The Organism as a Whole, from a Physicochemical Viewpoint

by Jacques Loeb

This indicates that the quantity of CaCl₂ required to counteract the injurious effects of a pure solu­tion of NaCl increases approximately in propor­tion to the square of the concentra­tion of the NaCl solu­tion.[262] The reader will notice that the eggs can survive and develop in a solu­tion of three times the concentra­tion of sea water, provided enough Ca is added.

It was found also that not only Ca but a large number of other bivalent metals were able to counteract the injurious action of an excessive NaCl solu­tion; namely Mg, Sr, Ba, Mn, Co, Zn, Pb, and Fe;[263] only Hg and Cu could not be used since they are themselves too toxic. The antagonistic efficiency of the bivalent cations other than Ca was, however, smaller than that of Ca. The following table gives the highest concentra­tion of NaCl solu­tion in which the newly fertilized eggs of Fundulus can still form an embryo.[264]

50 c.c. ¹⁰⁄₈ m NaCl+4 c.c. m/1 MgCl₂
50 c.c. ¹⁴⁄₈ m NaCl+1 c.c. m/1 CaCl₂
50 c.c. ¹¹⁄₈ m NaCl+1 c.c. m/1 SrCl₂
50 c.c. ⁷⁄₈ m NaCl+1 c.c. m/1 BaCl₂

On the other hand it was seen that in all the chlorides with a univalent cation, LiCl, KCl, RbCl, CsCl, NH₄Cl, the eggs could form embryos up to a certain concentra­tion of the salt; but that this concentra­tion could be raised by the addi­tion of Ca.

TABLE XVII

Concentrations at which the Eggs no longer Are Able to Form Embryos

In the Pure Salts			In the Same Salts with the Addition of 1 c.c. m CaCl2 to 50 c.c. Solution
LiCl	about 6/	32 m	>5/	8 m
NaCl	m/	2	>14/	8 m
KCl	>11/	16 m	>8/	8 m
	<6/	8 m
RbCl	>8/	8 m	>9/	8 m
	<7/	8 m
CsCl	>3/	8 m	>8/	8 m
	<4/	8 m

In short it turned out that the injurious action of the pure solu­tion of any chloride (or any other anion) with a univalent metal could be counteracted to a considerable extent by the addi­tion of small quantities of a salt with a bivalent metal. It was also found in the early experi­ments of the writer that the bivalent or polyvalent anions had no such antagonistic effect upon the injurious action of the salts with a univalent cation.

We therefore see that what at first sight appeared in the experi­ments of Herbst a necessity, namely, the presence of each constituent of the sea water, turns out as a special case of a more general law; the salts with univalent ions are injurious if their concentra­tion exceeds a certain limit and this injurious action is diminished by a trace of a salt with a bivalent cation.