Heisenberg writes about calculations about the theory of holes and on the self-energy of a particle. He replies to Pauli's question about the scattering of neutrons by protons and the difference between exchange forces and regular forces. He writes on the decay of the neutron and on his discussion with Bloch about the spin of the neutron being opposite to that of the proton.

Heisenberg writes more about the theory of holes and about another method for the elimination of an infinite charge density.

Heisenberg writes about the "Vertauschungsrelation" in the theory of holes.

Heisenberg makes some remarks on Fermi's paper. He writes on his matrix elements for pair creation and gives some calculations about the exchange energy of proton and neutron.

Heisenberg writes about charge density and finiteness of self-energy.

Heisenberg writes on the final results of the theory of holes. The whole scheme can be transposed into the quantum theory of waves. He talks about signs of a deeper connection between matter-field and radiation-field.

Heisenberg uses Dirac's method for the calculation of certain quantities. The concept of polarization of vacuum is not defined according to this theory.

Heisenberg writes in order to proceed with electrodynamics. One has to know the consequences of the present formalism. He asks for Pauli's opinion.

Heisenberg does not agree with Pauli about the identical situation of quantum electrodynamics and Fermi's theory, because the latter contains a universal constant of nature. He says that for high energies one has to expect completely different results. He writes that is the shower-formation is as an important consequence of Fermi's theory.

Heisenberg writes on the treatment of an example according to Neumann's method: the case of an electron in a force field with probably 1/2 for right or left spin. He talks of a application of the result to field theory, of the possibility of representing the state of a system by a matrix depending on a finite number of degrees of freedom, and of some of his doubts about this possibility.