81 



resembling two cones placed base to base. During development of 

 the gland, a secretion collects in the indented portions, and the upper 

 cuticle breaks away and forms the tender, yellowish hood, forming 

 the upper cone. By the increase of the secretion, the gland, as a 

 rule, is burst open at the surface of contact of the two cones. The 

 glandular scales easily break off the stalk by which they are attached 

 to their bases ; and so it comes about that in the preparation of hops 

 for the market a part of the lupulin falls out. By lupulin, however, 

 is also understood the secretory contents of the gland. 



The name has also been applied to an unknown alkaloid 

 recurring in hops. 1 



The contents of the lupulin granules do not consist of a single, 

 definite, chemical compound, but are composed of a mixture of 

 different bodies, the bitter substances predominating. The last it is 

 proposed to consider at length. 



Since very little is known concerning the chemical composition 

 of lupulin, it may be of interest to give here the analysis of the raw 

 material (commercial) employed by the author in his researches. 



The lupulin was completely exhausted with ether, and the ether 

 extract and the insoluble cellular residue separately examined. 



100 g. lupulin (i8'27 per cent, total ash) yielded on the average : 

 63*93 g. ether soluble extract. 

 36-07 g. lupulin cell walls. 



The ether soluble extract comprised the following constituents : 



Wax ... ., 0-18 per cent. 



a-resin (by precipitation with lead salt 



HAYDUCK'S method) I1 '55 



/?-resin (by titration, the a-resin being 



deducted) ... 43*31 



Ether soluble ash 2 0-17 ,, 



Other constituents (fat, oil, y- resin, &c.) ... 8-72 ,, 



1 Griessmayer. Dinglers' Polyt. Journal, 1874, 67 ; Zeitschrift fur Analyt. 

 Chemie, 1880, 105. 



2 Mineral substances contained in the ether extract. 



