Liposomes undergoing transformation were visualized by real time dark-field microscopy in order to study the role of lipid in morphogenesis of biological vesicular structures. Liposomes were found to transform sequentially in a well-defined manner through one of several transformation pathways. A circular biconcave form was an initial shape in all the pathway and it transformed into a stable thin flexible filament or small spheres via a variety or regularly shaped vesicles which possessed geometrical symmetry. The transformation was reversible up to a certain point in each pathway. Osmotic presure was found to be the driving force for the transformations. Biological membrane vesicles such as trypsinized red cell ghosts also transformed by similar phthways.
