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An alkaloid which is the active principle of tobacco. It is a colorless, transparent, oily liquid, having an acrid odor, and an acrid burning taste. It is intensely poisonous. Ure.

Having the power of acting; hence, exerting force, physical or moral; active in the production of effects; as, an operative motive. It holds in all operative principles. South.

By optics or sight; with reference to optics. Optically active, Optically inactive (Chem. Physics), terms used of certain metameric substances which, while identical with each other in other respects, differ in this, viz., that they do or do not produce right-handed or left-handed circular polarization of light. -- Op…

oyment of subjective and objective mechanical means to determine the accomodative and refractive states of the eye and the scope of its function in general."

consisting of one or several of the class of nitrogenous substances which are called extractives.

of making an ambitious display; unnecessary show; pretentious parade; -- usually in a detractive sense. "Much ostentation vain of fleshly arm." Milton. He knew that good and bountiful minds were sometimes inclined to ostentation. Atterbury.

To live too long, too luxuriously, or too actively. Milton. "Overlived in this close London life." Mrs. Browning.

ence; a passive condition; -- opposed to action. A body at rest affords us no idea of any active power to move, and, when set is motion, it is rather a passion than an action in it. Locke.

Not active, but acted upon; suffering or receiving impressions or influences; as, they were passive spectators, not actors in the scene. The passive air Upbore their nimble tread. Milton. The mind is wholly passive in the reception of all its simple ideas. Locke.

A highly refractive vitreous composition, variously colored, used in making imitations of precious stones or gems. See Strass.

Active; lively; brisk; smart; -- often applied to convalescents; as, she is quite peart to-day. [O. Eng. & Colloq. U. S.] There was a tricksy girl, I wot, albeit clad in gray, As peart as bird, as straight as bolt, as fresh as flowers in May. Warner (1592).

d to one's care for management or disbursement; embezzlement. Every British subject . . . active in the discovery of peculations has been ruined. Burke.

ilute hydrochloric acid (0.2 per cent, approximately) and the two together constitute the active portion of the digestive fluid. It is the active agent in the gastric juice of all animals.

Petrifying; petrifactive. Death with his mace petrific, cold and dry. Milton.

owish, translucent waxy substance, having a characteristic disagreeable smell. It is very active chemically, must be preserved under water, and unites with oxygen even at ordinary temperatures, giving a faint glow, -- whence its name. It always occurs compined, usually in phosphates, as in the mineral apatite, in bones…

s. The adult male is more or less tinged with red. -- Pine lizard (Zoöl.), a small, very active, mottled gray lizard (Sceloporus undulatus), native of the Middle States; -- called also swift, brown scorpion, and alligator. -- Pine marten. (Zoöl.) (a) A European weasel (Mustela martes), called also sweet marten, and y…

A supposed new element, a radioactive substance discovered by M. and MMe. Curie in pitchblende. It is closely related chemically to bismuth. It emits only alpha rays and is perhaps identical with radium F.

Affected with poppy juice; hence, figuratively, drugged; drowsy; listless; inactive. [R.] The poppied sails doze on the yard. Lowell.

To render active or potent. Coleridge.

sceptibility; -- called also passive power; as, great power of endurance. Power, then, is active and passive; faculty is active power or capacity; capacity is passive power. Sir W. Hamilton.