He agrees with Keller's paper on "Hidden variables" in quantum theory (P.R.89, 1040) as regards the role of probability in Bohm's interpretation and refers to his own paper in the anniversary volume (60th birthday) for L. the Broglie same subject.

Pauli replies to Kemmer's letter (14 February) to Fierz. He talks about his forthcoming lectures on field quantization and gives some remarks on Dirac's equations for particles with higher spin.

Pauli asks a question about a possible magnetic spin moment of yukons, and calculations in connection with this.

Pauli writes again on the question concerning de Broglie 's equation.

The letter talks of progress in meson theory.

The letter is about the impending visit of Pauli to England and Scotland.

The letter asks a question about a model for neutrinos with Delta-like interaction.

This letter is an addition to the letter of 15 April.

Pauli thanks Kemmer for his letter and his satisfactory results.

This letter contains another mathematical question in connection with an equation in de Broglies's theory which Pauli wants to criticize in his report to the Solvay-congress.