340 



STUDIES ON RESPIRATION. XIV 



pure solution of the other component. The arrangement is made 

 clear in the legend to the figure in each case by placing the words 

 "left" and "right" after the component. Thus Curve A shows 

 antagonism between NaCl (left) and La(N03)3 (right) in concentra- 

 tions of 0.8 M. A very small amount of La(N03)3 sufficed to antago- 

 nize NaCl, the optimum proportion being 99.8 parts of NaCl to 0.2 

 parts of La(N03)3. 



Since in a previous investigation^ it was found that one part of 

 CaCl2 was required to antagonize five parts of NaCl, it is evident 

 that La is much more effective than Ca in antagonizing Na. This 

 accords with the results of experiments by other investigators on 



TABLE I. 



Rate of Respiration of Bacillus suhtilis in Various Concentrations of Lanthanum 



Nitrate* 



Molecular concentra- 

 tion of La(N03)3-. 



Rate of CO2 produc- 

 tion 



0.8 







0.25 



21 



0.05 



38 



0.005 



66 



0.0005 



76 



0.00005 



91 



0.000025 



100 



0.0000060.0000025 



117 100 



* Each number (representing the average of three or four experiments) ex- 

 presses the rate (calculated as per cent of the normal) after an exposure of 1 hour. 

 Probable error of the mean less than 3 per cent of the mean. 



growth, length of life, electrical conductivity, etc. in which it is found 

 that trivalent cations are more effective than bivalent in antagonizing 

 monovalent cations.^ 



Curve B shows the effects of combinations of CaClo (left) and 

 La(N03)3 (right) in concentrations of 0.8 m. There is a slight amount 

 of antagonism which attains a maximum at 8 parts of calcium and 

 2 parts of lanthanum ; from this point the curve approaches rapidly 

 zero as the amount of lanthanum is increased. 



^ Cf. Loeb, J., The dynamics of living matter, New York, 1906. Osterhout, 

 W. J. v., Bot. Gaz., 1915, lix, 464. 



