The U. S. preparation contains the virtues of a troyounce of the flies in two pints of diluted alcohol. The British tincture is much weaker. This preparation is chiefly employed internally. (See vol. II. p. 644.) it may, however, be used as an external stimulant, either alone, or as an ingredient in compound stimulant lotions. But, as a mere rubefacient, it has nothing to recommend it over other substances, not liable to the objection of occasionally blistering; and, as an epispastic, it is much inferior to other preparations of the flies. Dr. Luton, of Rheims, has used tincture of cantharides by subcutaneous injection, administering twenty drops at once, with the view of curing obstinate neuralgic affections and other persistent local diseases, and with good effect. The only unpleasant symptom produced was a rather severe pain, followed by some swelling, which disappeared after a short time. (Arch. Gén., 6e sér., II. 386.)

Other species of Cantharis, and insects of the genera Mylabris and Meloe, all belonging to one natural family, possess the same vesicating property as Cantharis vesicatoria; and several have been used, or are now used, in different parts of the world, for the same purposes. We have in the United States several fine species of Cantharis, which have been found to equal the European species in virtues. One of these, the Cantharis vittata or potato fly, was recognized in our national Pharmacopoeia of 1850; and G. Nuttalli, which is said to be abundant beyond the Mississippi, is a large and beautiful insect, which may possibly at some future period enter into our officinal catalogue.