178 BOTANICAL GAZETTE [MARCH 
Summary 
Many salts when applied to a soil in small quantities increase 
the bacterial activities of that soil. This is manifest by an increased 
production of ammonia, nitrates, and soluble and organic phos- 
phorus, together with an increased nitrogen fixation. Usually, 
although not always, those salts which become toxic in the lowest 
concentration are the greatest bacterial stimulants. 
There is a very close correlation between toxicity of the various 
salts and the osmotic pressure produced in the soil, thus showing 
that toxicity is due in part to osmotic disturbances. Another 
factor of equal importance is the change in chemical composition 
ot the protoplasm resulting from the formation of salts of the protein 
other than those normally occurring in the living protoplasm, thus 
incapacitating them for their normal functions. 
Utas AGRICULTURAL EXPERIMENT STATION 
Locan, UTAH 
LITERATURE CITED 
- Brooxs, Matitpa, M., Comparative studies on respiration. VII. The 
respiration of Bacillus subtilis in relation to antagonism. Jour. Gen. 
Physiol. 7: 5-15. 1920. 
, Comparative studies on respiration. X. Toxic and antitoxic 
effects of magnesium in relation to the respiration of Bacillus subtilis. 
Jour. Gen. Physiol. 7: 331-336. 1920. 
. Brown, C. W., The influence of the composition of the medium upon the 
solvent action of certain soil bacteria. Report Mich. Acad. Sci. 9: 160-162. 
Lal 
Me 
w 
Bycuikutn, A., and Skatsk1, S., Work of the chemical laboratory of the 
Ploti Experiment Station. Godichnyi Otchet. Ploti Selsk. Khoz. Opytn. 
Stantsii 17:175-244; 259-275. 1911 (Abs. in Exp. Sta. Rec. 28:417). 
Gruncuam, C. S., The formation of calcium carbonate in the soil by 
bacteria. Jour. Agric. Sci. 4:145-149. 1911. 
6. Grazia, S. De, The cooperation of microorganisms in the utilization of 
insoluble phosphates of the soil with higher plants. Arch. Farmacol. Sper. 
Sci. Aff. 8:436-440; Staz. Sper. Agric. Ttal. 43:179-184. 1909 (Abs. in 
Ee. Sta. Rec. 23:20). 
. GREAVES, J. E., Effect of soluble salts on insoluble phosphates. Jour. 
Biol. Chem. 7: 287-319. 1910. 
, The influence of salts on the bacterial activities of the soil. Soil 
Science 2:443-480. 1916. 
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