well enough for the space of two or three months, but putrid
decomposition attacks the thoracic and abdominal viscera, as well as
the brain and thick muscles, at the end of this time.
5. A subject injected with alcoholic sublimate, then opened, emptied,
and macerated, afterwards exposed to the air, dries easily;[7] but
it assumes a deep gray colour, and the tissues become hardened to
such a degree, that it hardly preserves a human form. These are the
rigorous results of experience. In the preservation by the aid of
deuto-chloride, one portion of the subject is sacrificed to preserve a
few remains; the most noble of all the organs, the brain, the throne
of thought, cedes its importance to a few bones clothed with dried
muscles, and a skin transformed, and not easily known again.
[7] The deuto-chloride of mercury, like the salts of copper, arsenic,
iron, &c., are decomposed by gelatine, forming a new imputrescible
compound. The preservation is much more sure if a large quantity of
alcohol is used in drying the corpse.
These are but feeble advantages, and paid for much too dearly; for the
inconveniences and dangers of this mode of preparation, appears to us
sufficient to cause them to be abandoned.
It is very expensive, dangerous for the operators; it alters the
instruments, and the bodies which receive the influence of its
emanations. Recently, during the embalming of some great personage, all
the gildings of a vast saloon, where the operation was performed, were
destroyed by the action of the deuto-chloride.
Nevertheless, the embalmings made with this substance, and of which the
three first observations cited in this chapter are the most remarkable
examples in our knowledge, afford the most decided expressions of the
advanced state of the art.
What are the ameliorations resulting from our discoveries? They are as
follows: 1. A substance easy to manage without danger to the operator,
without any inconvenience to the instruments and other metals, is
substituted for the sublimate; 2. The operation can be entirely
finished in half an hour; 3. The numerous incisions, the mutilations,
the subtraction of the viscera, &c., the prolonged maceration, are
replaced by an injection through an opening of some lines in extent;
4. In place of a substance discoloured, leathery, and dried, reserving
more or less the human form, my process preserves the subject, such as
it is, at the moment of death, with the colour and suppleness proper
to each tissue;[K] 5. Finally, the expense which, by the preceding
method, amounts to from four hundred to two thousand dollars, need not
now exceed sixty dollars. Thus a body may be indefinitely preserved
for a sum less than the price of a leaden coffin furnished by the
undertakers, _a coffin which accelerates the putrid decomposition, in
place of preventing it_.
[K] When we visited and gave an accurate examination of the numerous
embalmed objects in M. Gannal’s museum, we did not observe any
specimens that had been finished long enough to dry, displaying such
perfection as that here stated.--_Tr._
I confine myself here to the announcing of some results obtained by my
predecessors; for previous to entering into details of the experiments
which I have tried, it remains for me to trace the picture of the means
employed down to our period for the preparation and preservation of
pieces of normal anatomy, pathological anatomy and natural history.
This will form the subject of chapter VII.
When I shall have made known the whole of the resources of this other
branch for the preservation of animal matters, each one can form an
accurate opinion, after a complete knowledge of the facts, of the part
which belongs to my labours, and of the place which they ought to
occupy in the scale of natural sciences.
CHAPTER VII.
METHODS OF PREPARING AND PRESERVING SUBJECTS OF ANATOMY, PATHOLOGY, AND
NATURAL HISTORY, PREVIOUS TO THE PROCESS OF GANNAL.
Among the investigations belonging to the domain of medicine, normal
anatomy and pathological anatomy occupy the first rank; they constitute
the necessary basis of exact study: all men of genius have experienced
this.
This conviction has been the source of the persevering efforts of
numerous distinguished savans, who reasonably supposed that they
would merit the esteem and gratitude of their species, if they could
succeed in composing collections of engravings, or artificial models,
representing the form, colour, &c., of each of the organs, or if they
could discover methods of preparation capable of preserving the organs
themselves with all the physical properties which they possessed at the
moment of death.
It is not necessary to enter into discussions upon the high importance
of these different kinds of investigations; for every one comprehends
it, and the gravest authorities have pronounced upon this matter.
Who does not know the vast importance which our illustrious Cuvier
attributed in the progress of the natural sciences, to him who first
conceived the idea of preserving objects in alcohol? It is perceptible,
indeed, at the first glance, that the most beautiful and valuable of
libraries for the physician and naturalist would be a collection of
artificial subjects; or still better, of all the organs of the bodies
of animals, and of man, skilfully prepared and preserved, without any
alteration of the properties which it is important to know.
