MECHANISM OF PROCESS 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 (FeS0 4 and SnCl 2 ) the resistance rose, but soon 

 fell below that of the control. 15 



In similar experiments with trivalent and tetravalent 



110' 





% 



90 



LIVING 



15 



\ x x 



r\ S\ f\ 



vv J^+ 



DEAD 



5 10 HOURS 



Fia. 19. Curve showing the net electrical resistance of Laminaria agardhii in 1000 c.c. sea 

 water plus 10 c.c. CaCh 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 (N0 3 ) 3 and Y (N0 3 ) 3 this was not the case 16 

 with Fe 2 (S0 4 ) 3 and Th (NO 3 ) 4 . 



These experiments were varied by adding strong 

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



"In the case of SnCl 2 this may be due to the acidity of the solution. 

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



"The solutions containing Fe a (SO 4 ), and Al, (SO 4 ) 8 were acid. The dry 

 Baits were added to the sea water in sufficient amounts to make the 

 concentrations as follows: 0.042 M La(N0 3 ) s , 0.006 M Ce(NO s ) s , 0.007 

 M, Y(N0 3 ) 3 , 0.0025 M Fe 2 (S0 4 ) 8 , 0.01 M A1 2 (S0 4 ) 3 , 0.006 M Th (NO 3 ) 4 . 



