This paper is an analysis of four neutrino experiments which are giving today positive evidence in favour of weak neutral current interactions : The search for muon neutrino elastic scattering on electrons in Gargamelle at CERN, the search for inclusive semi‐leptonic neutrino and antineutrino reactions in Gargamelle at CERN, the search for the same reactions but at higher energies at NAL in the 1A experiment and the search for one pion channel in the Argonne 12 feet bubble chamber.