Tetracera
in botany, a genus of Delimeæ, owing its scientific name to the fact that its four capsules are recurved like horns. Shrubs or small trees, often climbing, with alternate, stalked, feath- , ferten er-nerved, naked leaves, often rough above, and panicled or racemose inflorescence. A decoction of T. breyniana and T. oblongata is given in Brazil in swelling of the legs. T. tigarea is diaphoretic, diuretic, and antisyphilitic. TETRACHORDON. in music, an instrument similar in appearance to a cottage pianoforte, and like it played by finger-board, but the tone, instead of being produced by striking, is obtained by means of a cylinder of india-rubber charged with resin, kept in motion by a pedal, variety of tone being gained by the depth of pressure on the keys by the fingers. It is called the tetrachordon from an idea that its sounds are similar to those produced by a string quartet. The instrument is constructed also with selfacting machinery. Milton used the word as the title of one of his treatises on marriage, occasioned by his disagreement with his wife, Mary Powell. He explained the word in the sub-title: "Expositions upon the Four Chief Places of Scripture which treat of Marriage." a