ELECTRICAL CONDUCTIVITY OF FERTILIZED AND UNFERTILIZED EGGS. 57 



Table V 



The figures in brackets in columns 2 and 3 indicate the actual number of 

 minutes after the addition of sperm to the eggs. 



1. 



2 



Conclusions. 

 From these experiments I draw the following conclusions : — 

 That the entrance of the sperm into the egg causes an increase in 

 electrical conductivity of the egg. This condition usually attains 

 its maximum within ten minutes of adding sperm to ripe eggs. 

 That this increase in conductivity is followed by a process which 

 returns the conductivity of the egg to or towards that of the 

 unfertilized egg. 

 The chief limitation of the method lies in the fact that in order to get a 

 measurable change in resistance between the electrodes after fertilization, 

 the eggs must be concentrated to give an initial resistance of about 30-40 

 ohms. In order to cover the electrodes with the eggs, at least \ c.c. of eggs 

 is required. The volume of sea-water which the conductivity cell can 

 hold is about 10 c.c. ; the effect of these conditions is that when the eggs 

 are shaken in sea-water after the determination of their resistance they 



