70 



THE BITTER SUBSTANCES AND 

 RESINS OF HOPS. 



A SHORT HISTORICAL REVIEW OF THE MOST 

 IMPORTANT PROPERTIES OF THESE BODIES. 



BY DR. GEORG BARTH 



(Consulting Chemist at the Wissenschaftliche Station fur Brauerei at Munich). 



'"jPHE great importance which hops enjoy in the brewing industry, 

 as well as from an agricultural standpoint, has induced investi- 

 gators to undertake the examination of the chemical constituents of 

 hops. The great variety of substances present in the hop flower, 

 coupled with the ill- denned chemical character of some of them, have 

 resulted in a whole series of communications ever containing fresh 

 facts concerning the chemistry of the hop components ; but, unfortu- 

 nately, this material is marred by many inconsistencies. If our 

 knowledge in this domain were as extensive as its literature, the 

 constituents of hops ought to be among those bodies best known to 

 organic chemistry. Within recent years an extensive work on hops, 

 by BRAUNGART, 1 has appeared ; but the subject matter is by no 

 means well arranged. It is intended, therefore, in the following to 

 consider briefly all past investigations relating to the bitter 

 substance of the hop : 



IVES B was the first to indicate that lupulin contains a bitter 

 substance, soluble in water and alcohol. 



1 Munich, 1901. (Publisher: R. Oldenbourg.) 



2 American Journal of Science of Silliman, II, 1820, 302. 



