  We present an improved version of our earlier work on summing the planar
graphs in phi^3 field theory. The present treatment is also based on our world
sheet formalism and the mean field approximation, but it makes use of no
further approximations. We derive a set of equations between the expectation
values of the world sheet fields, and we investigate them in certain limits. We
show that the equations can give rise to (metastable) string forming solutions.
