214 BACTERIOLOGICAL METHODS 



bailii, Lindner. In beerwort. 



hyalosporus, Lindner. In beerwort. 



rouxi, Butroux. Found in fruit juices. 



soya, Saito. In soya sauce. 



unisporus, Hansen. In dutch cream. 



flaiia lactis, Krueger. Found in cheesy butter. 



hanseni, Zopf. In cotton seed meal. 



minor, Engelman. Found in bread. 



membranaefaciens, Hansen. 



anomalans, Hansen. Causing a fruity flavor. 



saturnus, Klocker. Isolated from soil. 



acidi lactici, Grotenfeldt. A milk-curdling yeast. 



fragilis, Jorgeusen. Found in Kephir. 



barkeri, Saccardo. In ginger beer. 



ludwigii, Hansen. From oak bark extract. 



comesii, Covara. From millet seed. 



octosforus, Bevjerinck. On dried currants. 



mellacei, Jorgensen. A top yeast developing a pleasant odor. 



guUulatas, Robin. Found in a rabbit. 



capsularis, Schionning. From soU. 



According to Hansen, Torulas also occur in great variety. 

 The Levure de sel is a yeast capable of developing in a lo to 15 per 

 cent, sodium chloride solution. Those desiring to obtain detailed 

 information regarding the complete fermentation processes in- 

 volved in the brewing of beer and other fermented drinks, must 

 consult the special technical treatises of which there are many 

 available. 



B. Acid-forming Ferments. — Dilute 'alcohol upon standing 

 exposed to the air, gradually becomes sour, losing its alcohol 

 more and more. This loss of alcohol and gain in acidity is due 

 to the action of ferments which split the alcohol into acetic acid 

 and water. The organisms which produce the acid-forming fer- 

 ments or enzymes mostly belong to the group bacteria (bacilli). 

 The more common and important species are Mycoderma (Bacillus) 

 aceti, B. Pasteuriannm, B. kiitzingianum, B. oxydans and B. 

 acetosum. The yeast Saccharomyces mycoderma is also capable of 

 forming acetic acid. The vinegar organisms are most active 

 at a temperature of 25° C. to 30° C. They are very slowly active 



