72 



TH. THJ0TTA 



It will be seen from table 1 that five of these strains continually 

 fermented the sugars like typical Morgan strains, not counting 

 a late fermentation of sucrose in strains I and V. Two strains, 

 however (II and IV) , had altered their characters so much, that 

 they no longer could be considered Morgan strains, having lost 

 the production of gas in glucose and acquired the faculty of pro- 

 ducing acid in mannitol and sucrose. Culturally they had accord- 

 ingly to be considered as dysentery-strains, a classification that 

 was so much more natural as both these strains on the second 

 examination had lost their motility as well. 



TABLE 1 



Result of second cultural examination • 



0, no fermentation. 



A, acid. 



A + G, acid and gas. 



Figures signify the day of the examination. 



In litmus whey all the typical strains grew without production 

 of acid, while one of the two dysentery like strains produced acid 

 in this medium. All the strains produced indol in beef broth on 

 the second examination. 



Thus it is obvious that the greater part of the Morgan strains 

 have kept their fermenting faculties unaltered after one and a 

 half years of growth on artificial media, while one typical strain 

 had reverted culturally to the characters of the dysentery bacilli. 



