Abstract: The apparatus includes a receptacle member in the form of at least one row of receptacles for receiving cell samples, each having a closed end and an open end, and a holder adapted to receive the receptacle member in a predetermined orientation and having an abutment for determining the position of a microscope slide relative to the receptacle to allow use of the receptacle member in a centrifuge for sedimentation of the samples through the open ends of the receptacles onto the microscope slide at predetermined positions. The preferred material for the receptacle member is one having a high degree of optical transparency whilst being substantially non-adherent to cells especially tumour cells and several suitable materials are described.