DRUGS AND CHEMICALS.
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Asit is of the utmost importance for the operator to get familiar with the drugs or chemicals he is called upon to handle, the history and properties of each one will be detailed at length in the following chapters:
Acetic Acid.—The acid liquid distilled when charcoal is prepared from wood, in close cylinders without access of air, contains this valuable acid in a very impure state; by subjecting this to further distillation the liquid is collected which is known as wood vinegar, or pyroligneous acid. By saturating this acid with lime, acetate of lime is produced, which by decomposition with sulphate of soda, furnishes sulphate of lime and acetate of soda; the latter salt being crystallized in a state of purity yields, by distillation with sulphuric acid, pure hydrated acetic acid in solution in water.
Acetic acid is also produced by the oxydation of alcoholic liquids, especially cider and wine, and in this impure and diluted form is called vinegar. In chemical works it is generally classed among the derivatives of alcohol.
Camphorated Acetic Acid.—This is largely used as a pungent and refreshing perfume, to remove fetid odors from bodies. Take of
Pulverize the camphor by means of a few drops of alcohol and dissolve it in the acetic acid.
Aromatic Vinegar.—This is another pungent and reviving perfume, formerly deemed a preventive of contagion, and which will be found very useful in removing foul smells from the chamber of death. Take of
Acetone, or Pyroacetic Spirit, and Pyroxilic Spirit, or Wood Naptha.—These are products of the distillation of wood, which are separated from the acid liquors after they are saturated with lime by simple distillation and rectification.
Owing to its cheapness, pyroxilic spirit has been extensively used in England, as a substitute for alcohol in the arts and manufactures.
Uses of Crude Pyroligneous Acid.—This acid having been incidentally described as the source of the acetic acid of commerce, it may be proper in this place to notice its uses. It acts on the principle of an antisepticand a stimulant; the former property being chiefly due to the presence of creasote.
Several cases in which it was successfully employed in the preservation of animal matter are reported by Dr. T. Y. Simmons, of Charleston, S. C. The crude acid has been so advantageously used for the above purpose that Mr. Wm. Ramsey was led to perform with it some very interesting experiments. Some fresh fish, simply dipped in the acid and afterwards dried in the shade, were effectually preserved, and when eaten, at the end of eight months, were found very agreeable to the taste. Fresh beef, dipped in the acid in summer for the space of a minute, was perfectly sweet the following spring.
Carbolic Acid, or Phenylic Acid.—It occurs in castor and the urine of many domestic animals.
Coal tar is distilled, the product between 300° and 400° is saturated with a strong solution of potassa, the oil is removed, the salt decomposed by muriatic acid; the carbolic acid washed with water, dried with chloride of calcium, rectified, cooled to about 12° F., the liquid decanted and the crystals quickly dried. It is in long colorless needles; not very soluble in cold water; more so in hot water; in all proportions in alcohol and ether; also soluble in concentrated acetic acid.
Commercial Creasote.—When obtained from coal tar is always contaminated with phenylic acid (carbolic acid.) Indeed, it is said that phenylic acid has been sold for creasote, which it closely resembles in properties.How far these properties may be similar, deserves to be studied; for if they should prove to be the same, the fact would lead to its substitution as a substance to be easily obtained pure, for the variable creasote.
Of all the properties of creasote, the most remarkable is its power of preserving animal matter; this property has suggested its name, derived from two Greek words which mean flesh preserver. Dr. Christison finds that creasote water is as good a preservative of anatomical preparations as alcohol, with the advantage of not hardening the parts; it is probably to creasote that the antiseptic properties of pyroligneous acid are owing.
Tannic Acid.—Some powder of nut galls is macerated in a bottle, with just enough ether to moisten it, for 24 hours, and then expressed in a powerful press; and the process of maceration and expulsion is repeated in the same way until the powder is exhausted; the liquors are mixed, the ether distilled off, and the residue dried by means of a water bath.
