Cut any soft solids into small pieces, put the whole into a porcelain basin, add as much hydrochloric acid as equals the probable weight of the dry matter in the mixture, and then water enough to form a thin pulp. Heat the basin over the vapour-bath, adding every five minutes about half a drachm of chlorate of potass, and stirring frequently, until the liquid become clear-yellow, homogeneous, and thin. Add now two drachms more of the chlorate; filter through linen, washing the residuum on the filter with boiling water; concentrate to a pound; add a strong solution of sulphurous acid till its odour predominates, and expel the excess of it by heat. The liquid is now ready for the transmission of hydrosulphuric acid gas, which should be transmitted in a slow stream for twelve hours. Wash away any sulphuret adhering to the tube by means of ammonia, and add the solution to the principal liquid; which is next to be left at a gentle heat about 80° F., in a vessel covered with paper, till the sulphureous smell entirely disappear. The precipitate, which contains organic matter as well as sulphuret, is then to be collected on a paper filter, washed, and dried with the filter over the vapour-bath. The animal matter is next destroyed, and the sulphuret converted into arsenic acid, by dropping on it fuming nitrous acid till the whole is moistened, drying the product thoroughly over the vapour-bath, moistening the residuum with concentrated sulphuric acid, heating the mixture again in the vapour-bath for two or three hours, and raising the heat afterwards gradually in a sand-bath to 300° F., till a charred brittle mass be obtained. This is to be heated over the vapour-bath with twenty parts of distilled water, filtered, and washed with boiling water on the filter till what passes through ceases to redden litmus. The solution, which ought to be colourless, is next acidulated with hydrochloric acid, and treated as formerly with hydrosulphuric acid gas. When the sulphuret has been collected on a small filter, diluted ammonia is to be sent through the filter as long as it dissolves any sulphuret, and is to be received in a weighed porcelain basin, in which the ammonia and water are to be driven off at a temperature not exceeding 212°. The sulphuret which is alone left may now be weighed by again weighing the basin; and one grain of sulphuret is equivalent to 0·803 of a grain of oxide of arsenic.—The authors add an elaborate process for obtaining from this the whole arsenic by reduction. But such a proceeding is unnecessary. It is sufficient in medico-legal inquiries to ascertain by the simpler method given above [p. 204], that it does yield by reduction with soda-flux a true arsenical crust, and that this yields by oxidation white, sparkling crystals with triangular facettes.