298 ACTION OF ALKALINE BIC ARBONATES, ETC. 
narcotia, strychnia, brucia, quinia, cinchonia and veratria, 
in the presence of tartaric acid, and fixed alkaline bicarbo- 
nates. The solutions of the salts I have mentioned were 
made in the proportion of 1 of salt, to from 200 to 500 of 
water (the action is precisely the same, whether we operate 
upon these solutions, or on decoctions of the extracts of the 
plants that contain these vegetable bases, provided they are 
properly prepared;) tartaric acid being added until the 
action of the acid becomes well marked, and afterwards 
supersaturated with one or other of the fixed bicarbonates ; 
it appears useless to add that the acid tartrates and alkaloids 
show the same result. 
The salts of morphia are not precipitated by the alkaline 
bicarbonates, but the salts of narcotia immediately produce 
a considerable white easily pulverised precipitate. If we 
wish to be satisfied of the complete absence of narcotine in 
a neutral solution, we employ sulphocyanuret of potassium ; 
this test, which produces no cloudiness in neutral solutions 
containing morphia, immediately causes a precipitate of a 
deep rose color, in those which contain narcotine, even in 
a quantity too small to be detected by weight. But we must 
always remember that a slight excess of sulphocyanuret re- 
dissolves the precipitate formed. 
The salts of strychnia, under the same circumstances, 
either produce easily pulverised precipitates, or furnish 
crystals of considerable size, according to the quantities of 
tartaric acid, bicarbonate of soda, or potassium employed, 
and according to the degree of dilution ; if the solution be 
very weak, there is no precipitate, if it be rather less so, and 
if it contains much tartaric acid, it still does not form an 
immediate precipitate by means of the two bicarbonates, 
but at the end of a quarter of an hour, we see very long 
and thin crystals appear, whose number continues to in- 
crease until all the strychnia contained in the solution is 
crystallised, we may perfectly satisfy ourselves that the so- 
lution contains no more strychnia or salt of strychnia, by 
