Lac*tes"cent (?), a. [L. lactescens, p. pr. of lactescere to turn to
milk, incho. fr. lactere to be milky, fr. lac, lactis, milk: cf. F.
lactescent.] 1. Having a milky look; becoming milky. [Obs.]
2. (Bot.) Producing milk or a milklike juice or fluid, as the milkweed.
See Latex.
Lac"tic (?), a. [L. lac, lactis, milk: cf. F. lactique. See Lacteal,
and cf. Galactic.] (Physiol. Chem.) Of or pertaining to milk; procured
from sour milk or whey; as, lactic acid; lactic fermentation, etc.
Lactic acid (Physiol. Chem.), a sirupy, colorless fluid, soluble in
water, with an intensely sour taste and strong acid reaction. There are
at least three isomeric modifications all having the formula C3H6O3.
Sarcolactic or paralactic acid occurs chiefly in dead muscle tissue,
while ordinary lactic acid results from fermentation. The two acids are
alike in having the same constitution (expressed by the name ethylidene
lactic acid), but the latter is optically inactive, while sarcolactic
acid rotates the plane of polarization to the right. The third acid,
ethylene lactic acid, accompanies sarcolactic acid in the juice of
flesh, and is optically inactive. -- Lactic ferment, an organized
ferment (Bacterium lacticum or lactis), which produces lactic
fermentation, decomposing the sugar of milk into carbonic and lactic
acids, the latter, of which renders the milk sour, and precipitates the
casein, thus giving rise to the so-called spontaneous coagulation of
milk. -- Lactic fermentation. See under Fermentation.
Lac"tide (?), n. [Lactic + anhydride.] (Chem.) A white, crystalline
substance, obtained from lactic acid by distillation, and regarded as
an anhydride; also, by extension, any similar substance.
Lac*tif"er*ous (?), a. [l. lac, lactis, milk + -ferous: cf. F.
lactifère.] Bearing or containing milk or a milky fluid; as, the
lactiferous vessels, cells, or tissue of various vascular plants.
{ Lac*tif"ic (?), Lac*tif"ic*al (?), } a. [L. lac, lactis, milk +
facere to make.] Producing or yielding milk.
Lac"ti*fuge (?), n. [L. lac, lactis, milk + fugare to expel.] (Med.) A
medicine to check the secretion of milk, or to dispel a supposed
accumulation of milk in any part of the body.
Lac"tim (?), n. [Lactic + imido.] (Chem.) One of a series of anhydrides
resembling the lactams, but of an imido type; as, isatine is a lactim.
Cf. Lactam.
Lac*tim"ide (?), n. [Lactic + imide.] (Chem.) A white, crystalline
substance obtained as an anhydride of alanine, and regarded as an imido
derivative of lactic acid.
Lac"tin (?), n. [L. lac, lactis, milk: cf. F. lactine. Cf. Galactin.]
(Physiol. Chem.) See Lactose.
Lac`to*a*bu"min (?), n. [L. lac, lactis, milk + E. albumin.] (Physiol.
Chem.) The albumin present in milk, apparently identical with ordinary
serum albumin. It is distinct from the casein of milk.
Lac`to*bu`ty*rom"e*ter (?), n. [L. lac, lactis, milk + E. butyrometer.]
An instrument for determining the amount of butter fat contained in a
given sample of milk.
Lac`to*den*sim"e*ter (?), n. [L. lac, lactis, milk + E. densimeter.] A
form of hydrometer, specially graduated, for finding the density of
milk, and thus discovering whether it has been mixed with water or some
of the cream has been removed.
Lac*tom"e*ter (?), n. [L. lac, lactis, milk + meter: cf. F. lactomètre.
Cf. Galactometer.] An instrument for estimating the purity or richness
of milk, as a measuring glass, a specific gravity bulb, or other
apparatus.
Lac"tone (?), n. (Chem.) One of a series of organic compounds, regarded
as anhydrides of certain hydroxy acids. In general, they are colorless
liquids, having a weak aromatic odor. They are so called because the
typical lactone is derived from lactic acid.
Lac*ton"ic (?), a. [From Lactone.] (Chem.) Of, pertaining to, or
derived from, lactone.
Lac*ton"ic, a. [From Lactose.] (Chem.) Pertaining to, or designating,
an acid obtained by the oxidation of milk sugar (lactose).
Lac`to*pro"te*in (?), n. [L. lac, lactis, milk + E. protein.] (Physiol.
Chem.) A peculiar albuminous body considered a normal constituent of
milk.
Lac"to*ry (?), a. Lactiferous. [Obs.] "Lactory or milky plants." Sir T.
Browne.
Lac"to*scope (?), n. [L. lac, lactis + scope.] An instrument for
estimating the amount of cream contained in milk by ascertaining its
relative opacity.
Lac"tose` (?), n. 1. (Physiol. Chem.) Sugar of milk or milk sugar; a
crystalline sugar present in milk, and separable from the whey by
evaporation and crystallization. It has a slightly sweet taste, is
dextrorotary, and is much less soluble in water than either cane sugar
or glucose. Formerly called lactin.