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Materia Medicet.

Part II.

Lytta vesicatoeia. Lond.

Meloe vesicatorius. Ed. Dub.

Insecta Cleoptera, Vesicantia. Syst. Nat. Gmelin, g. 2013,

Spanish fly. Blistering fly.

Off. —The insect.Lytta. Lond.Meloe vesicatorius. Ed.Cantharis. Dub.

These insects have a longish, green, and gold-shining bo-dy, with flexible green-striped ely tera, which cover the wholeback of the body, and conceal brown membranous wings.On their head they have two black articulated feelers. Theyare found on the fraxinus, sambucus, salix, ligustrum, &c. inSpain, Italy, France, and Germany. The largest come fromItaly, but the Spanish cantharides are preferred. They aregathered by shaking the trees on which they are, and catch-ing them on a cloth spread beneath it. They are then killedby the fumes of vinegar, and dried carefully in a stove. Themelolontha vitis is sometimes found mixed in considerablenumbers with the cantharides. They are easily distinguishedby their almost square body; and as they do not stimulatethe skin, they should be picked out before the cantharidesare powdered. In the East Indies the Meloe trianthema isused as a substitute.

The analysis of cantharides is still imperfect. Neumanngot from 1920 grains, 920 watery, and afterwards 28 alcoho-lic extract; and inversely, 400 alcoholic, and 192 watery.Lewis ascertained that their active constituent is entirely so-luble, both in water and in alcohol; for extracts made witheach of these solvents blistered, as far as could be judged,equally, and as effectually as cantharides in substance. Boththe residua were inactive. Thouvenel considered the vesi-cating power to reside in a green matter of an oily nature.Beaupoil in two substances, one yellow and the other black,both soluble in water, but separable by alcohol. Lastly, Ro-biquet, in a very detailed analysis, says, that neither of thesethree principles blisters of itself; but that this property isowing to their combination with a particular white crystallinesubstance, soluble in warm alcohol, separating as it cools, so-luble in*oils, and insoluble in water. He also found, besidesknown principles, free acetic acid, phosphate of magnesia, areddish-yellow oil insoluble in alcohol, and, lastly, uric acid.

Medical use. —Cantharides have a peculiar nauseous smell,and an extremely acrid burning ta=te. Taken internally,they often occasion a discharge of blood by urine, with ex-quisite pain. If the dose be considerable, they seem to in