RESEARCH SEMINAR. 313 



ample, mercury and copper are enormously more powerful than 

 the bivalent alkaline earth metals ; and hydrogen with one charge 

 is more active than other univalent metals. The author sug- 

 gested that this divergence from the theoiy probably meant that 

 it was the motion of the valence or charge which ultimately 

 determined its action and that the velocities or orbits differed for 

 the charges attached to different elements. Dr. Stieglitz sug- 

 gested that the affinity of the atom for its charge might vary and 

 account for these discrepancies. It occurred to the writer that 

 this affinity might be represented by the solution tension of the 

 element. The more easily the element is separated from a solu- 

 tion of its ions, the less is its affinity for the charge it carries as 

 an ion. I have accordingly compared the poisonous action of 

 the metals and negative elements with their relative solution ten- 

 sion as given by Nernst, using Fundulus eggs as test objects. 

 The least concentration of the solution of the chlorides of the 

 different metals which would just prevent the formation of an 

 embryo was determined. 



The result showed a marked inverse ratio between the solution 

 tension and poisonous action. Potassium with its great solution 

 tension is almost the least poisonous ; silver with a very low 

 tension is the most poisonous. The other metals arranged them- 

 selves in proper order, except that ferric iron, zinc and cadmium 

 were more poisonous than their position in the list of metals 

 would indicate. This discrepancy is probably due to the fact 

 that the solution tension is but a poor measure of affinity between 

 the charge and the element. The anions arrange themselves in 

 order, those parting with their negative charges most easily being 

 most poisonous. 



The correspondence is so close as to indicate clearly that the 

 affinity between the electric charge and the atom is a powerful 

 factor in determining physiological action, and that the less 

 strongly the charge is held, the more powerful is the action of 

 any ion. 



Experiments were also tried demonstrating that the action of 

 any cathion is modified by the action of the anion ; and that of 

 any anion is modified by the action of the cathion. There is 

 hence an antagonistic action between anions and cathions and the 



