As it 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
Camphor, half ounce,
Acetic Acid, 6½ fluid ounces.
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
Camphor, 2 ounces,
Alcohol, sufficient quantity to pulverize the Camphor,
Oil of Cloves, 1 fluid ounce,
Acetic Acid, very strong, 12 fluid ounces.
_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 antiseptic and 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 parts of 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:
Chloride of Lime, 1 pound,
Carbonate of Soda, 2 pounds,
Water, 1½ gallons.
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.
_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 and burns
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 of acetic 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 for _three_ months.
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.