Xanthine, a compound often found in urinary calculi, discovered by Marcet in a calculus weighing only 8 grs. According to Scherer, xanthine is a normal constituent of the body of many animals. He has found it in the urine of man, in the pancreas, spleen, and liver of oxen, in the thymus gland of the calf, and in the muscular flesh of the ox, the horse, and fishes. The formula of xanthine is C6H4N4O2. It may be artificially produced from uric acid, from which it differs only by one atom of oxygen, by the action of sodium amalgam, and from guanine by the action of nitric acid. It is nearly insoluble in cold water, sparingly soluble in boiling water, and insoluble in alcohol and ether. When heated in the air it burns with the smell of burnt hair. It unites with both acids and bases, forming usually crystallizable compounds.
Xanthorhamnine, a yellow coloring matter obtained from Persian or Turkey berries, the seeds of rhamnus amygdalinus, R. oleoides, R. saxatilis, and R. infectorius. According to Kane, its formula is C23H24O14, and it occurs only in the ripe seeds, being formed by the decomposition of chrysorhamnine contained in the unripe seeds. It may be also formed by boiling the unripe berries in water. It forms precipitates with the alkaline-earth metals, and aluminic and stannio salts. It dves fabrics mordanted with alumina a fine yellow, and those mordanted with iron salts black:
Xavier Aymon De Montepin, a French author, born at Apremont, Haute-Saone, March 18, 1824. He began life as a journalist, and wrote in conjunction with the marquis de Foudras the novels Les chevaliers clu lansquenet (10 vols., 1847) and Les xireurs d'autrefois (4 vols., 184«), to which he added many others equally descriptive of the elegant, demi-monde, and Bohemian life of Paris. He gained great notoriety by the suppression of his licentious Filles de platre (7 vols., 1855), but continued to produce other voluminous works of a similar character. Among the most recent are Le bigame, Le mart de Marguerite, Confessions de Tulla, Les drames de Vadultere, La comtesse de Nancey (all in 1873), and La toy ante (1873-'4). He also assisted the elder Dumas as a playwright.
Xenopdanes, a Greek philosopher, born in Colophon, Ionia, about 570 B. C, died in Elea, southern Italy, about 480. He quitted his native town as an exile, and probably lived for some time in Elea. He is regarded as the founder of the Eleatic school. He strongly combated the anthropomorphism of Hesiod and Homer, contending that God is one, selfexistent, unchangeable, the universal supreme intelligence. The few fragments of his poems extant were published by Karsten (1830), and are also given in Schneidewin's Elegiaci Groeci (1838), and those which relate to philosophy in Ueberweg's Grundriss der Geschichte der Philosophic. (See Eleatic School).