STRONG DRL\K AND TOBACCO SMOKE. 41 



added, it immediately bursts, and the coloured matter 

 discharged is seen to consist of excessively minute, some- 

 what spherical, particles of an oily nature, that move 

 freely and with great rapidity amongst each other with 

 a tremulous motion (Plate 6, hg. 22). This peculiar 

 motion may at times be observed in the contents of the 

 granules before they are broken. 



The structure of the bracts is identical with that of 

 the membrane, viz. a layer of oblong cells with thick 

 undulating walls (fig. 24), traversed here and there, 

 where veins occur, with delicate spnal vessels and woody 

 fibres. Minute hairs, with tuberculated surfaces, are 

 also present. 



A comman practice amongst hop-buyers is to take a 

 small quantity of the dried hop-fruit, place it in the palm 

 of one hand, and with three or four knuckles of the 

 other to chafe and bruise it. The value of the sample is 

 judged of by the aroma it emits, and the sticky, almost 

 resinous stains left upon the hand. This is a rough but 

 effective way of judging both of the number and pro- 

 duce of the lupulite granules by crushing them. Good 

 sound hops will yield about one-sixth part of their 

 weight of these grains ; analysed by the chemist they 

 are found to contain, besides a volatile oil, no fewer than 

 thirteen substances, more or less in combination with 

 each other. But it would appear that to the volatile oil, 

 soluljl.i in water and alcohol, and the bitter princijilc, 

 lupulite, the most valuable properties of the fruit 

 are due. 



