Pauli gives his reactions to the articles by Waddington and R Goldschmidt and the latter's book on adaptation and mutation. He writes on Oppenheimer and Delbrück's views. He also comments on Bohr's article "Physical science and the study of religions".

Pauli makes several technical requests. He writes about Stern's impending visit to Zürich.

Pauli sends a few informal lines in answer to Bohr's letter of the 3rd March. Meanwhile he has seen Delbrück and received from him a report about his meeting with Bohr in Copenhagen. He said that Bohr changed his mind on these biological questions soon after he had sent his letter to Pauli. This seems to Pauli quite satisfactory as he is now rather convinced that there is no causal connection between the happenings in a gene and the environment (milieu) of the organism. Now Pauli has spoken with Delbrück and also with other biologists he sees much better where the real problems are. Meanwhile another of their common friends, Otto Stern, passed through New York on his trip from California to Europe. Bohr will soon see him in Copenhagen.

Pauli writes that Einstein's philosophical point of view is not "deterministic", as Born believes, but "realistic". He explains it for the case of a macro-body and refutes part of it. He adds remarks classical and quantum mechanics.

Lorentz transformations, time inversion.

Draft for changing the paper on archetypes in Kepler's theory.

Pauli writes about the failure to decide mathematically wether the renormalized and Lorentz-invariant quantization of electrodynamics constitutes a consistant theory. He writes about his visits to Hamburg and Copenhagen and to the relativity conference in Berne.

Pauli asks Thellung to send the English edition of his book on Kepler to Rabi.