74 



MICRO-ORGANISMS AND FERMENTATION. 



sinuous border; puncture-cultivations give a white stripe, 

 which soon extends to the bottom of the glass ; the gelatine 

 forms fissures which become filled with the growth, while at 

 the same time a speck is formed on the surface. Experiments 

 carried out with pure cultures of this bacterium in beer-wort 

 have shown that one and the same form includes several 

 species, which have a somewhat different action on wort. 



i! 



s! \ 



ee^ ^^ 



FIG. 14. 



Leuconostoc mesenterioid.es Cienkowski, after Zopf. A, cell cluster of the 

 variety with no envelopes, taken from a potato cultivation ; B, series 

 showing the development of a cultivation grown in gelatine, free from 

 sugar ; B a, has no envelopes ; B b, the same after 24 hours' growth in a 

 solution of molasses, the envelopes are already seen but are not strongly 

 developed ; B c, after 48 hours' growth in molasses, the envelopes are 

 more strongly developed and partly encased in each other ; O, a small 

 gelatinous mass from which the cells have been expelled. 



They are all included under the name Bacillus viscosus. 

 If sterilised wort is infected with this bacterium and alcoholic 

 yeast added after the lapse of some hours, the liquid becomes 



