From the clinical point of view the study of analgesia revolves about four factors—the patient, the medicament, the method of testing, and the investigator. Each contributes a significant component to the end result— the effectiveness of a particular drug under investigation. To standardize all factors other than the unknown, the medicament, has been the primary task of all good analgesic studies. Perhaps we have labeled the wrong factor the "unknown." Instead of the drug that is at least a chemical entity with definitive properties, the unknown should be the patient. Any study designed to eliminate or decrease the number of variables inherent in the patient as an experimental subject does not accurately evaluate the medicament for general clinical use. It is possible by such a study to determine, perhaps, the specificity of the medicament for the relief of a particular type of pain or condition, but it cannot be concluded