conclusion that if corrosive sublimate had been added to the syrup the vegetable extractive or the molasses with which it was made so concealed it or decomposed it into calomel that it could not be detected. In 1829 Giraudeau was prosecuted for selling secret medicines, and for this offence was fined 600 francs. But the interesting feature of this trial was the testimony of Pelletier, Chevallier, and Orfila that the Rob contained no mercurial. They reported that the formula given by the maker might be the correct one, but that in that case the mixture would contain too small a quantity of active substances to possess the energetic properties claimed for it. Guaiacum and sarsaparilla were the principal ingredients, but there were also lobelia, astragalus root, several other herbs, and a little opium. The history of this discussion is related at some length in Dr. Michelon's "Histoire Pharmacotechnique et Pharmacologique du Mercure" (1908).
Red Precipitate.
Red precipitate was one of the first preparations of mercury known. It is traced to Geber, but when the works attributed to that chemist were written is doubtful. Avicenna in the tenth century was acquainted with it. In his writings he says of the metal mercury that "warmed in a closed vessel it loses its humidity, that is to say its liquid state, and is changed into the nature of fire and becomes vermilion." Being obtained direct from mercury acted on by the air, it became known to the early chemical experimenters as "precipitatus per se." Paracelsus obtained it by acting on mercury with aqua regia and heating the solution until he got the red precipitate. Then he reduced it to the necessary
