SPIRAL TWIST A\D. OPT. ACTIVPTY 



85 



While the preceding experiment was made on the rough 

 form (usually designated as the R-forni) of bacteria, we 

 repeated it with the smooth form (S-form). By "disso- 



20° 24° 28' 



32"" 36°C 



Fig. 6. Growth-temperature relation in dextral (D) and sinistral 

 (L) strains of Bacillus mycoides (R type) grown on solid medium. 

 The three sets of curves represent three series of experiments. The 

 size of the colonies grown at various temperatures is indicated in 

 terms of the size of the colonies grown at 20° as a unit. (From Gause, 

 1939.) 



