Cytoplasmic matrix: old and new questions.

Conferences on the nature of protoplasm have not been in vogue for perhaps some 30-odd years, in part for reasons that I wish to discuss, but, with the turning oftime's kaleidoscope, new patterns of organization have now emerged and a new synthesis is perhaps possible. Cell biology is passing from an analytical phase in which each component of the cell was isolated and characterized apart from other components to a new phase in which the integration of these components to give recognizable cell behavior once again is commanding considerable attention. In his introduction to this supplement, Porter points out that these questions on the cytoplasmic matrix and the integration of cellular function are a part of our heritage that extends back at least 100 years and were the subject of intensive experimental inquiry in the first few decades of this century. At least, we can confront the old