54 



BIOLOGY OF DEATH 



TABLE 4 



Experiments of Loeb and Leans on the Prolongation of Life of the Sea-urchin 



Egg by KCN 



From this table it is seen that in concentrations of 

 KCN from n/750 to n/1000 the eggs developed perfectly 

 into swimming larvae. In other words, by the addition 

 of this very small amoimt of KCN, the life period has 

 been prolonged to three times what it would normally 

 be under the same environmental conditions. Concen- 

 trations of KCN weaker than n/'lOOO were incapable of 

 producing this result, or at best, if development started, 

 the process came very quickly to an end. In stronger 

 concentrations than n/400 the eggs were evidently poi- 

 soned, and no development occurred. 



Other experiments of Loeb's show that the lethal 

 effects of various toxic agents upon the egg cell may be 

 inhibited or postponed for a relatively long time, by 