It must be admitted that a collection in which all the organs would
be disposed in series, where they would be seen passing by their
successive degrees of increment and decrement, offering their
differences, individual and sexual, their points of contact and
separation in the various classes of the animal kingdom, their
anomalies, their pathological affections, their intimate structure,
&c., it must be admitted I say, that such a collection would be an
inexhaustible source of knowledge; it would acquire additional value by
the addition of a series of pieces representing the detailed anatomy of
each of the parts involved in surgical operations.
But this library, so eloquent and instructive, does it exist at the
present time? Do we possess the means of forming such? The examination
of the various processes, ought to furnish us with an answer to this
question; it will besides enable our readers to estimate for themselves
the part that our method may enjoy in the accomplishment of this object.
And first, in admitting the utility of _engravings_ of _models in
wax_, and in _artificial carton_,[L] in _white wood_, or in other
compositions kept secret by their authors, we feel that whatever may
be the accuracy of these different representations, they never can
afford but an incomplete idea of the thing represented. 1st. _Plates
and engravings_, so advantageous for reference, to recall the study
made upon the corpse, have lost their importance in proportion as
the means of obtaining dead bodies have become more easy: they are
calculated to render great service and contribute to the progress of
science in the fine anatomical works of Meckel, Lauth, Haller, Zinn,
Hunter, Cruikshank, Cowper, Vic-d, Azyr, and of numerous other learned
authors; at the present day, even, they are justly esteemed in the
great works of MM. Cloquet, Bourgerie, &c. (The plates of the work of
M. Bourgerie, are executed with remarkable care, and will form an epoch
in the history of anatomical works.) But they occupy a secondary place,
only to aid the memory; for of whatever good they may be, they must
always have many inconveniences: 1. They fatigue attention, because it
is necessary so often to multiply the figures, when it is requisite to
examine an object under all its aspects where it is of importance to
perceive it; 2. The organs are rarely seen of their natural dimensions;
3. Whatever may be the exactitude of the drawing, it is difficult to
form a just idea of the relief and dimension of the organs; 4. The
relations which they indicate are always incomplete; it is impossible
thus to represent all the organs in their position, and in their
natural relations.
[L] A composition of papier maché, with which Dr. Azoux has so
beautifully represented anatomical subjects.--_Tr._
2d. _Models in wax_, nearer to nature than plates, reproduces objects
with admirable truth for the eye, but for the eye only. They were
recently estimated of such importance, that courses on modelling were
introduced into the schools in many cities of France; nevertheless, it
cannot be concealed that pieces thus prepared leave much to be desired:
1. The relations of the organs which they indicate are very limited: 2.
It is necessary then to multiply them to infinity, if it be desirable
to represent under various points of view, the different points of
the human body, which is indispensable, in order to comprehend their
relations and connections: 3. And still the mind comprehends with
difficulty the totality of objects viewed in a great number of pieces:
4. They cannot be handled and displaced as is requisite for study,
without injury to them.
3d. _Artificial pieces_, which possess many of the inconveniences of
wax models, are more proper to give a knowledge of the parts, which
enter into the structure of man; nevertheless, if they be white wood,
like the subjects of Fontana, or in Carton, like those of Ameline, or
of M. Azoux,[8] they leave much to be learned of the properties which
are requisite to an accurate and complete knowledge of the parts.
Finally, these three means of communicating knowledge possess their
degree of utility, but they can never support a comparison with the
proper matter of the organs; they may serve to complete a museum, but
never to form one; so we content ourselves to mention them here, in
order to assign them a rank.
[8] The subjects prepared by M. Azoux, are however, more proper to
facilitate and extend the study of anatomy; they are far superior to
dried objects. It is desirable that every amphitheatre should possess
one of these subjects.
Anatomical pieces which place before the eyes the organs, themselves,
are then the elements, “par excellence,” for the formation of
collections, which are to serve as studies of normal anatomy, of
pathological anatomy, and of natural history, but, the preparation
and preservation of these pieces is a new science; we ought not
to be astonished at it, notwithstanding the advanced state of our
anatomical knowledge, if we reflect on the difficulties of all kinds,
which prejudice excited in our predecessors. It is stated, it is
true, that Ruysch, had discovered the means of preserving the dead
body, with _all the appearance of life, without drying, with florid
complexion, and supple limbs_. But, is this really the fact? and have
we not good reasons to doubt such assertions, since no collection of
anatomical pieces, prepared by this process, has descended to us, and
no explanation has confirmed our knowledge of them?
We may then conclude, that the means of preparing and preserving, does
not date much earlier than the commencement of the present century.
