MUTUALLY ANTAGONISTIC ACTION OF SALTS 319 



the eggs live for less than thirty days in the first two solutions, but in 

 the third, which corresponds in composition with a concentrated 

 Ringer's Solution, the eggs live for an indefinite period and develop 

 normally. Evidently the toxic properties of sodium chloride are 

 neutralized or antagonized by admixture with a small proportion of 

 other inorganic salts. When the correct mixture is obtained the solu- 

 tion is devoid of toxicity and we speak of it as a "Physiologically 

 Balanced" salt solution. Evidently Ringer's solution and sea-water are 

 physiologically balanced solutions in so far as the tissues of Fundulus 

 are concerned. 



Sodium chloride is not peculiar in exerting a toxic effect in pure 

 solution. In fact it may be said that any salt without admixture 

 with other salts is more or less toxic for living protoplasm. This is 

 very clearly demonstrated by the following among very many experi- 

 ments of this character which we owe to Loeb. 



Antagonism between sodium chloride and zinc sulphate (Fundulus). 



Percentage of 

 - eggs which 



Solution. develop: 



lOOc.c. H 2 O ................. 49 



lOOc.c. H 2 O + 8 c.c. l/32m ZnSO 4 .......... 



100 c.c. 8/8m NaCl + 8 c.c. l/32m ZnSO 4 ........ . 1 



100 c.c. 7/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 6 



100 c.c. 6/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 8 



100 c.c. 5/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 29 



100 c.c. 4/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 34 



100 c.c. 3/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 37 



lOOc.c. 2/8m NaCl + 8 c.c. l/32m ZnSO 4 ......... 38 



Evidently a very dilute solution of zinc sulphate is highly toxic for 

 Fundulus eggs. Sodium chloride in excess is also very toxic. A definite 

 admixture of these two toxic salts may be found, however, which is 

 almost devoid of toxicity. 



In the above experiment we have an instance of antagonism between 

 a monovalent metal and a divalent metal. Antagonism may also 

 be displayed between two monovalent metals or between two divalent 

 metals. The following is an illustrative example: 



Antagonism between magnesium chloride and strontium chloride 

 (Fundulus) . 



Percentage of 



eggs which 



Solution. develop: 



100 c.c. 5/8m MgCl 2 ............. 



100 c.c. 5/8m MgCl 2 + 1 c.c. of 5/8m SrCl 2 ..... ' . 25 



lOOc.c. 5/8m MgCl 2 + 2 c.c. of 5/8m SrCl 2 ...... 22 



100 c.c. 5/8m MgCl 2 + 3 c.c. of 5/8m SrCl 2 ...... 9 



lOOc.c. 5/8m MgCl 2 + 4 c.c. of 5/8m SrCl 2 ...... 



lOOc.c. 5/8m MgCl 2 + 5 c.c. of 5/8m SrCl 2 ........ 



Similar antagonism was found to subsist between lithium chloride 

 and zinc sulphate, potassium chloride and zinc sulphate, ammonium 

 chloride and zinc sulphate, sodium acetate and lead acetate, sodium 

 chloride and manganese chloride, sodium chloride and cobalt chloride, 



