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YEAST 111 



collect at its surface into a scum, which is blown 

 up by the emerging air-bubbles into a thick, foamy 

 froth. Another moiety sinks to the bottom, and 

 accumulates as a muddy sediment, or " lees," 



When this action has continued, with more or 

 less violence, for a certain time, it gradually 

 moderates. The evolution of bubbles slackens, 

 and finally comes to an end ; scum and lees alike 

 settle at the bottom, and the fluid is once more 

 clear and transparent. But it has acquired 

 properties of which no trace existed in the 

 original liquid. Instead of being a mere sweet 

 fluid, mainly composed of sugar and water, the 

 sugar has more or less completely disappeared ; and 

 it has acquired that peculiar smell and taste which 

 we call " spirituous." Instead of being devoid of 

 any obvious effect upon the animal economy, it 

 has become possessed of a very wonderful influence 

 on the nervous system ; so that in small doses it 

 exhilarates, while in larger it stupefies, and may 

 even destroy life. 



Moreover, if the original fluid is put into a still, 

 and heated moderately, the first and last product 

 of its distillation is simple water ; while, when the 

 altered fluid is subjected to the same process, the 

 matter which is first condensed in the receiver is 

 found to be a clear, volatile substance, which is 

 lighter than water, has a pungent taste and smell, 

 possesses the intoxicating powers of the fluid in 

 an eminent degree, and takes fire the moment it 



