11 February 1972
Vol 175, Issue 4022

About The Cover

Involute spiral waves propagatin after disruption of spontaneously formed circular waves in a layer (1 millimeter in depth) of Zhabontisky-Zaikin reagent. Small circles are carbon dioxide bubbles. Rotation period is 60 seconds; propogation velocity is 3.3 millimeters per minute at 6° (actual size of dish, 9 centimeters in diameter). See page 634. [Ken Harvey, Photographic Section, MRC Laboratory of Molecular Biology, Cambridge, England]