awoke Bm ee ee teat Ci eat at Nh tale acee se ba dF Scalp lesions usually accompanied epilation (plates 13,17, and 19). Some individuals tended to develop new scalp lesions over a period of about a month. Neck lesions were usually of “necklace” distribution, beginning at the front usually and spreading posteriorly. They were more severe in wanen where the thick hair touched the nape of the neck. Neck lesions are illustrated in plates 14. Axillary lesions (plate 11) usually consisted of coalescing papules. Antecubital fossae lesions usually were characterized by thickened plaque formation. Several babies and one waman developed lesions in the anal region which though not deep were painful due to excoriation of the epidermis. They healed rapidly. Lesions of a deeper nature were seen on the scalp, neck, feet, and in one case on the ear. The early pigmented lesions were similar to those described above but tended to be larger. They were characterized by transepidermal necrosis with wet desquamation leaving weeping, crusting ulcerations. Vesiculation was not observed except with foot lesions which developed bullae, frequently several centimeters in diameter, beneath thickened pigmented plaques. After several days the bullae ruptured and desquamated leaving raw ulcers. Some of these lesions, particularly of the feet, became secondarily infected requiring specific antibiotic therapy. However, most healed rapidly and new epithelium covered the ulcerated areas in a week or ten days. Foot lesions are illustrated in plates 5-10; months to heal. One ear lesion (plates 13-16) took several The repigmentation process in some of these deeper lesions presented certain abnormlities. Neck lesions tended to develop a dusky, grayish~brown pigmentation associated with a thickened “orange peel” appearance. Histological appearance of epidermal rugosity was also noted in these lesions (see section on histopathology). In addition, the deeper lesions of the feet failed to repigment, remaining a pink to white color. At examination 6 months and 1 year after the exposure, the skin appeared normal with no residual changes in the vast majority of cases. to show slight evidence of residual damage. However, same of the deeper lesions continued Foremost among these was the ear lesion which showed healing but with considerable scarring, atrophy, scaling of the epidermis, and gross telangiectasis. This was the only lesion in which future breakdown appeared likely. By 6 months the hyperpigmentation and thickening of the skin of the neck lesions had greatly subsided and by 1 year little of this residual change cculd be seen. Foot lesions continued to show no repigmentation at sites of deepest involvement and same atrophy of the skin in these areas was apparent. b. Microscopic Biopsies were taken of seven neck, and one axillary lesion in the Rongelap group during the third to fourth week after exposure. At the time of biopsy these lesions were in the hy- perpigmented stage with little or no desquamation. Most of the biopsies were taken from indi- viduals. with lesions of greater than average severity. A second series of biopsies (repeats in three individuals) were taken from this group, four at the seventh week and five at the eighth week post-exposure. These were taken from the neck and antecubital fossae. All of these lesions had desquamated and the depigmented skin had repigmented to a dusky, gray color with some thickening of the skin (“‘orange-peel’”’ appearance), plates 25 and 27. Biopsies were not taken from open lesions or from the feet for fear of infection. A third series of 11 biopsies were taken from the Rongelap group at 6 months along with several control biopsies from unex— posed natives. Material was obtained from sites of previous lesions, mostly in individuals who had previous biopsies. All biopsy wounds healed rapidly within a week to 10 days with no secondary complications. The microscopic findings are summarized as follows: First series — 3rd to 4th week. Epidermts. — Transepidermal damage was noted with a few intervening arcades showing less damage (plates 21 and 22). 429 The epidermis in the most ex-