  We present a way for calculating the Lagrangian path integral measure
directly from the Hamiltonian Schwinger--Dyson equations. The method agrees
with the usual way of deriving the measure, however it may be applied to all
theories, even when the corresponding momentum integration is not Gaussian. Of
particular interest is the connection that is made between the path integral
measure and the measure in the corresponding 0-dimensional model. This allows
us to uniquely define the path integral even for the case of Euclidean theories
whose action is not bounded from below.
