  Assuming the solar and atmospheric neutrino deficits to be due to neutrino
oscillations, it is shown that the 3X3 mass matrix spanning the e, mu, and tau
neutrinos may have already revealed a seesaw mass pattern. Also, this matrix is
the natural reduction of a simple 5X5 seesaw mass matrix with one large scale,
the 4X4 reduction of which predicts that a fourth neutrino would mix with the e
and mu neutrinos in such a way that oscillations between them may occur just
within the detection capability of the LSND (Liquid Scintillator Neutrino
Detector) experiment.
