Lion makes remarks on his dialectical view of "historical causality" in response to Pauli (in: Dialectica : 8 (1954), pp.283). She asks about its applicability to physical causality.

Lopes writes about the derivation of the interaction operators by the perturbation method, with special reference to Schwinger's results.

Lopes replies to Pauli's letter of 25 July, with special reference to two questions put by Pauli : 1) Use of the angular momentum integral for the reduction of the rigorous wave equations. 2) The problem of an additional term giving a contribution to the quadrupol moment.

Lopes reports on his investigation of the scattering of fast netrons by protons in the strong coupling meson theory.

Lopes writes about the interaction energy of two heavy particles in the pseudoscalar meson theory, with reference to calculations by Kemmer.

Lopes reports on his investigation of the angular distribution of high energy neutrons by protons in the pseudoscalar theory with a strong coupling.

Following Pauli's letter of 14 March, Lopes compares his paper "On the particle picture of quantized Bose Fields I" with Dirac's paper.

Lorentz invites Pauli to the Solvay-congress (24-29 Oct.). He gives the names of the participants and says that the subject for discussion is the new quantum mechanics.

Lüders makes more remarks about his own theory of the neutrino field, and about the two-component theory with conservation of lepton-charge.

Lüders replies to Pauli's letter of 3 Dec as regards the significance of "hermiticity" for his calculations.