442 PROTOPLASM 



Loeb was inclined to think of elements as physical rather than 

 as chemical entities. For him, calcium played its role in life 

 because it is bivalent and because it possesses two electrical 

 charges, rather than because it is the element calcium. If 

 Loeb's viewpoint is true, then any other bivalent element with 

 two electrical charges should be able to replace calcium as an 

 antidote. Experiments by Loeb prove that out of six bivalent 

 elements, five antagonize sodium equally well. The experiments 

 had to do with the percentage of Fundulus eggs that develop 

 into embryos in solutions of various salts. It must be remem- 

 bered that the six elements are alike in but one respect (in the 

 experiments under consideration), viz., that they all antagonize 

 sodium. This does not mean that they can in all other respects 

 replace each other in the life of an organism. 



Percentage 

 of Eggs That 

 Develop into 

 Solution Embryos 



100 cc. % M. NaCl 



100 cc. % M. NaCH- 2 cc. 1 M. BaCU 90 



100 cc. ^^ M. NaCl + 2 cc. ^e M. SrCls 90 



100 cc. M M. NaCl+ 2 eel M. MgCla 75 



100 cc. ^^ M. NaCl + 2 cc. M M. CaCh 88 



100 cc. % M. NaCl + 4 cc. H M. NiCh 5 



100 cc. % M. NaCl + 8 cc. H28 M. ZnSOi 75 



For Loeb, then, antagonism became simply a question of the 

 opposing influence of monovalent elements on the one hand and 

 bivalent elements on the other. As an antidote one element was 

 as good as another in its own group. R. Lillie found that while 

 practically any bivalent cation will annul or diminish the toxic 

 influence of sodium chloride, the efficiency of the elements in 

 this respect put them into the following decreasing series (in 

 which M/2 NaCl was mixed with M/200 of the bivalent metal) : 

 Mg > Ba > Ca > Sr > Mn > Fe > Co > Ni > Cd > Pb > 

 Zn > Cu. (It is interesting that the last three strongly toxic 

 elements copper, zinc, and lead should antagonize, i.e., prevent 

 the poisonous action of, the relatively harmless salt sodium 

 chloride. This becomes more comprehensible when it is realized 

 that the concentration of the sodium is one hundred times as 

 great as that of the heavy metals.) 



