Fierz gives a differential equation and the canonical description of its solution.

Fierz writes about Pauli's jocular remarks concerning parity.

Fierz makes historical comments on the parity problem and different attitudes towards the idea of symmetry and perfection in Kepler, Galileo, Newton and Leibniz.

Fierz explains further his considerations as regards the two component theory of the neutrino with special reference to Weyl's and Majorana's theories.

Fierz makes philosophical and historical remarks on the problem of the mirror image.

Fierz comments on Jordan's attempt at deriving the gravitational equations from a variation-principle. He writes on speculations on the possibility of explaining life scientifically.

Fierz replies to a remark by Pauli on the lack of mirror-invariance. He refers to a story in Greek mythology.

Fierz makes further remarks on the elimination of non-physical states in connection with the Lee-model.

Fierz talks about the derivation of the Casimir-pressure exerted on two neighbouring metal plates by the zero-point radiation field.

Fierz discusses the unitary representations of the Lorentz group for general functions expanded in vector functions of Harish-Chandra. He applies to Majorana'a equations published in: Nuovo Cimento: 1932.