346 CANNABACE^ 



to the grower, males have never been subject to special selection 

 and improvement. 



It is somewhat curious that, although female seedlings show 

 considerable variation, we have never seen any morphological 

 differences among males, no matter what their origin, except in 

 one or two solitary instances where the 'bines' were a paler 

 colour than usual. 



Raising from 'seed' is, however, the only way of obtaining 

 new and vigorous distinct varieties, but as the practice involves a 

 great deal of time, labour, and patience in the selection and 

 subsequent propagation of the plant, it is rarely attempted. 

 With one or two unimportant exceptions all the modern intro- 

 ductions have been casual selections of individual plants which 

 have shown some peculiarity different from their neighbours 

 in an ordinary hop garden. 



Yield. — The hop crop is subject to very great fluctuation, 

 due to adverse climatic influences and the attack of parasitic 

 fungi and insects. 



Cultivation and the application of manures also very largely 

 modify the yield. On some farms not more than five or six cwt. 

 of dry hops is obtained even in the best seasons, while on others 

 a ton per acre is not uncommon. 



The average crop in this country for the last ten years is about 

 8 cwt. of dry hops per acre. 



Composition. — The secretion contained in the ' lupulin ' or 

 hop-glands is a complex mixture of several substances, the chief 

 of which are {a) hop-oil and {b) resins. 



The hop-oil is an essential volatile oil, which gives the hop 

 strobile its characteristic aroma ; it appears to be secreted most 

 vigorously when the gland is young. 



The different aroma of the different varieties is no doubt due 

 to uninvestigated compounds present in the hop-oil. 



Of the resins three varieties have been isolated. Two of 

 these, designated soft-resins, are intensely bitter, and communi- 



