81 



after Benedict '). It goes without saj'ing that sterilisation was 

 applied in these experiments. The fermentation-flasks conriected with 

 the mercury tube were kept at a temperature of 23° — 25° and the 

 fermentation took place at the same temperature in the flasks used 

 for the determination after Benedict. 



These series of experiments go to show by eitlier method (hat a 

 distinct fermentation takes place in the volutin-free cultures of Torula 

 moiiosa, Saccharomyces cerevisiae and Jjactose-yeast. The fluid used 

 was free from phosjfliate and contained J to 2| perc. glycose, 0.05 

 perc. MgSO,, a trace of KNO3, 0,2 perc. peptone or, to make sure 

 of the absence of any volutin in thousands of yeast-cells, 0,2 perc. 

 asparagin or glycocoll instead of peptone. Peptone, however, serves 

 our purpose quite well; especially in comparative fermentation-tests 

 it was quite immaterial whether over against the richly filled yeast- 

 cells of the volntin-containing culture an occasional cell containing 

 a few volutin-granules, emerges in the vokitin-free culture. As said 

 before, peptone yields the advantage of a larger growth. Into the 

 culture-fluid thus prepared, yeast-cells were inoculated from 

 a culture-tube. At tlie commencement as well as at the end 

 of each experiment the absence of volutin was verified. In the 

 experiments with asparagin or glycocoll the same substance was 

 also made use of for the culture of the volutin containing yeast 

 with the addition of 0,1 perc. KH^PO^. Occasionally also the entire 

 volutin-free culture was transferred from a tube to a flask of a phos- 

 phate-free fluid, and the fermentation was compared with that which 

 was brought about also in a phosphate-free fluid by a nearly equal 

 quantity of Torula monosa loaded with volutin-granules. In this way 

 a greater uniformity was obtained in the medium in which the 

 fermentation took place, than with a phosphate-containiug control- 

 fluid ; still, a perfect uniformity was never obtained, since it may 

 be possible that these volutin-containing cells, rich in nucleinic acid, 

 as has been said on page 9, of themselves furnish phosphate to 

 the medium on which they have been planted. I subjoin some of 

 my experiments and their results: 



1 October 1916. Two flasks A and B each with 25 c.c. 2 perc. 

 glycose, 0,05 perc. MgSO^, 0,1 perc. glycocoll and a trace of KNO, 

 (consequently phosphate-free). The preparations used are all chemic- 

 ally pure. To A is added a culture of Torula monosa cultivated on 

 a phosphate-free medium, (only a few cells with volutin, at most 

 one in a thousand); to B is added a culture full of volutin-granules, 



1) Vide Nagasaki, Zeitschr. fur physiol. Ghem. Bd. 95, p. 61, 

 Proceedings Royal Acad. Amsterdam, Vol. XX. 



