In the preceding paper, using the so-called ow variable representation, we reported the formulation of the Korteweg-deVries (KdV) and the Burgers equations to express mass transports. The transport theories were constructed by pertaining to correspondence with the Toda lattices. Our present purpose is to understand a connection between these nonlinear wave equations formulated independently from the generalized form of the Kawasaki-Ohta equation. For this purpose, we formulate the Burgers equation from the KdV in correspondence to a transition from the dispersive Toda lattice to a dissipative model. For this formulation, we employ an external mechanical perturbation method. The paper is concerned with a variation method as to how to prepare a perturbation Lax bracket for the Burgers formulation. Variations in one of the Lax operators are assumed to be 9 -1 as an obstruction operator against the convection ows expressed by 9 in the repulsive potential ΓΏeld. We conclude that the obstruction is caused by attractive interactions. The main point is that the Burgers equation is transformed to a nonlinear di usion equation by the Hopf-Cole transform. The variation method and the argumentation for the Burgers formulation are proved by this transformation.