A sufficient condition for the existence of positive solutions of the
nonlinear boundary value problem u ''(t) + f(t, u(t)) = 0, 0 < t < 1,
u'(0) = u(1) = 0 is constructed, where f : [0, 1) x (0, infinity) -->
(0, infinity) is continuous, f(t, u) is locally Lipschitz continuous,
and f(t, u)/u is strictly decreasing in u > 0 for each t is an element
of (0, 1).