20 



HEREDITY AND SEX 



THE EARLY ISOLATION OF THE GERM-CELLS 



There is much evidence to show that the germ-cells 

 appear very early in the development of the individual 

 when they are set aside from the cells that differentiate 

 into the body cells. This need not mean that the germ- 

 cells have remained unmodified, although this is at 



Fig. 6. — Chromatin diminution and origin of the germ-cells in Ascaris. 

 (After Boveri.) 



