Results of mercury staining in human lower motor neurons and kidney after exposure to metallic mercury. (A) No stainable mercury is present in hypoglossal motor neurons or in nearby glia. LFB-HgAMG, bar = 50 μm. (B) No stainable mercury is present in C3 anterior horn spinal motor neurons (arrows) or surrounding glia. LFB-HgAMG, bar = 50 μm. (C) Heavy mercury staining is present in renal tubules, but not in glomeruli (asterisks). Hematoxylin-HgAMG, bar = 200 μm.