  We study the Kondo effect in an ultrasmall metallic grain, i.e. small enough
to have a discrete energy-level spectrum, by calculating the susceptibility chi
of the magnetic impurity. Our quantum Monte Carlo simulations, and analytic
solution of a simple model, show that the behavior changes dramatically
depending on whether the number of electrons in the grain is even or odd. We
suggest that the measurements of chi provide an effective experimental way of
probing the grain's number parity.
