A method and apparatus is provided for detecting and recording a specific type of electric pulse induced in metal electrodes by the living tissue of humans, other animals or plants, and by certain organic and inorganic models of such living tissue. The purely passive system detects the electric energy produced by the living source as it interacts with the crystalline lattice of conductive metal electrodes to produce a train of oscillating pulses, the amplitude of whose envelope decays as a linear function of log-time. Specific aspects of these pulses can be used to study the state of the living, or non-living, source and to detect changes in this state over time. The results of such studies of living sources can be interpreted, respectively, in terms of the state of health, or disease, of the source and of changes in the state of health, or disease, of the source, and can thus be used to recognize, characterize and evaluate conditions of the living organism and to quantify the effects of therapies and putative therapies.