YEAST 421 



Fabroni, in the end of the last century) that this inner matter 

 which was contained in the bag, which constitutes the yeast 

 plant, was a substance containing the elements carbon and 

 hydrogen and oxygen and nitrogen ; that it was what 

 Fabroni called a vegeto-animal substance, and that it had 

 the peculiarities of what are commonly called " animal 

 products." 



This again was an exceedingly remarkable discovery. 

 It lay neglected for a time, until it was subsequently taken 

 up by the great chemists of modern times, and they, with 

 their delicate methods of analysis, have finally decided 

 that, in all essential respects, the substance which forms 

 the chief part of the contents of the yeast plant is identical 

 with the material which forms the chief part of our own 

 muscles, which forms the chief part of our own blood, 

 which forms the chief part of the white of the egg ; 

 that, in fact, although this little organism is a plant, and 

 nothing but a plant, yet that its active living contents 

 contain a substance which is called " protein/' which is of 

 the same nature as the subtance which forms the foundation 

 of every animal organism whatever. 



Now we come next to the question of the analysis of the 

 products, of that which is produced during the process of fer- 

 mentation. So far back as the beginning of the 16th century, 

 in the times of transition between the old alchemy and the 

 modern chemistry, there was a remarkable man, Von 

 Helmont, a Dutchman, who saw the difference between the 

 air which comes out of a vat where something is fermenting 

 and common air. He was the man who invented the term 

 " gas," and he called this kind of gas " gas silvestre " so 

 to speak gas that is wild, and lives in out of the way places 

 having in his mind the identity of this particular kind of air 

 with that which is found in some caves and cellars. Then, 

 the gradual process of investigation going on, it was dis- 

 covered that this substance, then called " fixed air," was 

 a poisonous gas, and it was finally identified with that kind 

 of gas which is obtained by burning charcoal in the air, which 

 is called " carbonic acid." Then the substance alcohol was 

 subjected to examination, and it was found to be a combina- 

 tion of carbon, and hydrogen, and oxygen. Then the sugar 

 which was contained in the fermenting liquid was examined 

 and that was found to contain the three elements carbon, 

 hydrogen, and oxygen. So that it was clear there were in 

 sugar the fundamental elements which are contained in the 



