FERMENTATION PHENOMENA. 431 



races, and that of L. BOUTROUX (V.). According to M CREMER 

 (I.), Isevulose or d-fructose is also fermented by Sacch. apiculatus ; 

 and the same applies also to mannose or seminose. On the other 

 hand, F. VOIT (I.), E. FISCHER and H. THIERFELDER (I.) are 

 unanimous in stating that a fourth hexose, cZ-galactose, is un- 

 affected by this fungus. So far as our knowledge extends, not a 

 single member of the disaccharide group is fermented by Apicu- 

 latus ; a fact demonstrated by E. C. Hansen in respect of 

 saccharose and lactose, and by this authority and AMTHOR (I.) in 

 respect of maltose. According to these workers, Sacch. apicu- 

 latus is capable of forming only small quantities of alcohol in 

 beer worts, namely, from the hexoses contained therein. 



The fact that this budding fungus ferments hexoses, but not 

 disaccharides, justifies the assumption that it cannot secrete 

 inverting enzymes like invertase and maltase ; and this has been 

 confirmed, so far as invertase is concerned, by the experiments of 

 HANSEN (IX.). On the other hand, when the disaccharides are 

 inverted for instance, by heating with a little acid they come 

 within the sphere of action of this fungus, as is also the case when 

 the latter is associated in the nutrient liquid with a budding 

 fungus that secretes invertase. 



In order to utilise the aforesaid behaviour of Sacch. apiculatus 

 toward sugars, for the purposes of the analytical chemist, K. 

 AMTHOR (I.) proposed to employ it in cases where small quantities 

 of dextrose have to be determined in presence of disaccharides, e.g., 

 in beer wort, a definite quantity of the previously boiled sample 

 being inoculated with Apiculatus yeast. This latter consumes 

 only the dextrose, the percentage of which can then be estimated 

 by the amount of alcohol (or carbon dioxide) formed. A modifi- 

 cation of this method was proposed by A. BAU (I.), who defended 

 it in subsequent papers (II., V. and IV.) from certain objections 

 urged against it by H. ELION (II ). Nevertheless, in view of the 

 susceptibility of this ferment to alcohol, he was constrained to 

 admit that the method can only be used when the dextrose con- 

 tent of the sample is low, and that, even in such event, one 

 cannot be certain whether the whole has been fermented. Even 

 with this limitation, however, the method is useless to the practi- 

 cal analyst, owing to the sluggish fermentation of the hexoses. 

 This is evident from the statements of AMTHOR (II.), who 

 inoculated sterile wort with /Sacch. apiculatus and found the pro- 

 duction of alcohol amounted to 0.66 per cent, by volume at the 

 end of twenty-seven days, 0.79 per cent, after a further fifty-four 

 days, 1.2 per cent, nine months later, and 1.5 per cent, after a 

 further nine months, i.e., twenty -one months in all. Hence, 

 even assuming as has not yet been proved that all the hexose 

 is eventually fermented, the method must be regarded as far too 

 slow for practical purposes. The trouble bestowed on its elabora- 

 tion, however, has not been wasted, since it affords physiological 

 VOL. ii : PT. 2 2 E 



