Schafroth replies to Pauli's questions about his paper on supraconductivity.

Bohr writes on the significance of detachment in scientific work, the interaction of the observer with the course of events, the freedom of choice of the experimental arrangement and on the difference between the role of observer in biology and quantum mechanics.

Pauli writes about the theory of real supraconductors. He talks about his visit to Holland. He writes about his talk with Casimir on supraconductivity.

Thirring presents his model for a renormalized quantum theory along with difficulties applying it to nuclear problems. He discusses the work of Petermann, Edwards and Keberle. He writes about his travel plans to Italy and Yugoslavia.

Weisskopf writes about Feynman's and Peterman's theory on the proton and neutron mass difference.

Pauli gives new results on field renormalization, pair theory and quantum electrodynamics.