148 MICRO-ORGANISMS AND FERMENTATION. 



I. The greater majority do not ferment maltose. Many 



of these induce a more or less vigorous fermentation in 

 solutions of dextrose and invert-sugar. Some (Torula 

 forms) invert saccharose, and many possess no inver- 

 tive ferment (Mycoderma cerevisice, Torula forms, 

 Sacch. apiculatus). 



II. Only one species (Monilia Candida) ferments maltose, 

 saccharose (direct), and dextrose, without however 

 possessing any invertive action. 



From the above it is clear that, as pointed out by Han-sen, 

 the Saccharomycetes cannot be characterised merely as 

 alcoholic ferments. 



When we consider the behaviour of the above-named 

 fungi in the fermentation industries, it is at once seen that it 

 is only amongst the Saccharomycetes that species occur which 

 rapidly and vigorously ferment maltose. The yeasts for 

 breweries and distilleries must therefore be looked for from 

 among the true Saccharomycetes. The fungi not included 

 in the genus Saccharomyces, of which by far the greater 

 majority do not ferment maltose, are scarcely capable of 

 plaving any important part in these industries ; on the other 

 hand they can be employed in the manufacture of wines 

 from grapes, berries, and fruits, since several of them are able 

 to induce just as vigorous a fermentation in solutions of 

 dextrose and invert-sugar, as the Saccharomycetes. 



It is perfectly clear from the above that a suitable species 

 must always be selected. 



These different properties of the various species of 

 budding-fungi are of special importance in analytical 

 chemistry in cases where solutions containing several different 

 carbohydrates are under examination. In fact Hansen 

 expressed the opinion that it will be possible in this way 

 to arrive at a more exact quantitative determination of the 

 different carbohydrates in wort. Several chemists have been 

 recently engaged on this problem, but a true solution has not 

 yet been found. 





