On the Chemical and Natural History of LupuUne. 211 



3 (Ci2Hio02)+2 (CioHs) ; that of the oil rectified between 

 + 150 and 160 degrees (302° and 320° Fahr.) by C12H10O2 + 



^^10118 = ^522111802. 



The process by which it may be obtained as free as pos- 

 sible from extraneous matter, consists in preparing a tinc- 

 ture of lupuline with alcohol, of 36 degrees ; to treat this 

 liquid with an alcoholic solution of tartaric acid, which 

 forms a precipitate somewhat abundant, of bitartrate of 

 ammonia. The liquid separated from the precipitate, is 

 added to a little water, and submitted to gentle heat in a 

 capsule exposed to the air ; the alcohol, in evaporating, 

 leaves separate, at the end of two or three days, the resinous 

 matter of the solution, acid and bitter. This bitter liquid 

 is then deprived of the excess of tartaric acid which it con- 

 tains, and then made to digest with some carbonate of lead 

 recently precipitated ; the mass, evaporated at the lowest 

 possible temperature, is treated by boiling alcohol, which 

 dissolves only the bitter matter. 



Resinous Matter. 



The resinous matter is very abundant in lupuline ; it forms 

 itself alone nearly two-thirds of its weight ; it retains always 

 a certain quantity of the volatile oily products, which gives 

 to it a variable consistence, and preserves at the same time 

 the peculiar odour of lupuline. It is oxidized by contact 

 with air, especially in presence of w^ater, and its colour then 

 passes from a golden yellow to a deep brown tint, at the 

 same time that it hardens. It is largely soluble in water, 

 to which it communicates the property of lather by agita- 

 tion. This solution presents an acid reaction, and is com- 

 pletely altered by evaporation in contact with air. 



The alkalies dissolve it in the cold, and separate an in- 

 soluble part. This resin, insoluble in the alkalies and in 

 water, is soluble in alcohol ; it is dry, friable and inodorous. 

 The alkaline solution, saturated by an acid, sets free the 

 resinous matter with its original properties, and retaining 

 some valerianic acid which is got by distillation. Lastly, 

 nitric acid with heat attacks this resin with energy, but 

 without producing special reaction which would serve to 

 characterise it. 



