資料來源 : Webster's Revised Unabridged Dictionary (1913)
Lactic \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}.
2. A state of agitation or excitement, as of the intellect or
the feelings.
It puts the soul to fermentation and activity.
--Jer. Taylor.
A univesal fermentation of human thought and faith.
--C. Kingsley.
{Acetous, or Acetic}, {fermentation}, a form of oxidation in
which alcohol is converted into vinegar or acetic acid by
the agency of a specific fungus or ferment ({Mycoderma
aceti}). The process involves two distinct reactions, in
which the oxygen of the air is essential. An intermediate
product, aldehyde, is formed in the first process. 1.
C2H6O + O = H2O + C2H4O
Note: Alcohol. Water. Aldehyde. 2. C2H4O + O = C2H4O2
Note: Aldehyde. Acetic acid.
{Alcoholic fermentation}, the fermentation which saccharine
bodies undergo when brought in contact with the yeast
plant or Torula. The sugar is converted, either directly
or indirectly, into alcohol and carbonic acid, the rate of
action being dependent on the rapidity with which the
Torul[ae] develop.
{Ammoniacal fermentation}, the conversion of the urea of the
urine into ammonium carbonate, through the growth of the
special urea ferment. CON2H4 + 2H2O = (NH4)2CO3
Note: Urea. Water. Ammonium carbonate.
Note: Whenever urine is exposed to the air in open vessels
for several days it undergoes this alkaline
fermentation.
{Butyric fermentation}, the decomposition of various forms of
organic matter, through the agency of a peculiar
worm-shaped vibrio, with formation of more or less butyric
acid. It is one of the many forms of fermentation that
collectively constitute putrefaction. See {Lactic
fermentation}.
{Fermentation by an} {unorganized ferment or enzyme}.
Fermentations of this class are purely chemical reactions,
in which the ferment acts as a simple catalytic agent. Of
this nature are the decomposition or inversion of cane
sugar into levulose and dextrose by boiling with dilute
acids, the conversion of starch into dextrin and sugar by
similar treatment, the conversion of starch into like
products by the action of diastase of malt or ptyalin of
saliva, the conversion of albuminous food into peptones
and other like products by the action of
pepsin-hydrochloric acid of the gastric juice or by the
ferment of the pancreatic juice.
{Fermentation theory of disease} (Biol. & Med.), the theory
that most if not all, infectious or zymotic disease are
caused by the introduction into the organism of the living
germs of ferments, or ferments already developed
(organized ferments), by which processes of fermentation
are set up injurious to health. See {Germ theory}.
{Glycerin fermentation}, the fermentation which occurs on
mixing a dilute solution of glycerin with a peculiar
species of schizomycetes and some carbonate of lime, and
other matter favorable to the growth of the plant, the
glycerin being changed into butyric acid, caproic acid,
butyl, and ethyl alcohol. With another form of bacterium
({Bacillus subtilis}) ethyl alcohol and butyric acid are
mainly formed.
{Lactic fermentation}, the transformation of milk sugar or
other saccharine body into lactic acid, as in the souring
of milk, through the agency of a special bacterium
({Bacterium lactis} of Lister). In this change the milk
sugar, before assuming the form of lactic acid, presumably
passes through the stage of glucose. C12H22O11.H2O =
4C3H6O3
Note: Hydrated milk sugar. Lactic acid.
Note: In the lactic fermentation of dextrose or glucose, the
lactic acid which is formed is very prone to undergo
butyric fermentation after the manner indicated in the
following equation: 2C3H6O3 (lactic acid) = C4H8O2
(butyric acid) + 2CO2 (carbonic acid) + 2H2 (hydrogen
gas).
{Putrefactive fermentation}. See {Putrefaction}.