128 



being the yellowish green imbricated membranous bracts and 

 stipules. If these leafy organs are removed from the strobile, the 

 axis will be seen to be hairy and have a zigzag course, bearing 

 rudimentary branches on alternate sides. Some of the leafy bodies 

 enfold at their bases minute fruits : these are the bracts (fig. 72, b) ; 

 others, the stipules, do not. The fruits are minute achenes, and are 

 partially surrounded by a perianth (fig. 72, c). Both the minute 

 fruits and the bases of the bracts are sprinkled over with yellowish 

 shining translucent glands, which contain volatile oil and constitute, 

 when separated, the drug lupulin. 



The odour of fresh hops is strong and characteristic, although 



scarcely agreeable ; the taste strongly 

 aromatic and disagreeably bitter and 

 acrid. By keeping, the aroma becomes 

 less powerful but also less agreeable, the 

 bracts and stipules turn yellow, and the 

 glands acquire a brown colour. 



The student should strip the bracts and 

 stipules from the strobile and observe 



(a) The zigzag hairy axis, 



(b) The bracts enclosing fruits and 



bearing glands. 



a 



FIG. 72. Hop. a, strobile of 

 the Hop, natural size. 6, 

 bract enfolding at its base 

 a small fruit, and showing 

 lupulin glands, natural size. 

 c, fruit magnified, showing 

 lupulin glands. (Tschirch.) 



Constituents. The composition of hops 

 is very complex. They contain volatile 

 oil, tannin, sugar, fatty acids, resins, &c. 

 The volatile oil (0-3 to 1-0 per cent.) 

 consists chiefly of the terpene humulene. 

 The bitterness is due to a number of 

 substances only one of which, humulol, 

 has been obtained crystalline and pure. 

 Some of these substances are soluble in water, others are constituents 

 of the resin ; xanthohumol is an orange yellow, crystalline body. 

 One of the constituent resins yields by oxidation valerianic acid, a 

 reaction that explains the change in the odour when hops are kept. 



Uses. The volatile oil produces sedative and soporific effects, 

 whilst the bitter substances are stomachic and tonic ; hops accordingly 

 improve the appetite and promote sleep. 



CUBEBS 



(Fructus Cubebse) 



Source, &C. Cubebs are the fruits of Piper Cubeba, Linne filius 

 (N.O. Piperacece), a dioecious woody climber indigenous to Java, 

 Sumatra, and Borneo, and apparently cultivated also in those islands, 



