March 21, 1913] 



SCIENCE 



436 



the electrolyte and the surface of the living 



VI. THE ALTERATION OP THE SEMI-PERMEA- 

 BILITY OF CELL WALLS BY ELECTROLYTES 



Those who have worked with Pfeffer's 

 semi-permeable cells report that it is very 

 difficult to maintain cells in the state of 

 ideal semi-permeability. It seems that the 

 semi-permeability of living organs suffers 

 also if they are exposed to solutions ab- 

 normal in concentration or constitution or 

 both. The normal medium for the cells of 

 our body is a liquid which contains NaCl, 

 KCl and CaClj in a proportion which is 

 almost identical with the one in which 

 those salts appear in the ocean. In such 

 solutions, if their concentration is right, 

 the cell walls may keep their specific semi- 

 permeability as long as they live. If, how- 

 ever, the cells or organs are put into solu- 

 tions of other salts, or of solutions with 

 only one of the three salts just mentioned, 

 the semi-permeability is lost sooner or later 

 and death follows. The possible explana- 

 tion is that the interactions between salts 

 and surface of the living organ lead in this 

 case to a modification of the physical quali- 

 ties of the surface of the living organ. 



In 1899 the writer found that the newly 

 fertilized eggs of a marine fish, Fundulus, 

 will develop normally in distilled water 

 and the fish will hatch. If, however, the 

 eggs are put into an m/2, or still better 

 %m, NaCl solution immediately after fer- 

 tilization they will die without forming an 

 embryo. If a small but definite amount of 

 a salt with a bivalent metal is added to 

 the NaCl solution the eggs will form em- 

 bryos. The explanation of these facts is 

 as follows: 



If the newly fertilized eggs are put into a 

 %m NaCl solution the NaCl makes the egg 

 membranes, which are naturally impreg- 



^^Beutner, Biochem. Zeitschr., Vol. 47, p. 73, 

 1912. 



nable to salts, gradually permeable. NaCl 

 enters the egg and the germ is killed. If a 

 little Ca is added to the NaCl this modifi- 

 cation of the membrane is inhibited, no 

 NaCl enters the egg and the germ can live 

 and develop. In distilled water the mem- 

 brane remains also impermeable to salt 

 (and to water) and the embryo likewise 

 develops.^" 



The writer has recently published a 

 series of experiments which furnish a 

 proof for this assumption.-" Only the gen- 

 eral character of this proof can be indi- 

 cated here. The eggs of Fundulus have a 

 specific gravity of a little over 1.0580 (cor- 

 responding to ^%m NaCl solution). If 

 such eggs several days after fertilization 

 are put into a 3m solution of NaCl -)- 

 KCl + CaCU in the proportion in which 

 these three salts occur in the sea-water, the 

 eggs will float at the surface of the solu- 

 tion for four days or longer. Then they 

 will shrink and fall to the bottom of the 

 test tube. The membrane is impermeable 

 to water and salts and remains so for a 

 series of days even in a 3m solution of 

 NaCl -f KCl -f CaCl,. Finally it becomes 

 permeable for water and to a lesser degree 

 for salts and the eggs shrink and fall to 

 the bottom. If, however, the eggs are put 

 into a 3m solution of NaCl they will also 

 float at first; but the increase in permea- 

 bility and the shrinking begins in three 

 hours. If we put the eggs into a solution 

 of CaCU from i%m to 2y2m they float at 

 first, but the shrinking begins in 20 min- 

 utes and the eggs sink to the bottom. If 

 we put the eggs into a mixture of 48 c.e. 

 3m NaCl + 2 c.e. i%m CaCl^ they will 



"Loeb, Science, Vol. 34, p. 653, 1911. Re- 

 printed in ' ' Mechanistic Conception of Life, ' ' 

 Chicago, 1912; Pfluger's Archiv, Vol. 107, p. 252, 

 1905. 



" Loeb, Biochemische Zeitschr., Vol. 47, p. 127, 

 1912. 



