are cultivated in the process of brewing ; they appear 

 in nature on the surface of fruits, causing a ferment- 

 ation of their juices after they (the fruits) have been 

 crushed. They appear as moulds on the surface of 

 fermented liquids, such as beer and wine, causing 

 further decomposition. They are the cause of the 

 disease known as Thrush. 



Yeast cells growing in a saccharine solution cause 

 fermentation to be set up. The sugar is decomposed 

 into Carbon di-oxide and Alcohol. A minute quantity 

 of glycerine and succinic acid are formed at the same 

 time. The alcohol remains in the liquid, and carbon 

 di-oxide is given oif. 



If the fluid be free from oxygen f ermentadoii takes 

 place, but the yeast cells do not grow, they pass into 

 a dormant condition and finally perish. Dead yeast 

 cells do not cause fermentation. 



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