21 



99 



relation bclwecn lactic acid and by-products. In the case of tlu- l)clacocci. however, it 

 is otherwise, as they form from l;evuh)se, and therefore also from saccharose, more acetic 



Table IV, 



Table 

 No. 



Species of bacteria 



No. 



Addition 

 of 

 chalk 



Sugar 

 ferniented, 

 corrected 

 «Zoo 



Acetic 



formed 

 •loo 



Acetic acid 

 percentage 

 of fermented 

 sugar 



XV 



Strßjjtococciis crcinoris 



20 



/ 

 \ 



J- 







31 



1,0 

 1,0 



3 

 14 



XXVIII 





11 



1 







52 

 Ui 



0,5 

 0,4 



1 

 3 



XXVIII 



) helvelicum 



12 



r 







52 

 lit 



0,8 

 1,2 



1 



6 



XXIX 



Streptobaclerium casei 





I 







52 

 12 



1,2 

 1,0 





XXIX 





18 



( 







52 

 10 



0,5 



1 







[ 



0,5 





XXIX 







\( 



+ 



52 



1,<I 



1 











18 



1,0 



G 



acid and gas than from other hexoses. Table V shows the fermentation of lævuiose and 

 i^rape sugar in a strain of strong gas developing character (Bctacoccus arabinosaceus Nr. 12). 



Table V. 



Species of sugar 



Sugar 

 fermented 



Lactic 



acid 

 formed 



Acetic 



acid 

 formed 



Hest 





»;oo 







"i 00 



Lævuiose 



19,1 



,3,0 



2,5 



13.G 



Dextrose 



' 12,8 



5,6 



0,5 



<;,7 



As will be seen, this coccus forms almost as much acetic acid as lactic acid from lævu- 

 iose. but on the other hand, only ^ as much acetic acid as lactic acid from grape sugar. 

 The fermented sugar which is not transformed into acid (the remainder in the last column 

 of the table) has not all been formed into gas (carbonic acid and hydrogen) at any rate 

 not in the case of the lævuiose culture, which gave a very distinct mannite reaction. 



Xow one molecule of hexose can by the lactic acid bacteria be simply broken up into 

 two molecules of lactic acid, whereas sugars having a smaller number of carbon atoms, 

 will of course be otherwise divided. It would seem reasonable beforehand to suppose that 

 pentoses would be broken up into equivalent quantities of lactic acid and acetic acid, 

 and as a matter of fact, there is really always a large quantity of acetic acid formed when 

 pentoses are fermented by lactic acid bacteria. As a rule, however, we obtain considerably 

 less acetic acid and more lactic acid than would answer to the equation 



C5 /^lo O5 = C, //ç 0, - C.Î //, 0.,. 



