NAT. OUDER. — SCABRID^. 169 



Sensible and Chemical Properties. — The dried strobiles have 

 a pecuhar fragrant odor, and a very bitter, somewhat aromatic, and 

 a shghtly astringent taste. New hops are of a pale, greenish- 

 yellow hue, and appear like thin, transparent leaves ; by long 

 keeping their color changes to a yellowish-brown. The watery 

 infusion has a pale straw color, is rendered muddy by the mineral 

 acids ; alkalies deepen its color ; it strikes an olive with sulphate 

 of iron ; is jjrecipitatcd by solutions of nitrate of silver, tartarized 

 antimony, superacetate of lead, and alcohol : and when rubbed 

 Avith magnesia, or lime, a rod dipped in muriatic acid discovers the 

 presence of ammonia. By distillation in water, an essential oil is 

 obtained. The virtues of hops are extracted by alcohol, ether, and 

 boiling water ; by long boiling the aromatic properties are dissipated. 



From the experiments of Dr. Ives of New York, it appears, that 

 the active properties of hops reside in a powder, which may be rea- 

 dily separated from the strobiles, by merely sifting in a fine sieve. 

 This substance forms about one-sixth part of their weight, and to it 

 Dr. Ives has given the name lupuUn. According to Dr. Ives' analy- 

 sis, 120 grains of lupulin contain about — of tannin .5 grains, extrac- 

 tive matter 10, bitter principle 11, wax 12, resin .36, lignum 46. — 

 The extractive matter is soluble in water only ; the bitter principle 

 is soluble in water and alcohol ; the wax is soluble only in alkalies 

 and boiling ether ; the resin is soluble in ether and alcohol ; the 

 aromatic and bitter properties of the lupulin are more readily and 

 completely imbibed by alcohol than water, and much sooner by both 

 when hot than when cold ; about five-eighths of lupulin are soluble 

 in water, alcohol and ether, three-eighths being vegetable fibrous 

 matter. M. Payer and A. Chevalier have confirmed Dr. Ives' opin- 

 ion, that the properties of the hop reside in the lupuhn, or the yel- 

 low grains which are scattered over the membranous scales of the 

 strobiles. They also discovered a volatile oil in lupulin, which is 

 similar in odor to the hop, but much more penetrating. The fol- 

 lowing process has been practised by M. Planche, for purifying 

 lupulin. 



