114 ON A NEW TEST FOR BILE AND SUGAR. 
ART. XXIX.-ON A NEW TEST FOR BILE AND 
SUGAR. 
By Dr. M. Pettenkofer. 
The phenomena about to be described, and of which an 
abstract was given in a former number of this Journal (vol. 
ii. p. 468,) were discovered by the author in studying the 
products of decomposition of the bile ; the accuracy of this 
test depending upon several collateral circumstances rela- 
ting to the purity of the reagents and use of proper propor- 
tions, we have deemed it necessary to notice these at greater 
length. 
The author remarked that when ox-gall had been treat- 
ed with sugar, and concentrated sulphuric acid was added 
until the precipitated choleic acid had begun to redissolve, 
the^mixture became considerably heated, and the liquid as- 
sumed a deep violet tint, similar to that of hypermanganate 
of potash. It was at first considered that this remarkable 
alteration might depend upon the decomposition of the bili- 
ary colouring matter; but it was found equally to occur, 
nay even more evidently, with the bile which had been de- 
colorized, and with pure biline obtained by Berzelius's me- 
thod. All the attempts to separate the new product in an 
isolated state have hitherto completely failed. The author 
consequently confines his observations to the application of 
this phenomenon as a test (a) for bile (choleic acid,) and 
(b) for sugar. The following is the method of proceeding : 
A small quantity of the liquid supposed to contain the bile 
(if the substance be solid it must be treated with alcohol, 
and the solution evaporated) is poured into a test-tube, and 
two-thirds of the volume of sulphuric acid added by drops. 
The heat of the mixture must be kept below 144° Fahr., 
otherwise the choleic acid will be decomposed. From 3 
to 5 drops of a solution of 1 part of cane-sugar to 4-5 of 
