A non-powered device intended to be used by a healthcare professional to manually record and display haematological cell counts of white blood cell populations in a clinical specimen, as observed under a microscope. It consists of multiple mechanical tally counters with a lever representing each white blood cell type (e.g., basophil, eosinophil, lympocyte) which the operator depresses to record an observed cell type. Totals for population counts are displayed on the device and used to subsequently calculate the percentages for each population.