【医】 白桦

Betulin \Bet"u*lin\, n. [L. betula birch tree.] (Chem.)
a term originally applied to a substance obtained as a resin
or tar by extraction from the outer bark of the common
European white birch ({Betula alba}); now referring to the
chemical compound ({C30H50O2}) having a
cyclopentanophenanthrene ring system, which is the main
constituent of that extract, and which may be obtained
crystalline; -- called also {birch camphor}. --Watts.
[1913 Webster +PJC]


Birch \Birch\ (b[~e]rch), n.; pl. {Birches} (-[e^]z). [OE.
birche, birk, AS. birce, beorc; akin to Icel. bj["o]rk, Sw.
bj["o]rk, Dan. birk, D. berk, OHG. piricha, MHG. birche,
birke, G. birke, Russ. bereza, Pol. brzoza, Serv. breza, Skr.
bh[=u]rja. [root]254. Cf. 1st {Birk}.]
1. A tree of several species, constituting the genus
{Betula}; as, the white or common birch ({Betula alba})
(also called silver birch and lady birch); the dwarf birch
({Betula glandulosa}); the paper or canoe birch ({Betula
papyracea}); the yellow birch ({Betula lutea}); the black
or cherry birch ({Betula lenta}).

2. The wood or timber of the birch.

3. A birch twig or birch twigs, used for flogging.

Note: The twigs of the common European birch (B. alba), being
tough and slender, were formerly much used for rods in
schools. They were also made into brooms.

The threatening twigs of birch. --Shak.

4. A birch-bark canoe.

{Birch of Jamaica}, a species ({Bursera gummifera}) of
turpentine tree.

{Birch partridge}. (Zo["o]l.) See {Ruffed grouse}.

{Birch wine}, wine made of the spring sap of the birch.

{Oil of birch}.
(a) An oil obtained from the bark of the common European
birch ({Betula alba}), and used in the preparation of
genuine (and sometimes of the imitation) Russia
leather, to which it gives its peculiar odor.
(b) An oil prepared from the black birch ({Betula lenta}),
said to be identical with the oil of wintergreen, for
which it is largely sold.


Birch \Birch\ (b[~e]rch), n.; pl. {Birches} (-[e^]z). [OE.
birche, birk, AS. birce, beorc; akin to Icel. bj["o]rk, Sw.
bj["o]rk, Dan. birk, D. berk, OHG. piricha, MHG. birche,
birke, G. birke, Russ. bereza, Pol. brzoza, Serv. breza, Skr.
bh[=u]rja. [root]254. Cf. 1st {Birk}.]
1. A tree of several species, constituting the genus
{Betula}; as, the white or common birch ({Betula alba})
(also called silver birch and lady birch); the dwarf birch
({Betula glandulosa}); the paper or canoe birch ({Betula
papyracea}); the yellow birch ({Betula lutea}); the black
or cherry birch ({Betula lenta}).

2. The wood or timber of the birch.

3. A birch twig or birch twigs, used for flogging.

Note: The twigs of the common European birch (B. alba), being
tough and slender, were formerly much used for rods in
schools. They were also made into brooms.

The threatening twigs of birch. --Shak.

4. A birch-bark canoe.

{Birch of Jamaica}, a species ({Bursera gummifera}) of
turpentine tree.

{Birch partridge}. (Zo["o]l.) See {Ruffed grouse}.

{Birch wine}, wine made of the spring sap of the birch.

{Oil of birch}.
(a) An oil obtained from the bark of the common European
birch ({Betula alba}), and used in the preparation of
genuine (and sometimes of the imitation) Russia
leather, to which it gives its peculiar odor.
(b) An oil prepared from the black birch ({Betula lenta}),
said to be identical with the oil of wintergreen, for
which it is largely sold.