58 THE HOP. 



acid, partially of an aldehydic nature. The substance 

 is insoluble in water, but easily soluble in alcohol, 

 ether, etc. It is easily oxidized to valerianic acid, and 

 Bungener attributes the presence of this acid in old 

 hops to this cause." 



Various figures are given for the percentages of 

 the true bitter principle, but owing to the widely differ- 

 ing opinions in regard to the exact nature of the one or 

 more bitter substances contained in hops, it is not 

 thought wise to repeat these figures. Hayduck. found 

 at least three resinous bodies in hops. Data in regard 

 to the percentages of these resins are not at hand, but 

 Blyth publishes, in his treatise on foods, an analysis of 

 lupulin by Dr. Yves, which shows 30 per cent, of resin. 



Several analysts have devoted considerable time to 

 the detection of an alkaloidal, or other constituent of 

 hops, which will account for the narcotic or stupefying 

 effect of beers, in the brewing of which large propor- 

 tions of hops are used. Moritz and Morris, in their 

 book already mentioned, state that while this view as 

 first announced by Graham is reasonable, it is not at all 

 improbable that the higher alcohols developed at the 

 higher temperatures prevalent in the English practice 

 of brewing are also important factors in producing a 

 beer possessing a greater stupefying effect than the 

 lager beers produced on the continent. 



Griessmeyer reported an alkaloid to which he gave 

 the name of lupulin. Griess and Harrow separated a 

 base from beer which proved to be cholin. Griess- 

 meyer denied the presence of cholin as such in hops, 

 stating that it exists combined with other bodies as 

 lecithin, a body of very complicated constitution. 



Southby, in his work on practical brewing, states 

 that by distilling hops in a current of steam he was able 

 to obtain from 1.5 to 2 per cent, of volatile oil, quanti- 

 ties decidedly in excess of the others given above. 



Moritz and Morris state that the chemistry of hops 



