14 STUDIES ON RESPIRATION. VIII 



and upon the production of NH3 by Bacillus subtilis respectively. 

 The fact that both salts are monovalent may be a factor in explaining 

 their peculiar behavior. 



Curve C of Fig. 5 shows antagonism between KCl and CaCl2. 

 This was also observed by Lipman^ in the production of NH3. The 

 maximum efifect is found at 9 KCl to 1 CaCl2, where the rate of respi- 

 ration is 100 per cent. In comparing this curve with Curve A (NaCl 

 and CaCl2) one can readily observe that more KCl is required to 

 antagonize CaCl2 than would be required of NaCl. It is interesting 

 to observe that KCl is the least toxic of the three salts, and that it 

 is the least effective in influencing respiration. This agrees with 

 the results of Lipman^ on the production of NH3 by Bacillus subtilis. 



There are no similar investigations on the respiration of plants 

 with which a comparison might be made. Some interesting studies 

 have been made on sea urchin eggs by Warburg,'^ by Loeb and Was- 

 teneys,^ and by Meyerhof,^ an account of which is given in a recent 

 summary by Osterhout.^" The results obtained with bacteria agree 

 with those of Loeb and Wasteneys in that there is no rise in rate 

 in NaCl, except in 0.15 m concentration in which the rise is only 

 30 per cent which is insignificant compared with that obtained by 

 Warburg^ and Meyerhof^ (200 to 500 per cent). On the whole 

 the results are more nearly in agreement with those of Loeb and 

 Wasteneys.^ 



In order to find out what effect was produced on the bacteria 

 while they were being acted upon by the salts, a few recovery experi- 

 ments were tried. After the bacteria had remained in the salt so- 

 lution for an hour, they were centrifugated and thoroughly washed 

 in dextrose solution and centrifugated again. The supernatant fluid 

 was then drained off, 2 cc. of dextrose solution were added, and their 

 respiration was measured. It was found that within ' a period of 

 less than | hour the rate became normal. 



A control experiment was made by substituting the same salt in 

 the same molecular concentration as was removed from the bacteria 



^ Warburg, O., Z. physiol. Chetn., 1910, Ixvi, 305; Biochem. Z., 1910, xxix, 414. 

 *Loeb, J., and Wasteneys, H., Biochem. Z., 1910, xxviii, 340; 1911, xxxi, 168. 

 » Meyerhof, O., Biochem. Z., 1911, xxxiii, 291. 

 ^0 Osterhout, W. J. V., /. Gen. Physiol., 1919-20, ii, 1. 



