Monte Carlo computer simulations of a liquid of model anisotropic molecules at various temperatures have been performed for the first time with a system large enough to be representative of a liquid crystalline domain. Although the molecules are not confined to a lattice, the behavior of the simulated system is found to be in surprisingly good agreement with the predictions of the Flory-Ronca-Irvine lattice theory. Our results indicate that reliable computer experiments on the relationships between molecular constitution and properties of liquid crystalline materials are nowadays feasible, provided that the absence of spurious effects related to the system size is carefully checked in each case.