ANTAGONISM 



145 



It is easy to see how such a mechanism must exist if 

 the formation of the salt compound takes place at a 

 surface (at the external surface of the cell or at internal 

 surfaces). In a surface, substances usually exist in a dif- 

 ferent concentration from that which they have elsewhere 



loo 



Fig. 62. — Curve of net electrical resiatance of Laminaria agardhii in 65 NaCl + 35 CaCli 

 (unbroken line), the trial curve (broken line) calculated from the velocity constants Ka^ 

 .000481 and Km= .00859. Each observed point represents the average of six or more experi- 

 ments: probable error of the mean less than 10% of the mean. All readings were made at 

 15° C. or corrected to this temperature. 



in the solution. If NaCl and CaClg migrate into the sur- 

 face, so as to become more concentrated there than in the 

 rest of the solution, their concentration in the surface must 

 increase as their concentration in the solution increases 

 until a certain point (called the saturation point) is 

 reached. Beyond this point an increase in their concen- 

 tration in the solution produces no effect on their 

 concentration in the surface. 



When this stage has been reached the formation of 



10 



