Monthly Status Report, May 1951 ~2- Biology and Medicine of the new Committee on Radiation Studios was held at the National Cancer Institute on May 13 with Dr. James 4. Sterner, Chairman, presiding. (Or. Sterner is a Consultant to the Division). Several proposals of research projects in the general field of radiation studies including one dealing with radiation effects on the neurophysiology of the monkey were approved for support subject to joint approval by the National Cancer Advisory Council. woe Operation Greenhouse During tha third shot at Operation Greenhouse a modified Biomedical Test Program was carried out with the remusining animals not used for the principal Biomedical Test Program in the second ghot. Tha purpose of this program wag to verify some of the results from the second shot and to collect additional data on the efficiency of biological dosimeters. Blological dosimetry values were determined by counting the various kinds of chromosome breaks in the pollen mother cells af the plant, Tradescantia, by measuring the loss in weight of the spleen and thymus of mice after exposure, and wy determining the 1D 50 of mice. Dosimetry values from these experiments are being compared with values obtained by physical meagurements such as film badges. Flash burn studies indicated that the time for maximum burn occurred at about 0.3 of a secom after the initiation of the explosion. At present this is a tentative value, however it indicates that there is not time to dodge behind a protection to minimize flash burning. The blast wave, of course, travels much slower, The LD 50 for neutron exposure with mice was investigated as well as the LD 50 with gamma radiation on mica, doga, and swine. Autopsies were performed on dogs ani swine, tissue samples werepreserved for analysis in this country. The 3,100 surviving mice from Operation Greenhouse have been returned to the Oak Ridge National Laboratory. There they wilt be kept for observations on the effect of the radiation on their Livespan and for pathological changes such as development of cataracts | ‘ SUES es The principal scientific investigators concerned with the Blomadical Program at Operation Greenhouse will devote the sumer to analysing their | data at Los Alamos, August 1. Detailed results are scheduled for complstion by 7 a ae GPO OFFICE > wooo on. ene n eee eee en---e- 16—55741-1