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CHOLEIC ACID. 425
separated as an oily mass which becomes crystalline on cooling. The
alkali salts are not readily soluble in alcohol, and on the evaporation of
alcohol they may crystallize. The specific rotatory power of the
Ljdium salt l
is (a) D = +30.01° (2.29 per cent concentration) to +27.40°
(7..")’,) per cent concentration). The watery solution of the alkali salts,
when not too dilute, is precipitated immediately or after some time by
Lead acetate or by barium chloride. The barium salt crystallizes in fine,
silky needles, and is rather insoluble in cold, but somewhat easily soluble
in warm water. The barium salt, as well as the lead salt, which is
insoluble in water, is soluble in warm alcohol.
Choleic Acid (C25H42O4, Latschinoff) is another cholic acid which,
according to Lassar-Cohn,2
has the formula, C24H40O4. This acid,
which occurs in varying but always small quantities in ox-bile, and also
in gall-stones (H. Fischer and P. Meyer 3
) yields dehydrocholeic acid,
C24H34O4, and then cholanic acid, C24H34O7, and isocholanic acid on
oxidation.
Choleic acid crystallizes when free from water in hexagonal vitreous
prisms with pointed ends, melting at 185-187° C. The crystalline acid
containing water melts at 135-140° C. (Latschinoff). The acid
dissolves in water with difficulty and is also relatively difficultly soluble
in alcohol. It has an intensely bitter taste and gives the Mylius iodine
reaction for cholic acid, and also the color reaction of cholic acid with
’hydrochloric acid. The specific rotation is (a) D = +48.87° (Vahlen).
The barium salt which crystallizes from the hot alcoholic solution as
spherical aggregations of radial needles is more difficultly soluble in
water than the corresponding cholate.
Desoxycholic Acid, C24H40O4, is the name given by Mylius 4
to a
cholic acid isolated by him from putrid ox-bile, also in gall-stones (Ktis-
ter) and in faeces (Fischer 5
), and which is formed from the cholic acid
(on the putrefaction of the bile) by reduction. This last is still very
improbable, and the investigations of Ekbom do not support such an
assumption. On using perfectly pure cholic acid he was able to regain
it almost quantitatively after the action of metallic sodium on the alcoholic
solution of the acid, or of zinc and alkali. By treatment with zinc
and glacial acetic acid a reaction took place, but the product was a
mixture of mono- and diacetyl derivatives. The observation of Pregl
1
See Vahlen, Zeitschr. f. physiol. Chem., 21.
2
Latschinoff, Ber. d. deutsch. chem. Gesellsch., 18 and 20; Lassar-Cohn, ibid.,
and Zeitschr. f. physiol. Chem., 17. See also Vahlen, Zeitschr. f. physiol. Chem., 23.
3
Zeitschr. f. physiol. Chem., 76.
4
Ber d. d. chem. Gesellsch, 19 and 20.
5
Kuster, Zeitschr. f. physiol. Chem., 69; H. Fischer, ibid., 73.
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