8 A. J. GOLDFARB. 



consequent enlargement and partial separation of the first two 

 blastomeres, into an elongated double ball; and finally a more and 

 more complete separation. The blastomeres fell apart com- 

 pletely. 



There can be no doubt that F. R. Lillie ('14) and Loeb's 

 observations that blastomeres do fall apart in old eggs is correct. 



Separation of blastomeres occurred in every experiment in 

 which the observations were made over a sufficiently long 

 period. And once begun the blastomeres continued to separate 

 with successive cleavages until there was in place of the egg, a 

 flattened mound of minute blastomeres, stuck to the bottom of 

 the dish or to one another. And with increasing age, more and 

 more eggs passed through this history. 



As might have been anticipated, the onset of separation varied 

 with different females according to the physiologic condition of 

 the eggs at liberation. Separation was first observed in experi- 

 ment 3, when the eggs were 6 hours old; in experiment 4, when 5 

 hours old (i female) and 8 hours old (in the other 2 females); 

 in experiment 5, 8 hours old in one female, later, in the other 5 

 females; in Arbacia, the eggs of one female, experiment 16, 

 showed the separation phenomenon when 18 hours old, 2 other 

 females when 24 hours old, and 2 others when 42 hours old. 

 In experiment 15, separation was observed in 3 females when 

 eggs were 24 hours old, in experiment 17 when 23 and 28 hours 

 old, etc. In Toxopneustes, and Hipponoe" separation usually 

 occurred in 8 to 10 hours after liberation, in Arbacia usually not 

 before 24 hours. 



With the continued and complete separation of the blastomeres 

 in successive cleavages, an increasing number, of. the fertilized 

 eggs died and with their disintegration many of the non-sepa- 

 rating eggs also died. 



There can no longer be any doubt that there were no 

 fertilization membranes about these aging eggs. Glazer ('14) 

 urged that separation was due to the absence of the fertil- 

 ization membrane. It is far more probable that the absence 

 of the membrane together with the physiologic changes in the 

 protoplasm (the result of aging) are both responsible for the 

 separation of the blastomeres. 



