BIRTH OF THE MACROMOLECULE

The science of chemistry has made considerable advances over the last few hundred years in the characterization of ''small'' molecules which can be purified and studied by melting, distillation, crystallization and solubility in various liquids. When the study of ''large'' natura l and biological molecules, limited in these properties, rose in signi ficance at the turn of the century, it was first attempted to explain their properties by the concepts of colloid chemistry of aggregation a nd complex formation. The struggle for the acceptance of the concept o f the natural or biological covalently bonded macromolecule, as recall ed by Herman Mark, is one of the interesting chapters in recent scienc e history. A specific phase in the establishment of the macromolecular concept centered around the development by The Svedberg of the analyt ical ultracentrifuge, a versatile tool of highly practical and profoun d thermodynamic significance.