VIII. B, 6 Barber: Dysentery Bacilli 557 



be an acid-former. This culture lost its power of fermenting 

 saccharose after several transfers on ordinary agar, and an 

 acid-forming culture on saccharose also failed to form acid in 

 subcultures. In order to test the composition of this originally 

 saccharose-fermenting strain, 30 single cells were isolated from 

 a culture which had been carried through several transfers on 

 ordinary agar and which had never been grown on saccharose. 

 None of the 30 cultures obtained from these cells formed acid 

 on saccharose agar. Apparently the saccharose-fermenting va- 

 riations of this strain of dysentery bacilli are less permanent 

 than the maltose-fermenting variations of Flexner strain 105200. 



