Glomerulus and Nerve

Despite the frequency with which death investigation is depicted in the media, few (if any) on-screen forensic scientists appear to use microscopy as a tool to determine cause and manner of death. The reality is that microscopy is one of the pillars on which a good-quality investigation may rest and can reveal information that is otherwise unavailable. Pathologists use histology (the study of the microscopic structures of human tissues) to diagnose natural disease, identify injuries, or evaluate the presence and meaning of foreign material like soot in a gunshot would or bulking agents used in the preparation of illicit drugs. The application of polarized light may offer an additional histological perspective.

Because thin slices of tissue are colorless under the microscope, dyes that bind and delineate cell structures are added during the generation and processing of glass slides. The standard stains used by almost all pathologists are hematoxylin and eosin, which color parts of the cell pink and purple. Normal microanatomic structures are commonly encountered during microscopic examination, like the functional unit of the kidney as shown in Glomerulus or the bundles of sensory fibers caught in the cross-section in Nerve. Other dyes - known categorically as "special stains" - can be used to highlight aspects of cellular morphology, identify foreign material or deposits of disease-causing proteins, or distinguish cell types from one another.