- 143 - change at all and remained between 46 and 47 years. The mean age at death of radiologists was 55.8 years in 1934-1939; 59.3 years in 1940-1949; 64.5 years in 1950-1959 and 70.1 years from 1960. The rate of this increase was higher than that of the general male population, so that from 1960 on the two curves expressing the increase in the average age at death versus time crossed with each other. The life-shortening observed in preceding years could not be attributed to any one cause in particular, such as leukaemia, but was the aggregate of shorter life-spans associated with many causes of death. Leukaemia had a higher risk (about 5 times) among radiologists than among the male population at large, but it occurred rarely and only after a number of years of occupational exposure. It was more common in radiologists after 40 years of age, but more common before 40 in the general population. excessive incidence of leukaemia in radiologists decreased. In recent years the From the above findings Warren and Lombard concluded that radiation protection measures had been effective in providing adequate safeguards for the radiology specialists. 351. Miller and Jablon [M27] searched for late radiation effects among men trained as radiology technicians in the United States Army during the Second World War. The mortality experience of this group of people (6560 persons in total) was compared over the period 1946-1963 with that of other groups trained by the Army as pharmacy (1522 persons) or medical laboratory technologists (5304 persons). It was difficult to ascertain the radiation dose but it was concluded from ancillary evidence, in the absence of more complete records, that they received substantially greater radiation that did patients exposed to x rays for diagnosis. Causes of death were investigated and in only 1 out of 16 possible comparisons between exposed and non-exposed groups there was a statistically significant difference of any interest in the present context. It referred to an excess of tumours of the respiratory tract which was elevated among radiologists: however, the difference between expected and observed values was due in part to the low mortality rate from this cause of death in the control samples. No sig- nificant excess of leukaemia was found among the radiographers, but in a study of this size a two- to three-fold increase in the risk of leukaemia could have gone undetected. 352. No information on life-span-shortening was reported as such. There was yet another report from Japan on the mortality and causes of death of radiology technicians during the period 1966-1972 [K19]. Among these technicians affiliated to the Japanese professional association there were dur- ing the above-mentioned period 134 deaths, a number much lower than expected, age