  In a previous work, a world sheet field theory which sums planar phi^3 graphs
was investigated. In particular, a solitonic solution of this model was
constructed, and quantum fluctuations around this solution led to a string
picture. However, there were two problems which were not treated
satisfactorily: An ultraviolet divergence and a spurious infrared divergence.
Here we present an improved treatment, which eliminates the ultraviolet
divergence in the normal fashion by mass and coupling constant renormalization.
The infrared problem is taken care of by choosing a classical background which
forms a one dimensional crystal. The resulting picture is a hybrid model with
both string and underlying field theory excitations. Only in the dense graph
limit on the world sheet a full string picture emerges.
