monocellular layers of cell containing biological fluid such as blood by spinning a sample slide bearing a sample to be analyzed in the practice of the improved method and use of the improved apparatus the slide is positioned with the sample bearing surface thereof facing downwardly so that the force of gravity aids rather than hinders monocellular layer formation such layer formation is further facilitated by spinning of the slide in a holder provided with integral wall means shielding the sample from the buffeting effect of circumambient air to thereby avoid premature drying of the sample minimize cell distortion and prevent aerosol formation application_number US 12212180 A description referring now to the drawing the improved apparatus of the present invention comprises a motor 10 which is preferably electrically powered and a slide holder 11 the latter being adapted to accommodate a slide such as the microscope slide 12 shown in fig1 to 3 the motor 10 may be line powered or it may be battery powered to facilitate portability of the apparatus motor 10 has a vertical drive shaft 13 which in the illustrated embodiment has an upper end portion of square cross section the slide holder 11 is preferably molded of any suitable organoplastic material such as polystyrene polycarbonate abs resin and linear polyethylene and is generally rectangular in plan view as shown in fig1 holder 11 has a rectangular horizontal bottom wall 14 and wall means in the form of upstanding parallel longitudinally extending side walls 15 and 16 which with bottom wall 14 provide said holder and open ended channel shape a cylindrical hub 17 depends centrally from the bottom wall 14 the latter being formed with a circular thickened portion 18 coaxial with said hub the hub 17.