  A proposed solution of the anomalous behavior of the electron spectrum near
the endpoint of tritium $\beta$-decay is offered. It is based on a new theory
of mass in which mass becomes a dynamical variable, and the electron in the
tritium $\beta$-decay has a narrow mass distribution. The predicted Kurie plots
explain the main feature (``$m_{\nu}^2 < 0 $'') of this anomalous behavior.
