(2) The lack of vitei statistics to be found on the Marshallese imposes a serious difficulty in interpretation and evaluation of the medical date. (3) The uncertainty of exact ages of some of the Marshallese, largely due to lack of written birth records. It came to light during the pest examinations that there were some uncertainties in the ages of chile dren. It is hoped that these ages may be established more firmly so that the growth ‘and development studies in the children may be placed on a firmer basis. . (4) Difficulties in obtainingwhat could be considered as entirely adequate populations to act ag comparison groups for the irradiated people. Three separate groups have been used for comparison in the past, Though each group matched well for age and sex, the first two groups proved use satisfactory due to difficulties in locating the people for subsequent examinations. Fortunately, by 3 years post-exposure, it was found that a large group of Rongelap pecple who had been away from their home island at the time of the accident had returned to live with their fellow Rongelap people. Secause they were of the same stock and matched reasonably well for age and sex, these people were uniquely appropriate to serve as a come parison population. They returned to Rengelap with the other Rongelapese and were used again as the comparison population for the 4 year survey. III, Results. The present status of the Marshallese people will be brought up to date by a brief summary of the past findings accompanying the present findings. During the first 24 to 48 hours after exposure, about two-thirds of the Rongelap people experienced anorexia and nausea. A few vomited and