CHAPTER XXXII 



History of Soil Microbiology, its Past, Present, and Future 



"The history of a science is not merely a chronicle of discovery, but a 

 study of the relation of methods and ideas in progress and the applica- 

 tion of the conceptions thus gained to guide us in present and future 

 work." — Henderson. 



Every science, especially every biological science, goes through, in 

 the course of its development, a series of stages which can be briefly 

 summarized as follows: 



1. Ecological stage, including description and classification. Here 

 we are largely interested with the description of the organisms, their 

 morphology and taxonomy. 



2. Physiological stage, or a study of the activities of the organisms 

 in question. 



3. Experimental stage, whereby changes in the physiology of the 

 organisms are studied, as a result of experimental conditions. 



4. Mathematical stage, when formulae are developed to express in 

 exact language the mechanism of the physiological processes. 



Finally, we find that every science, when it reaches a certain stage 

 of development, branches off into several new sciences. 



The age of a science is definitely indicated by the stage in which 

 it is in. Soil microbiology is only a science in the making; but, while 

 it has not left as yet the ecological stage and the very methods of study 

 are still undergoing active change, it has already reached the stage 

 when expressions are found for a correlation between the activities 

 of the microorganisms and the environmental conditions. This science 

 includes not only a study of soil microorganisms and their activities 

 under experimental conditions, but also the resultant phenomena of 

 the sum total of their activities in the soil. The fact that numerous 

 groups of organisms, the activities of which may be supplementary or 

 antagonistic, exist in a very complex medium, the soil, under very 

 complex environmental conditions, tends to complicate the subject 

 still further. The science of soil microbiology is also beginning to 

 branch off into soil mycology, algology, protozoology, nematology, 

 etc., as well as soil biochemistry. 



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