A film demonstrating Canti's research into cell behaviour in real-time and time-lapse. This a compilation of three films; 'The segmentation of the fertilised rabbit ovum' (also known as 'Cleaveage of the fertilised rabbit ovum'), 'Stages in the normal development of the chick embryo in vitro' and 'The femur from a 5 1/2 day chick embryo'.