The Influence of Environment 315 



TABLE XVIII Continued 



These experiments indicate that the ratio of 



CNa-fK 



CCa+Mg 



remains very nearly constant with varying concentra- 

 tions of CNa+K. 



In former experiments on jellyfish the writer had 

 shown that there exists an antagonism between Mg 

 and Ca 1 , and this observation was subsequently con- 

 firmed by Meltzer and Auer 2 for mammals. It was 

 observed that in a solution of NaCl+KCl+MgCl 2 

 the larvag of the barnacle were also not able to remain 

 at the surface for more than a few minutes, while an 

 addition of some CaCl 2 made them swim permanently 

 at the surface. Various quantities of MgCl 2 were 

 added to a mixture of m/4 or m/2 NaCl+KCl, to find 



1 Loeb, J., Jour. BioL Chem., 1905-06, i., 427. 



3 Meltzer, S. J., and Auer, J., Am. Jour. PhysioL, 1908, xxi., 400. 



