CJD is caused by a prion.  While prions are not affected by formaldehyde,
they are inactivated by phenol.  Several antique fixatives include phenol.
They should produce safe paraffin sections of CJD material.  Hetherington's
fluid is 100 ml absolute ethanol, 75 ml chloroform, 50 ml phenol, and 25 ml
glacial acetic acid; it dehydrates as well as fixes.  Lendrum's fluid is 75
ml absolute ethanol,  10 ml chloroform,  10 ml water,  4 ml phenol, and 3 ml
glacial acetic acid.  I suspect that Behrens' fluid contains too little
phenol (1%) to be an effective disinfectant.