The essentials and the terminology of the contract are preserved in most modern systems of law. But in English law mandate, under that name, can hardly be said to exist as a separate form of contract. To some extent the law of mandatum corresponds partly to the law of principal and agent, partly to that of principal and surety. "Mandate" is retained to signify the contract more generally known as gratuitous bailment. It is restricted to personal property, and it implies the delivery of something to the bailee, both of which conditions are unknown in the mandatum of the civil law (see BAILMENT).
MANDAUE, a town of the province of Cebú, island of Cebú, Philippine Islands, on the E. coast and E. coast road, about 4 m. N.E. of the town of Cebú, the capital. Pop. (1903), 11,078; in the same year the town of Consolación (pop. 5511) was merged with Mandaue. Its climate is very hot, but healthy. The principal industries are the raising of Indian corn and sugar-cane and the manufacture of salt from sea-water. Cebú-Visayan is the language.
MANDELIC ACID (Phenylglycollic Acid), C8H8O3 or C6H5·CH(OH)·COOH, an isomer of the cresotinic and the oxymethylbenzoic acids. Since the molecule contains an asymmetric carbon atom, the acid exists in three forms, one being an inactive "racemic" mixture, and the other two being optically active forms. The inactive variety is known as _paramandelic acid_. It may be prepared by the action of hydrochloric acid on the addition compound of benzaldehyde and hydrocyanic acid:--
C6H5CHO + HCN + HCl + 2H2O = C6H5·CHOH·COOH + NH4Cl,
(F. L. Winckler, _Ann._, 1836, 18, 310), by boiling phenylchlor-acetic acid with alkalis (A. Spiegel, _Ber._, 1881, 14, 239), by heating benzoylformaldehyde with alkalis (H. v. Pechmann, _Ber._, 1887, 20, 2905), and by the action of dilute alkalies on [omega]-dibromacetophenone (C. Engler, _Ber._, 1887, 20, 2202):--
C6H5COCHBr2 + 3KHO = 2KBr + H2O + C6H5·CHOH·CO2K.
It crystallizes from water in large rhombic crystals, which melt at 118° C. Oxidizing agents convert it into benzaldehyde. When heated with hydriodic acid and phosphorus it forms phenylacetic acid; whilst concentrated hydrobromic acid and hydrochloric acid at moderate temperatures convert it into phenylbrom- and phenylchlor-acetic acids. The inactive mixture may be resolved into its active components by fractional crystallization of the cinchonine salt, when the salt of the _dextro_ modification separates first; or the ammonium salt may be fermented by _Penicillium glaucum_, when the _laevo_ form is destroyed and the _dextro_ form remains untouched; on the other hand, _Saccharomyces ellipsoïdeus_ destroys the _dextro_ form, but does not touch the _laevo_ form. A mixture of the two forms in equivalent quantities produces the inactive variety, which is also obtained when either form is heated for some hours to 160° C.