Abstract
1. The non-hibernating eggs of the silkworm were cauterized at the cleavage stages, 4 and 7 hours after egg-laying; they were fixed 84 hours after laying to examine the relational feature between the differentiation of germ cells and the degree of injury.
2. When the degree of injury falls within about 10% for the entire. circuit of the cross section of the egg, the non-splitted embryos are formed, while it is over 10% the formation of the splitted ones is resulted.
3. The germinal cytoplasm was found to exist in the silkworm; it corresponded to the presumptive genital region observed at the blastoderm stage. There was no correlational evidence between the extent of the germinal cytoplasm and the number of germ cells. From this result the proliferation of the primordial germ cells may probably go ahead the completion of the blastoderm.
