BACTERIA AND FERMENTATION 



Saccharomyces Pastorianus I. Oval or club-shaped cells, 

 occurring in after-fermentation of wine, etc., and producing 

 a bitter taste, unpleasant odour, and turbidity. The spores 

 frequently occur in the air of breweries. 



5. Pastor. II. Elongated cells, possessing an invertose 

 ferment. They do not, like 5. pastor /., produce disease in 

 beer. 



vS. Pastor. III. Oval or elongated cells, producing turbid- 

 ity in beer. Grown on yeast-water gelatine, the colonies 

 show after sixteen days crenated hairy edges. 



Saccharomyces Apiculatus. Lemon-shaped cells. They 

 give rise to a feeble alcoholic fermentation, and produce two 

 kinds of spores round and oval ; they appear at the onset 

 of vinous fermentation, but give way later on to 5. cerevisice. 



Saccharomyces My coder ma. Oval or elliptical cells, often 

 in branching chains. They form the so-called " mould " 

 on fermented liquids, and develop on the surface without 

 exciting fermentation. When forced to grow submerged 

 they produce a little alcohol. 



Saccharomyces Exiguus. Conical cells, appearing in the 

 after-fermentation of beer. 



Saccharomyces Pyriformis. Oval cells, converting sugary 

 solutions containing ginger into ginger-beer. 



Saccharomyces II 'lids , Hansenii, et Aquifolii produce a 

 small percentage of alcohol. 



2. Acetous Fermentation. 



Cause, Mycoderma aceti ; medium, wine and other alcoholic liquids ; result, 

 the formation of vinegar. 



If alcohol be diluted with water, and the specific ferment 

 mixed with it and exposed to the air at 22 C., it is rapidly 

 converted into vinegar. The change is accompanied by the 

 absorption of oxygen, one atom of which combines with 

 two of hydrogen to form water, and a substance remains 



