(for carbon monoxide in the blood) add to blood twice its volume of a solution of sodium hydroxide of 1.3 specific gravity: normal blood will form a dingy brown mass with a green shade if spread thin on a white surface; but if carbon monoxide is present, the mass is red, and so is the thin layer. (for xanthine) add the substance to be tested to a mixture of chlorinated lime in a porcelain dish; a dark-green ring is formed at first.
