ON ALOINE. 
227 
exposure to the air in desiccation. It is completely neutral ; its 
taste, at first sweetish, very soon becomes intensely bitter. Spar- 
ingly soluble in the cold, it dissolves more easily by the aid of 
heat. The alkalies and alkaline carbonates dissolve it easily in 
the cold, forming a liquid of an orange yellow, which deepens ra- 
pidly upon contact with the atmosphere, from the absorption of 
oxygen. Boiled with alkalies or strong acids, it is rapidly trans- 
formed into a brown resin. It colors a solution of chloride of lime 
at first yellow, then brown. It is not precipitated by corrosive 
sublimate, nitrate of silver, or neutral acetate of lead. Concen- 
trated sub-acetate of lead produces a precipitate of an intense yel- 
low, soluble in an excess of water, and becoming deeper colored 
on exposure. 
Fuming nitric acid dissolves it cold, without the slightest disen- 
gagement of gas, forming a reddish-brown liquid. Sulphuric acid 
added in great excess to this solution throws down a yellow pul- 
verulent body, which explodes when heated, and probably contains 
the elements of hyponitric acid. When aloi'ne is digested with 
warm and concentrated nitric acid, it is transformed into chrysam- 
mic acid with disengagement of copious red fumes. There is not 
in this reaction the slightest trace of picric acid. By dry distilla- 
tion, aloi'ne furnishes a volatile oil of an almost aromatic odor, and 
a considerable quantity of a resinous substance. Burnt upon a 
platinum plate, it melts and takes fire burning with a yellow and 
brilliant flame. There remains a charcoal, difficult to incine- 
rate. 
According to the analysis of M. Stenhouse, the composition of 
aloi'ne is represented by the formula. 
C 34 H 18 Q4 
which has been verified by the analysis of a bromated compound, 
consisting of 
To obtain this bromated compound, which crystallizes more readily 
than pure aloi'ne, M. Stenhouse adds bromine to a cold aqueous 
solution of aloi'ne. It forms instantly a yellow precipitate which 
increases by repose, while the supernatant liquid assumes a very 
acid reaction, consequent upon the formation of hydrobromic acid. 
By dissolving the precipitate in warm alcohol, and cooling the so- 
lution, bromated alo^ne is obtained in brilliant yellow needles, 
