MECHANISM OF PEOCESS OF DEATH 45 



100 PER CENT 



same) an experiment was made in 

 which the concentration of cal- 

 cium ions was kept undiminished. 

 For this purpose there was added 

 to a saturated solution of 

 Ca(0H)2 (in distilled water) suffi- 

 cient CaCla 1.42 M to make the 

 conductivity equal to that of sea 

 water. Tissue was placed in this 

 and also in CaClg 0.278 M. In 

 spite of the fact that the concen- 

 tration of calcium ions was practi- 

 cally the same in the two solutions 

 the behavior of the tissue was 

 markedly different. In pure 

 CaClg the net resistance rose to 

 171% of the original net resis- 

 tance while in CaClj + Ca(0H)2 

 it rose to only 113%. At the end 

 of forty-five minutes the resis- 

 tance in CaClg was 146%, while in 

 CaCl2+Ca(0H) ^ it was only 23%. 



These experiments make it 

 evident that small amounts of 

 NaOH are able to produce a con- 

 siderable increase in permea- 

 bility." 



Let us now consider those sub- 

 stances which increase the resis- 

 tance of the tissue. In general we 

 find thatbivalentkations are very effective in this respect^^ 



"C/. Osterhout (1914, F). 

 "C/. Osterhout (1915, D). 



Fig. 17. — Curves of net electrical 

 resistance of Laminaria agardhii 

 in a solution containing NaCl 97.2 

 mols of NaCl to 2.8 mols of CaCh 

 (uppermost curve) ; a solution con- 

 taining 97.2 mols NaCl to 2.8 mols 

 Ca(0H)2 (middle curve) and in 

 NaCl 0.52 M (lowest curve). All 

 the solutions had the conductivity 

 of sea water. AH readings were 

 taken at 18° C. or corrected to this 

 temperature. Each curve repre- 

 sents a single typical experiment. 



