HISTORY OF SOIL MICROBIOLOGY 839 



contributions are distributed throughout the whole field of soil micro- 

 biology. His studies embraced symbiotic and non-symbiotic nitro- 

 gen-fixing bacteria, sulfur-oxidizing bacteria, nitrate and sulfate re- 

 ducing bacteria, actinomyces, algae, etc. The bulk of Winogradsky 's 

 work was limited, but the quality is of the highest, it stands for the 

 most classical work in the science of soil microbiology. 



The study of decomposition of nitrogenous organic compounds in 

 the soil is closely connected with the names of Pasteur (1863), Miintz 

 and Coudon (1893) and Marchal (1893), who pointed out that various 

 bacteria and fungi are capable of breaking down proteins with the 

 rapid formation of ammonia. Here belongs the work of Gayon and 

 Dupetit (1881) on nitrate reduction, of Deherain (1886) on the de- 

 composition of farmyard manure, and Wollny (1897) who studied 

 organic matter as a whole. The beginning of the study of cellu- 

 lose decomposition by bacteria is closely connected with the name 

 of Omeliansky, but neither the organisms nor the chemistry of the 

 process were completely understood for a long time. Attention 

 should also be called in this connection of the important contribu- 

 tion of Ferdinand Cohn to the classification and description of a number 

 of heterotrophic soil bacteria, followed by the work of A. Meyer and 

 his associates on the spore-forming bacteria of the soil, as well as by 

 Chester and others. The name of one other man should be mentioned 

 here, that of Caron (1895) ; he was neither a chemist nor a bacteriologist, 

 but a practical agriculturist who contributed a great deal to the stimu- 

 lation of the theoretical and practical interest in the subject of soil 

 microbiology. Caron demonstrated that any soil treatment which 

 leads to an increase in the number of microorganisms also leads to an 

 increase in crop productivity; fallowing of a heavy soil can be used in 

 place of green manure. Although the practical agriculturists, by 

 pointing out the great importance of microorganisms in soil processes 

 and, therefore, in agriculture, often aroused great interest in the soil 

 processes, the influence was frequently not far reaching. The practical 

 men expected that soil microbiology would revolutionize agriculture 

 just as medical bacteriology revolutionized medicine, but this did not 

 materialize. Where this influence was strongest, especially in Germany 

 and in the United States, some people came to believe that, outside of 

 legume inoculation, there is nothing to the whole science of soil micro- 

 biology. This attitude toward a science which lies at the very roots of 

 all soil economy and will no doubt influence, in the future, the whole 

 agricultural practice, could result only from a lack of sufficient knowl- 

 edge concerning the problems under consideration. 



