198 Dr, Ives on the Chemical Properties and Economical [March, 

 following proportions :— -In two drams (or 120 grains) of lupulin, 

 there is : 



Grains. 



Tannin 5 



Extractive matter 10 



Bitter principle 11 



Wax 12 



Resin 36 



A woody fibrous substance, or lignin .... 46 



Exp, 12. — Two drams of the leaves,''^ from which all the 

 lupuhn had been separated, were digested 12 hours in six ounces 

 of boiling water. The infusion was bitter, and exceedingly 

 unpleasant to the taste ; it possessed none of the aromatic flavour 

 and peculiar bitter of the lupuhn. When filtered and evaporated, 

 it yielded five grains of nauseous extract. The same leaves 

 were again digested in six ounces of proof spirit : after 12 hours, 

 the infusion was filtrated, and, by evaporation, yielded five grs. 

 of extract, similar to the last. The same leaves were digested 

 24 hours in alcohol ; the infusions manifested none of the sensi- 

 ble properties of the hop ; it gave by evaporation four grains of 

 extract. The taste of none of the extractive matter obtained 

 from the leaves was sufficiently characteristic of the hop to desig- 

 nate that it was obtained from that article.f 



From this and other similar experiments leading to the same 

 results, I think it is conclusively proved, that the virtue of the 

 hop resides exclusively in the lupulin ; that the leaves contain a 

 nauseous extractive matter, which is imparted to water and to 

 alcohol, and which, instead of adding to the bitter and aromatic 

 flavour of the lupulin, partially neutralizes or destroys it. 



The obvious inference from these results was, that the lupulin 

 was the only part of the hop essential to economical purposes ; 

 an inference so little anticipated, that it became an important 

 subject of inquiry, whether that part of the plant was duly esti- 

 mated by practical brewers — whether it had been regarded by 

 authors as preferable to the leaves, and if so, what impediment 

 or what consideration prevented its beins separated from the 

 chaflF. _ ... 



On making inquiry of a number of brewers in this city, it was 

 ascertained that there was about one in three who considered 

 this powder useful, in common with other parts of the plant. It 

 was known to all that hops were used principally for their anti- 

 septic powers, or to preserve the beer from acetous fermentation ; 

 but neither practical brewers, nor scientific writers on brewing, 



• It will be understood that by tlie kavcs are meant the calices which form the flower, 

 or that part of the hop commonly used in brewing. 



+ It is necessary to remark that great care was taken to procure the leaves for this 

 experiment perfectly free from the lupulin, which is ordinarily attached to them in great 

 abundance. This cannot be done by threshing them. 



