Blood-lymphocytes from 42 persons reacted, as expected, in the leucocyte-culture with an increased DNA-synthesis, measured by the uptake of tritiated thymidine during the last 16 h of a five days culture, if mercurybichloride was added at the onset of culture. The logarithms of the activity-indices were nearly symmetrically distributed. When the lymphokine-activity in the culture supernatants was studied with the indirect leucocyte-migration-test, using autologues leucocytes, there was a bimodal distribution of the logarithmic migrationindices with a high top in the negative area (migration-inhibition) and a lower one in the positive area (migration-stimulation). These phenomena had no detectable correlations to sex, age, or dermatosis of the patients.