Previously we found that the isolated sacculus of Escherichia coli could be expanded from its equilibrium surface area by lowering the pH. I had also shown theoretically that the chemiosmotic process would lower the pH by several units in the very near vicinity of the outside of the cytoplasmic membrane. Together these facts suggest a new model for gliding motility of Gram-negative micro-organisms. The model proposes that the volume enclosed by the sacculus of the gliding cells is normally enlarged either by an on-going respiratory process, by the photosynthetic generation of a protonmotive force, or by ATPase action. These energy-utilizing processes cause charge separation which results in the ejection of protons to the outside of the cytoplasmic membrane lowering the pH in the adjacent peptidoglycan sacculus, causing it to expand. It is postulated here that the gliding cell controls special shunts that allow protons to return freely to neutralize the excess negative charges remaining inside the cell. When these shunts are activated, a series of physical processes occur which result in the shrinkage of the regions where the special shunts are functional, and conversely, slight expansion where they are not. This expansion wedges the cell in the substratum; i.e. favors hydrogen bonds between the cell surface and the environmental surface of slime layers. When the shunts are turned off, the volume changes are reversed, and the cell inches forward. This could lead to movement on surfaces and could account for other properties associated with gliding motility. More generally, this could be the prokaryote's substitute for the mechanoenzymes, such as the actin, of the cells of higher organisms. It also could be the basis of other motions exhibited by prokaryotes, in particular it may account for the rotation of the flagellar motor.