308 
DR. HASSALL ON THE FREQUENT PRESENCE 
appear that the tests, as laid down in books, for cyanourine are scarcely less 
distinctive*. 
Cyanourine is described as a dark blue powder, destitute either of taste or odour ; 
it is scarcely soluble in water, moderately so in boiling - alcohol (the solution being 
blue), but it is deposited on cooling. It is dissolved by dilute acids, the solution 
being brown or red, according to the quantity of acid. With sulphuric acid a 
brown liquid is formed, which on evaporation leaves a residue of a carmine colour 
soluble in water; it is precipitated from its acid solution by ammonia, lime-water, 
and by the fixed alkalies. It gives a brown solution with nitric acid, and like 
indigo, is converted into nitropicric acid. It is said to be principally distinguished 
from indigo by its forming a reddish-brown solution with sulphuric acid, and by not 
subliming, when heated, in a test-tube. Urine containing cyanourine is of a blue 
colour, the colouring matter on repose falling as a sediment. 
Heller| applies the term uroxanthin to the colouring principle or material of the 
urine ; and that of uroglaucin to a blue pigment which he considers to be developed 
from uroxanthin under the influence of disease. This pigment, dried, forms a powder 
of a coppery lustre resembling indigo, and dissolves in alcohol with a splendid 
purple colour; its occurrence is said to be especially frequent in Bright’s disease. 
According to Heller, cyanourine is simply a mixture or combination of uroglaucin 
and urrhodin, and both these latter are but the products of uroxanthin, the colouring 
matter of healthy urine. 
It would appear, therefore, that there are no very essential differences between 
cyanourine and uroglaucin, while there are so many points of resemblance between 
them both and indigo, that one is led strongly to suspect that they are simply 
some condition or modification of indigo. Not only do these substances agree in 
many of their chemical reactions with indigo, but they also very closely resemble it 
in their ultimate composition. 
Great care should be taken to obtain these blue deposits in as pure a state as 
possible for analysis, for being in general found in alkaline urines, they are very apt to 
be contaminated with large quantities of animal matter, Vibriones, triple phosphate, 
&c. The presence of the animal matter obscures the action of concentrated sulphuric 
acid on indigo, it being charred by that reagent, and a reddish-brown solution is 
formed instead of a blue one. It also interferes with the sublimation of the indigo 
and the elimination of the characteristic vapours, as also with its conversion into 
aniline ; lastly, indigo as well as cyanourine frequently furnishes a blue solution 
when boiled with alcohol. I cannot help therefore considering it to be highly pro- 
bable that the blue pigments which have been set down as uroglaucin and cyanourine, 
have in most cases really been indigo, and -possibly have been so in all : it is, at least, 
* Braconnot, Journal de Chemie Medicale, tom. i. p. 454. 
■f Arch. f. Chem. u. Mikrosk., bd. 2. s. 161, 173. 
