[Dionysus], the god of the vine or wine; the son of [Zeus] and [Semele] (q. v.), the "twice born," as plucked first from the womb of his dead mother and afterwards brought forth from the thigh of Zeus, which served to him as his "incubator." See [Bacchus].

[Diophantus], a Greek mathematician, born in Alexandria; lived presumably about the 4th century; left works in which algebraic methods are employed, and is therefore credited with being the inventor of algebra.

[Dioscor`ides], a Greek physician, born in Cilicia, lived in the 1st century; left a treatise in 5 books on materia medica, a work of great research, and long the standard authority on the subject.

[Dioscuri], twin sons of Zeus, Castor and Pollux, a stalwart pair of youths, of the Doric stock, great the former as a horse-breaker and the latter as a boxer; were worshipped at Sparta as guardians of the State, and pre-eminently as patrons of gymnastics; protected the hearth, led the army in war, and were the convoy of the traveller by land and the voyager by sea, which as constellations they are still held to be.

[Diphilus], a Greek comic poet, born at Sinope; contemporary of Menander; was the forerunner of Terence and Plautus, the Roman poets.

[Diphtheria], a contagious disease characterised by the formation of a false membrane on the back of the throat.

[Dippel, Johann Konrad], a celebrated German alchemist; professed to have discovered the philosopher's stone; did discover Prussian blue, and an animal oil that bears his name (1672-1734).

[Dippel's Oil], an oil obtained from the distinctive distillation of horn bones.

[Dircæan Swan], Pindar, so called from the fountain Dirce, near Thebes, his birthplace.

[Dirce], the wife of Lycus, king of Thebes, who for her cruelty to Antiope, her divorced predecessor, was, by Antiope's two sons, Zethos and Amphion, tied to a wild bull and dragged to death, after which her carcass was flung by them into a well; the subject is represented in a famous antique group by Apollonius and Tauriscus.