EXPERIMENT STATION BULLETINS. 387 



CONCLUSIONS. 



1. If it follows that the germs which produce the greater acidity 

 in the medium give the most marked dissolution and that the solvent 

 action occurs only in a medium in which there is a noticeable increase 

 in the acidity, then we should say that the solvent is an acid or an acid 

 compound produced by the bacterial growth. 



2. But if there is a definite soheut action and no change in the 

 acidity detectable, then we should say that the solvent action is not 

 due entirely to acid compounds. 



o. From all that we have gathered from oiu* limited experiments, 

 we are of the opinion that acid is not the sole solvent. 



4. Certain soil bacteria under favorable conditions do have the power 

 of converting small quantities of insoluble phosphates into a soluble 

 form independent of acid formation. 



5. When the bacterial growth is accompanied by acid formation, 

 there is a decided solution of the insoluble phosphate. 



