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168 fluid, of a sweetish taste when first applied to the tongue, but speedily producing a sharp burning sensation. Its chemical properties have not been properly examined; but according to Fontana, it is soluble in water, and when alcohol is added to the solution, it is precipitated in the form of a white powder, which converts vegetable blue into red. Its action is so powerful, that the writer just named calculates that a grain in weight would kill a pigeon in a few seconds. Allied to the preceding, are the acid secretions of ants and a few other insects, which, however, have not been traced to any special secreting organ, but seem to be diffused throughout the system. Vaquelin and Fourcroy conceived the former to be composed of acetic and malic acid, but Suensen has recently demonstrated that the earlier chemists were correct in regarding it as of a peculiar nature, and that the name Formic acid ought therefore to be retained. Berzelius gives the following analysis of it; hydrogen, 2, 84; carbon, 32, 40; oxygen, 67, 76. It is sometimes ejected by the anus; and Lacordaire affirms, that in tropical countries ants are to be met with (Gen. Ponera) armed with stings, which inflict as painful a wound as those of bees. Gallic acid has been obtained from the grain weevil, (Calandra granaria) and what has been named bombic acid from the silk-worm. It is probably one of these that is employed by certain Lepidoptera to loosen the end of their cocoons, when they wish to obtain egress. In the absence of special secreting vessels, the