The author examines the nature, preparation, and medicinal use of cod-liver oil, tracing earlier clinical experience that prompted renewed attention. He summarizes methods of extraction, common formulations, recommended doses and topical versus internal application, and reports characteristic physiological responses: initial aggravation of pain followed by gradual relief, promotion of warmth and perspiration, acceleration of pulse, and occasional digestive disturbance with impaired appetite requiring emesis. He notes the oil's offensive taste and odor and measures used to disguise them, describes observed benefits in chronic rheumatic and stiffened-limb conditions, outlines contraindications such as fever or local soreness, and cautions against indiscriminate use.