Jost is interested in Janner's problem. Pauli is going to lecture on it.

Heisenberg writes on an invariance property of the ghost solutions.

Pauli replies to Heisenberg's letter of 19 June.

Pauli writes about Schafroth's correspondence with the editors of Phys. Rev.

Pauli thanks them for the received papers. The letter gives an account of Thirring's cut-off method and its preliminary results in the case of a scalar field interacting with a fermion field. Pauli believes that a good new theory is only possible on the basis of entirely new physical ideas. In connection with that, he is impressed by a remark by Landau on a connection of a cut-off moment of quantum electrodynamics with gravitational interaction.