36 EFFECTS OF IONIZING RADIATION third to the sixth or eighth day, and was characterized by a more severe erythema; (3) The third phase at 8 to 12 days, was characterized by vesicle and bullae formation. The erythema spread to new areas during the following 2 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; (4) The fourth phase or chronic stage was characterized by further breakdown of skin with necrosis in areas which were damaged sufficiently to compromise the blood supply. Atrophy of the epidermis and loss of epithelial structures took place, which necessitated skin grafting in somecases. Robbinse¢ a/. (7) reported six cases accidentally exposed over muchof their bodies to scattered cathode rays from a 1200 kv primary beam with exposure time of about 2 minutes and a rough estimation of dose to the skin of between 1000 and 2000 rep. The lesions described were similar to those reported by Knowlton e¢ af. with a primary erythema 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 pigmentation. Crawford (8) reports a case of cathode ray burns of the hands which were similar to those described by Robbinse¢ ai. Experimental beta radiation burns in human beings have been reported by Low-Beer (9) and Wirth and Raper (10). Both inves- tigators used P*? discs applied to the flexor surface of the arms, forearms, or thighs for varying lengths of time. Low-Beer reported “monophasic” skin reactions. He found that a calculated dose of 143 rep to the first millimeter of skin, ignoring self-absorption, pro- 5003121 duced a threshold erythema. Dry, scaly, des- quamation was produced by 7200 rep in the first millimeter and bullous, wet desquamation was produced by 17,000 rep to the first milli- meter. Erythema developed in 3 to 4 days, followed later by pigmentation and desquama- tion with higher doses. Recovery was ob- served with doses of 17,000 rep. The lesions later showed depigmented centers with hyperpigmented edges (also seen in the present cases). Wirth and Raper (10) produced primary erythema within 6 hours after exposure to a dose of 635 to 1180 rep of P® radiation. _ Mi- nute vesicles with dry, spotty desquamation were noted with 1180 rep at about the fifth to sixth weeks post-exposure. Twenty-three Japaneses fishermen were exposed to the same fallout material which involved the Marshallese and Americans. There were many similarities in appearance of skin lesions that developed. Pigmentation wasalso common in the Japanese and some degree of erythema was reported (11) which wasnot seen in the Marshallese. Distribution of lesions was not the same dueto different parts of the body being protected by clothing. For example, in the Japanese scalp lesions and epilation were more common on the crown of the head since handkerchiefs were usually worn around the head leaving the crown exposed. Shoes protected the feet of the Japanese, but lesions of the hands between thumbandindexfinger were common, apparently due to handling contami- nated fishing lines. Lesions with belt line dis- tribution occurred in the Japanese fishermen but not the Marshallese. Similar mild lesions were observed on several American sailors who were on ships of the task force exposed to fall- out. From available information, the severity and course of the lesions in the Japanese fishermen appeared to be similar to those seen in the Rongelap Marshallese group. The lesions in this report did not follow precisely the same course as those beta radiation lesions described by Knowlton, Robbins, and others (6-10) and they presented certain unique features which merit further discussion.