November 17, 1911] 



SCIENCE 



655 



The relative tolerance of various cells and 

 animals for abnormal salt solutions is, 

 however, not the same, a point which we 

 shall discuss later on. 



What is the role of the salts in these 

 cases? The botanists have always consid- 

 ered salt solutions as nutritive solutions. 

 It is a well-known fact that plants require 

 definite salts, e. g., nitrates and potassium 

 salts, for their nutrition, and the question 

 now arises whether the three salts NaCl, 

 KCl and CaClj, which are needed for the 

 preservation of animal life, play the role 

 of nutritive salts. Experiments which I 

 made on a small marine fish, Fundulus, 

 proved beyond question that this is not the 

 case. If the young, newly hatched fish are 

 put into a pure solution of sodium chloride 

 of the concentration in which this salt is 

 contained in sea-water, the animals very 

 soon die. If, however, KCl and CaClj be 

 added to the solution in the right proportion, 

 the animals can live indefinitely. These fish, 

 therefore, behave in this respect like Gam- 

 marus and the tissues of the higher ani- 

 mals, but they differ from Gammarus and 

 the majority of marine animals inasmuch 

 as the fish can live long, and in some cases, 

 indefinitely, in distilled and fresh water, 

 and certainly in a very dilute solution of 

 sodium chloride. From this fact I drew 

 the conclusion that KCl and CaClj do not 

 act as nutritive substances for these ani- 

 mals, that they only serve to render NaCl 

 harmless if the concentration of the latter 

 salt is too high. I succeed in showing that 

 as long as the sodium-chloride solution is 

 very dilute and does not exceed the con- 

 centration of m./8, the addition of KCl 

 and CaClj is not required. Only when the 

 solution of NaCl has a concentration above 

 m./8 does it become harmful and does it 

 require the addition of KCl and CaClj. 



The experiments on Fundulus, therefore, 

 prove that a mixture of NaCl + KCl + 

 CaClo does not act as a nutritive solution, 

 but as a protective solution. KCl and 

 CaCL are only necessary in order to pre- 

 vent the harmful effects which NaCl pro- 

 duces if it is alone in solution and if its 

 concentration is too high. We are dealing, 

 in other words, with a case of antagonistic 

 salt action; an antagonism between NaCl 

 on the one hand and KCl and CaClj on the 

 other. The discovery of antagonistic salt 

 action was made by Ringer, who found that 

 there is a certain antagonism between K 

 and Ca in the action of the heart. When 

 he put the heart of a frog into a mixture 

 of NaCl + KCl he found that the contrac- 

 tions of the heart were not normal, but they 

 were rendered normal by the addition of a 

 little CaClj. A mixture of NaCl + CaClj 

 also caused abnormal contractions of the 

 heart, but these were rendered normal by 

 the addition of KCl. Ringer drew the 

 conclusion that there existed an antagonism 

 between potassium and calcium, similar to 

 that which Schmiedeberg had found be- 

 tween different heart poisons, e. g., atropin 

 and muscarin. Biedermann had found 

 that alkaline salt solutions cause twitehings 

 in the muscle and Ringer found that the 

 addition of Ca inhibited these twitehings. 

 Since these experiments were made many 

 examples of the antagonistic action of salts 

 have become known. 



It had generally been assumed that the 

 antagonistic action of two salts was based 

 on the fact that each salt, when applied 

 singly, acted in the opposite way from that 

 of its antagonist. We shall see that in cer- 

 tain cases of antagonistic salt action at 

 least this view is not supported by fact. 



What is the mechanism of antagonistic 

 salt action? I believe that an answer to 



