Search the Dictionary

. -- Primitive sheath. (Anat.) See Neurilemma. -- Primitive streak or trace (Anat.), an opaque and thickened band where the mesoblast first appears in the vertebrate blastoderm.

A thickened opaque spot on the wings of certain insects.

The yellowish white opaque creamy matter produced by the process of suppuration. It consists of innumerable white nucleated cells floating in a clear liquid.

A mineral which is opaque in its natural state, but is said to change its color and become transparent by heat.

ptocrystalline massive forms varying in color and degree of transparency, being sometimes opaque.

ntgen rays upon a sensitive surface, photographic or fluorescent, especially a picture of opaque objects traversed by the rays.

Direct observation of objects opaque to light by means of some other form of radiant energy, as the Röntgen rays. -- Ra`di*o*scop"ic (#), *scop"ic*al (#), a.

ted vacuum tube by the electrical discharge. It is capable of passing through many bodies opaque to light, and producing photographic and fluorescent effects by which means pictures showing the internal structure of opaque objects are made, called radiographs, or sciagraphs. So called from the discoverer, W. C. Röntgen…

id (as the wall of the vacuum tube). Röntgen rays are noted for their penetration of many opaque substances, as wood and flesh, their action on photographic plates, and their fluorescent effects. They were called X rays by their discoverer, W. K. Röntgen. They also ionize gases, but cannot be reflected, or polarized, o…

To cover lighty, as a painting, or a drawing, with a thin wash of opaque color, or with color-crayon dust rubbed on with the stump, or to make any similar additions to the work, so as to produce a softened effect.

taining a softened effect, in painting and drawing, by the application of a thin layer of opaque color to the surface of a painting, or part of the surface, which is too bright in color, or which requires harmonizing.

Semiopaque.

e and Trona. Sodium chloride, common, or table, salt, NaCl. -- Sodium hydroxide, a white opaque brittle solid, NaOH, having a fibrous structure, produced by the action of quicklime, or of calcium hydrate (milk of lime), on sodium carbonate. It is a strong alkali, and is used in the manufacture of soap, in making wood…

o colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.

t; diaphanous; pellucid; as, transparent glass; a transparent diamond; -- opposed to Ant: opaque. "Transparent elemental air." Milton.

s scrofula or phthisis. This is composed of a hard, grayish, or yellowish, translucent or opaque matter, which gradually softens, and excites suppuration in its vicinity. It is most frequently found in the lungs, causing consumption. Tubercle bacillus (Med.), a minute vegetable organism (Bacillus tuberculosis) discover…

onsisting of a screen of paper or glass with a central aperture the edges of which become opaque by intensible gradations.

Covered with an opaque white powder.