4.0 Introd: ction FoLLowince THE Detonation of a nuclear des ie at the Pacifie Proving ¢rreund uo the Spring of 1954, 28 Americans and 39 Marshallese were exposed to fallout radiations Sixty-four «1 the Marshallese on Rongelay atoll i Crrouyp. I received anestimated 175 of camma radiation as measured in air; 1s Marshaliese on Adding inae atoll (Group [7 received (0 or. 25 Amer ‘ans on Rongerk atoll Crroupe EEL) received 7 r.: and 157 Marshallese oF [ror k atoll Grouy 1V) received 14 r Det riled ustory of the event.as wellasclinveal ar i taternad contamina tion findings are reported respectively a1 Chap ters I, TT and V. Thos chapter presents the hematological findings 1 the exposed indis ie uals during the first 1] weekscat 6 months. ina ut 12 months after -apos:re Since it is gener:lly agreed shat the degree of change in the formed +lements of the bloou is the most useful «mica index of the -everits of radiation damage, per pberal blood changes were relied upon as a maior ii mi evaluating the degree of radiation tijues i eich exposed individual. In adeattion hanges in the mean blood counts of the exposec groups were fol lowed closely to aid ui evaluating the changing status and probable proguesix of the exposed groups. Therefore emynasi- vas plieed on standardized systeriati: erial determurutt.ons in order that indivienar acd zroap trends could be evalunted adequitels Mn GE was Heres sary to observe the large ramber of exposed individuals at frequent itervaiis, the nuniber of different procedt res toat could be done was necessarily limited. Determinations emploved were chosen au the basts of Knows clinical value, and ease and rapidity sara sv hien they could be done reliably under fell aborarory conditions Accordingly cone datic and broehen: ont studies were omitte | An extensive literatur tologic effect of rac iatia eviest oon the ema These deta inet ttis defer dties attendant on comparing them with tee resent resuits are discussed later in this bar oweat! +.1 HE Methods asctaregesar ExasaNations PNcLUDED total reatrophile, lymphocyte and plateoots, and hematocrit deterninations. Poikoo ste. e Whenever possible. am entire exposure group ootierea oto single day with 2 days oc- easatatly cequired to complete the larger SEOs tapillirs blood. usuatly obtained from the ni ver ond turels from the heel or ear was used. fe pipettes were filled for beth the leukocyte WG oiatelet counts. From each pipette a sig hemocytometer chamber was filled. AL popetfes were rotated fur To minutes, and the eile vere allowed to settle for LO minutes in the atieespometer: hamber before counting. A 3 pereer to aeetie wid diluting: fluid was used for ‘etal dew coevte Ounts. The blood was diluted sth loypereesnt ummonium oxalate for platelet cunts dad ceurted in flat bottom hemocytemrrors sing a dark phase contrast microscope Peo olood smears were made using a ‘aver one glass slide for spreading. One ood Smrend owas fixed ane methyl alcohol. The wher aos tamed by Wright's method, from cvredi ou teeter] differential count was made. Hematocmdt Piidary were performed using heparinized tubes One end of the capillary tube caste use led and the tube was centrifuged in / odalhiury ceurrifuge at 12.500 rpm for 3 hyd Pps I.very effort was made to maintain uniform Pooeeqaires in every phase of the laboratory oth Che number of personnel changes fora woveroproc)editire was held toa miinimluni: perce cr tas blood frome a single puncture 15