5OO THE INSECT WORLD. 



than would be that of other species of the same family which are not 

 gregarious, but which have the same medicinal properties. The 

 presence of the Cantharides is manifested by the strong penetrating 

 odour which they diffuse to some distance. When, by aid of this 

 smell, they are discovered, generally settled on an ash, they are col- 

 lected in the following manner : Very early in the morning a cloth 

 of light tissue is stretched out at the foot of the tree, and the branches 

 are shaken, which causes the insects to fall (PLATE XII.). These, 

 numbed by the cold of the night, do not try to escape. When there 

 is a sufficient quantity, the four corners are drawn up and the whole 

 plunged into a tub of vinegar diluted with water. This immersion 

 causes the death of the insects. They then carry them to a loft, or 

 under a very airy shed. To dry them they spread them out on hurdles 

 covered with linen or paper, and from time to time, to facilitate the 

 operation, they are moved about, either with a stick or with the hand, 

 which is more convenient ; but it is then necessary to take the pre- 

 caution of putting on gloves, for, if touched with the naked hand, 

 they would cause more or less serious blisters. The same precaution 

 must be observed in gathering them. 



When the Cantharides are quite dry, they put them into wooden 

 boxes or vessels of glass or earthenware hermetically sealed, and 

 preserve them in a place protected from damp. With these pre- 

 cautions, they may be kept for a long while without losing any of 

 their caustic properties. Dumeril made blisters of Cantharides which 

 had been twenty-four years in store, and which had lost none of their 

 energy. When dry, they are so light that a kilogramme contains 

 nearly 13,000 insects. Aretius, a physician who flourished at 

 Rome in the first century. of our era, seems to have been the first to 

 employ Cantharides, reduced to powder, as a means of vesication. 

 Hippocrates administered them internally in cases of dropsy, apoplexy, 

 and jaundice. But it is pretty nearly established that the Cantha- 

 rides of the ancients were not the same species used at the present 

 day ; they were, probably, a kindred species, the Mylabris chicorii. 

 A blistering principle has been extracted from these insects, called 

 Cantharadine. This organic product presents itself under the form of 

 little shining flakes, without colour, soluble in ether or oil. One atom 

 of this matter applied to the skin, and particularly to the lower lip, 

 makes the epidermis rise instantaneously, and produces a small 

 blister filled with a watery liquid. In spite of the corrosive principle 

 which the Cantharis contains, it is attacked, like other dried insects^ 

 by the Dermestes and the Anthrenus, which feast on them without 

 suffering the smallest inconvenience. 



