Contents

21 January 1977
Vol 195, Issue 4275

About The Cover

Erythrocyte membranes attached to polylysine-coated polyacrylamide beads (2000: 1). The positively charged beads facilitate isolation of cell membranes whose protoplasmic surfaces are fully accessible to further probing. See page 302. [B. S. Jacobson and D. Branton, Harvard University, Cambridge, Massachusetts]