U.S. Pat. Nos. 5,248,480 and 5,393,494 to Greenfield et al. describe an apparatus and method for drawing a fluid sample into a slide assembly for viewing through a microscope. The fluid is drawn from a container by way of a reversible pump. The fluid, such as a urine sample, is drawn in from the container through a glass slide and after viewing purged from the slide by reversing the pump so that it can draw flushing liquid back through the slide into the fluid sample container.
U.S. Pat. No. 3,352,280 describes an automatic stain apparatus for staining biological specimen. A dyeing apparatus is described in U.S. Pat. No. 4,025,393. An apparatus wherein a slide is moved to a staining station and then to a buffer station and thence to a rinsing station is described in U.S. Pat. No. 4,034,700.
These prior art techniques, other than the Greenfield patents, for the handling of samples either are too complex or involve physical exposure to the biological specimen being reviewed and are not readily suitable for a safe handling by the operator who evaluates the particular specimen in the slide.