Systematic variations in the mass-to-light ratios of elliptical and spiral galaxies are examined. It is suggested that a major component of the apparent peculiar velocity field on large scales may be these variations over cluster scales. A dispersion in the mass-to-light ratio of elliptical galaxies is attributed to tidal stripping during cluster formation. The dispersion is strongest in cluster cores and is specific to galaxies that have undergone the bulk of their star formation prior to cluster formation. Evidence is presented to support this explanation of the variations.