## Abstract

The irreducible relativistic wave equation for a particle having two different mass states and positive charge, given by Bhabha, has been written in a form similar to that given by Rarita & Schwinger for the Dirac-Fierz-Pauli equation for a particle of spin $\frac{3}{2}$. The components of the wave function are written as Dirac four-component wave functions, having in addition a tensor index, and one ordinary Dirac four-component wave function. The only matrices which enter into the formulation are the Dirac matrices. An explicit representation of Bhabha's matrices in terms of the Dirac matrices is obtained. The solutions for spin $\frac{3}{2}$ are just those given by the Dirac-Fierz-Pauli equation, but the solutions for spin $\frac{1}{2}$ differ from the Dirac solutions in having additional non-vanishing components.