The film begins with a morula that already contains more than 30 cells . The mulberry-like surface is now hardly discernable since the cells on the surface have already flattened out. In the interior one can make out the gradual creation of a fluid bubble (the blastocyst cavity). The volume of single cells decreases and the "cell envelope" becomes thinner and thinner. The rhythmic expansions and contractions finally lead to the freeing of the embryo. The growth in size of the embryo following the hatching is evident.