232 
A TEST FOR CINCHONINE IN QUININE. 
amount of sulphate of quinine is dissolved in tartaric acid ; 
it is diluted from two hundred to three hundred ])arts of 
pure water, and an excess of bicarbonate of potash or soda 
added. Under the influence of the tartaric acid, M. Opper- 
mann states that the quinine does not yield any precipitate, 
whilst the other base gives an abundant deposit. 
I have several times repeated these two processes, and 
must confess that I found them totally deficient in accuracy; 
for in the first the chloride of lime, whilst forming with the 
sulphate of cinchonine a more apparent precipitate, did not 
the less dissolve the whole when added in sufficient excess. 
With respect to the second, the bicarbonates of potash and 
soda equally furnished abundant precipitates, which was 
formed more or less slowly in the tartaric solutions. Some- 
times I obtained no precipitate either in one or the other 
salt. The want of success which I experienced, induced 
me to follow a different method, which, although requiring 
more time, leads, when carefully made, to very good results, 
according to experiments which I have made upon mixtures 
of sulphates of quinine and cinchonine in the proportions 
of 2, 4, 10 and 15 per cent, of the latter. 
. From twenty to thirty grms. of the sulphate of quinine 
to be examined are dissolved in a certain quantity of dis- 
tilled water slightly acidulated, and an access of caustic soda 
added to the solution. The collected and washed precipi- 
tate is saturated with hot acetic acid; the mixture solidifies 
on cooling to a crystalline mass, which is thrown upon a 
filter of fine linen and expressed ; the clear solution evapo- 
rated to one half, yields on cooling more crystals, which are 
separated in the same manner. The mother- water is then 
decomposed again with dilute caustic soda, and the pre- 
cipitate formed is, after washing, treated in the cold either 
by ether or by alcohol of 0.923. After this treatment, it is 
boiled twice, or more frequently, in absolute alcohol, and 
filtered boiling hot. The alcoholic solution, evaporated 
with care and to dryness, leaves the cinchonine in minute 
