Cellular Membranes In Development

In the recent revolution in our knowledge of the organization of living systems the discovery of the ubiquity of membranes, all with a remarkably constant structure, ranks in importance with the finding that nucleic acids are the hereditary material. Vitalism has at last been buried with the realization that protoplasm has a morphology clearly related to its function. Anatomy has come into its own again, and at the ultrastructural level it has achieved a new significance as physiology and biochemistry studied at a point in time. The biochemist has ceased to think of cells as bags of enzymes which he must isolate and study; his analytical approach has had its successes, but he knows now that cells are three-dimensional systems whose integrity is destroyed in the test tube. The anatomist, for his part, has realized that structure at the molecular and supramolecular level only become meaningful in relation to function. The disciplines static in time have recognized mobility; the disciplines with time as a variable have recognized the need for a structural basis to account for the ordered complexity within a cell. Both meet in this volume in the study of membranes.