” - . + A ow : 73 oe ERY (si snails in the 80000 r and 40000r groups, half of the snails in the 20000 r group and 5 of the controls had died, but none died in the 10000 r group. the controls. Mortality rates in other groups were similar to By the end of the month 7 controls had died and mortalities in other groups were: 20000 r, 5; 10000 r, 0; 5000. r, 13 2500 r, 1; 1000 r, 0; and 500 r, 4. The relatively high mortality in the 500 r group may possibly be. attributed to rough handling, as they were the first ones irradiated. Project X, Bikini Resurvey of 1948. In the counting and sample preparation laboratory, periodical counts were continued of the selected Bikini and Eniwetokplates for determining rate of decay of the activity. The preparation of ashed samples of Bikini and niwetok materials for U.C.L.A. was continued, The technique of preparing coral samples for counting was changed. The present procedure is to pulverize the sample with a mortar and pestle, place about one-half a gram of sample on a plate and cover with 0.5% solution of Formvare in ethylene dicloride to make sample adhere to plate. Results are good. For the purpose of separating those samples of low activity from those of background only, a recount was started of the Bikini fish samples that on first count were only 4 counts or less higher than background, A check on the ashing technique used up to the present time indicates that considerable activity may have been driven off during the process. Samples in which acid was not used in preparation gave substantially higher counts than those prepared by the original method. This is to be investigated further. tepeta mm ame pos ARCHIVES