654 



SCIENCE 



[N. S. Vol. XXXIV. No. 881 



animals, and that, as a kind of inheritance, 

 we still carry diluted sea-water in our 

 blood. Statements of this kind have mainly 

 a metaphorical value, but they serve to 

 emphasize the two facts, that the three 

 salts, NaCl, KCl and CaClj, exist in our 

 blood in the same relative proportion as in 

 the ocean and that they seem to play an 

 important role in the maintenance of life. 

 I intend to put before you a series of 

 experiments which seem to throw some 

 light on the mechanism by which the solu- 

 tions surrounding living cells influence 

 their duration of life. 



In order to give a picture of the extent 

 to which the life of many animals depends 

 upon the cooperation of the three salts I 

 may mention experiments made on a small 

 marine crustacean, Gammarus, of the Bay 

 of San Francisco. If these animals are 

 suddenly thrown into distilled water, their 

 respiration stops (at a temperature of 

 20° C.) in about half an hour. If they are 

 put back immediately after the cessation 

 of respiration into sea-water, they can re- 

 cuperate. If ten minutes or more are al- 

 lowed to elapse before bringing them back 

 into the sea-water, no recuperation is pos- 

 sible. Since in this case death is caused 

 obviously through the entrance of distilled 

 water into the tissues of the animals, one 

 would expect that the deadly effect of dis- 

 tilled water would be inhibited if enough 

 cane sugar were added to the distilled 

 water to make the osmotic pressure of the 

 solution equal to that of the sea-water. If, 

 however, the animals are put into cane- 

 sugar solution, the osmotic pressure of 

 which is equal to that of sea-water, the 

 animals die just about as rapidly as in dis- 

 tilled water. The same is true if the os- 

 motic pressure of the sugar solution is 

 higher or lower than that of the sea-water. 



The sugar solution is, therefore, about as 

 toxic for the animals as the distilled water, 

 although in the latter case water enters 

 into the tissues of the animal, while in the 

 former case it does not. 



If the sea-water is diluted with an 

 equal quantity of distilled water in one 

 case, and of isotonic cane-sugar solution 

 in the other case^ in both cases the dura- 

 tion of life is shortened by practically the 

 same amount. 



If the crustaceans are brought into a 

 pure solution of NaCl, of the same osmotic 

 pressure as the sea-water, they also die in 

 about half an hour. If to this solution a 

 little calcium- chloride be added in the 

 sea-water the animals die as rapidly as 

 proportion in which it is contained in the 

 without it. If, however, both CaCls and 

 KCl are added to the sodium chloride so- 

 lution, the animals can live for several 

 days. The addition of KCl alone to the 

 NaCl prolongs their life but little. 



If KCl and CaCla are added to a cane 

 sugar solution isotonic with sea-water, the 

 animals die as quickly or more so than in 

 the pure cane-sugar solution. 



If other salts be substituted for the three 

 salts the animals die. The only substitu- 

 tion possible is that of SrCL for CaCL. 

 We find also that the proportion in which 

 the three salts of sodium, calcium and 

 potassium have to exist in the solution 

 can not be altered to any extent. All this 

 leads us to the conclusion, that in order to 

 preserve the life of the crustacean Gam- 

 marus, the solution must not only have a 

 definite concentration or osmotic pressure 

 but that this osmotic pressure must be 

 furnished by definite salts, namely, sodium 

 chloride, calcium chloride and potassium 

 chloride in the proportion in which these 

 three salts exist in the sea-water (and in 

 the blood) ; this fact could also be demon- 

 strated for many other marine animals. 



