When a dilute colloidal suspension of 50-mum polyamide particles is exposed to a deformable interface, spontaneous flow occurs. This flow is orderly, reproducible, and shows a proportional dependence on particle concentration. The same type of flow was also observed in a silicon oil suspension. Placing a glass plate on the interface dampens the flow, eventually extinguishing it completely. Upon removing the plate, the flow resumes. This leads to the belief that a new surface effect is being observed and may be important in a number of industrial applications where a free interface of a colloidal suspension is present.