Abstract: The invention relates to a procedure for high enrichment of fetal cells as a product, whereby after a withdrawal of maternal blood, the blood fraction and centrifugation, an antibody cocktail with Anti-w, Anti-r antibodies, which specifically bond to transferring receptor molecules as antigens of the surfaces of nucleated stem cells of red blood corpuscles, and Anti-i antibodies, which specifically bond to Antigen-i as antigens of the surfaces of nucleated stem cells of red blood corpuscles, and/or Anti i plus antibodies, which specifically bond to intracellular structures of fetal stem cells and/or the intracellular molecules of fetal stem cells and/or membrane fragments of fetal stem cells is added and fetal cells with 105 to 107 enrichment are separated from the cell preparation.

Abstract: A damping material (19) is provided on one of the two side faces (7, 8), of a magnetic head having two plate shaped ferrite core limbs (3, 4). The material consists of a synthetic resin filled with less than 30% by volume of filler having a density of more than 10.times.10.sup.3 kg/m.sup.3. The filler is at least 74% by weight of the damping material and the density of the damping material is larger than 4.times.10.sup.3 kg/m.sup.3 and its modulus of elasticity ranges between 10.sup.7 and 10.sup.9 Pa.