An educational film, a movie through a microscope, in two parts. Within minutes after the egg drops in the water, fertilization occurs and contractions start. Soon, in a fertilized egg, we see the germinal disc divide into two blastomeres. Divisions continue; contractions re-occur at the cap as it covers the egg. Title cards in French tell us what to watch for. Muscular movements and circulation appear; the heart beats. In part two, we see blood circulation begin as red cells develop on the surface of the yoke. They mass toward the heart. Arteries form, blood flows. The egg hatches and blood flows to new areas.

Director: Jean Painlevé