In vitro fertilization and early embryogenesis: a cytological analysis

A cytological analysis of events of fertilization and early embryogenesis in vitro has been made with the light and electron microscopes. Special attention was paid to the initial phases of fertilization, mitochondrial changes during embryogenesis, and cell association. This study discloses that happenings taking place in vivo during fertilization and early embryogenesis are recapitulated in vitro. The events of mammalian fertilization and the development of the preimplantation embryo are now accessible to precise experimental analysis in vitro.