Dissolve the carbonate of soda in 3 pints of water by the aid of heat; to the remainder of the water add, by small portions at a time, the chloride of lime, previously well triturated, stirring the mixture after each addition; set the mixture by for several hours that the drugs may subside, then decant the clear liquid and mix it with the solution of carbonate of soda. Lastly, decant the clear liquor from the precipitated carbonate of lime, pass it through a linen cloth and keep it in bottles secluded from the light. It is a colorless alkaline solution, having a faint odor of chlorine, and an alkaline taste; it owes its antiseptic properties to containing hypoclorous acid which is readily liberated by the addition of even a weak acid and, on exposure to the air, by the absorption of carbonic acid. One of its principal uses is to purify the air in dissecting rooms and hospitals, in which case it acts by decomposing sulphurated hydrogen, against which gas when inhaled, it is also an antidote. _Nitrate of Lead._—Take of litharge 4½ ounces; dilute nitric acid one pint. Dissolve the litharge to saturation by the aid of a gentle heat; filter, and set the liquor aside to crystallize; concentrate the residual liquid to obtain more crystals. This is a beautiful white salt, of a sweet astringent taste and soluble in 7½ parts of water and in alcohol. It has recently been found useful in the correction of fetid odors, dependent upon the presence of sulphurated hydrogen or hydrosulphate of ammonia, which it decomposes. It will not prevent the putrefaction of animal matter, but it will be found extremely useful, as a disinfectant of putrescent animal fluids. _Ledoyen’s Disinfecting Fluid_.—Which is greatly esteemed abroad, is a solution of this salt in water, in the proportion of two ounces of salt to one pint of water. _Corrosive Sublimate._—By the action of boiling sulphuric acid on mercury, the hipersulphate is first formed. When this is heated with common salt mutual exchange takes place, and bichloride of mercury and sulphate of soda, the former of which sublimes are produced. Corrosive sublimate is in heavy, white crystalline masses, of a styptic and metallic taste, soluble in about 20 parts of cold water, much more so in alcohol. A solution of corrosive sublimate precipitates albumen and forms with it a definite insoluble compound, to which property its use as an antiseptic is due. Corrosive sublimate has the property of retarding putrefaction. Animal matters immersed in its solution shrink, acquire firmness, assume a white color, and become imputrescible. On account of this property it is usefully employed in preserving anatomical preparations. We have seen a head prepared in this manner which had for seven years resisted the attacks of decay and insects, and been subjected to all changes of temperature.