A. T. CAMERON AND M. S. HOLLENBERG 



419 



Experimental Series 1 and 3 has been taken as 6.5.) The halide 

 curves for muscle are logarithmic; those for nitrate and chlorate do 

 not show this relationship. The decrease is probably due to the 

 combined effect of temperature per se (especially evident at higher 

 temperatures and due presumably to an acceleration of all metabolic 

 processes in the tissue) and of temperature in increasing the toxic 

 effect of the foreign ion. 



K&Cl 



40 80 120 I60 200 hours 



Fig. 1. Effect of temperature on the survival period of frog muscle immersed 

 in various Locke solutions. 



Introduction of any foreign ion into the Locke solution, under 

 constant temperature conditions, decreases the survival period. This 

 must be regarded as due to toxicity of the foreign ion. The greatest 

 relative toxic effect appears to be produced by an initial slight re- 

 placement of chloride ions. Further replacement does not produce 

 such a relatively great effect. This is shown by the curves for frog 

 muscle in Fig. 2. Nerve and heart data yield similar curves. 



It is therefore apparent that even small traces of such foreign 

 ions (including bromide and iodide) are distinctly, though but slightly 

 toxic. This is not in agreement with Finckh's conclusions, but is 

 in general agreement with Kruse's results. Since, in solutions con- 

 taining only a small percentage of replacements by the foreign ions, 

 the survival period is in most cases at least several days, it seems un- 



