In an article on grenz rays, which appeared in 1941,1 the therapy of nevus flammeus was discussed, and I reported on a series of 38 cases, treated with this modality. The total dose used in those cases was about 10,000 r. The individual doses varied between 800 and 1200 r, and a radiation of a half value of 0.02 to 0.03 mm. of alumi