371 STATE BOARD OF AGRICULTURE. 



SERIES III. 



The Nutrient Solution used iu Series III. contained its nitrogen in 

 the form of Beef Extract and Peptone and had the following composi- 

 tion : 



BEEF BROTH. 



Beef Extract (Leibig) 3.0 grams 



Peptone (Witte) 10.0 " 



Sodium chloride 5.0 " 



■ Distilled water 1000 c. c. 



Germ No. 8 gave the largest amount of soluble phosphoric acid in 

 this series, 0.82%, while B. subtilis produced the least, 0.09%. On the 

 whole this series shows the least solvent action of any. A possible ex- 

 planation of this may be found in the fact that the beef broth being a 

 better nutrient than either of the two preceding solutions, the germs 

 have grown very vigorously at the start and have set free in the solution 

 such quantities of decomposition products that the solution has become 

 "auto-toxic," so to speak, for the culture. The vitality of the organisms 

 thus lowered, their solvent action is reduced in proportion. Further- 

 more, it would seem from the negative results obtained on the thirty 

 day analyses, that these decomposition products have exerted a decided 

 reverting action upon the water soluble phosphates since in all but 

 three cultures, the water soluble phosphoric acid after thirty days was 

 less than in the sterile control. The detailed analyses are shown in 

 Table No. 6. 



