Toxic AND ANTITOXIC EFFECTS OF IONS 721 



The addition of ^ to 2 c.c. of m KC1 or K 2 SO 4 occasionally 

 yielded results, in that 1-5 per cent, of the eggs formed 

 embryos. Lithium salts showed themselves to be even less 

 active. I occasionally obtained a slight antitoxic action by 

 the addition of large amounts of NH 4 salts. Whether 

 hydrogen ions can yield better results must be determined 

 through further experiments. 



7. Not only can the poisonous effects of a pure sodium- 

 chloride solution be annihilated through the addition of 

 small amounts of bivalent or trivalent kations, but it seems 

 as though the same holds for all salts which, like NaCl, have a 

 univalent kation and anion. No embryos develop in a f m LiCl 

 solution. By the addition of small amounts of Ca(NO 3 ) 2 , 

 BaCl 2 , SrCl 2 , or MgCl 2 , 50-60 per cent, of the eggs were 

 caused to form embryos, which developed normally. Other 

 kations of a higher valency were not tested. I obtained 

 entirely similar results in regard to KC1. In a -f in or even 

 a ^ra KC1 solution an egg may occasionally develop. When 

 a small quantity of MgCl 2 , Ca(NO 3 ) 2 , SrCl 2 , BaCl 2 or 

 FeSO 4 was added, the poisonous effects of the pure KC1 

 solution were annihilated. Of salts having other bivalent 

 kations, only ZnSO 4 (a single experiment) was used. An 

 effect was obtained in this case also, but it was less striking 

 than in the case of the other bivalent kations. 



NH 4 C1 seems to be the least toxic of all the salts men- 

 tioned thus far. Even in a ^m NH 4 C1 solution an embryo 

 could form occasionally. This immunity of the Fundulus 

 egg against NH 4 C1 is perhaps related to its great immunity 

 against urea. I cannot get rid of the suspicion that a per- 

 centage of the NH 4 ions is perhaps done away with in the 

 metabolism of the egg. I obtained striking antitoxic effects 

 with small amounts of SrCl 2 and, although less definite, 

 of FeSO 4 . Ca(NO 3 ) 2 increased the number of embryos 

 formed, though not as greatly as the other salts with a 



