on an evergreen shrub or tree, Ligustrum incidum, which is found throughout central China from the Pacific to Thibet, but the insect chiefly abounds in the province of Sy'Chuen. It is met with also in Yunnan, Hunan, and Hupeh. A small quantity of a superior description, is produced in Kinhwa Chehkiang province. Much attention is paid to the cultivation of this tree; extensive districts of country are covered with it, and it forms an important branch of agricultural industry. In planting, they are arranged like the mulberry in rows about twelve feet apart, and both seeds and cuttings are employed. If the former, they are soaked in water in which unhusked rice has been washed, and their shells pounded off; when propagated by cuttings, nches an inch in diameter are recommended as of the most suitThe ground is ploughed semi-annually, and kept perfree from weeds. In the third or fourth year they are d with the insect. After the wax or insect has been gath

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ered from the young trees, they are cut down, just below the lower branches, about four feet from the ground, and well manured. The branches which sprout the following season are trimmed, and made to grow in nearly a perpendicular direction. The process of cutting the trunk within a short distance of the ground is repeated every four or five years, and as a general rule, they are not stocked until the second year after this operation. Sometimes the husbandman finds a tree which the insects themselves have attained, but the usual practice is to stock them with the nests of the insect, which is effected in spring. These nests are about the size of a "fowl's head," and are removed by cutting off a portion of the branch to which they are attached, leaving an inch each side of the nest. The sticks, with the adhering nests, are soaked in unhusked rice-water for a quarter of an hour, when they may be separated. When the weather is damp or cool, they may be preserved in jars for a week; but if warm, they are to be tied to the branches of the trees, to be stocked without delay, being first folded between leaves. By some, the nests are probed out of their seat in the bark of the tree without removing the branches. At this period they are particularly exposed to the attacks of birds, and require watching. In a few days after being tied to the tree, the nests swell, and innumerable white insects, the size of "nits," emerge, and spread themselves on the branches of the tree; but soon with one accord they descend towards the ground, where, if they find any grass, they take up their quarters. To prevent this, the ground beneath is kept quite bare, care being taken also that their implacable enemies, the ants, have no access to the tree.

Finding no congenial resting place below, they reascend and fix themselves to the lower surface of the leaves, where they remain several days, whence they repair to the branches, perforating the bark to feed on the fluid within. From nits they attain the size and appearance of "pediculus hominis." Having compared it to this, the most familiar to them of all insects, our authors deem further description superfluous. Early in June they give to the trees the appearance of being covered with hoar frost, being changed into war, soon after this they are scraped off, being previously sprinkled with water. If the gathering be deferred till August they adhere too firmly to be easily removed. Those which are suffered to remain to stock trees the ensuing season secrete a purplish envelop about the month of August, which at first no larger than a grain of rice; but as incubation proceeds, it expands, and becomes as large as a fowl's head, which is in spring, when the nests are transferred to other trees, one or more to each, according to their size and vigor, in the manner already described.

On being scraped from the trees, the crude material is freed from its impurities, probably the integuments of the insect, by spreading