None of them, however, has had for object the preservation of the
entire subject: that which offers us the most numerous parts united
in the same preparation has only a reference to anatomy, properly so
called; it is the process of M. Swan, of England, given by him as a new
method of making dried anatomical preparations, preserving to them the
appearance and the advantages of fresh preparations, without possessing
the inconveniences of them; this process is, as we shall see, only
an application of the discovery of Chaussier, on the preservative
properties of the deuto-chloride of mercury. We give it here, before
passing in review the methods of preparation practised for each organ
or each tissue.
“In order to describe the manner of making these preparations, I shall
only take the arm by way of example.
“The member should be selected as clear from fat as possible. A
solution of two ounces of oxymuriate of mercury, in half a pint of
rectified spirits of wine, must be injected into the arteries, and the
day after make another injection with the same quantity of white spirit
varnish, to which must be added one-fifth part of turpentine varnish,
and a small quantity of vermillion. The limb should next be placed
in hot water, and remain there until it is sufficiently heated for a
coarse injection into the arteries, and even the veins if necessary. If
the veins are to be injected they had better be emptied of blood, with
water, before forcing into the arteries the solution of oxymuriate of
mercury, because there returns always by the veins some portion of this
injection which coagulate the contained blood, and hinders the coarse
injection from passing into the smaller branches.
“After the limb has been injected it may be dissected. Every time
the work is left, it is better that the parts uncovered, should be
enveloped in a linen cloth wet with water; and when the dissection is
recommenced a great advantage will be remarked, which is that the parts
injected with the solution of the sublimate will suffer very little
alteration in several days, and are found in the same state in which
they were left, whilst, by the common method, in one or two days, all
is so changed that there is little profit in seeing what has been
done, and if the dissection is long, they will scarcely be recognised
when finished.
“Another advantage is that it may be dissected any where, since the
preparation is without odour.
“When all the parts are uncovered, and all the fat and cellular
tissue has been removed, the member thus prepared must be put into
a solution of two ounces of oxymuriate of mercury, to one pint of
rectified spirits of wine, and let remain entirely covered with this
for at least fifteen days, for it cannot remain too long. A box of
oak, painted white and varnished is the best recipient for the limb,
whilst in solution; the cover must fit closely, in order to prevent the
evaporation of the spirits of wine.
“The member must be withdrawn every two or three days, and any
remaining cellular tissue is to be removed, and when returned to
the tub the part which previously touched the bottom must be placed
uppermost. The best thing upon which to place the preparation, when
withdrawn from the solution, is a butcher’s tray, after having been
well oiled; without this precaution the tray imbibes moisture, from
which results a great loss of the solution. When the limb has remained
long enough in the solution, it is to be taken out, to be painted and
varnished.
“Before proceeding to these operations, the member kept in a state of
extension, is suspended and dried, then endued with white varnish. On
the same day the nerves, the tendons, and tendinous expansions, ought
also to be varnished; which must be repeated once a day, for three
consecutive days. The fifth day, the tendons, ought to be covered with
a layer of yellow varnish, and white paint mixed in equal parts; this
operation is to be repeated the seventh, eighth, and ninth day. The
nerves, must also be endued, as often as necessary, with a mixture of
equal parts of white paint, and white varnish.
“As soon as the muscles have become stiff, they may be painted, taking
care that the nerves and tendons, are not touched by the paint. Nearly
a month after the limb has been withdrawn from the solution, those
of the nerves and tendons that are not sufficiently coloured should
be repainted and varnished, as often as may be judged necessary. But
always allowing a day’s interval between each application of paint and
varnish.
“These operations being finished, wash lightly the tendons and nerves
with boiled flax seed oil; this layer being dry, give a second over the
whole limb; finally, several layers of copal varnish will terminate
the operation. The first layer of copal varnish to be applied to the
arteries with a slight addition of vermillion, and of Prussian blue,
for the veins.
“In order to preserve the liver, it is necessary first to inject the
vena porta and excretory ducts with white varnish, to which has been
joined one-fifth of turpentine varnish, and some coloring matter, such
as red lead. Then make the coarse injection, after which the liver
is to be put into the solution for a least fifteen days; it is not
necessary to heat it before injecting. The ligaments are to be prepared
in the same manner as the tendons.
“We give below the paints, and varnishes, employed in the preceding
preparations:
1.--_White Varnish._
℞. Canada balsam, spirits of turpentine, _a.a._ 3 ℥.
Mastic Varnish. 2 ℥.
Put the whole in a bottle, and agitate until it is perfectly mixed.
2.--_Mastic Varnish._
℞. Powdered mastic. 4 ℥.
