~13- the changes were largely confined to the upper part with edema, telangiectasis of vessels with perivascular infiltration of lymphocytes. filled with melanin were prominent. Chromatophores Figure 15 shows some of these changes in a pigmented lesion biopsied 3 weeks after exposure. By 6 months there was considerable improvement in the histological appearance of the lesions. The following changes were found to persist in varying degrees: focal atrophy of the stratum granulosum, slight focal pigmentary disturbances in cells of the basal layer, and slight disturbances in polarity of the epithelial cells in basal papillary projections. In the dermis, telangiectasis of slight to moderate degree persisted.* The treatment of the lesions during the acute period was very similar to the treatment of thermal burns, mild lesions requiring only daily cleansing and application of bland antipruritic lotions and ointments. with 1% phenol was soothing. Calamine lotion With more severe lesions analgesic and anesthetic ointments were helpful in allaying more painful symptoms and in keeping the skin soft in lesions that were dry and thickened. Antibiotics applied locally and/or parenterally were used for secondary infections. me 12.6.3 Exposure to Internally Absorbed Isotopes. There were no acute effects observed in the Marshallese that could be specifically attributed to the exposure to internally absorbed radionuclides. This is in contrast to serious late effects associated with the irradiation of the thyroid gland by radioiodines taken up during their period of acute exposure. This bears out the contention that iodine is the most hazardous element in fallout. It might be argued that the gastrointestinal symptoms noted early in the Marshallese were to some extent caused by the radionuclides transient in the *Histological studies were carried out by Dr. David A. Wood, San Francisco, California and Dr. Stuart Lippincott, Upton, New York. 9001310