On the Chemical and Natural History of Lupuline. 207 



Chemical History of Lupuline. 



The matter contained in the gland, which I designate 

 by the name of Lupuline, has a very complex composition ; 

 its constituent principles may be classed into two groups : 

 the one embracing those that are volatile, and are obtained 

 by distillation with water ; the other those that are fixed, 

 or at least not volatile with steam. 



Examination of the Volatile Princi'ples. 



The product of distillation consisted of a solution decidedly 

 acid, which reddened tournesol paper, and upon which 

 floated an essential oil, coloured occasionally of a most 

 beautiful green. 



The proportion between the quantity of essential oil and 

 of acid of the liquor distilled varied according to the quality 

 of lupuline employed in the operation. Besides, the lupu- 

 line when as fresh as possible, furnished at once a less acid 

 liquor and a greater quantity of essential oil than the older 

 lupuline, which gave, on the contrary, more acid and less 

 essential oil ; the latter is likewise drier and more resinous 

 than that obtained with the freshest lupuline. 



The quantities of essential oil which I obtained with the 

 lupulines of different ages, have given me the folio wing- 

 proportions : — With recent lupuline I obtained as much as 

 1 from 100 of the essence, while with older lupuline I have 

 had not more than 0*61 from 100, that is near my propor- 

 tion. 



Volatile Acid of Lupuline. 



If we next separate the essential oil from the acid liquid 

 obtained, as I have described, by distillation of lupuline 

 with water, and saturate the liquid with some carbonate of 

 soda, and then evaporate to dryness, it yields as residue a 

 mass of a soapy mature, which liquefies by heat and becomes 

 very solid on cooling, it is with difiiculty permeable by water, 

 which, however, ultimately dissolves it completely ; it, in 

 short, comports itself like the compounds of fatty acids with 

 alkalies.. 



This mass, dissolved in a small quantity of water and 



