CAN SEA WATER MAINTAIN THE BEAT OF THE 

 HEART OF FRESH WATER ANIMALS? 



THEO. C. BURNETT. 



(From the Rudolph Spreckles Physiological Laboratory of the 

 University of California.) 



In 1900 Loeb 1 introduced the idea of physiologically balanced 

 solutions, i. e., "salt solutions which contain such ions in such 

 proportions as to annihilate completely the poisonous effect 

 which each constituent would have if it were alone in solution." 

 On this basis blood, sea water and Ringer's solution are examples 

 of balanced solutions. Loeb 2 was led to this idea by the obser- 

 vation that young Fundulus, which live in sea water, can also 

 live in distilled water, while they die rapidly in a pure solution 

 of sodium chloride (or any other salt) of the same osmotic 

 pressure as sea water. Now we know that the life of the heart is 

 sustained in blood and in Ringer's solution ; the question arises 

 is it equally well sustained in sea water that has been made iso- 

 tonic with the blood. We have already a few facts in this regard. 

 Rogers 3 found normal sea water to be an excellent sustaining 

 fluid for the heart of the marine crab, and Garrey, 4 says "the 

 mammalian muscle lives longer in isotonic sea water than in any 

 other inorganic solution tested." Osterhout 5 experimenting with 

 Vauclieria sessilis, a green alga common in running water, found 

 it would grow well and live indefinitely in sea water with a con- 

 centration approximating 3/32 M. According to Van't Hoff the 

 composition of sea water is as follows : 100 mols. NaCl ; 2.2 



1 Loeb, J., "On the Artificial Production of Normal Larvae from the Unfertillized 

 Eggs of the Sea Urchin (Arbacia)," Am. Jour: Phys., Vol. 3, 19CO, p. 434. Also 

 " Studies in General Physiology," p. 590. 



2 Loeb, J., " On Ion-proteid Compounds and Their Role in the Mechanics of Life 

 Phenomena, ". 4m. Jour. Phys., Vol. 3, 1900, p. 327. 



3 Rogers, C. G., "The Effects of Various Salts upon the Invertebrate Heart," 

 Jour. Exper. Zo'ol., Vol. 2, 1905, p. 237. 



4 Garrey, Walter E., " Twitchings of Skeletal Muscles Produced by Salt Solutions, 

 etc.," Am. Jour. Phys., Vol. 13, 1905, p. 186. 



5 Osterhout, W. J. V., " Extreme Toxicity of Sodium Chloride and its Prevention 

 by Other Salts," Jour. Biol. Chem., V ol. 1, 1905-6, p. 363. 



203 



