  The first quantization of the relativistic Brink-DiVecchia-Howe-Polyakov
(BDHP) string in the range $1<d<25$ is considered. It is shown that using the
Polyakov sum over bordered surfaces in the Feynman path integral quantization
scheme one gets a consistent quantum mechanics of relativistic 1-dim extended
objects in the range $1<d<25$. In particular the BDHP string propagator is
exactly calculated for arbitrary initial and final string configurations and
the Hilbert space of physical states of noncritical BDHP string is explicitly
constructed. The resulting theory is equivalent to the Fairlie-Chodos-Thorn
massive string model. In contrast to the conventional conformal field theory
approach to noncritical string and random surfaces in the Euclidean target
space the path integral formulation of the Fairlie-Chodos-Thorn string obtained
in this paper does not rely on the principle of conformal invariance. Some
consequences of this feature for constructing a consistent relativistic string
theory based on the "splitting-joining" interaction are discussed.}
