36 EFFECTS OF IONIZING RADIATION third to the sixth or eighth day, and was char- acterized 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 breakdownof 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. Robbins e¢ ad. (7) reported six cases accidentally exposed over much of their bodies to scat- tered 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 et ai. with a primary erythema de- veloping 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 char- acterized by further breakdown of the skin. In comparison with severe roentgen ray reac- tions 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 multi- phasic reactions and absence of pigmentation. Crawford (8) reports a case of cathode ray burns of the hands which were similar to those described by Robbinsez ai. 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 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 co the first milli- meter of skin, ignoring self-absorption, pro- duced a threshold erythema. Dry, scaly, de: quamation was produced by 7200 rep in th first millimeter and bullous, wet desquamatio was produced by 17,000 rep to the first milli meter. Erythema developed in 3 to 4 day: followed later by pigmentation and desquams tion with higher doses. Recovery was ob served with doses of 17,000 rep. The lesion later showed depigmented centers with hyper pigmented edges (also seen in the presen cases). Wirth and Raper (10) produced primar erythema within 6 hours after exposure to dose of 635 to 1180 rep of P™ radiation. M. nute vesicles with dry, spotty desquamatio were noted with 1180 rep at about the fifth t sixth weeks post-exposure. Twenty-three Japaneses fishermen were e3 posed to the same fallout material which ir volved the Marshallese and Americans. Ther were many similarities in appearance of ski lesions that developed. Pigmentation wasals common in the Japanese and some degree erythema was reported (11) which was not see in the Marshallese. Distribution of lesions wa not the same dueto different parts of the bod being protected by clothing. For example,i the Japanese scalp lesions and epilation wer more common on the crown of the head sinc handkerchiefs were usually worn around th head leaving the crown exposed. Shoes prt tected the feet of the Japanese, but lesions c the hands between thumb and index finger wei common, apparently due to handling contam nated fishing lines. Lesions with belt line di: tribution occurred in the Japanese fisherme but not the Marshallese. Similar mild lesior were observed on several American sailors wi were on ships of the task force exposed to fal out. From available information, the severi! and course of the lesions in the Japanese fishe men appeared to be similar to those seen in tl Rongelap Marshallese group. The lesions in this report did not follo precisely the samecourse as those beta radiatic lesions described by Knowlton, Robbins, ar others (6-10) and they presented certain uniq! features which merit further discussion.