COMPARATIVE STUDIES ON RESPIRATION. 



VIII. The Respiration of Bacillus Subtilis in Relation to 



Antagonism. 



By matilda MOLDENHAUER BROOKS. 

 {From the Laboratory of Plant Physiology, Harvard University, Cambridge.) 



(Received for publication, June 15, 1919.) 



Although the antagonistic effects of salts on certain bacteria have 

 been studied, no attempt has been made to ascertain whether any 

 relation exists between these effects and the respiration. The in- 

 vestigations described in this paper were undertaken with a view 

 to obtaining some hght on this question. 



The first attempt to study antagonism in relation to bacteria was 

 made by Lipman.^ He used the production of NH3 by Bacillus 

 subtilis as an index of metabolism. He allowed cultures of Bacillus 

 subtilis to grow over night in various salts and combinations of salts 

 in the proportions found in sea water, and measured the production 

 of NH3. There was a considerable decrease in the production of 

 NH3 when the salts were used singly, but this did not occur when 

 combinations of salts were made in the proportions found in sea 

 water. 



Winslow and Falk.^ have observed antagonistic effects in experi- 

 ments on Bacillus coli. These investigators found that cultures sus- 

 pended in solutions of NaCl or CaCl2 were decreased in number; 

 that higher concentrations produced steriKzation of the culture; and 

 that a combination of NaCl and CaCl2 in the molecular proportions 

 of 5 : 1 was favorable to the growth of the organism. 



^ Lipman, C. B., Bat. Gaz., 1909, xlviii, 105; 1911, xlix, 41. 

 2 Winslow, C.-E. A., and Falk, I. S., Proc. Soc. Exp. Biol, and Med., 1918, xv, 

 67. 



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