HORSE-CHESTNUT, Aesculus, L. (Germ., Rosska-stanie ; Fr., marronnier cV hide), a genus of trees or shrubs indigenous to North America and mountainous regions in Mexico, New Granada, Persia, North India, and the Malayan peninsula, of the natural order Sapin-dacece and suborder Sapindece, having exstipulate, opposite, digitate, 5- to 9-lobed leaves, an irregular campanulate or tubular 5-lobed calyx, 4 to 5 petals, 5 to 8 stamens, one style, a 3-celled ovary, with 6 ovules, of which 3 or more abort, exalbuminous seeds, and a smooth or echinate coriaceous capsule. The Common Horse-chestnut, JH. Hip-pocastanum, L., has been stated to be a native of Thibet, and to have been brought thence to England in 1550; it is now, however, thought to be indigenous in the moun-tains of northern Greece, where it occurs wild at 3000 to 4000 feet above sea-level (Gard. Chron., 1880, i. 488). Matthiolus, who attributes the origin of the name of the tree to the use of the nuts by the inhabitants of Constantinople for the relief of short-windedness and cough in horses, remarks that no ancient writer appears to have made mention of the horse-chestnut. Clusius (Rariorum plautarum hist., lib. i. p. 8, 1601) describes it as a vegetable curiosity, of which in 1588 he had left in Vienna a living specimen, but of which he had not yet seen either the flowers or recent fruit. The dry fruit, he says, had frequently been brought from Constantinople into Europe. The tree grows rapidly; it flourishes best in a sandy, somewhat moist loam, and attains a height of 50 to 60 or more feet, assuming a pyramidal outline. Its boughs are strong and spreading. The buds, conspicuous for their size, are protected by a coat of a glutinous sub-stance, which is impervious to water ; in spring this melts, and the bud-scales are then cast off. The leaves are com-posed of 7 obovate-cuneate radiating leaflets (see vol. iv. p. 112, fig. 115); when young they are downy and droop-ing. From the early date of its leafing year by year, a horse-chestnut in the Tuileries is known as the " Marronnier du 20 Mars." The flowers of the horse-chestnut, which are white dashed with red and yellow, appear in May, and sometimes, but quite exceptionally, again in autumn (Gard. Chron., 1868, p. 1116); they are very numerous on each rachis, and form a thyrse. Comparatively few of them afford mature fruit. The fruit is ripe in or shortly before the first week in October, when it falls to the ground, and the three-valved thorny capsule divides, dis-closing the brown and at first beautifully glossy seeds or nuts, having a resemblance to sweet chestnuts, and com-monly three or else two in number. For propagation of the tree, the nuts may be sown either when fresh, or, if preserved in sand or earth, in spring. Drying by ex-posure to the air for a month has been found to prevent their germination. The cotyledons do not rise to the surface of the soil. Rooks are wont to remove the nuts from the tree just before they fall, and to disperse them in various directions (R. Ellison, Berwickshire Naturalist, quoted in J. of Forestry, Apr. 1880, pp. 877, 878).
The bark of the horse-chestnut contains a greenish oil, resin, a yellow body, a tannin, C26H24012, existing likewise in the seeds and various parts of the tree, and decomposable into phloroglucin and msciglyomlic acid, C7H603, also cesculetin hydrate, and the crystalline fluorescent compound msculin, of the formula C2iH240i3 (Rochleder and Schwarz), with which occurs a similar substance fraxin, the paviin of Stokes (Q. J. Ohem. Soc, xi. 17, 1859 ; xii. 126, 1860), who suggests that its presence may perhaps account for the discrepancies in the analyses of ajsculin given by different authors. From the seeds have been obtained starch (about 14 per cent.), gum, mucilage, a non-drying oil, phosphoric acid, salts of calcium, saponin, by boiling which with dilute hydrochloric or sulphuric acid atsculic acid is obtained, quercitrin, present also in the fully developed leaves, cescigenin, C12H20O2, and ozsc\iletin, C9H604, which is procurable also, but in small quantity only, from the bark. Rochleder has described as constituent principles of the cotyledons aphroda3scin, C58H820 23, a bitter glucoside, argyrcescin, C27H42012, cescinic acid, C24H40O12, and quei-azscitrin, C41H46023, found also in the leaves. To prepare pure starch from the seeds, Flandin (Oompt. Rami, xxvii. 391, 1848 ; xxviii. 138, 1849) recommends kneading them, when peeled and bruised, in an aque-ous solution of to of their weight of sodium carbonate. E. Staffel (Ami. d. Ohem. u. Pharm., lxxvi., 1850, p. 379) after dry-ing found, in spring and autumn respectively, 10'9 and 3'38 per cent, of ash in the wood, 8'68 and 6'57 in the bark, and 7'68 and 7'52 in the leaves of the horse-chestnut. The ash of the unripe fruit contains 5877, that of the ripe kernel 61-74, and that of the green shell 75-91 per cent, of potash (E. Wolff).
