-5and scarring of the skin. complete. Repigmentation may be long delayed or may never be Only about 20 per cent of the Marshallese group referred to devel- oped ulcerating lesions and secondary infection occurred in a few cases. Le- sions on the dorsum of the feet were generally the most severe, showing bullae formation followed by ulceration (Fig. 6). At three years after exposure some of these lesions sontime to show incomplete repigmentation of the skin with atrophy or scarring in some casea (see Fig. 7). Epilation may ocour along with the development of the skin lesions. The head region is more sensitive to epilation than the axillary, pubic, or eyebrow regions. If the radiation dose to the follicles has not been too high, re- growth of hair commences in several months. 4f the skin dose is high. complete. Permanent epilation may result Usually by five or six months, regrowth of hair is In the Marshallese group, spotty epllation of varying degrees oc- curred in 90 per cent of the children and about 30 per cent of the adults (Fig.&). Regrowth of hair commenced in all cases about 3 months post-exposure and by 6 months, hair was of normal color, texture and abundance (Pig. 9). Though change of color of hair from black to gray has been frequently observed in animals (Hance and Murphy; Chase), regrowth is usually of normal color in the human being. However, Conard and Tessmer have reported a case in which ragrowth of the hair of the eyebrows (previously black) regrew white in a lesion presumably due to fission product contamination. 6.2 CHRONIC EFFECTS, CARCINOGENESIS. radiation, imperfect healing may result. Following large doses of beta Damage to the vessels of the dermis may result in sufficient impairment of circulation to cause cycles of break~ down and repair of the epidermis or chronic, indolent ulcers may result. commonly seen are atrophy, scarring, keratosis and telangiectatic vessels. Also The hair follicles, sweat and sebaceous glands may be injured sufficiently to result