RADIOACTIVITY AND RECOVERY OF THE LAND PLANTS AT ENIWETOK ATOLL, Since the summer of 1946, the 1954-1957 Laboratory of Radiation Biology of the University of Washington has conducted studies at the Eniwetok Proving Ground to evaluate the distribution of radioactivity in aquatic and atolls of the western terrestrial organisms Pacific and adjacent of the areas. These studies were made either shortly after a nuclear device had been detonated or after intervening periods varying several to many months. The results of the investigations 7 conducted in i946 ' 7 1947 1) , 1948 '7), 1949/3), ana 1952 (4) indicated the need for a study of the reinvasion of organisms from in an area contaminated by radiation, or regrowth as well as a study of the decline of radioactivity in these organisms (changes in the amount of radioactivity of samples collected at various times). A study of this nature was aetonation of an atomic device the spring of 1954. undertaken (Nectar) Facilities were following the at Eniwetok Atoll in made available at the Eniwetok Marine Biological Laboratory on Elmer (Parry) Island by the Division of Biology and Medicine of the United States Atomic Energy Commission, and logistic support to carry out the sampling program was furnished by Joint Task Force Seven Gr. of Operation Castle.