420 YEAST 



undergoing a process of multiplication by budding, just as 

 effectual and just as complete as the process of multiplication 

 of a plant by budding ; and thus this Frenchman, Gagniard 

 de la Tour, arrived at the conclusion very creditable to his 

 sagacity, and which has been confirmed by every observation 

 and reasoning since that this apparently muddy refuse 

 was neither more nor less than a mass of plants, of minute 

 living plants, growing and multiplying in the sugary fluid in 

 which the yeast is formed. And from that time forth we have 

 known this substance which forms the scum and the lees at 

 the yeast plant ; and it has received a scientific name 

 which I may use without thinking of it, and which I will 

 therefore give you namely, " Torula." Well, this was a 

 capital discovery. The next thing to do was to make out 

 how this torula was related to other plants. I won't weary 

 you with the whole course of investigation, but I may 

 sum up its results, and they are these that the torula is 

 a particular kind of a fungus, a particular state rather, of 

 a fungus or mould. There are many moulds which under 

 certain conditions give rise to this torula condition, to 

 a substance which is not distinguishable from yeast, 

 and which has the same properties as yeast that is 

 to say, which is able to decompose sugar in the curious way 

 that we shall consider by-and-by. So that the yeast plant 

 is a plant belonging to a group of the Fungi, multiplying and 

 growing and living in this very remarkable manner in the 

 sugary fluid which is, so to speak, the nidus or home of the 

 yeast. 



That, in a few words, is, as far as investigation by the 

 help of one's eye and by the help of the microscope has 

 taken us. But now there is an observer whose methods 

 of observation are more refined than those of men who use 

 their eye, even though it be aided by the microscope ; a 

 man who sees indirectly further than we can see directly 

 that is, the chemist ; and the chemist took up this question, 

 and his discovery was not less remarkable than that of the 

 microscopist. The chemist discovered that the yeast plant 

 being composed of a sort of bag, like a bladder, inside which 

 is a peculiar soft, semifluid material the chemist found that 

 this outer bladder has the same composition as the substance 

 of wood, that material which is called " cellulose," and 

 which consists of the elements carbon and hydrogen and 

 oxygen, without any nitrogen. But then he also found 

 (the first person to discover it was an Italian chemist, named 



