RT Journal A1 JODAR EO T1 TAnning from ultraviolet irradiation brought out by blood transfusion JF American Journal of Diseases of Children JO American Journal of Diseases of Children YR 1939 FD November 1 VO 58 IS 5 SP 1047 OP 1049 DO 10.1001/archpedi.1939.01990100129012 UL http://dx.doi.org/10.1001/archpedi.1939.01990100129012 AB While it is well known that pigmentation of the skin, or tanning, results from ultraviolet irradiation with a mercury vapor lamp and that different persons vary in their susceptibility to the effects produced, the exact mechanism of this process has as yet not been satisfactorily explained. This report suggests that ultraviolet irradiation may at times sensitize the cells of the skin so that tanning is produced only when the necessary products for pigment formation are supplied by the blood of a normal person.Mayer1 presented this theory of pigment formation: "... pigment, as we see it in the skin, is the product of the reaction of an enzyme contained in the epithelial cells, and a colorless chromogen which is very closely related chemically to dioxyphenylalanin ('dopa') if not identical with it.... Local pigmentation probably results only when there is some degree of hyperemia and associated damage to the cells, with