DEVELOPMENT OF SOIL BACTERIOLOGY 1 1 



deal with nitrogen and organic matter of the soil but they act on 

 sulfur, forming sulfuric acid; they form acids which liberate 

 phosphorus, potassium, calcium, and the many other foods needed 

 by the plants. It is the problem of the worker in soil bacteriology 

 to learn how to speed up the work of the beneficial and to sup- 

 press or weed out the injurious. Advances have been made in 

 this realm, but for the most part it is a virgin field which awaits 

 the coming of the untiring worker who cares to thrust in his 

 sickle and reap. For truly the harvest will be rich enough to 

 satisfy the most fastidious. 



