A Sugar Bacterium. 



7£ 



been added to furnish the necessary combined nitrogen for the growth 

 of the organism. The yeast-water was prepared by boiling yeast in 

 water for several minutes, and then filtering and sterilising. In one 

 experiment an ordinary beer wort was used without addition of more 

 nitrogenous matter. 



The liquids were carefully and repeatedly sterilised in the flasks 

 before the organisms were added. 



The fermentations were conducted at a temperature of about 20° C 

 The marked feature of the fermentation set up by the conjoint organ- 

 ism was the production of a considerable acidity, the liquid after a 

 few days having the appearance and flavour of lemonade. The acidity 

 proved to be due to acetic and succinic acids. 



As considerable differences of behaviour were soon manifested, we- 

 subjoin the results of, typical fermentations. 



Acetic Succinic 

 Alcohol. acid. acid. 

 Per cent. Per cent. Per cent. 



I. Beer wort, 150 c.c. :• — 



The yeast produced 3-5 0*0124 0-068 



The bacterium produced 0-1734 0-3 



II. Cane sugar, 150 c.c. of 10 per cent, 

 solution containing 15 c.c. yeast 

 water : — 



Yeast produced 



Bacterium produced 



Yeast + bacterium (in the form 

 of the conjoint organism) pro- 

 duced 



III. Dark brown sugar (mixture of cane 



sugar and levulose), proportions as 

 in II :— 



Yeast produced 



Bacterium produced 



Yeast + bacterium separately 

 sown produced 



Conjoint organism produced ... 



IV. Grape sugar, proportions as in II : — 



Yeast produced 



Bacterium produced 



Yeast + bacterium produced . . . 

 Conjoint organism produced ... 



5-0 



o-oi 



0-057 







0-7 



0-57 



5-0 



0-048 



0-078 



4-75 



0-026 



0-137 







0-596 



0-416 



4-0 



0-124 



o-i 



3-7 



0-306 



0-168 



2*2 



0-013 



0-049 







0-012 



0-018 



2-0 



0-02 



0-097 



2-0 



0-15 



0-046 



The formation of the alcohol was thus shown to be due exclusively 

 to the yeast, and in its production the influence of the bacterium was 

 VOL. LXV. G 



