In a study of time-dose relationships based on Hodgkin''s disease, an iso-effect recovery curve was calculated using the "minimum corroborated tumor lethal dose" tactic. Its slope of 0.25 suggested thatHodgkin''s disease tissue was capable of recovery from radiation effects, and that its rate of recovery more closely resembled that of carcinoma than a radiosensitive lymphoma such as mycosis fungoides. In one-half of cases of Hodgkin''s disease, all the lesions in a single patient responded consistently to irradiation, being either radiosensitive or radioresistant. However, among the remaining patients there was a mixed pattern of rate of tumor shrinkage. This invalidated the use of "rate of shrinkage" for clinical or radio-biologic purposes. Analysis of the relation of dose to local control corroborates the empirical clinical technique of employing radical irradiation to involved and uninvolved areas, using tumor doses of 3,500 to 4,000 rads in approximately 28 days. This had yielded from 93 to 96% local control. The "equivalent single dose" for Hodgkin''s disease is 1,750 rads when the aim of dosage is local control, and 1,178 rads for a "minimum corroborated tumor lethal dose.".