TWELVE FIGURESMost investigations of the effects of irradiation on the thymus (reviewed by Murray, '48) hare emphasized the damage done to the thymic cells in terms of injuries to the nuclei. The present study is concerned with the distribution of lipids in the cytoplasm of the cells of thymuses from irradiated mice. It was found that lipids accumulated as soon as 4 hours after exposure to x rays, and decreased in amounts after 5 days.
MATEETAL AND METHODSThe mice used in this work were mostly of the C57 B1/6 strain obtained from the Roscoe B. Jackson Memorial Laboratory, Bar Harbor, Maine, and were divided into three age groups: 20-30 days, SO-100 days and mice as old as could be procured. The latter were animals of different strains approximately 360-540 days old. The mice were held in a plastic cage (Haber, '49) and received single, total body, sublethal doses of 410 r. The radiation factors were 250 ICV., no filter, 3 min., 50 em, TSD.Mice from each age group were killed at 4, 8, 12, 18, 24, 36, 72 hours and 5, 7, and 9 days after x-radiation. Thymuses were studied from 125 experimental animals and 35 non-This investigation was