154 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 



The reader will notice the striking difference in the behavior 

 of NH 4 OH and NaOH. Low concentrations of NH 4 OH (0.5 

 c.c. per 50 c.c. solution) raise the rate of oxidations in the 

 fertilized egg almost to the maximal height and a further rise 

 in the concentration has only a slight effect upon the rate of 

 oxidation. Low concentrations of NaOH raise the rate of oxi- 

 dation only a little, and the efficiency of NaOH rises steadily 

 with an increase in its concentration. We could not go beyond 

 the concentrations used in this experiment, since the addition 

 of 3 c.c. N/10 NaOH to 50 c.c. m/2 NaCl+KCl+CaCl 2 leads 

 already to a cytolysis of the eggs. 



It is also of interest to point out that in the eggs of S. pur- 

 puratus fertilization by sperm raises the rate of oxidation to 

 about five or six times the amount of that in the unfertilized 

 eggs. This seems to indicate that with NH 4 OH it is not pos- 

 sible to raise the rate of oxidations in the unfertilized egg 

 beyond the limit to which it can be raised by the fertilization 

 with sperm. It is not possible to decide whether the same 

 holds true for NaOH. 



The fact that a base reaches its maximum effect at so low 

 a concentration is not confined to NH 4 OH but is also shared 

 by the amines as the following table shows. NH 4 OH and 

 ethylamine were compared. 



TABLE XXVIII 



Ethylamine reaches its maximal efficiency at the concentra- 

 tion of 0.4 c.c. base to 50 c.c. of the neutral liquid; and for 



