1821.] and Medicinal Virtues of the Commoji Hop. 197 



caused no change ; by evaporation, it yielded 15 grs. of a veiy 

 bitter extract. The same hipuhn was digested again in boihng; 

 water — animal gelatin added to the filtered solution, induced no 

 precipitate ; by evaporation, an additional quantity of six grs» 

 of the vs^atery extract was obtained. 



Exp. 8. — The extract obtained in the last experiment, was put 

 into pure alcohol, and frequently agitated. After 24 hours it 

 was filtered ; 10 grs. had been redissolved by the alcohol, and 

 an insoluble mass, weighing 1 1 grs. was left upon the filter. 



Exp. 9. — The same lupulin which was used in the seventh 

 experiment was now digested in alcohol. The infusion was 

 highly bitter, and of a fine yellow colour ; it gave by evaporatioa 

 24 grs. of resin. By digesting in a second portion of alcohol, 12 

 grs. more of resin were obtained, less bitter, but otherwise like- 

 the last. 



Exj). 10. — The lupulin which was the subject of the last expe- 

 riment, after having been thus boiled in water, and digested in. 

 alcohol, was put into a small retort, and boiled in two ounces of 

 ether. While boiling, it was filtered into a vessel containing cold 

 water, by which means 12 grs. of wax were obtained.^ 



Exp. 11. — Half an ounce of lupulin was boiled successively ia 

 ^ater, alcohol, and ether. On weighing the insoluble residuum,, 

 it was found that five -eighths of the whole had been taken up byj 

 the solvents. i 



From the foregoing experiments, all of which were, with some 

 variation, frequently repeated, I infer, that the lupuhn contains, 

 a very subtle aroma, which is yielded to v/ater and to alcohol, 

 and which is rapidly dissipated by a high heat ; that no essen- 

 tial oil can be detected by distillation in any portion of the hop ;. 

 that the lupulin contains an extractive matter, which is solublet 

 only in water ; that it contains tannin, gallic acid, and a bitter 

 principle, which are soluble in water and in alcohol ; that it con- 

 tains resin, which is dissolved by alcohol and by ether, and wax, 

 which is soluble only in alkalies and in boiling ether ; that it 

 <jontains neither mucilai>:e, gum, nor gum-resin ; that the aromatia 

 and bitter properties of the lupulin are more readily and com- 

 pletely imbibed by alcohol than by water, and much sooner by 

 both when they are hot than when they are cold ; that about 

 five-eighths of the whole substance is soluble in water, alcohol, 

 and ether, there being about three-eighths of it vegetable fibrous 

 matter. These proximate principles exist in very nearly the 



* The usual method of separating wax from vegetables, by boiling them in caustic 

 ammonia, and then supersaturating the alkali with vinegar, or with diluted sulphuric 

 acid, is tedious, and the results unsatisfactory. The following is a much more easy and 

 beautiful process. After digesting the substance in boiling water and cold alcohol, let it 

 be boiled in ether, and the solution strained, while boiling, into cold water. The wax, 

 which is held in solution by boiling ether, is thrown down as soon as the ether is cooled 

 by the water, and its specific gravity being greater than that of ether, and less than that 

 of water, it forms a beautiful partition between them. If the ether be suffered to evapo^ 

 rate, the wax may be taken from the water entire. 