Properties: Pure tannic acid is solid, uncrystallizable, white or slightly yellowish, inodorous; very soluble in water, and much less soluble in alcohol and ether, and insoluble in the fixed and volatile oils.
Tannic acid precipitates solutions of starch, albumen and gluten, and forms with gluten an insoluble compound which is the basis of leather.
Chromic Acid.—To 100 parts, by measure, of cold saturated solution of bichromate of potassa, 150 partsof sulphuric acid are added and allowed to cool; the sulphuric acid unites with the potassa, and the chromic acid crystallized in deep red needles, very soluble and deliquescent.
It is a powerful oxydizing and bleaching agent. Small animals, as mice, etc., after being immersed in the acid were so completely dissolved after 20 minutes, that no traces were left of either their claws, hair, bones or teeth.
Sulphurous Acid.—It is prepared by exposing to heat a mixture of one part concentrated sulphuric acid with one part of mercury, or one-third part of copper filings, washing the gas by passing it through a little water, and condensing it in water which is well cooled. Professor Proctor directs the gas evolved from four ounces of copper turnings, and eight fluid ounces of sulphuric acid, to be condensed into four pints of water.
Sulphurous acid is a gas which dissolves largely in water and has a smell of burning sulphur.
Liquor Chlorinated Soda—Labarraque Disinfecting Solution.—It is prepared as follows:
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 eachaddition; 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.
Hyposulphite of Soda.—This salt may be economically prepared by the following process: 16 ounces finely powdered carbonate of soda are mixed with 5 ounces flowers of sulphur, and heated in a porcelain dish with constant agitation until it takes fire andburns to sulphite of soda; this is dissolved in water and boiled with sulphur and thus forms hyposulphite acid; it is then evaporated to crystallization.
It is easily soluble in water; the solution gradually deposits sulphur; 1 to 4 ounces dissolved in the necessary quantity of water, and with the subsequent addition of 3 fluid ounces of sulphuric acid for each ounce of the salt, will liberate the hyposulphurous acid, which immediately decomposes into sulphur and sulphurous acid.
Solution of Chloride of Zinc.—Made in the proportion of 1 ounce of chloride of zinc dissolved in 1 pint of water. It is a powerful deodorizing and disinfecting agent in neutralizing noxious effluvia and in arresting animal and vegetable decomposition.
The concurrent testimony of a number of observers shows that it acts as an excellent disinfectant for hospitals, dissecting rooms, etc. When injected into the blood vessels, it preserves bodies for dissection without injuring their texture. The advantage is claimed for it, that while it destroys putrid odors, it has no smell of its own.
Alumina.—Dissolve alum in six times its weight of boiling water, add solution of carbonate of soda in slight excess, agitate for a few minutes, filter, and wash the precipitate with distilled water; the product is hydrate of alumina.
Acetate of Alumina.—A solution of this salt is obtained by saturating acetic acid with hydrated alumina and cannot be evaporated without the loss ofacetic acid. It has a faint smell of acetic acid and a sweetish taste, and possesses strong antiseptic properties.
Sulphate of Alumina.—Saturate diluted sulphuric acid with hydrated alumina, evaporate and crystallize; it is in thin, flexible plates, of a pearly lustre, sweet and astringent taste; soluble in twice its weight of cold water, but not in alcohol. Its chief use is as an antiseptic; a solution of 1 pound to a quart of water is used to preserve dead bodies; as a lotion it may be used in a somewhat less concentrated form.
The salts of alumina have been ascertained by Mr. Gannal to be powerful preservatives of animal matter. Among these the sulphate is to be preferred on account of its easy preparation and moderate price. Its aqueous solution was found by Mr. Gannal to be very effectual in preserving bodies, when injected into the blood vessels; in the summer season bodies were preserved for thirty days or more; in the winter forthreemonths.
For use in the winter, a quantity of the solution sufficient for injecting one body, may be made by adding a pound, avoirdupois, of the salt to a quart of water; for use in warm weather, the solution must be saturated.