The Physiomedical Dispensatory by William Cook, M.D., 1869
Description: Natural Order, Cucurbitaceae. This is the common watermelon of our gardens, so much cultivated for its large, juicy, and saccharine fruit. It is unnecessary to give any detailed description of it. A variety is called the citron, and its thick rind is sometimes preserved; though this is not the imported and fragrant citron, which is found in shops as a confection and is a variety of the lime-treeCitrus limetta.
Properties and Uses: The seeds of watermelon contain a large quantity of mucilage, and probably some relaxing properties also. These virtues exist mainly in the husk, and may be extracted by hot water without breaking the seed open. This mucilage is pleasant, and not ropy; and acts well upon the stomach, bowels, kidneys, bladder, and urethra in all acute inflammatory conditions of these organs. It is principally used in acute renal difficulties and scalding of urine; and not only protects the passages, but increases the flow of the watery portions of the urine. It may also be used as a drink in acute dysentery. Two drachms of the seeds may be infused for an hour in a quart of hot water, and the infusion drank freely, at intervals of two hours.
Medical Herbalism journal and medherb.com