A Manual of the Chemistry of the Carbon Compounds

THE OJIEMISTMY OF
COMPOUNDS CONTAINED IN BILE AND OTHER SECRETIONS.
Bile contains a number of peculiar compounds, some of them
occuring also in other parts of the animal organism.
Glycodwlic AcidO^^O^ is conveniently prepared by evaporating
fresh OK-bile on a water bath nearly to dryness, exhausting the residue
with alcohol of 90 per cent, evaporating the solution, and heating
with milk of lime to preeipibate the colouring matter. On adding
dilute sulphuric acid to the cold filtrate and leaving it to stand,
glycocholic acid crystallizes out, which is purified by pressing it
between filter-paper, dissolving the residue in lime-water, and
precipitating the acid with dilute sulphuric acid.
It crystallizes in white needles, having a bitterish sweet taste. In
concentrated sulphuric acid it dissolves, forming a colourless liquid,
which oa adding a solution of sugar becomes violet.
When glycocholic acid is boiled with dilute acids, or alkalis, it is
resolved into glyeoooll or anridacotic acid, and cliolic acid C^H^Oj,
which crystallizes from alcohol in brilliant octahedrons. By protracted
boiling with acid3 it is converted into dyslysin CMH80O3, an amorphous,
neutral substance, which is reconverted- into cholic acid by the
action of caustic potash.
Tauroclwlic Acid C^H^NSOj is prepared by dissolving fresh
ox-bile in water and precipitating glycocholic acid, colouring matters
and other substances with lead acetate. To the nitrate a little basic
lead acetate is added, which removes the remainder of the glycocholic
acid, and then the clear solution is precipitated by adding some more
lead acetate and ammonia. The lead taurocholate is decomposed by
hydrogen sulphide, and thus the free acid is obtained, crystallizing in
fine silky needles. By heating it with water it is resolved into
cholic acid and taurine (page 102).
Hnuiau bile contains principally glycocholic acid, and only a small
quantity of taurocholic acid, which occurs alone in the bile of
the dog.
Hyoglycocliolic Acid C^H^NOj and hyotawoeholie acid C^H^SOQ
exist in the bile of tho pig and have been resolved into gyeocoll,
or taurine and Uyocholic acid C5H40O4, a compound resembling
cliolic acid.
C/icnotatirocholic Acid Ca)ir49lirSO8 is homologous with hyotaurocholic
acid, and occurs in the bilo of the goose; it yields, as products
of decomposition, taurine and chcnoclwlic acid C^H^O^
Lithofetlic Acid C^H^O^ forms the chief constituent of the once
celebrated " oriental bezoar-stones," which are said to be biliary
calculi from a species of antelope. It crystallizes from alcohol in
small transparent six-sided prisms, which with sulphur acid and
sugar give the same reaction as glycocholic acid.