Compartmentation is one of the most pervasive features of biological systems, so it should come as no surprise to observe it within cells. P. Friedrich has referred to "microcompartmentation" as metabolite sequestration by coupled enzymes in which the dimensions of the compartment take on those of the metabolite plus surrounding boundaries of the participating enzymes. R. Chambers and Kopac observed that droplets of various kinds of oil would spontaneously coalesce with the eggs, entering the cytoplasm. Kopac and Chambers proposed reasonably that the absence of the Devaux effect in undamaged cells reflected the absence of significant concentrations of diffusible proteins of the size that would absorb onto the droplets. P. L. Paine, S. B. Horowitz, and colleagues have developed and used an ingenious "reference phase technique" to explore intracellular diffusion, among other phenomena. The method follows the motion of solutes between an injected gel reference and the surrounding intracellular aqueous phase in both directions.