  We give, for the first time, the critical complete text of a manuscript by
Ettore Majorana, conserved in the same file of the lecture notes for his course
on Theoretical Physics at the University of Naples. He probably refers to a
seminar delivered in that University. Some passages reveal a physical
interpretation of the Quantum Mechanics which anticipates of several years the
Feynman approach in terms of path integrals, independently of the underlying
mathematical formulation.
