MUTUAL ANTAGONISM OF INORGANIC SALTS 325 



cell for water and for substances which are soluble in water, but 

 insoluble in fats. 



Of course the alteration of the texture of the interstitial protein 

 jelly which ensues when cells are immersed in abnormal inorganic 

 media may be expected, not only to affect the permeability of the cells, 

 but also a variety of other properties of the cells, and in this way to 

 affect a variety of their functions. Thus, as Loeb has pointed out, 

 the effects of diverse salt solutions, and especially those of calcium 

 precipitants upon the phenomena of motility, are not solely and directly 

 to be attributed to changes in the permeability of the superficies of 

 the contractile elements. Indeed it would be manifestly unreasonable 

 on a priori grounds to make such an assumption. The permeability 

 of the cells having been affected, however, the salts which penetrate 

 them induce further changes which modify their performance of func- 

 tion. This is very clearly indicated by the following experiments in 

 which Loeb sought to ascertain whether the ratio of ^ or of jjjg~$~C 

 which is requisite for the maintenance of life is the same as that required 

 for the maintenance of motility. The eggs of Fundulus were immersed 

 in solutions of sodium chloride of varying concentration, and the con- 

 centration of calcium chloride which had to be added to each sodium 

 chloride solution to permit fifty per cent, of embryos to form was 

 determined. It was found that if the concentration of sodium chloride 

 varies in the ratio 1:2:3 the requisite additions of calcium chloride 

 vary in the proportion 0.3 : 1.3 : 3.2. In other words, if we double the 

 concentration of sodium chloride we must quadruple the amount of 

 calcium chloride, and if we triple the concentration of sodium chloride 

 we must add about ten times as much calcium chloride. To permit 

 normal development and therefore, presumably, to maintain normal 

 Permeability calcium chloride must be added almost in the ratio of the 

 square of the concentration of the sodium chloride. 



Now when we turn to the proportion of calcium necessary for the 

 maintenance of unimpaired Motility we find a very different relation- 

 ship obtaining. For this investigation the newly hatched larva? of a 

 barnacle (Balanus eburneus) were employed. These larvae are incessant 

 swimmers, and they rise to the surface of the water. They are able to 

 live in sea-water varying in concentration from Vie m to 6 /s m. When the 

 larvae are put into a pure solution of NaCl+KCl in the proportions in 

 which these two salts exist in sea-water, they will all fall to the bottom 

 of the vessel which contains them. They are unable to swim, although 

 they may live for a number of hours in such a solution. If one salt 

 with a bivalent cation be added, for example CaCl 2 or Srds in sufficient 

 quantity, they will rise to the surface but they cannot stay there very 

 long. If, however, enough of a mixture of CaCl 2 +MgCl 2 is added, in the 

 proportions in which calcium and magnesium are present in sea-water, 

 the larvae will rise to the surface and remain there, constantly swimming. 

 Various concentrations of the Na+K mixture were employed and the 

 concentration of bivalent cations, Mg+Ca, required to preserve motil- 



