_g._ Solutions of the alkalies, which dissolve the albumen, leave the coloring matters intact, and consequently do not decolorize the fabric. If the latter is afterwards subjected to the action of hydrochloric acid, the coloring matter is dissolved, forming a solution that leaves upon evaporation to dryness a residue containing iron, which gives a blue coloration with ferrocyanide of potassium, and a red coloration with sulphocyanide of potassium. _h._ The coloring matter of blood dissolves in boiling alcohol, to which sulphuric acid has been added, to a brown dichroic fluid (appearing green by transmitted light, and red by reflected light). A mixture of rust and blood exhibits the same phenomenon. _i._ If substances containing blood are heated in a dry tube, an odor resembling that of burnt horn is emitted. In case the stained fabric is a substance that would produce this odor, (such as wool, silk, or hair), the test naturally loses all value. _j._ If the fluid obtained by treating the stains either with water or alkali is evaporated with a little carbonate of potassa, and the residue heated, at first at 100°, then to redness, in a glass tube to which a fresh quantity of carbonate of potassa has been added, cyanide of potassium is formed. When cold, the tube is cut above the part containing the fused mixture, the mass heated with iron-filings and water, the fluid filtered, and the filtrate then acidulated with hydrochloric acid: ferrocyanide of potassium will be present in the fluid, and upon adding a drop of solution of perchloride of iron a green, or blue, color will be produced, and a precipitate of Prussian blue gradually thrown down. If the stained cloth is non-nitrogenous (_per ex._: hemp, linen, or cotton), instead of treating it with water, it may be heated until pulverulent, mixed with carbonate of potassa, the mixture calcined, and the operation then completed as just described. This test having given affirmative results, the operations should be repeated with an unstained portion of the cloth, to remove all doubt that the indications obtained do not really originate from the fabric.