122 MOLECULES, VIRUSES, AND BACTERIA 



to know the composition of the medium in which the spores are grown 

 and in which the a-picohnic acid is producing its eflFect. Therefore, I 

 indicate at this point the composition of the medium— see Table III. 



TABLE III 



Medium Used for Growth and Sporulation 

 of Bacillus Cereiis T. 



Compound Percentage 



FeS04'7H20 ■ 0.00005 



CuS04'5H20 0.0005 



ZnS04'7H20 0.0005 



MnS04'H20 0.005 



MgS04 0.02 



(NH4)2S04 0.2 



CaCl2'2H20 0.08 



K2HPO4 0.5 



Yeast Extract 0.2 



Glucose 0.1 



Final pH 7.25-7.45 



Table IV shows the effect of added metal ions on the inhibition with 

 a-picolinic acid. The only mineral ions that reverse the inhibition are 

 zinc, cobalt, and nickel. It is to be noted that manganese, magnesium, 

 calcium, iron, and copper do not have this effect. Nor can we reverse 

 the inhibition by increasing the normal minerals of the medium four- 

 fold. From these data one might conclude that a-picolinic acid does 

 bring about its inhibition by removing some essential ion. If this is so, 

 then the ion must be bound more firmly than the ions of manganese, 



TABLE IV 



Effects of Minerals on the Inhibition of Sporulation 

 of Bacillus Cereus T. by a-Picolinic Acid 



Mineral Added Sporulation 



Mn++ - 



Mg++ - 



Ca++ - 



Fe++ - 



Cu++ -• 



Zn++ + 



Co++ + 



Ni++ '-f 



