​”Supplement to the American Dispensatory,” authored by John King and John Uri Lloyd in 1880, serves as a significant addition to the original “American Dispensatory.” This supplement reflects the dynamic nature of pharmacological knowledge during the late 19th century, a period marked by rapid advancements in medical science and a growing interest in botanical remedies. The authors, both prominent figures in the field of eclectic medicine, aimed to provide updated information on medicinal substances, ensuring that practitioners had access to the most current therapeutic options available at the time.​

The supplement delves into the properties, preparation methods, and therapeutic uses of various medicinal agents, including both newly discovered compounds and traditional remedies that had gained renewed interest. For instance, it discusses substances like bichloride of ethylene, highlighting its proposed benefits and limitations as an anesthetic. Such detailed examinations underscore the authors’ commitment to evaluating the efficacy and safety of medical treatments, a practice that was becoming increasingly important in the evolving landscape of healthcare.​

Beyond individual substances, the work emphasizes the importance of understanding the chemical composition and physiological effects of medicinal agents. This approach reflects a broader shift in medical practice towards a more scientific and evidence-based methodology. By meticulously documenting the characteristics and applications of various remedies, King and Lloyd contributed to a more systematic and analytical framework for pharmacology, bridging the gap between traditional herbal knowledge and emerging scientific principles.​

In essence, the “Supplement to the American Dispensatory” stands as a testament to the transitional period in medical history, where traditional practices began to intertwine with scientific inquiry. It not only provided contemporary practitioners with valuable insights into new and existing treatments but also laid the groundwork for future developments in pharmacology and therapeutics. The supplement’s comprehensive and methodical approach continues to offer historical insights into the evolution of medical knowledge and the enduring quest to improve patient care.