The most basic notion of a
solution of a differential equation is that of a function that is differentiable enough to
plug into it (without demanding continuity of the derivatives of highest order) and
that, of course, makes the equation a true statement when you do plug it in. The
lack of continuity of the derivatives has posed many obstacles in treating
these solutions. In this paper we overcome several of these obstacles in the
case of algebraic differential equations by using the Darboux property of
derivatives.