refracting medium


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refracting medium

See medium.

refracting medium

The fluids and transparent tissues of the eye that refract light rays passing through them toward the retina: the cornea, aqueous humor, lens, and vitreous humor.
See also: medium

medium

pl. media, mediums [L.]
1. an agent by which something is accomplished or an impulse is transmitted.
2. a substance providing the proper nutritional environment for the growth of microorganisms; called also culture medium.

basic nutritive medium
one adequate for the growth requirements of most bacteria.
contrast medium
a radiopaque (positive) substance, or (negative) gases used in radiography to permit visualization of body structures.
culture medium
a substance used to support the growth of microorganisms or other cells.
dioptric medium
refracting medium (see below).
disperse medium, dispersion medium
the continuous phase of a colloid system; the medium in which a colloid is dispersed, corresponding to the solvent in a true solution.
enriched medium
modification of a basic medium for the growth of fastidious bacteria. Common additions are blood, serum or egg yolk.
indicator medium
a type of bacteriological medium which may contain a fermentable sugar plus a pH indicator that gives a color change. It is used to identify bacteria on the basis of a characteristic biochemical reaction.
refracting medium
the transparent tissues and fluid in the eye through which light rays pass and by which they are refracted and brought to a focus on the retina.
medium sausage
a technique for examining meat for bacterial contamination. The solid medium is made up in the form of a sausage and slices are removed from it after application of the exposed end to the suspect meat.
selective medium
formulated to facilitate the isolation of specific bacteria, they contain substances to inhibit growth of others.
transport medium
formulated to preserve a specimen, usually tissue or microbiological swab, and minimize bacterial overgrowth for the time necessary to transport it to the laboratory.