CONDUCTIVITY AND PERMEABILITY 221 



changing from net resistance to protoplasmic resistance 

 we merely shift the value of the constants. The questiop. 

 arises whether this affects the general conclusions drawn 

 from the study of net resistance. In order to decide this 

 question the constants for CaClg and for various mixtures 

 of NaCl and CaClg were ascertained; these are given in 

 Table XII.^* 



TABLE XII. 

 Velocity Constants at 16°C. 



There are two points of principal importance in the 

 consideration of these constants : (1) It has been shown*' 

 that the value of Z'^-^JE'jif increases regularly as the per 

 cent, of CaCla in the surface of the cell increases. That 

 this is also true in the case of protoplasmic resistance is 

 evident from Fig. 94. (2) It was also pointed out that as 

 the per cent, of CaClg in the solution decreases from 62 to 

 1.41% the value of iTjif first decreases (reaching a mini- 

 mum at 4.76% ) and then increases. It was found that the 



" These are approximate values, obtained graphically. The con- 

 stants of the curves of protoplasmic resistance are designated as E-.p 

 (corresponding to jK^ ) and JTj^p ( corresponding to K^). The curves of 

 protoplasmic resistance may show less inhibition at the start than those 

 of net resistance. 



'" See page 151. 



