This paper attempts to interpret recent data on the distribution of polarization in the Crab Nebula in terms of the internal structure of the nebula. If the depolarization by bright filaments which is observed at A = 6 cm also occurs at A = I'55 cm, as low resolution studies suggest, a magnetic field component along the line of sight of Bii > 2 x I0- Gauss exists in some of these filaments. The polarization behaviour in the direction of the optical bays may be explained if they contain thermal gas. If the rotation measure of the pulsar NP 0532 is characteristic of the interstellar medium, as suggested by Manchester, it is likely that all the rotation of the plane of polarization intrinsic to the nebula occurs in condensations of gas with gaps of density Ne < 10-2 cm-a in between. The distribution of Faraday rotation intrinsic to the nebula does not show the pattern to be expected for a toroidal magnetic field `wound up' by the pulsar.