SELF-GRAVITATING FUNDAMENTAL STRINGS

We study the configuration of a typical highly excited string as one s lowly increases the string coupling. The dominant interactions are the long-range dilaton and gravitational attraction. In four spacetime di mensions, the string slowly contracts from its initial (large) size un til it approaches the string scale where it forms a black hole. In hig her dimensions, the string stays large until the coupling reaches a cr itical value, and then it rapidly collapses to a black hole. The impli cations for the recently proposed correspondence principle are discuss ed. [S0556-2821(97)03824-1].