Production of Antibiotic Substances 



275 



T.vHi.E G^i. Srn\ ivAL OF Bactkria Added to Sqil and THf:iii Kkfect upon the 

 Soil Micuouiologicai. Pf)PULATiON 



Organisms Ili-covcrcd * 



Inoculuiu 



Control soil 

 E. coli added f 

 E. coli added J 

 E. coli added 

 Control soil 

 E. coli added 

 E. coli added J 

 E. coli added 



* In thousands per gram of soil. 



t Washed suspension of E. coli cells added at start and after 5 days. 



I CaCOs added to soil. 



Fig. 107. Cup method for quantitative measurements ot concentration of anti- 

 biotics. 



