23. =Skin.= Color (racial differences), brown, gray or black pigmentations in Addison’s disease, pellagra, syphilis, vitiligo, xanthoma, chloasma, pigmented nodes or nævi, argyria, arsenical poisoning, pernicious anæmia, xeroderma pigmentosum, chronic jaundice, vagabond’s skin, tan, following blisters, plasters, cupping, use of croton oil, Roentgen irradiation, effects of violet rays, melanotic tumors, pregnancy, etc.; bronzing in Addison’s and chronic icterus; lemon yellow in chlorosis and pernicious anæmia; yellow to dark green in icterus; grayish-brown in potassium chlorate poisoning; bluish-red (cyanotic) in cardiac insufficiency; yellowish-bluish-red (“Herz-farbe”) in cases of complete loss of compensation; cherry-red or rose-red in carbon-monoxide or hydrocyanic acid poisoning, rarely as the result of an erythema, although this condition usually disappears after death; dirty sallow to grayish or greenish in tumor cachexia and poisoning with H_{2}S; white after severe hemorrhage, cachexia of chronic Bright’s disease, leucoderma, vitiligo, albinism, leprosy, etc.; red, yellow, green or brown in hemorrhages according to their age. Eruptions should be classified and described as to location, abundance, stage, etc. (macules, papules, wheals, desquamation, scales, blebs, bullæ, pustule, tubercles, ulcers, abscess, phlegmon, herpes, crusting, granuloma, etc.). With the exception of chicken-pox and small-pox the eruptions of the acute exanthemata disappear after death, as do all erythematous rashes except in rare instances. Emphysema of the skin should be differentiated from œdema. The most common lesions of the skin are acne, eczema and syphilis. Tuberculosis (lupus) is not uncommon; anthrax, favus, rhinoscleroma, actinomycosis and blastomycosis and Aleppo or Delhi boil are more rarely seen. Tinea versicolor and tricophyton (barber’s itch and the various forms of ringworm) are the most common parasitic affections. In the Southern states ground-itch due to the hook-worm is the most common. Leprosy should be considered in connection with individuals coming from Norway, Sweden and Finland and other leper-foci. The most common tumors of the skin are all the various forms of hæmangioma and lymphangioma (freckles, moth patches, naevi, moles, warts, birth-marks), fibroma, lipoma and squamous-celled carcinoma (horny and basal-celled types). The latter is the most common form of malignant tumor. Sarcoma of the skin is more rare; the melanotic sarcoma, arising usually in a pigmented mole, is the most common form. Next to this is the round-cell sarcoma or lymphosarcoma (mycosis fungoides, leukaemic and aleukaemic lymphocytoma, etc.). Spindle-cell sarcoma, angiosarcoma, endothelioma and other forms are less common. Sebaceous cysts (wen, atheroma, steatoma) are very common. Less frequent are molluscum contagiosum, xanthoma (endothelioma lipomatodes), myoma, myxoma, chondroma and osteoma. Adenoma sebaceum and sudoriparum are rare. Other conditions of the