The parameters of the interaction of slow neutrons with deuterium are important in the development of theories of nucleon-nucleon interactions. They also determine the slowing down of neutrons in D2O systems as characterized by the calculational bench mark of the neutron age. Differential measurements of claimed high accuracy have been reported in the past several years which cast doubt on the knowledge of these parameters. A consistent set of parameters which will also reproduce the neutron age can be derived from precision measurements only by rejecting two measurements of claimed high accuracy. There remains a need for further differential measurements of adequate precision to verify the choice of neutron-deuterium parameters.