TOXICITY OF ACIDS TO INFUSORIA 



79 



by the addition of NaCl, but at 0.01 M is decreased. With 

 Euplotes the addition of NaCl to the alkahne earth chlorides 

 increases their antitoxic action somewhat at all concentrations, 

 except in the case of SrClo : here it increases the antitoxic action of 

 SrClo, 0.001 M, but decreases that of SrCls 0.01 M. 



The same general results are obtained with formic acid (table 

 8). With butyric and caproic, however, somewhat different 

 results appear, especially in the mixtures containing NaCl. The 

 addition of NaCl diminishes the toxicity of butyric acid to 



TABLE 3 



BUTYRIC 0.001 N. 



Concentration of salts M 



Monovalent cations 



Bivalent cations 



Alone 



Plus NaCl 



Plus BaCl. 



Plus CaCl. 



Plus MgCl2 



Plus Sr Clo 



Plus BaCl2 plus NaCl. 

 Plus CaCla plus NaCl. 

 Plus MgCl2 plus NaCl 

 Plus SrCl2 



LENGTH OF LIFE IN MINUTES 



Paramecium 



005 

 0005 



0.01 

 0.001 



10 



7 

 50 



8 

 10 



8 

 60 

 15 

 15 



0.05 

 0.005 



12 



10 

 70 

 11 

 25 



35 



•80 



15 



45 



0.1 

 0.01 



12 



9 

 65 



7 

 30 



25 

 60 

 15 

 30 



Euplotes 







005 

 0005 



0.01 

 0.001 



20 



40 

 70 

 12 

 40 



80 

 120 



60 

 120 



0.05 

 0.005 



80+ 



60 

 90 

 15 

 50 



180+ 

 180+ 

 180+ 

 180+ 



0.1 

 0.01 



80 



70 



120 



23 



45 



180+ 

 180+ 

 180+ 

 180+ 



Paramecium as it does in the case of acetic. With Euplotes 

 NaCl is highly toxic if used alone or in conjunction with acetic, 

 but when added to butyric it becomes an efficient antagonist and 

 increases the length of life ten times (table 3) . Caproic (table 4) is 

 more difficult to antagonize but even so NaCl 0.1 M decreases 

 toxicity to Euplotes by three-fourths instead of increasing it as 

 it does with acetic. The efficiency of the alkaline earth chlorides 

 is: 



Paramecium: Ca > Sr > Ba = Mg 

 Euplotes: Ca > Sr > Ba > Mg 



