SU (3) and Weak Interactions

Assuming the existence of two more neutrinos ${{\nu }_e}^{\prime }$ and ${{\nu }_{\mu }}^{\prime }$, it is suggested that the leptons fit in SU(3) triplets and that the lepton-lepton and lepton-baryon interactions are SU(3) symmetric. Possible existence of a SU(2) symmetry for these interactions is also considered. For either symmetry four neutrinos seem essential and we point out how experiment can test the existence of the two new neutrinos.