NOVEMBEE 17, 1911] 



SCIENCE 



661 



as soon as the solution contains 17 or more 

 molecules of NaCl to one molecule of KCl, 

 the toxic action of KCl is considerably 

 diminished, if not completely counteracted. 

 The following table may serve as an ex- 

 ample. 



TABLE ni 



More accurate determinations showed 

 that already a 3/16 m. NaCl solution ren- 

 ders the solution of 2.2 c.c. m./2 KCl in 

 100 c.c. of the solution harmless. 



It was next determined whether different 

 concentrations of KCl required different 

 concentrations of NaCl. It was found that 

 the coefficient of antagonization KCl/NaCl 

 has an approximately constant value, 

 namely, about 1/17, as the following table 

 shows. 



TABLE rV 



Coefficient of 

 Antagonization 



0.6 C.C. ni./2 KCl rendered harmless in 



100 c.c. 3/64 m. NaCl 1/16 



0.7 c.c. m./2 KCl rendered harmless in 



100 c.c. 4/64 m. NaCl 1/18 



0.9 c.c. ni./2 KCl rendered harmless in 



100 c.c. 5/64 m. NaCl 1/17 



1.0 c.c. m./2 KCl rendered harmless in 



100 c.c. 5/64-6/64 m. NaCl 1/16-1/19 



1.1 c.c. m./2 KCl rendered harmless in 



100 c.c. 6/64 m. NaCl 1/17 



1.65 c.c. m./2 KCl rendered harmless in 



100 CO. 5/32 m. NaCl 1/19 



2.2 c.c. m./2 KCl rendered harmless in 



100 c.c. 6/32 m. NaCl 1/17 



2.75 c.c. m./2 KCl rendered harmless in 



100 c.c. 7/32 m. NaCl 1/16 



3.3 c.c. m./2 KCl rendered harmless in 



100 c.c. 9/32 m. NaCl 1/17 



What happens if we vary this ratio ? If 

 we add too little NaCl to the KCl solution, 

 namely, only 1 to 10 molecules NaCl to 

 1 molecule of KCl, the solution becomes 

 more harmful than if KCl is alone in solu- 

 tion; if we add considerably more than 17 

 molecules NaCl, e. g., 50 molecules to one 

 molecule of KCl, the solution becomes toxie 

 again ; and the more so the higher the con- 

 centration of NaCl. This indicates that 

 the antagonistic effect requires a rather 

 definite ratio of the two salts. This fur- 

 nishes the reason why an m./2 solution can, 

 as a rule, not be rendered completely harm- 

 less by the mere addition of KCl, but that 

 in addition CaCl, is needed. 



If we add to 100 c.c. m./2 NaCl enough 

 KCl to make the ratio KCl : NaCl = 1/17 

 we find that the antagonization of KCl: 

 NaCl becomes incomplete. If the amount 

 of KCl in 100 c.c. of the solution exceeds 

 2.2 c.c. m./2 KCl, antagonization is still to 

 some extent possible, but it becomes more 

 incomplete the higher the concentration of 

 KCl. For this reason it is not possible to 

 render an m./2 solution of NaCl harmless 

 by the mere addition of KCl. 



CaCU acts upon KCl similarly as does 

 NaCl, but it acts more powerfully ; i. e., the 

 coefficient of antagonization, KCl/CaCl^, 

 is several hundred or a thousand times as 

 great as that of KCl/NaCl, as the follow- 

 ing table shows. 



1.1 c.c. m./2 Ka in 100 e.e. H^O 



require 0.1 m./lOO CaCl; . . 550 



1.65 c.c. m./2 KCl in 100 c.c. H-,0 



require 0.5 m./lOO CaCl^ .. 165 



2.2 c.c. m./2 KCl in 100 e.e. HjO 



require 0.3 m./lOO CaClj . . 366 



2.75 e.e. m./2 KCl in 100 e.e. HjO 



require 1.0 m./lOO CaClj . . 137.5 



3.3 c.c. m./2 KCl in 100 c.c. H,0 



require 1.6 m./lOO CaClj . . 103 



