A constant scalar kernel in the Salpeter equation has the effect of reducing the mass of quarkonium in the region of {l angle}{ital p}{r angle}/{ital m} greater than 1. This effect has no {ital J} dependence, and is common to all the states. For the realistic potential including this kernel, {ital m}{sub {pi}} becomes small faster than any other meson masses as this constant becomes larger. When this constant is a Lorenz vector, it has no such effect.