The role of the concentration of hydroxylions in the antagonistic action of K and Ca upon Na

It has been proved during the last years that quite generally in animals, plants and bacteria, a poisonous solution of NaCl can be rendered harmless through the additon of small quantities of CaCl₂ + KCl. A number of years ago I published results of experiments which indicated that the rôle of Ca in these experiments was fundamentally different from that of K. When fertilized eggs of Fundulus were put into m/2 solution of NaCl which killed the eggs in a comparatively short time it was found that small quantities of CaCl₂ or certain other salts with a bivalent metal rendered the solution comparatively harmless; while the same cannot be accomplished through the addition of KCl, LiCl or NH₄Cl to the m/2 solutions of NaCl.

Recently I was able to show this difference in the action of Ca and K in a rather striking way. The fertilized eggs of Strongy-locentrotus were put in the following four solutions: first NaCl; second, Na + K; third, Na + Ca; fourth, Na + Ca + K. The experiments were made with neutral as well as with acid and alkaline solutions. It was found that in the neutral and acid solution the antagonistic effect of K prevailed over that of Ca, which was very slight; while in alkaline solutions the antagonistic effect of Ca was comparatively strong, while that of K was rather slight.

If newly fertilized eggs of the sea urchin are put into a mixture of NaCl + KCl, one finds that if the solution is neutral, the eggs segment rather normally and they may reach the 64 cell stage. If, however, the solution is made faintly alkaline the eggs are cytolized without segmenting.