A device for mixing at least two separate sources of components that, when mixed, form a combined fluid stream is described. The device comprises a passageway adapted to communicate with at least one of the at least two separate sources and a porous mixing member in communication with the passageway that comprises a three-dimensional lattice defining a plurality of tortuous, interconnecting passages therethrough. The porous mixing member has physical characteristics to sufficiently mix the components, which characteristics include a selected one or more of mean flow pore size, thickness and porosity. At least another of the at least two separate sources is provided within the formation of the porous mixing member.