94 MICRO-ORGANISMS AND FERMENTATION. 



cases. An addition of hops to lager-beer exerts a retarding 



FIG. 25. Crenothrix Kuhniana (after ZOPF): a e (600 : 1), cocci in different stages 

 of division ; /(600 : 1), small, round cocci-zoogkea ; g (natural size), zooglcea ; h (600 : 1), 

 colony of short filaments composed of rod-like cells, originating from the germination 

 of a small collection of cocci ; i ?, filaments, partly straight, partly spirally curved 

 {I, m), of very varying thickness, with more or less pronounced contrast between the 

 base and apex, and different stages of division of their members and sheaths ; the 

 sheathed filament r shows short rods at the base, which higher up are divided into 

 small cylindrical pieces ; at the apex the cocci are seen arising from the longitudinal 

 divisions of the cylindrical discs. 



influence on these bacteria, as on the majority of bacteria 

 occurring in beer. 



