A system for mixing or reconstituting agents including engageable syringe barrels, one of which having a male engagement region and the other a female engagement region. Each of the male and female engagement regions is provided with a screen. The screens are closely spaced from one another when the first and second syringe barrels are engaged with one another. The screens may take the form of a mesh, a plurality of protuberances, or cantilevered wedges having tapering thicknesses.