Histological sections, prepared from control (CTL) mouse skin and mouse skin 1–5 days post NM exposure, were stained with Gomori's trichrome containing hematoxylin, which stains nuclei blue/black, eosin which stains keratin and cytoplasm red, and aniline blue which stains collagen I/III royal blue. One representative section from 3 mice/treatment group is shown (original magnification, × 400). E, epidermis; D, dermis; S, sebaceous gland; HF, hair follicle; asterisk, eschar; star, collagen deposition. Left panels, mouse skin treated with NM; right panels, mouse skin treated with NM and 4338.