DEVELOPMENT OF SOIL BACTERIOLOGY 21 



Bacteria are the universal scavengers which lick up the dead 

 bodies of plants and animals as completely and nearly as rapidly 

 as fire. Were it not for them the w^orld in time would be filled 

 with never-changing organic matter. The plant residues, trees, 

 and animal bodies would remain in the soil, and with them the 

 carbon which is required by the green plant. Bacteria, in getting 

 their required energy, are continually liberating carbon so that it 

 may start again on its constructive journey. If carbon and nitro- 

 gen could but speak, what wonderful tales they would tell ! The 

 chemist, the bacteriologist, and the farmer each would be wiser, 

 for many of the changes through which carbon and nitrogen pass 

 due either to the action of the one-celled plants, bacteria, or that 

 of the wheat or alfalfa, are so complex that the scientist even 

 with his apparently magical methods cannot follow them. 



Bacteria grow in cream, making churning easier. They give 

 to butter its characteristic flavor. They cause the ripening of 

 cheese, thus giving to it the peculiar flavor in opposition to the in- 

 sipid taste of the fresh cheese. 



These are only a few of the many ways in which bacteria bene- 

 fit the human race. They are at work in the silo rendering the 

 food more palatable and nutritious for cattle. They give to 

 sauerkraut and pickles their flavor. They take part in the tanning 

 of leather, the retting of flax, the curing of tobacco, and help us 

 in a thousand and one ways which we little suspect. One of the 

 most instructive and interesting tasks set for man is to know 

 and learn how to govern these tiny plants. 



Some writers even argue that the disease-producing microbes 

 are beneficial. They slay plants and animals so thaf the material 

 of which their bodies are composed may be used by omers. It is, 

 however, more logical to consider that they formerly were harm- 

 less or that they may have been beneficially growing on the sur- 

 face of plants and animals and decomposing dead material. Later 

 in the struggle between them and their host some were routed 

 and disappeared, while others became true parasites preying upon 

 plants and animals. These are now the outlaws in bacterial 

 society. 



