  In this letter we show how string winding modes can be constructed using
topological membranes. We use the fact that monopole-instantons in compact
topologically massive gauge theory lead to charge non-conservation inside the
membrane which, in turn, enables us to construct vertex operators with
different left and right momenta. The amount of charge non-conservation inside
the membrane is interpreted as giving the momentum associated with the string
winding mode and is shown to match precisely the full mass spectrum of
compactified string theory.
