268 HOPS. 



accompaniment of the phenomenon and not its cause. He 

 was, however, able to prove that the bacillus discovered by 

 him, and described as very similar to the Bacillus {fluorescens) 

 putidus Fliigge, is the generator of ammonia and trimethyl- 

 amine in hops, which latter product is never found in sound 

 hops. ■ 



The following inforrnation is taken from Behrens' highly 

 interesting work : — 



1. Spontaneous heating — which need not be dreaded 

 when the hops contain not more than 8 to 10 per cent, of 

 moisture — is due to the development and activity of various 

 micro-organisms, different kinds acting in different cases. 



2. The mould fungi {Aspergillus, Penicillium, etc.), occurring 

 on hops that have spontaneously heated, destroy the acid 

 content of the hops, and convert the salts of the organic 

 acids into carbonates. 



Harz found the following varieties of mould fungi on 

 damp hops : Aspergillus glaums, Penicillium glauoum, Mucor 

 nigricans, Mucor racemosus, Mucor mucedo, Cladospnrium peni- 

 cilloides, Haplotrichum roseum, Ulocladium botrytis. 



Matthews and Lott discovered, in addition, Oidium 

 lupuli. 



3. Of the anaerobic organisms, yeasts have been dis- 

 covered in hops. 



Owing to the great importance, to both brewer and 

 grower, of the changes occurring in hops during storage, 

 attempts have been made from time immemorial to discover 

 ways and means of maintaining the quality of the goods 

 unimpaired for long periods. Nevertheless, though much 

 has teen accomplished by careful drying, close packing 

 in double air-tight packets of dressed canvas, and storage 

 in cool, dry stores, the results have never given perfect satis- 

 faction, mainly because the prepared sacking does not ensure 

 the thorough exclusion of air. 



