ON COLOC YNTHINE . 
69 
fering from them in several of its properties, so as to induce the be- 
lief that it is a body sui generis. 
Colocynthine is more soluble in water than resin ; it is, like them, 
highly inflammable. It is an oily fluid at a temperature below the 
boiling-point of water, of a pale yellow color ; but at an ordinary 
temperature it solidifies into a reddish-brown resinous body. When 
dissolved in weak acids and alkalies, it separates unchanged upon 
the evaporation of the solution. It is not volatile when isolated, as 
might be supposed from the experience of those who have been en- 
gaged in preparing extract of colocynth, although in any form it is 
intensely bitter. 
Colocynthine possesses neither basic nor acid properties, although 
Vauquelin and others have assumed to the contrary, having obtained 
a precipitate in its aqueous solutions by some metallic salts. But 
this reaction most likely arose from the colycynthine not being ab- 
solutely pure on which they experimented, as I do not find that it is 
thus effected when prepared according to a process which I have 
devised and found unobjectionable. Moreover, this method of pre- 
paration is incompatible with the existence of such a property. 
The process I recommend is as follows : — Exhaust with suc- 
cessive portions of cold distilled water the pulp of colocynth pre- 
viously freed from the seeds, until the pulp is deprived of its bitter- 
ness ; filter the solution, and heat it to the boiling point ; add, whilst 
hot, diacetate of lead, until no further precipitation ensues ; when 
cold, filter, and to the clear liquid add diluted sulphuric acid care- 
fully as long as a precipitate is thrown down ; again boil to remove 
the free acetic acid, and filter to separate the sulphate of lead. By 
this means all the organic matter, except the colocynthine, is re- 
moved. Evaporate the filtrate cautiously to near dryness, and dis- 
solve the colocynthine out of the residuum by means of strong alco- 
hol, which leaves the salts undissolved as sulphates. By evapo- 
rating the alchoholic solution the colocynthine may be obtained 
pure. 
This process is more complex than those recommended by Vau- 
quelin and Braconnot ; but, nevertheless, it is easy of execution. 
Colocythine dissolves in strong sulphuric acid, but evidently is at 
the same time decomposed. The solution is dark brown, and upon 
being diluted with water a precipitate of a carbonaceous nature is 
