Résumé : We have fully analysed all events with a single electron obtained in an exposure of BEBC to the 350 GeV wide-band neutrino beam at CERN. The data agrees well with expectations based on the calculated νe flux and assuming μ-e universality. Using both the rate and the kinematic distributions, improved limits are set on νe → νX, νμ → νe, νμ → ντ mixing. © 1981.