ation at the Nevada Proving Grounds, 16 horses developed lesions resulting from fallout de- posit on their backs (5). Knowlton et al. (6) described burns of the hands of four individuals who were handling fission product material following detonation of a nuclear device. These burns were due largely to beta radiation. The gross lesions of the hands occurred from an exposure of about one hour, resulting in doses between 3,000 and 16,000 rep of beta radiation (maximum energy about 1 Mev) with a small ganma component considered to be insignificant. The lesions were described as developing in four phases: (1) An initial phase which began almost immediately after exposure and consisted of an erythema with tingling and burning of the hands, reaching a peak in 48 hours and subsiding rapidly so that by 3 to 5 days there was a relative absence of signs and symptoms; (2) A second phase which occurred fram about the third to the sixth or eighth day, and was characterized by a more severe erythema; (3) The third phase at 8 to 12 days, which was characterized by vesicle and bullae formation. The erythema spread to new areas during the following two weeks, and the active process subsided by 24 to 32 days. The bullae dried up, and desquamation and epithelization took place in less severely damaged areas; and (4) The fourth phase or chronic stage was characterized by further breakdown of skin with Necrosis in areas which were damaged sufficiently to compramise the blood supply. Atrophy of the epidermis and loss of epithelial structures took place, which necessitated skin grafting in sane cases. Robbins et al. (7) reported six cases accidentally exposed over much of their bodies to scattered cathode rays (beta) from a 1,200 kv primary beam with exposure time of about 2 minutes and a rough estimation of dose to the skin of between 1,000 and 2,000 rep. The lesions described were similar to those reported by Knowlton et al. with a primary erythem developing within 36 hours; secondary erythema with vesiculation and bullae formation appearing about 12 to 14 days later; and, in the more severely affected, a tertiary phase characterized by further breakdown of the skin. In comparison with severe roentgen ray reactions these investigators stressed the unique periodicity of cathode ray burns, relative absence of deep damage to the skin, less pain, greater rapidity of healing, and absence of pigmentation. These points would apply to the Marshallese lesions except for the multiphasic reactions and absence of pigment-— ation. Crawford (8) reports a case of cathode ray burns of the hands which were similar to those described by Robbins et al. Experimental beta radiation burns in human beings have been reported by Low-Beer (9) and Wirth and Raper (10). Both investigators used P** discs applied to the flexor surfaces of the arms, forearms, or thighs for varying lengths of time. LowBeer reported “monophasic” skin reactions. He found that a calculated dose of 143 rep to the first millimeter of skin, ignoring self-absorption, produced a threshold erythema. Dry, scaly desquamation was produced by 7,200 rep in the. first millimeter and bullous, wet desquamation was produced by 17,000 rep to the first millimeter. Erythema developed in three to four days, followed later by pigmenttation and desquamation with higher doses. Recovery was observed with doses of 17,000 rep. The lesions later showed depigmented centers with hyperpigmented edges (also seen in the’ pre- sent cases). Wirth and Raper (10) produced primary erythema within six hours after exposure to a dose of 635 to 1,180 rep of P®* radiation. Minute vesicles with dry, spotty desquamation were noted with 1,180 rep at about the fifth to sixth weeks post-exposure. There were 23 Japanese fishermen exposed to the same fallout accident which involved the Marshallese and Americans. There were many similarities in appearance of skin lesions that developed. Pigmentation was also cammon in the Japanese and some degree of erythema was re—ported accampanying some of their lesions (11) which was not seen in the Marshallese. Distribution of lesions was not the same due to different parts of the body being protected by clothing. For example, in the Japmese scalp lesions and epilation were more common on the crown of the head since hankerchiefs were usually worn around the head leaving the crown exposed. Wearing 434