  The nuclear neutron-proton contact is introduced, generalizing Tan's work,
and evaluated from medium energy nuclear photodisintegration experiments. To
this end we reformulate the quasi-deuteron model of nuclear photodisintegration
and establish the bridge between the Levinger constant and the contact. Using
experimental evaluations of Levinger's constant we extract the value of the
neutron-proton contact in finite nuclei and in symmetric nuclear matter.
Assuming isospin symmetry we propose to evaluate the neutron-neutron contact
through measurement of photonuclear spin correlated neutron-proton pairs.
