A Manual of the Chemistry of the Carbon Compounds

464 TUB CHEMISTRY OP
gallic acid or digallic acid, because sqgar lias been obtained from it,
and alcohol is formed by the fermentation of nutgalls.
Caffeetannie Acid C,6HJgO8 exists in coffee and Paraguay tea ; it is
a yellow brittle mass, which does not precipitate a solution of gelatin,
and gives with ferric chloride a green precipitate. On boiling it with
potash it yields a sugar and cciffeic acid CgH^OH^CgHjj.COjH
(page 397).
Quinotanndc Add is a substance resembling tannin, and exists in
combination with quinine and other alkaloids in Cinchona-barks. It
gives with ferric chloride a green precipitate, and on boiling it with
an acid it yields a sugar and cineluma-red Cj,H2«Ou, which also
occurs in the free state in the barks; it is a brownish-red amorphous
body, having acid properties. By fusing it with potash it yields
acetic acid and protocatechuic acid.
Quercotannic Acid-is found in the bark of the oak, and forms a
yellowish-brown mass, which precipitates ferric salts deep-blue, and is
resolved by boiling dilute acids into a sugar and amorphous qxicrcwred;
on fusing this body with potash, phloroglncin and protocateehuie
acid are produced.
Similar tannic acids occur iu the roots of TormentUla offidnalis,
Kravwria triandra, and Aspidium Filiz-mas. They are resolved by
dilute acids into sugars and red nmorphous bodies, yielding, by fusing
with potash, phloroglucin and protocatechuic acid.
Gatechufannic And is a body resembling tannin, and is contained
in " catechu," a brown extract which is prepared in India from Acacia
Catechu and other trees. It precipitates gelatin and yields a dirtygreen
precipitate with ferric chloride. Catechu contains, besides this
acid, a crystalline body called catechin Cu^O^, which exists in
larger quantity in the catechu from Nauclea Gambir. It colours ferric
salts green, and reduces the solutions of the noble metals. When
heated it yields pyrocatechin, and when fused with potash it is decomposed
into phloroglucin and pyrocaleclniic acid.
Kinoiaanie Acid forms the principal constituent of "kino," a reddish-brown
extract, which is prepared from the juice of Pterocarpus
eWiwwetts and Goccoldba uvifenu It gives with ferric salts a green
precipitate, and yields phloroglucin when it is fused with potash.
Mmtannic Acid, or Maclurin C,8H18O0 + H2O, is the colouring
matter of "fustic," or the wood of Morm tinetoria, and separates from
a hot aqueous solution as a yellow crystalline powder. It colours
ferric salta green, and is resolved by potash into phloroglucin and
protocatechuic acid.
Fustic contains also worm CUH.OS> which is sparingly solnble in
water, and crystallizes in pale yellow needles. By the action of
sodium-amalgam and water it is converted into phloroglucin.
HaO + ^ = 2CaH9O3
Scojtarin CnHMO,0 exists in the common broom (Spartium scoparivnt),
and separates from alcohol in small colourless crystals,