EXPERIMENT STATION REPORTS. 



257 



CULTURES OF NODULE-FORMING BACTERIA SENT OUT DURING THE CALENDAR 



YEAR 1915 AND UNTIL JUNE 30, 1916. 



Cultures of other micro-organisms were sent out from this laboratorj- 

 between June 30, 1915, and June 30, 1916, in the following numbers: 



Alcohol-acetic 14 



Bad. lactis acidi 9 



Bad. hulgaricum 19 



Miscellaneous from stock room 77 



Connected with the distribution of alcohol-acetic cultures a number 

 of samples of vinegar sent in from different parts of the State were 

 analj'zed and the results with suggestions returned. (Chas W. Brown.) 



Mr. Morgan has continued his studies with the soil solution and its 

 method of extraction as devised in this laboratory. I feel that progress 

 is being made in this work. His report follows: 



The data derived from the study of the soil solution obtained by the 

 oil pressure method is now ready for publication. The experiments as 

 reported a year ago showing the results of the action of micro-organisms 

 upon nitrogenous compounds, as dried blood, tankage, cottonseed meal, 

 were continued together with others showing the effects of the micro- 

 organisms upon ammonium sulfate and sodium nitrate and phosphate 

 rock. 



Mr. O. M. Gruzit, graduate assistant in this department, has shown, 

 in his study of the effects of some acids, alkalis and inorganic salts on 

 soil bacteria in soil solution, that these soil bacteria in the few soils 

 used developed best when the reaction was N/1000 alkaline (-1° Fuller's 

 Scale). An acid reaction of N/1200 killed about 98 percent while an 

 acid reaction of N/2860 inhibited the growth of 46.5 percent of tbe 

 bacteria in soil solution. 



It has also been found that the reaction of the soil solution changes 

 gradually from alkaline into an acid condition due to bacterial activi- 

 ties. The effect of the various potassium, nitrate and phosphate salts 

 did not show great differences upon the number of bacteria, but it did 

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