Report is given of examinations carried out on 40 healthy males and 29 healthy females in the months of January, March, June and October, with determination of the hemoglobin, the number of erythrocytes and reticulocytes, the sedimentation rate, the white cell and differential counts. The hemoglobin value appears to be lowest in October, the number of reticulocytes highest in June, the sedimentation rate lowest in June. The remaining figures present no exact seasonal variations. Some individuals have a high leukocyte level, others a low one. Normal values are illustrated.