D. O. SHIFXS 



decrease. The counts of small lymphocytes were done as the result of sug- 

 gestions made by Dr. O. A. Trowell of Harwell. 



The clinical significance of the changes which were observed in these 

 newer tests is not known at present, beyond the fact that abnormal values 

 persisting for some time were associated in other individuals with lassitude 

 and fatigue. 



If it is a fact that the smaller lymphocytes are the older, more mature ones, 

 then the considerable reduction in their numbers, the total numbers of all 



Change in small 

 lymphocyte count 



KOO 



1200 



1000 



800 



600 



AOO 



200 



93-* 



-566 



Change; fall of 391% 



First 

 test 



Tests A -7 

 months later 



Figure 7. Results of tests on occupationally exposed persons 



lymphocytes showing no significant reduction, would probably indicate a 

 more rapid turnover of the lymphocytes. This increase in turnover might 

 amount to 30 per cent so that the lymphopoietic system would be working 

 at increased capacity. If this condition should continue for 20 to 30 years, 

 as it may well do in those whose livelihood is in radiation work, the effects 

 might be significant with regard to the expectation of life. 



The dosages for those occupationally exposed were not known but they 

 were working in conditions considered satisfactory by those in authority in 

 their organizations. At the time these tests were made monitoring was 

 unsatisfactory. In those instances for which monitoring records were available 

 the exposures were less than • 3 r free air dose per week. 



45 



