338 CANNABACE^ 



The ' Lupulin 'Glands of the Hop. — In the interior of a 

 full-grown hop strobile are seen a large number of golden-yellow 

 pollen-like grains attached to the outer surface of the bracteoles, 

 especially near their bases. The perianth surrounding the fruit 

 is also studded with them, and a smaller number are present 

 upon the bases of the bract-like stipules. They are not met 

 with upon the ordinary leaves or stems of the plant. When 

 hops are shaken or knocked about these small grains are easily 

 detached, and may be obtained in the form of a bright yellow 

 powder sometimes spoken of as ' hop-meal ' or ' lupulin' 

 Among hop-growers this powder is often designated the 'con- 

 dition ' of the hop, and so far as a brewer is concerned the chief 

 value of a sample depends upon the amount and nature of the 

 ' hop-meal ' present in it, all the rest of the hop, such as its 

 axis, bracts, and fruits, having little more than an indirect and 

 comparatively small value in the production of beer. 



In an unripe 'hop' the 'lupulin' particles are brilliant and 

 transparent, of a golden yellow hue. As the ' hop ' ripens they 

 lose their transparency, becoming opaque, and assume a pale 

 sulphur or citron yellow colour. This change in transparency 

 of the ' lupulin,' which is easily observed with a pocket lens, is 

 the best criterion of the ripeness of a hop. In practice hops are 

 generally picked unripe ; they should, however, be left until a 

 few opaque citron yellow particles are seen interspersed among 

 the transparent ones on the lower bracteoles. 



When rubbed between the finger and thumb, the 'lupulin' 

 feels oily, and emits a characteristic odour which, in the best 

 varieties, is somewhat pleasant, while in the less valuable coarser 

 kinds the odour resembles that of garlic. 



Each particle of 'hop-meal' or 'lupulin' has the form and 

 structure given in Fig. io6. It originates from a single epidermal 

 cell, and at the time the ' hop ' is just showing the ' brush,' 

 appears in the form of a hollow cup supported on a very short 

 stalk, consisting of two or three cells (2, Fig. 106). The cup is 



