  A general three quark bound state satisfying the Pauli principle, and
conserving angular momentum and isospin, is used to investigate the spin
structure of nucleons at high $x$. It is shown if {$F_{1n}/F_{1p}$$\to$1/4},
then both $A_{1p}$ and $A_{1n}$, as well as quark spin distribution $\Delta
u/u$, will approach 1 as $x$$\to$1 in polarized deep inelastic scattering. The
spin distribution $\Delta d/d$ does not approach 1, but is bound by the limits
$-{1/3}\le\Delta d/d\le 0$ for any $x$.
