  The high-energy limit of stringy symmetries, derived from the decoupling of
two types of zero-norm states in the old covariant first quantized (OCFQ)
spectrum of open bosonic string, are used to reproduce Gross's linear relations
among high-energy scattering amplitudes of different string states with the
same momenta. Moreover, the proportionality constants between scattering
amplitudes of different string states are calculated for the first few
low-lying levels. These proportionality constants are, as suggested by Gross
from the saddle point calculation of high-energy string-loop amplitudes,
independent of the scattering angle $\phi_{CM}$ and the order $\chi $ of string
perturbation theory. The decoupling of degenerate positive-norm states, which
is valid to \QTR{it}{all} energy, can also be derived from these stringy
symmetries. The high-energy limit of this decoupling is found to be consistent
with the work of Gross and Manes.
