Induction of a time keeping mechanism by ASA in the Sauromatum appendix. Sections of one pre D-day appendix were placed in the control solution (treated with buffer only) for 1:20 h (A) and sections of a second pre D-day appendix were placed in the control solution for 3 h (B). Subsequently, ASA was added at various concentrations. Opening of the door of the environmental chamber in order to add ASA to the control solution caused a temperature spike at 1:20 h and 3 h from the beginning of the experiment. Environmental chamber temperature was ~21°C. The legends are identical for A and B. Temperature profiles are a subtraction of the control from a treatment.