Abstract: A method of preparing a cell block for cytological examination of cellular material such as fine needle aspirate material comprises depositing gel medium, preferably an algin medium, and sample material in an enclosure defined by a support web, and then causing the gel medium to set to form a button that can be subjected to processing routines to produce a processed button embeddable in embedding medium. The gel medium and the sample material are preferably codeposited in the enclosure by centrifugation, the support web being prewetted with a setting agent for the gel medium.A carrier that serves to support the support web during deposition and that is foldable to form a processing cassette for the deposited and set button is also disclosed.