^4 SOIL BACTERIOLOGY 



peroxid to the soil in large test-tube. Shake the tube at 

 regular intervals. 



Note —For this test 3 per cent hydrogen peroxid should be made neutral 

 or faintly alkaline to phenolphthalein with dilute sodium hydroxid and 

 diluted to 1.5 per cent. 



6. Record the volume of oxygen evolved from a definite 

 quantity of peroxid after ten, thirty, and sixty minutes. 



Sullivan, M. X., and Reid, F. R., Bui 86, U. S. Dept. Agr., Bur. Soils, 



1912. 



Lohnis, F., Landvartschaftlich-bakteriologisches Praktikum, p. 120, 

 1911. 



