The Development of Egg-Fragments

Abstract

The study of isolated blastomeres has shown that they continue to divide as though still in contact with their fellows, and that whole embryos of half size develop in some cases but incomplete embryos in others. These results demonstrate that the conditions determining the form of the later cleavage are already present after the completion of the first division of the egg. How much before this time the future course of events has been determined, so far at least as the cleavage is concerned, has been studied by cutting the egg into fragments, both before and after the entrance of the spermatozoon.

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