73 



serves to dissolve the adherent brown syrup without attacking the 

 crystals, and by its means LERMER finally obtained shining white 

 crystals, which, however, in 12 hours exhibited some alteration, 

 and gradually changed into a resinous, amorphous, yellow mass. 

 In the pure state LERMER'S " hop-bitter acid " is stated to be 

 remarkable for its ready crystallisability. 



According to LERMER the substance forms brilliant, rhombic, 

 glass-like prisms, which are extremely brittle, and so insoluble in 

 water that no bitter flavour can be detected when the crystals are 

 placed whole, or crushed, on the tongue. A diluted alcoholic 

 solution, however, exhibits a distinct bitter flavour. The crystals 

 are very readily soluble in alcohol, ether, chloroform, carbon 

 disulphide, benzene, turpentine, and similar solvents. 



From the elementary composition of the copper compound 

 LERMER endeavoured to deduce its empirical formula. 



The analytical data for the copper salt point to the formula 

 CuO.C 32 H 35 O 7 (C = 6), and according to LERMER indicate a 

 certain relationship with other bitter substances, such as Absynthiin 

 and Jalapinolic acid. In addition, LERMER refers to several other 

 bodies obtained by him from hops, one of which forms felted, silky 

 needles, melting at over 110 C. 



In his researches concerning hop-tannic acid, Exn 1 , in 

 conclusion, refers to hop bitter, which he prepares in the following 

 manner : 



Hops are extracted with ether which dissolves ethereal oil, 

 chlorophyll, a crystalline white, and an amorphous brown resin 

 The white resin remains behind when the ether residue is taken up 

 with alcohol. (This is LERMER'S Myricin a wax.) 



The resin present in the alcoholic solution is separated from 

 the bitter principle by addition of water, and settles out on standing 

 (the turbid liquid passes through a filter) leaving the bitter in 



1 Dingier' s Polyt. Journal, 1878, 228, 354; also Zeitschrift f. d. ges. Brauwesen* 

 1878, 293. 



