§§ 522. 523-] COLCHICINE. 431 
Colchicine contains four methoxvl groups, and its constitutional 
formula is considered to be C 15 H 9 [NH(CH 3 CO)](COOCH 3 )(OCH 3 ) 3 . 
Its melting-point is 143°-147°. It is usually a white, gummy mass. 
It is easily soluble in cold water, in alcohol, and in chloroform. The 
solutions are lsevo-rotatory. It is hardly soluble in ether. From its 
aqueous solution it is deposited in large yellow rhombic crystals of 
the sparingly soluble hydrate, (C 22 H 25 0 6 N) 2 3H 2 0. It forms also two 
crystalline compounds with chloroform, containing respectively 1 and 
2 molecules combined with 1 molecule of chloroform. Boiling with 
dilute acids or alkalies in closed tubes yields colchiceine, C 21 H 23 N0 6 . 
Colchiceine contains three methoxyl groups. It crystallises with one 
molecule of water and melts at 140° ; when anhydrous it melts at 172°. 
It dissolves but little in cold, copiously in boiling water. Colchiceine is 
a monobasic acid, forming salts with the alkalies, and colchicine is its 
methyl ester. 
Zeisel 1 has formed acetotrimethylcolchicinamide (NHAcC 15 H 9 (OMe) 3 
CONH 3 ) by heating colchicine with alcoholic ammonia in closed tubes 
for four hours at 100°. The amide is crystallised from hot alcohol; it is 
readily soluble in dilute HC1, almost insoluble in water ; when a strong 
hvdrochloric acid solution of the amide is treated with a small amount of 
•/ 
potassium nitrite a splendid violet colour is produced. 
§ 522. Tests. —Ferric chloride, if added to an alcoholic solution of 
the alkaloid, strikes a garnet-red ; if to an aqueous solution, a green or 
brownish-green ; nitric acid added to the solid substance gives a violet 
colour. Erdmann’s reagent (nitrosulphuric acid) gives in succession 
green, dark blue, and violet colours, ultimately turning yellow, changed 
on addition of an alkali, to raspberry-red. Mandelin’s reagent (1 grm. 
of ammonium vanadate in 200 grms. of sulphuric acid) gives a green 
colour. 
§ 523. The alkaloid colchicine is not official, but is in pharmaceutical 
commerce usually in combination with other drugs, such as extract of 
nux vomica ; colchicine salicylate is also not infrequently prescribed 
for rheumatic affections. The preparations of the British Pharmacopoeia 
are :— 
(a) Colchicum corms. —Extract of colchicum, essentially consisting 
of the juice squeezed out of the fresh corms, deprived of starch by 
deposition, heated to 100°, filtered through flannel, and evaporated to 
a soft extract at a temperature not exceeding 70°. 
Colchicum wine , made by macerating 200 grms. of the conns to the 
litre of sherry wine. 
( h ) Colchicum seeds. —Tincture of colchicum, made by percolating 
100 grms. of the seeds with 70 per cent, alcohol, made up to a litre. 
Half the strength of the corresponding preparation of the British 
1 Monatsh., ix. 1-30. 
