IV 



YEAST 1 25 



amygdalin and synaptase, which can be extracted, 

 in a separate state, from the bitter almonds. The 

 amygdalin thus obtained, if dissolved in water, 

 undergoes no change; but if a little synaptase be 

 added to the solution, the amygdalin splits up 

 into bitter almond oil, prussic acid, and a kind of 

 sugar. 



A short time after Cagniard de la Tour dis- 

 covered the yeast plant, Liebig, struck with the 

 similarity between this and other such processes 

 and the fermentation of sugar, put forward the 

 hypothesis that yeast contains a substance which 

 acts upon sugar, as synaptase acts upon amygdalin. 

 And as the synaptase is certainly neither organized 

 nor alive, but a mere chemical substance, Liebig 

 treated Cagniard de la Tour's discovery with no 

 small contempt, and, from that time to the pre- 

 sent, has steadily repudiated the notion that the 

 decomposition of the sugar is, in any sense, the 

 result of the vital activity of the Torida. But, 

 though the notion that the Torula is a creature 

 which eats sugar and excretes carbonic acid and 

 alcohol, which is not unjustly ridiculed in the 

 most surprising paper that ever made its appear- 

 ance in a grave scientific journal, 1 may be un- 



1 "Das entrathselte Geheimniss der geistigen Gahrang (Vor- 

 laufige briefliche Mittheilung) " is the title of an anonymous 

 contribution to Wohler and Liebig's AnnaUn der Pharmacic 

 for 1839, in which a somewhat Rabelaisian imaginary descrip- 

 tion of the organisation of the "yeast animals" and of tho 

 manner in which their functions are performed, is given with a 



