Measurements of the splay, twist, and bend elastic contants have been made on a series of lyotropic liquid crystals of poly-γ-benzyl-l-glutamate formed in concentrated solutions of non-aggregating solvents. The solvent dependence of the persistence length of the macromolecule was also examined. The influence of solvent on the elastic properties of the liquid crystal is distinguished from that of polymer conformation. With such separation of variables, the results are broadly in accord with predictions of flexible rod models. The variation of the elastic constants with molecular weight, however, depends upon solvent.