The equilibrium Lame equation in two-dimensional and three-dimensional spaces can be presented as conductivity in magnetic field equations, with Lorentz force expression. This allows us to apply the perturbation theory and generalise the Lame equation, and obtain a new equilibrium equation with all responses of compression and tension (it means that compression in one direction leads to tension in the perpendicular direction and vice versa, if the boundaries are fixed). The solution in recurrent integral form for contributions to all orders of Poisson ratio is then obtained.