IONS AND SALT ACTION. 73 



0.9-1 per cent, CaCl 2 0.02-0.024 per cent, KC1 0.02-0.042 per cent, 

 NaHCO 3 0.01-0.03 per cent. Each of the salts NaCl, GaCl 2 and KC1 

 individually has a poisonous action upon the organ but this action is 

 counteracted by the presence of the two other salts (antagonistic salt 

 action). 



This neutralizing action of salts has been studied during recent 

 years especially by J. LOEB and his collaborators. As general results 

 it has been found that the most favorable quantity relations of the 

 three salts NaCl, KC1 and CaCl 2 for the maintenance of life is the same 

 as exists in blood.. Especially interesting are the experiments with the 

 Fundulus heteroclitus, a genus of killifish. This fish, it is remarkable, can 

 also live in distilled water and is therefore within wide limits, not depend- 

 ent upon the osmotic pressure of the surrounding medium. For this 

 reason it is specially suited for the study of the poisonous action of salts 

 or mixture of salts. KC1 in concentrations in which it exists in sea water 

 acts as a poison upon these fishes, if it is alone in solution. The same 

 is true for NaCl. On the contrary these fishes live for an indefinite 

 time in a pure CaCl2 solution in a concentration similar to sea water. 

 One mol. KC1 can be very nearly de-toxicated by 17 mol. NaCl or by 8J mol. 

 Na 2 S04. \ mol. K 2 S04 is just as poisonous as 1 mol. KC1. The toxicity 

 of the potassium salts is therefore dependent upon the K ions and the 

 de-toxicating substance on the Na ion. CaCl 2 de-toxicates a KC1 solu- 

 tion even when ^ mol. CaCl 2 to 1 mol. KC1 is present. SrCl 2 shows 

 almost as great a de-toxicating action as CaCl 2 . NaCl in concentra- 

 tions, in which it occurs in sea-water can only be incompletely de-toxi- 

 cated by KC1; only by the addition of CaCl 2 can the complete de- 

 toxication be brought about. The poisonous action of acids upon 

 Fundulus can be arrested by neutral salts. 1 Fundulus can accommodate 

 themselves to a rise in temperature; a rise in temperature can be more 

 easily endured when the concentration of the surrounding medium is raised 

 at the same time (LOEB and WASTENEYS). Can fishes also accommodate 

 themselves to an abnormal concentration of the surroundings as long 

 as the rise in concentration takes place gradually? In both cases the 

 accommodation, according to LoEB, 2 depends upon a slow proceeding 

 process, possibly a tanning of the surface of the animal. 



The fertilized eggs of the Fundulus develop, according to LOEB, just 

 as well in water free from salt as in sea-water. If the fertilized eggs are 

 placed in a NaCl solution of the same osmotic pressure as the sea-water 



iBioch. Zeichr., 31, 450; 32, 155, 308; 33, 480. 489 (1911); 39, 167; 43, 181 



(1912). 



2 Loeb and Wasteneys, Joura. of exp. Zool., 18, 543 (1913) and Loeb, Bioch. 



Zeitschr., 53, 391 (1913). ...... .. 



