404 MICRO-ORGANISMS AND FERMENTATION. 



can form two kinds of buds, and that the oval buds must 

 develop one or more new buds before they can assume the 

 typical form. The question then is : Under what conditions 

 are those two kinds of buds developed ? It was shown by 

 means of culture experiments that the lemon-shaped buds 

 are developed especially during the early stages of the culture, 

 but are afterwards crowded out by the oval forms. 



A further description of the fungus from a physiological 

 and biological standpoint will now be given. 



Sacch. apiculatus is a bottom-fermentation yeast, capable- 

 of exciting alcoholic fermentation in beer-wort ; the fermenta- 

 tion in this liquid is, however, a feeble one, only 1 per cent. 

 by volume of alcohol being produced, whilst a bottom-yeast 

 under the same conditions gives 6 per cent. This arises from 

 the fact that Sacch. apiculatus cannot ferment maltose. Hansen 

 also found that it does not secrete invertase. On the other 

 hand, it excites a vigorous fermentation in 15 per cent, and 

 10 per cent, solutions of dextrose in yeast-water, and in one 

 experiment as much as 3 per cent, by volume of alcohol was 

 formed. After three months the liquid still gave the sugar 

 reaction whilst the amount of alcohol had not increased during 

 the last six weeks. The fungus was thus unable to complete 

 the fermentation. In another of Hansen's experiments as 

 much as 4-3 per cent, by volume of alcohol was produced. 



According to Rohling, the application of oxygen increases 

 the formation of alcohol by 5 to 8 per cent., both the life 

 energy and the power of resistance of the cells being greatly 

 increased. Without oxygen, alcohol formation amounted to- 

 2-3 to 3 per cent. The cells are very sensitive to chemical 

 reagents. Sulphurous acid (0-025 per cent.) almost entirely 

 prevents its fermentative activity (sulphuring casks), and 

 alcohol acts very restrictively. On the other hand, tannin 

 only acts at a strength of 0-5 per cent. 



It was found from experiments, in which a mixture of this 

 fungus with Saccharomyces cerevisice was grown in beer-wort, 

 that it was crowded out by the latter, being the weaker species, 

 although it retarded the growth of Sacch. cerevisice to no small 

 degree. 



In flasks with the same beer-wort, and at the same tempera- 



