Heisenberg must cancel his participation in the philosophical congress in Zurich because of his journey to the U.S.A.

Pauli gives his views on mutations and selection. He makes remarks on Klein's work and Heisenberg's attempts at a unified field theory. Pauli makes plans for a relativity congress.

Pauli writes about a letter written by Schafroth who suggests an explanation of supraconductivity. He comments on a discussion on evolution in a meeting of biologists, in which Pauli participated and on the reasons for the resentment of physicists by biologists.

Pauli talks about Fröhlich's reaction to Schafroth's paper. He comments on Feynman's paper.

Pauli talks about a confusion in Källén's calculations in the last letter.