\Fer"ment\, n. [L. fermentum ferment (in senses 1 & 2),
perh. for fervimentum, fr. fervere to be boiling hot, boil,
ferment: cf. F. ferment. Cf. 1st {Barm}, {Fervent}.]
1. That which causes fermentation, as yeast, barm, or
   fermenting beer.
Note: Ferments are of two kinds: ({a}) Formed or organized
      ferments. ({b}) Unorganized or structureless ferments.
      The latter are also called {soluble or chemical
      ferments}, and {enzymes}. Ferments of the first class
      are as a rule simple microscopic vegetable organisms,
      and the fermentations which they engender are due to
      their growth and development; as, the {acetic ferment},
      the {butyric ferment}, etc. See {Fermentation}.
      Ferments of the second class, on the other hand, are
      chemical substances, as a rule soluble in glycerin and
      precipitated by alcohol. In action they are catalytic
      and, mainly, hydrolytic. Good examples are pepsin of
      the dastric juice, ptyalin of the salvia, and disease
      of malt.
2. Intestine motion; heat; tumult; agitation.
         Subdue and cool the ferment of desire. --Rogers.
         the nation is in a ferment.           --Walpole.
3. A gentle internal motion of the constituent parts of a
   fluid; fermentation. [R.]
         Down to the lowest lees the ferment ran. --Thomson.
{ferment oils}, volatile oils produced by the fermentation of
   plants, and not originally contained in them. These were
   the quintessences of the alchenists. --Ure.

\Fer*ment"\, v. t. [imp. & p. p. {Fermented}; p. pr. &
vb. n. {Fermenting}.] [L. fermentare, fermentatum: cf. F.
fermenter. See {Ferment}, n.]
To cause ferment of fermentation in; to set in motion; to
excite internal emotion in; to heat.
      Ye vigorous swains! while youth ferments your blood.
                                               --Pope.

\Fer*ment"\, v. i.
1. To undergo fermentation; to be in motion, or to be excited
   into sensible internal motion, as the constituent
   oarticles of an animal or vegetable fluid; to work; to
   effervesce.
2. To be agitated or excited by violent emotions.
         But finding no redress, ferment an rage. --Milton.
         The intellect of the age was a fermenting intellect.
                                               --De Quincey.