Table 4.7 ATLINGINAR GROUP MEAN BLOOD COUNTS AE PIMESOR PEAK DI PRR SSTOON Platelets «103 W.B.C. Case No, (Average from Dis 39 ta ot) (Average trom Diy 26 to 30) Neutrophiles Lymphocytes tAveraye from Davy WO to Sb Average from Day 39 toad Age Less Than 5 8 9780 4 ABD dy VS70 44 O20 210 us SOTO GL7O $U50 240 3700 Shoo RI woo 240 Sao 21 . 215 3470 Tah 3620 ARGO 180 2550 ueia S600 Age 6 to 14 Age Greater ‘Than bb ) b170 W75 Aa70 Mi LR70 4070 ros 2200 2270 28 G2 70 115 29 31 O7T50 5650 aTL0 11h 145 L270 41 44 45 50 5) 5120 61450 5650 7050 7750 12400 5070 4100 2950 110 2220 250 3050 215 180 95 170 105 185 2270 3700 4170 3970 4620 4120 2000 1470 2900 2950 3670 59 70 4.5 . . 3000 : . 1750 RONGELAP GROUP The absolute neutrophile count of both the younger and older age groups fell during the second week to a valuc, approximately 70 to 80 per cent of that of the controls (see Fig. 4.1). Following the depression of the total neutrophile count during the second week, the values were unstable until the fifth week. At this time the beginning of a second drup (P < 0.0L) was noted for both age groups, and a tow value of approximately 50 per cent of controls was reached, The count was maintained at approximately 75 per cent of contro] values from the seventh week to the end of the study. Although both age groups followed the same general time pattern of response, the lower age group was below that of the older group throughout most of the observation period. The absolute lymphocyte count of the older age group (Fig. 4.2) had fallen by the third day to a value approximately 55 per cent of the control group. This value was maintained through- out the study, and there was no definite evidence of an upward trend during the study. The values for the younger age group likewise fell before the third day to a value approximately 25 per cent of the control, following which there was a significant upward trend. With the total! lymphocyte count, there is a consistent difference between the two age groups. However, during the first four weeks the difference ts accentuated when expressed as per cent decrease because of the relatively high lymphocyte levels in the lower age contro] group. After this period the differences expressed as per cent are less marked since recovery was more rapid in the younyer age proup. The cellular elements chiefly responsible for the fluctuations in total white bluod cell count can be determined by comparing the total white, neutrophile and lymphocyte counts (Fig. 4.3). It is seen that the lymphocyte count remained essentially constant throughout the period of study, while the total neutrophile count fluctuated with a pattern essentially identical to that 79