 The resulting effective theory of baryon bound states of QCD (which describes protons and neutrons), then, has mass terms for these, disallowed by the original linear realization of the chiral symmetry, but allowed by the spontaneously broken nonlinear realization thus achieved as a result of the strong interactions.The Nambu-Goldstone bosons corresponding to the three broken generators are the three pions, charged and neutral.The next section outlines how a small explicit breaking in the lagrangian gives these three pions a small mass.