\Fer`men*ta"tion\, n. [Cf. F. fermentation.]
1. The process of undergoing an effervescent change, as by
   the action of yeast; in a wider sense (Physiol. Chem.),
   the transformation of an organic substance into new
   compounds by the action of a ferment, either formed or
   unorganized. It differs in kind according to the nature of
   the ferment which causes it.
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}.