To diagnose lumpy jaw, the fluids exuding from the bony lump or other abscesses are sampled or aspirated if the infection has not broken through the skin.[1] Tissue samples from the lesion can be examined by histopathology after being embedded in paraffin wax, cut into 4- to 5-mm sections, and stained with hemolysin and eosin stains.[2] The clubs could also be stained by carbol fuchsin with decolourisation by weak hydrochloric acid and counter-staining with methylene blue, Van Gieson's stain, or aniline gentian violet followed by treatment with alcohol.[3] A. bovis can be identified histologically by its basophilic colonies and club-shaped reaction product visible in neutrophilic granulomatous lesions.[16] The club-shapes, also called Spendore-Hoeppli proteins, seen on histological slides are the result of the bacteria being encased in a calcium-phosphate protein complex, as the host attempts to wall off the infection.[16] Another diagnostic feature is the presence of "sulfur" granules,[4] which is pathognomonic for actinomycosis.[16] These granules are small, yellow clumps of exudate that are visible to the naked eye with a similar appearance to grains of sulfur, and are mainly composed of bacterial filaments and host calcium phosphate.[16]