A Manual of the Chemistry of the Carbon Compounds

490 TME CHEMISTBT OF
dissolving in alkalis and alcohol with a brown colour; it is found in
small quantity in biliary calculi
Biliprasin CjgHjjNjOg occurs in biliary calculi, and in the ox-bile.
It is a dark-green powder, insoluble in water, and dissolving in
alcohol with a green colour, and in alkalis with a brown colour.
When nitric acid containing a little nitrous acid is added to an
alkaline solution of any of these colouring matters of bile, the liquid
first assumes a yellow colour, changing successively into green, blue,
violet, red, and finally again into yellow.
Bilihwniin. is a dark brown substance existing in all biliary
calculi, and which is also the final product produced by exposing an
alkaline solution of the other colouring matters of bile to the air.
Cystine C8H-NSO8 occnrs in the form of calculi or sediment in the
bladder. On dissolving it in ammonia, and allowing the solution to
evaporate, it is obtained in small, colourless, six-sided plates. On
heating it with soda-solution it yields sodium sulphide, and when
treated with zinc and hydrochloric acid it gives off hydrogen sulphide.
It has probably the following constitution:—^^(SHXNH^COjjH.
Kynurmic Add CjoH^NjOg exists in the urine or the dog, and
forma, in the pure state, silver-white glistening needles containing 2
niolecnlcs of water; it is insoluble in water, but dissolves in concentrated
acids. Barium Ki/nurcnate C^HjjBaNjO,, + 3H2O is
sparingly soluble in water and crystallizes in glistening compact
needles.
When kynurenic acid is heated to 265° it melts, giving off carbon
dioxide, and being converted into Kynurine C^H^NJOJ, crystallizing
from warm water in beautiful transparent prisms, melting at 210°.
The hydrochloride C.8H,4N2O2(C1H)2 + 2H2O forms colourless
needles, and yields, witn platinic chloride, the compound C18HuNiO2
(O1H). + PtCl4, existing in beautiful crystals.
Lithurie And C^H^NOg.—A peculiar kind of calculi, which are
voided with the urine by oxen fed on the stalks of Indian corn in
Toskana, consist of the magnesium saltof this acid (C16H,8NO9)2Mg ;
it crystallizes from boiling water in small nionoclinic, transparent
prisms, which on heating decompose, giving oft' the smell of burnt
sugar. The free acid crystallizes from hot water in fine, silky, white
needles, melting at 205°,
Hxcretin C2?H3(lO is contained in human fteces, and crystallizes
from hot alcohol in small needles. By the action of bromine it is
converted into dibronuxcretin CMH84Br2O, crystallizing from etheralcohol
in hard, globular masses.