NITRIC ACID ON VARIOUS VEGETABLES. 
423 
alkali is slightly supersaturated with either hydrochloric or acetic acids, the scoparine 
is thrown down as a white precipitate, which appears however to be a little more com- 
pact and denser than before its solution in the alkali. When this precipitate, after 
being washed to remove any adhering sal-ammoniac, is again dissolved in boiling 
water, it forms a pale yellow solution, which, when it is allowed to cool very slowly, 
deposits a quantity of pale yellow prisms arranged in stars, which attach themselves 
to the bottom and sides of the containing vessel, while some gelatinous scoparine re- 
mains floating in the centre of the liquid. 
As scoparine appeared to crystallize out of its aqueous solutions with considerable 
difficulty, a quantity of it, while still but imperfectly purified, was evaporated to dry- 
ness on the water-bath and then treated with boiling spirits of wine. A small por- 
tion of it remained undissolved, and the yellowish solution, which was formed after it 
had remained for a day in a covered glass vessel, did not crystallize ; but when a por- 
tion of the alcohol was slowly evaporated, the scoparine precipitated in the gelatinous 
state. The solution was therefore again heated, when the gelatinous matter dissolved ; 
and on leaving the solution to spontaneous evaporation, in the course of two or three 
days the bottom and sides of the glass became covered with short prisms of scoparine, 
arranged in little stars, precisely similar to those obtained by slow cooling from the 
aqueous solution. These crystals were then dried by pressure between folds of bibu- 
lous paper and were again dissolved in hot spirits of wine, and after twelve hours 
they crystallized in short prisms of a pale yellow colour and possessing considerable 
lustre. If these crystals are boiled with a quantity of strong or absolute alcohol, in- 
sufficient for their entire solution, a portion dissolves, while that which remains ap- 
pears to undergo a kind of molecular change, and becomes more difficultly soluble, 
both in hot alcohol and in water. It may be easily restored to its original state 
again (from this apparently allotropic condition) by dissolving it in ammonia and 
neutralizing with acetic acid, when the scoparine precipitates as a jelly and becomes 
as soluble as before. If it is then treated therefore with boiling water it readily dis- 
solves, and on allowing the solution to cool very slowly, the scoparine crystallizes out 
in small stars, possessing all its original properties. 
Scoparine, when prepared in any of the ways above described, has, as we shall pre- 
sently see, invariably the same composition. It is tasteless and inodorous, and does 
not affect either litmus or turmeric paper. It dissolves very readily in caustic and 
carbonated alkalies, and it is also soluble, to some extent, in concentrated acids, the 
colour of its solutions being greenish yellow. When the alkaline or acid solutions 
of scoparine are boiled it is slowly decomposed, being changed into a greenish-brown 
resinous matter. Scoparine dissolves pretty readily in lime and baryta water, but not 
nearly to the same extent as in ammonia and the fixed alkalies. When its ammo- 
niacal solution is left to spontaneous evaporation in the open air, almost the whole 
of the ammonia volatilizes and the residue forms a greenish gelatinous mass. A 
solution of hypochlorite of lime changes scoparine to a deep green colour, probably 
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