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The Maxwell-Einstein equations for a fluid comprised of more than one type of particle are not a determinate system even if an equation of state is added. The problem of what the charge distribution is in such fluids is therefore also not determinate. To complete the definition of the problem, more equations are needed. We obtain these for the simple case of a static spherically symmetric multicomponent system (imbedded in a Minkowskian background) by minimizing the energy of the fluid with respect to variations in the number densities of the constituents, with the side conditions that the total number of each constituent is constant during the variations. This procedure results in a determinate set of hydrostatic equilibrium equations, the sum of which is the familiar Tolman-Oppenheimer-Volkoff equation. Some general conclusions can be drawn. For example, the necessary and sufficient condition for charge neutrality is that the mass-energy density be some (arbitrary) function of some (arbitrary) linear combination of the number densities. Thus since it is well known that the electrons in a white dwarf star at absolute zero form a degenerate gas, there must be a charge imbalance throughout such a star. This imbalance can then be computed self-consistently. An over-all physical interpretation of the new equations is that in equilibrium at any point in the fluid the sum of the nongravitational forces per unit energy is the same for constituent 1 as for constituent 2 and so on. This is the analog of the corresponding (Galilean) statement for gravitational forces that is valid even without equilibrium.

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