GENERAL PHYSICAL CONSTITUTION OF LIVING MATTER 47 



many eggs form embryos as in normal sea water* It is a striking 

 fact that not only the salts of such bivalent metals which occur in the 

 sea water or the body, e.g. Ca and Mg, render the pure NaCl solution 

 harmless; but also such salts as do not occur in the body, or are posi- 

 tively poisonous, e.g. Sr, Ba, Co, Zn, Pb, and others. An example will 

 illustrate these antagonistic effects between the salts of the univalent and 

 bivalent metals. 



Percentage of the Fundulus Eggs 

 Nature of the Solution which form an Embryo in this 



Solution 

 100 c.c. \ m NaCl 0°/ 



100 c.c. I m NaCl + i c.c. — CaSO, •><>/, 



64 



100 c.c. f m NaCl + i c.c. ^ CaSO, i% 



64 ' ■^ '" 



100 c.c. f m NaCl + 2 c.c. |^ CaSO. 20% 



64 " 



100 c.c. I m NaCl + 4 c.c. ~ CaSOj 75 % 



100 c.c. I m NaCl + 8 c.c. f^ CaS04 70% 



64 



It is remarkable how small a quantity of calcium suffices to render 

 the NaCl solution harmless. The anion has nothing to do with this 

 effect of the calcium salt, as the result remained the same when any 

 other soluble calcium salt was used, e.g. Ca(N03), or CaCl^. The 

 results also remained the same when in the place of the Ca salts, Sr, Ba, 

 Co, Zn, or Pb salts were used, and even the quantities of the salt required 

 to make the NaCl solution harmless were about the same for all the 

 salts. I think it is one of the most striking facts known in toxicology 

 that a pure solution of NaCl of that concentration in which this animal 

 lives is poisonous, while this solution can be rendered less harmful or 

 harmless by adding so poisonous a substance as Ba, Co, Zn, Pb, etc. 



If the eggs of Fundulus are raised in a solution of a salt with another 

 univalent cation than Na, e.g. K, Li, or NH^, we find that beginning with 

 a certain concentration a solution of each of these salts becomes a poison 

 for the eggs of Fundulus, that is to say, does not allow any egg to form 

 an embryo. If, at that concentration of one of these salts, a small but 

 definite amount of a salt with a bivalent cation is added, the eggs form 

 embryos and they are able to develop. Trivalent cations, like Al and 

 Cr, were also able to render the toxic concentrations of salts with a 

 univalent metal less harmful. The antitoxic effect of a tetravalent 

 cation, Th, however, was found to be only slight. 



* Loeb, Pfliiger's Archiv, Vol. 88, p. 68, 1901. Am. Jour. Physiology, Vol. 3, p. 327, 

 igoo; Vol. 6, p. 411, 1902. Loeb undGies, ^»^«-'j.ilrc4jw, VoU93„p. 246, 1902. I^eb. 

 Pfliiger's Archiv, Vol. 107, p. 252, 1905. 



