100 



SCIENCE 



[N. S. Vol. XLV. No. 1153 



ties of both reactions reach a minimum in a 

 definite mixture of NaCl + CaCl,. This 

 mixture contains the molecular proportions 

 95.24 NaCl + 4.76 CaCU. "We can account 



The extent to which these assumptions 

 enable us to predict the behavior of the 

 tissues in various mixtures is evident from 

 Table I. 



.100. NaCl + o. CaCls 



Fig. 1. Curves of electrical resistance of Laminaria in NaCl .52M, in CaCl^ .278if, and in mix- 

 tuxes of these (the figures show the molecular percent, of CaClj in the mixture). 



for this if we suppose that both the reac- 

 tions are inhibited by an organic salt^ 

 formed with a constituent X of the proto- 

 plasm according to the equation 



2NaCl + X+ CaCL = Na-ZCaCL,. 



We may also assume that the reaction 

 A — > ilf is catalyzed by CaCl,. This en- 

 ables us to account for the fact (which is 

 clearly evident from an inspection of the 

 curves) that the greater the proportion of 

 CaCla in the mixture the higher and more 

 rapidly the curve rises. 



3 The amount of this salt wUl be greatest in the 

 mixture of 95.24 NaCl + 4.76 CaCl, if the reac- 

 tion takes place in the surface and_ CaCL is 10 

 times as concentrated in the surface as NaCl. 



It is evident that the agreement between 

 observed and calculated values is re- 

 markably satisfactory. In regard to the 

 theoretical procedure it should be said that 

 in constructing equations for the curves the 

 minimum number of constants has been em- 

 ployed and the attempt has been made to 

 proceed with the fewest and the most nat- 

 ural assumptions. These assumptions ap- 

 pear to be very reasonable, for it is evident 

 that there must be two processes in order 

 to produce a rise and fall of resistance and 

 that their speed must be regulated by NaCl 

 and CaClj. It is also apparent that these 

 salts must enter into some sort of combina- 

 tion with a constituent of the protoplasm 

 and it is evident that this compound may 

 regulate the speed of these processes. 



