The present investigation was undertaken to determine whether the Ricketts theory of arcial growth of the mandible can be put to practical use by the clinician to predict mandibular morphology. Eight subjects (six girls and two boys) were selected from the earliest implant samples at the Orthodontic Department of Emory University School of Dentistry. The initial cephalograms were coded and sent to Ricketts, and a 6-year manual growth forecast using the arcial method was requested. The final cephalograms were traced and compared. The three tracings (initial, prediction, and final) were superimposed over the metallic implants and presented on a case-by-case basis. The forecasts, in form, were clinically acceptable in five of the eight cases. In two of the cases (girls) (Cases 2 and 4) a hand-wrist radiograph to determine skeletal age would have improved their accuracy. The forecast in Case 2 was not acceptable. In view of our results in this small sample, the arcial method appears valid for prediction of amndibular growth; however, hand-wrist radiographs will improve the accuracy of short-range predictions of the amount of growth expected. For this reason, the orthodontist should constantly monitor his patients, watching for each individual to assert himself.