BACTERIA IN AGRICULTURE. 339 



(Melilotus alba) were grown upon corn extract with agar. Again 

 considerable difficulty was encountered because of lack of information 

 regarding the behavior of this particular variety or species of rhizo- 

 bium in artificial culture media. It was not until the early part of 

 July that definite and satisfactory conclusions were reached regarding 

 the identity of this organism in the culture media indicated. The 

 rhizobia were now transferred to fresh corn extract media from time 

 to time for about six weeks; in order to effect the desired adaptive 

 changes in the microbes. Some preliminary field experiments were 

 carried on at a farm near Fairbury, Illinois. Plots of stubble ground 

 were selected in which oats had been grown during the season. The 

 ground was ploughed and harrowed repeatedly. Each plot of ground 

 was duplicated for control purposes. On August 10 the plots were 

 planted with white dent corn mixed with the rhizobia cultures and a 

 small quantity of water. The seeds germinated uniformly with no 

 appreciable differences in the various plots. Subsequent growth was 

 carefully observed for a period of four weeks. No very marked dif- 

 ference was noticeable. The corn treated with rhizobia grown in neu- 

 tral corn-extract agar seemed to thrive somewhat better than the rest, 

 but the difference was not sufficiently marked to be noteworthy. The 

 corn treated with acid agar corn-extract rliizobia showed no apparent 

 improvement over the normal or untreated corn. The same could be 

 said of the corn treated with crushed nodules of sweet clover. Oppor- 

 tunity did not present itself for making a comparative microscopic 

 examination of the roots of the corn of the various plots. Oats was 

 also experimented upon, but with no marked results. This in brief is 

 the outline of the experiments of 1903 and, although no satisfactory 

 results were obtained, the preponderance of experimental evidences 

 again seemed to point to ultimate success. In fact so sanguine had 

 the writer become of early marked success that he made application 

 for letters patent for the process, but the application in the form in 

 which it was presented was rejected on the patents by Nobbe and Hilt- 

 ner and by Hartleb. The specifications filed September 29, 1903, 

 read in part as follows : 



The invention relates to the process of fertilizing the soil and increasing the 

 yield of crops by means of specially modified pure cultures of the microbes or 

 organisms found in the soil and in the root nodules or tubercles of plants be- 

 longing to the leguminosae or bean family, and has for its object to render the 

 process more effective, much cheaper and practically without the expenditure of 

 additional labor. 



The living microbic fertilizer, consisting of the above mentioned modified 

 organisms is applied by simply mixing a small quantity of the culture with the 

 seeds just prior to planting, and introducing it into the soil simultaneously 

 with the seed. With the germination of the seed thus treated, the modified 

 microbes will also begin to multiply and appropriate for the use of the plant, 

 the free nitrogen of the air. 



