It is shown that the heterotic string emerges as a soliton in the type
I superstring theory in ten dimensions. The collective coordinates of
the soliton are described by a smooth, chiral worldsheet theory. Ther
e are eight bosonic and eight right-moving fermionic zero modes that a
rise from the partially broken supertranslations. In addition, there a
re 496 charged bosonic zero modes of the gauge field that describe a l
eft-moving WZNW model on a spin(32)/Z(2) group manifold. Small, stable
loops of the solitonic string furnish the massive states required by
duality that transform as spinors of spin(32).