  We derive stringy Ward identities from the decoupling of two types of
zero-norm states in the old covariant first quantized (OCFQ) spectrum of open
bosonic string. These Ward identities are valid to all energy and all loop
orders in string perturbation theory. The high-energy limit of these stringy
Ward identities can then be used to fix the proportionality constants between
scattering amplitudes of different string states algebraically without
referring to Gross and Mende's saddle point calculation of high-energy
string-loop amplitudes. As examples, all Ward identities for the mass level 4
and 6 are derived, their high-energy limits are calculated and the
proportionality constants between scattering amplitudes of different string
states are determined. In addition to those identified before, we discover some
new nonzero components of high-energy amplitudes not found previously by Gross
and Manes. These components are essential to preserve massive gauge invariances
or decouple massive zero-norm states of string theory. A set of massive
scattering amplitudes and their high energy limits are calculated explicitly
for each mass level to justify our results.
