Heisenberg talks about a reviewed discussion of the mathematical results for the three sectors V, N+2$\Theta$, N+V.

Addendum to appendix of last letter, giving Pauli' conclusion. The discussion with Heisenberg has not brought him nearer to a possibility of interpreting physically the formulae derived from the indefinite metric.

Heisenberg summarizes the mathematical results as regards dipole ghosts on which he ana Pauli agree.

Pauli comments on a paper by Salam and his B-field. He writes about the open question whether the rest mass of the B-particles is zero. He writes about the conservation of lepton charge, two-component theory and CP or T symmetry. He writes about Lüders' and Pauli's theorem, and Schwinger's previous theorem. He makes remarks on his calculations last autumn, connected with the "Pruett-factor".

Pauli suggests suspending the discussion until new points of view emerge.

Pauli is pleased whith Heisenberg's letter of 24 February and continues the discussion.