Heisenberg is glad about Pauli's agreement with him as regards the procedure for obtaining convergence. He makes a clarification of a further point and comments on the parity question.

Heisenberg reformulates his views on the group properties of the Hilbert-space I.

Heisenberg talks about a calculation which leads to a result different from that given by Pauli in his last letter.

Heisenberg continues his mathematical argument of his last letter.

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

Heisenberg replies to Pauli's arguments about the splitting of the dipole ghost by an interaction energy, and about the problem of causability in connection with his theory.

Heisenberg makes two remarks on Pauli's questions: 1) about complex eigenvalues of the system N+2$\Theta$, 2) about potentials of forces between elementary particles.