MECHANISM OF PEOCESS OF DEATH 47 



Zn) the addition to sea water of sufficient dry salt to 

 make the concentration 0.005 M kept the resistance above 

 that of the control for several hours (Fig. 18). In other 

 cases (FeSO.4 and SnClj) the resistance rose, but soon 

 fell below that of the control." 



In similar experiments with trivalent and tetravalent 



LIVING ■ ^ 



DEAD 



5 10 HOURS 



Fia. 19. — Curve ihowing the net electrical Tesistance of Laminaria agardhii in 1000 c.c. sea 

 water plu3 10 c.c. CaCIs 5.0 M. Upper curve, living tissue; lower curve, dead tissue. All 

 readings were taken at 18° C. or corrected to this temperature. Each curve represents a 



single experiment. 



kations it was found that while the resistance remained 

 above that of the control for ten hours or more in the 

 case of La (N03)3 and Y (N03)3 this was not the case^® 

 with Fe2(S04)3 and Th (N03)4. 



These experiments were varied .by adding strong 

 solutions to the sea water in place of the dry salt. The 



" In the case of SnCU this may be due to the acidity of the solution. 

 The concentration is .005 Jf in the case of each of these salts. 



" The solutions containing Fe^ (SO,), and AI, (SO,), were acid. The dry 

 salts were added to the sea water In sufficient amounts to make the 

 concentrations aa follows: 0.042 M La(NOj)j, 0.006 M Ce(NOs)s, 0.007 

 M, r(2V0,)s, 0.0025 M ¥e,{SO^)^, 0.01 M Al^ (SO,),, 0.006 M Th (NO3),. 



