  Relativistic theories of nuclear matter are discussed in a new pespective.
First the chiral character of the scalar nuclear field is introduced in the
framework of the linear sigma model. With the assumption that the nucleon mass
originates in part from the coupling to the quark condensate it is possible to
relate the optical potential for the propagation of the scalar field to the QCD
scalar susceptibility of the nucleon, on which indications exist from the
lattice evolution of the nucleon mass with the quark mass. Constraining the
parameters of the nuclear scalar potential by the lattice expansion parameters
a successful description of the nuclear saturation properties can be reached.
