MICHIGAN ACADEMY OF SCIENCE. 



KH 



ing 



Photographs of Petri dishes show- 

 the solvent action of bacteria 

 upon finely divided and washed cal- 

 cium carbonate and dicalcium and 

 tricalcium phosphates that are held 

 in suspension by a medium composed 

 of soil leachings, H% agar and 2% 

 dextrose. Nos. 1, 2, and 3 are cal- 

 cium carbonate, dicalcium phosphate 

 and tricalcium phosphate respectively. 



21 



