152 JOHN N. LOWE 



Reactions to salts 



The problem of salt action is one of the most interesting 

 within the scope of physiology and has wide applications. The 

 relation of various salts to heart beat is a long debated question. 



Howell ('98), p. 49, is of the opinion ''that the inorganic salts 

 of the blood and liquids of the heart tissues especially of the 

 calcium compounds, stand in a peculiar and fundamental rela- 

 tion to the initiation of the inner stimulus of the heart con- 

 tractions." Loeb ('00 a, '00 b) believes that the sodium cations 

 acting on the striped muscle to be the stimulating agents being 

 counteracted by the ions of potassium and calcium. The posi- 

 tion of Loeb is supported by Lingle ('00). Benedict ('05 and 

 '08) is of the opinion that the anion probably plays an important 

 role in the action of salt solutions upon heart beat. 



Mathews ('04 a, '04 b, '05, '06) maintains that in the action 

 of salt solutions on motor nerves, colloids, and sea urchin eggs, 

 the ionic potential of the salt, which is the reciprocal of the 

 solution tension, is an important factor in ionic action. R. S. 

 Lillie ('11, '12 a, '12 b) working with the larvae of Arenicola 

 and eggs of starfish, and McClendon ('10) on sea urchin eggs put 

 forth the hypothesis that ionic action is due to the modification of 

 the permeability of the plasma membrane. Loeb ('00 b) holds 

 that ionic action is due to the formation of ion protein com- 

 pounds, that is that the ions of the salt combine directly in some 

 way with the protein molecules of the living protoplasm. True 

 and Kahlenberg ('96) working with plants (Lupinus albus) be- 

 lieve that the anion is unimportant in the toxic action of the 

 salt. 



Spaeth ('13) working on the chromatophores in isolated scales 

 of Fundulus heteroclitus concludes that the anion in potassium 

 salts is of no importance in causing the initial contraction of the 

 chromatophores, but that in the secondary expansion of the 

 chromatophores the action of potassium is modified by the 

 anions. On the other hand, the duration of the sodium expan- 

 sion varies with the nature of the anion. 



