314 



MYRA MELISSA SAMPSON. 



exposure and the percentage of eggs affected suggested experi- 

 ments in which the eggs are removed from the filtrate before the 

 latter have had opportunity to produce any visible changes in 

 the eggs. If now there are invisible effects and if these are 

 orderly and significant, they should become noticeable after the 



Po 



jc-t: I ... 



70- 



to- 



to 



30 



20 



10 



1 /o 



GRAPH IV. Percentage of division and cytolysis of ova produced by sperm 

 filtrates on two sets of eggs Arbacia punclulata. i = Filtrate 6/30/21 from a 5 

 per cent, suspension. 2 = Filtrate 7/2/21 from a 5 per cent, suspension. A = one 

 set of eggs. B = second set of eggs. C = control eggs in S.W. 



eggs are transferred to sea-water. Cases in point are illustrated 

 in graphs X., XI., and XII., and indicate clearly that the gross 

 visible effects, distinct only after several hours, are preceded by 

 important changes which may develop in some of the ova within 

 a very few minutes. These changes may, after transfer of the 

 ova to sea- water, lead to progressive changes in the ova. 



The Effect of Filtrates Prepared from Heated Sperm. --The 

 statement was made by Winkler (1900) and by Morse (1912) 



