-----------+--------------+--------------+----------- _Number |_Concentration| _C.c. 3/8 m |_Value of of | of | CaCl₂+MgCl₂ | C_{Na+K}/ Experiment_| NaCl+KCl_ | Required_ | C_{Mg+Ca}_ -----------+--------------+--------------+----------- 1 | {m/16 | 0.3 | 27.8 | {m/8 | 0.4-0.5 | 37.0 | | | 2 | {m/8 | 0.5 | 33.3 | {m/4 | 0.9-1.0 | 35.1 | | | 3 | {3/16 m | 0.7 | 35.7 | {3/8 m | 1.3 | 38.5 | | | 4 | {m/8 | 0.5 | 36.0 | {m/2 | 1.8-1.9 | 39.2 | | | 5 | {m/4 | 0.8-0.9 | 39.2 | {m/2 | 1.6-1.7 | 40.3 | | | 6 | {5/16 m | 0.9 | 46.3 | {5/8 m | 1.7 | 49.0 | | | 7 | {3/16 m | 0.6 | 41.7 | {6/8 m | 2.4 | 41.7 -----------+--------------+--------------+----------- These experiments indicate that the ratio of C_{Na+K}/C_{Ca+Mg} remains very nearly constant with varying concentrations of C_{Na+K}. In former experiments on jellyfish the writer had shown that there exists an antagonism between Mg and Ca[271], and this observation was subsequently confirmed by Meltzer and Auer[272] for mammals. It was observed that in a solution of NaCl+KCl+MgCl₂ the larvæ of the barnacle were also not able to remain at the surface for more than a few minutes, while an addition of some CaCl₂ made them swim permanently at the surface. Various quantities of MgCl₂ were added to a mixture of m/4 or m/2 NaCl+KCl, to find out how much CaCl₂, was required to allow them to swim permanently at the surface. [271] Loeb, J., _Jour. Biol. Chem._, 1905-06, i., 427. [272] Meltzer, S. J., and Auer, J., _Am. Jour. Physiol._, 1908, xxi., 400. TABLE XIX