The wood of the horse-chestnut is soft, and serves only for the making of water-pipes, for turner's work and com-mon carpentry, as a source of charcoal for gunpowder, and as fuel. Newly cut it weighs 60 K>, and dry 35 lb per cubic foot approximately. The bark has been employed for dyeing yellow and for tanning, and was formerly in popular repute as a febrifuge and tonic. The powder of the dried nuts was at one time prescribed as a sternutatory in the Edinburgh Pharmacopoeia. It is stated to form with alum-water a size or cement highly offensive to vermin, and with two parts of wheaten flour the material for a strong bookbinder's paste. Infusion of horse-chestnuts is found to expel worms from soil, and soon to kill them if they are left in it (The Garden, xiii. 198, 1878). The nuts furthermore have been applied to the manufacture of an oil for burning, cosmetic preparations, and starch (v. sup.), and in Switzerland, France, and Ireland, when rasped or ground, to the bleaching of flax, hemp, silk, and wooL In Geneva horse-chestnuts are largely consumed by graz-ing stock, a single sheep receiving 2 lb crushed morning and evening. Given to cows in moderate quantity, they have been found to enhance both the yield and flavour of milk. Deer readily eat them, and, after a preliminary steeping in lime-water, pigs also. For poultry they should be used boiled, and mixed with other nourishment, The fallen leaves are relished by sheep and deer, and afford a good litter for flocks and herds.
One variety of the horse-chestnut has variegated leaves, and another double flowers. Darwin has observed that JE. Pavia, L., the Red Buckeye of North America, exhibits a special tendency, under unfavourable conditions, to be double-blossomed (Anim. and PL, ii. 168). The seeds of this species are used to stupefy fish. The Scarlet-flowered Horse-chestnut, JE. rubicunda, is a handsome tree, less in height, and having a rounder head than the common form. Another species, possessing flowers with the lower petals white with a red tinge, and the upper yellow and red with a white border, and fruit unarmed, is JE. indica. Among the North American species are the Foetid or Ohio Buckeye, JE. glabra, Willd., and JE. flava, Ait., the Sweet Buckeye. JE. californica, Nutt., when full-grown and in flower, is a beautiful tree, but its leaves often fall before midsummer.
See Loudon, Arboretum, i. 147, 462 ; Gard. Chron., 1843, pp. 7, 737 ; 1878, i. 768, 828, and ii. 53 ; Technologist, 1865, p. 3 ; Asa Gray, Man. ofBot., p. 117, 5th ed., 1872; Brewer and Watson, Gcol. Sun: Calif., "Bot."i. 106; ARBORICULTURE, vol. ii. p. 319; and, for the chemistry, Eochleder and Schwarz, Ann. d. Chem. u. Pharm., Ixxxvii., 1853, p. 186, and Ixxxviii. 356 ; C. Zwenger, lb., xc, 1854, p. 63; and Rochleder, Wien. Akad. Sitzu7igsber.,x\., 1860, xlv., 1862, xlviii., 1863, liv.-lvii., 1866-68. (F. H. B.)
Opera qiue extant omnia, "Comment.," lib. i. cap. cxxii. p. 184, Frankfort, 1598, fol.; ef. Gerard, Herball, p. 1443, 2d ed., 1633. For other derivations see Notes and Queries, 3d ser., x. 452, 523, and Gard. Chron., 1878, ii. 53.