53 HEMATOLOGIC OBSERVATIONS fall to reach a low of approximately 60 percent of control Jevels at the end of the 4th week. The value then returned to approximately the control level at the start of the 7th week, following which a second depression was noted. The platelet counts were at a level of 80 percent of the control value at the time of the last observation during the 8th post-exposure week. dividuals, Group I, rose from very lowlevels observed on day 3 to values approximating 35 percent of control during the second week, where it remained from the 3d to the Sth week (Fig. +7). The counts then decreased GROUP A-AGE < Monocytes and Eosinophiles, All Groups CONTROLS GROUP Table 4.7.—Group II Ailinginae Mean Blood Counts at Time of Maximum Depression Age Less Than 5 w.p.c. Plates Case No. from Day Neutra Lympho Platelets Neutro- L (Average (Average (Average 9, 750 8, 350 4, 570 215 185 180 3, 470 5, 600 3,520 | 4, 350 2, 350 2, 070 Age 6 to 15 48 6, 220 33 $1 6, 170 4, 700 210 240 240 2,970 3, 150 3, 700 2, 500 2, 320 | 2, 150 Age Greater Than 15 1 16 28 29 ol | 45 50 | | 51 a9 Ld Prey 3 wien a —_ i 70 175 195 3,570 2,200 5, 120 110 3, 050 6, 270 6, 750 5, 650 4] 43 6, 170 4, 670 | | | | 115 115 145 6, 150 215 7, 750 170 5, 650 7, 050 12, 400 5, 070 2, 370 2, 270 3,720 4, 100 2,950 2, 270 2, 220 2,450 3, 700 2, 000 2, 270 180 95 4,170 3,970 4,620 2,950 105 8, 120 3, 670 185 1, 470 2, 900 3,000 1, 750 | 16 24 32 40 46 POST EXPOSURE DAY 56 Fictre 4.7.—Serial eosinophile counts on those Icss than and greater than 5 years of age of Group I (Rongelap). ho- auto si) foraDay thomDay fom Day 6 8 44 -AGE > ub From Table 4.2 it is seen that the mean monoeyte count for Group I rose abruptly from an early value belowcontrol levels to a well-defined peak on day 12, following whichit fluctuated at values below the control level for the duration of the observationperiod. A similar time trend . was noted in Groups IT and IIT, EOSINOPHILES x 10° 4.35 The eosinophile count in the older age in- (p>0.01) and remained at a value approximately 15 percent of control throughout the remainder of the study. The time trend of response wassimilar in the younger age individuals, however changes in the youngerage group were relatively greater if considered in terms of the control values. Similar trends in eosinophile count were not evident in other exposure groups. It is possible that the rise in eosinophiles represents that reported by Minot and Spurling (11) as occurring “ two to three weeks after short wavelength irradiation”. 4.36 Hematocrit, All Groups The hematocrit values forall exposed groups are shownin Table 4.8. When hematocrits were first done on the 22d day, mean values for Giroups [ and II were belowthose of the control population. <A significant trend in values after this time could not be detected statistically.