Previous studies suggest that the biological activity of agonists can be transferred to water by electromagnetic means [1-7]. Since July 1995, in keeping with these results, we have digitized, recorded, and 'replayed' to water the activity of acetylcholine (ACh) or water (W) as control. ACh and W were recorded (16 bits, 22 KHz), for 1-5 sec, via an especially designed transducer, on the hard disk of a computer equipped with a Sound Blaster 16 card. Files were digitally amplified and the signal of digitally recorded ACh or W was replayed for 15 min, via the transducer, to 15 ml, W-containing plastic tubes. W thus exposed (dACh, dW) was then perfused to isolated guinea-pig hearts. In 13 open experiments, coronary flow variations were (%, mean + SEM, nb of samples): W+dW(not stat. diff.), 3.3 + 0.2, 20; dACh, 16.2 + 1.0, 33, p = 4.1 e- 10 vs W+dW; ACh (0.1 M), 23.4 + 2.8, 12, p = 5 e-3 vs dACh. In 25 blind experiments: W-fdW, 3.6 + 0-3, 61; dACh, 20.4 + 1.3, 58, p = 1 e-16 vs W+dW; ACh (0.1 M), 28.1 + 2-3, 24, p = 3 e-3 vs dACh. Atropine inhibited the effects of both ACh and dACh. Moreover, we have recently transferred specific digital signals via telephone lines. These results indicate that the molecular signal is composed of waveforms in the 0-22 Khz range. They open the way to purely digital procedures for the analysis, modification and transmission of molecular activity.