EFFECTS OF AGING UPON GERM CELLS. 5 



eggs, fused together permanently, either in the egg stage, or in 

 the course of subsequent early development. The processes in- 

 volved in the fusion of eggs or embryos, and the various types 

 of larvae resulting from such fusions I have descibed elsewhere 

 (Goldfarb, '13, '15). 



For the present my interest lies not in the fusion process, per 

 se, nor in the various correlated phenomena, but rather in fusion 

 as another evidence or symptom of aging or deterioration of the 

 eggs. 



The observations may be summarized as follows: 



"Spontaneous" fusion of eggs occurred in all three species of 

 eggs, and in all cultures in which the eggs had aged sufficiently. 



"Spontaneous" fusion occurred in unfertilized as well as in 

 fertilized eggs. 



In unfertilized eggs fusion was usually complete, giving rise 

 to "giant" eggs which measured 8, 10 and 13 units diameter, 

 whereas the control eggs measured but 6 units. These volumet- 

 ric differences indicate, as Driesch pointed out, the number of 

 eggs which were united into the single giant egg. 



A number of observers have recorded the "spontaneous " occur- 

 rence of giant eggs or fused larvae (Herbst, Morgan and Wilson, 

 Nussbaum and Oxner). These spontaneously formed giant eggs 

 or fused larvae, it is very probable, arose as in my cultures by 

 the natural deterioration of aging eggs, affecting the different 

 structures of the egg in a manner so favorable to the fusion 

 process. 



Fusion occurred also among fertilized eggs. The resulting 

 degree of completeness of fusion was conditioned largely, if not 

 exclusively, by the stage in development when fusion first began. 

 The earlier the fusion the more complete, and vice versa, the 

 later, the less complete. Early fusion gave rise to "single" 

 larvae, either giant or normal. Late fusion gave rise to double 

 larvae of many types (Goldfarb, '15). 



Fusion began at widely different ages, i. e., at widely different 

 periods after the liberation of the eggs. In Toxopneustes, 

 experiment 6, the eggs of one female fused when 2 hours old, 

 another when 5 hours old; in experiment 8, when 5 hours old; 

 experiment 2, when 6 hours old; experiment n, when 23 hours 