Dissolve in a pint of spirits of turpentine.
Agitate daily, until the mastic is dissolved.
3.--_Yellow Varnish._
Infuse one ounce of gum-gutta in powder in eight ounces of spirits of
turpentine for fifteen days; then, with equal parts of this clear drawn
liquor, Canada balsam, and mastic varnish, form the yellow varnish.
4.--_White Paint._
Three ounces of white lead, and an ounce of spirits of turpentine
serves to form it.
5.--_Paint for the muscles._
It is made of Lac, Prussian blue, and white varnish, to which is added
one quart of turpentine varnish.
6.--_Red Injection._
℞. Wax, 4 ℥.
Copal varnish, 1/2 ℥.
Red lead, 1/2 ℥.
Vermillion, 1 ʒ.
Melt together.
7.--_Green injection._
℞. Wax, 4 ℥.
Blue dross, 1/2 ℥.
Copal varnish, 1/2 ℥.
8.--_Blue injection._
To form this it is only necessary to add to the green injection, half a
drachm of powdered Prussian blue.”
The advantages of such preparations do not answer, in any degree, to
the promises of the title; the artificial preparations of M. Azoux are
much more preferable, since his cartons represent the form which the
anatomical pieces of Swan have lost by desiccation.
SECTION 1.--_Generalities of the operations which precede preservation._
Desiccation and immersion in liquids are the only means of preservation.
The choice of subjects which are to serve for these preparations,
says M. le Docteur Patissier, is not a matter of indifference.
Young subjects, and lean women, are preferable for the nerves and
bloodvessels; adults, and thin and dry old men, for the preparation of
bones which it is intended to articulate, and which it is desirable
to obtain in their greatest degree of development; individuals of an
athletic constitution for muscular preparations.
The most favourable time for the preparation and preservation of
anatomical subjects, is generally during a cold and dry winter, or
the ardent heat of summer; the more rapid is the evaporation of the
humidity of animal matters, the more sure is their preservation.
The method of preservation ought to be preceded by some other
operations, such as _dissection_, _maceration_, _injection_,
_ablution_, _corrosions_, _ligature of vessels_, _separation and
distention of parts_.
_a._ _Dissection._--It consists in stripping the part which it is
intended to preserve, of the tissues and organs which are foreign to
it: if the object be the preparation of muscles, for example, these
organs are left alone with their insertions in the bones, or rather,
the vessels, previously injected, preserve their relations with the
muscles and the bones. Nevertheless, in the dissection of the hard
parts, whether it is proposed to follow the branches of the vessels
and nerves which penetrate, or are distributed in their substance, or
whether it is desired to develop and render their organization more
apparent; it is less convenient to have recourse to instruments than
to chemical re-agents, which bring into view the parts which it is
desirable to study. When the object is the preparation of a bone only,
the operation consists of two parts, _excarnation_, and _etiolation_,
the details of which will be presented in the article upon bony tissues.
_b._ _Macerations and corrosions._--These operations are frequently
brought into use by the naturalist: water, acids, alkalies, volatile
oils, &c., serve to produce varied effects in the preparation of the
different tissues. The maceration of different portions of the skeleton
is produced by water. The employment of other liquids has for object,
in attacking several parts which they dissolve, to expose others which
it is desirable should be left bare.
Thus, in order to absorb the grease which exudes from the skeletons
of certain fish, or of bones, the maceration of which has not been
perfected, it is useful to steep the piece in a marly alluminous paste,
which must be alternatively put to dry and soften in the sun, in order
that the clay may absorb the fetid oils with which the bones are
impregnated.
In order to dissolve the grease with which certain parts are covered
some time after their preparation, as happens to some natural
skeletons, it is often necessary to steep the piece in an alkaline
liquor, or rather, to allow it to macerate for some weeks in a very
penetrating volatile oil. It is only by the aid of such processes
that we are able to follow encephalic nerves in many of the cetacea,
although these parts present in these animals extremely singular
dispositions.
It is with the same view that should be macerated either in water
elevated to a certain degree of temperature, or in acid liquors,
the hard tissues, in the interior of which it is proposed to denude
certain parts. Thus the nerves and vessels of the roots of the nails,
the horns, the skin, cannot be well exposed but by this process. The
canals, which traverse certain bones, cannot, as we have already shown,
be easily followed, unless the piece has remained for a longer or
shorter time in an acid liquor.
Macerations in alkaline and etherial liquors are still of great
assistance, as the researches so happily conceived and executed by
Bichat have proved.
Finally, corrosions are indispensable to the removal of the parenchyma
from injected preparations, when it is intended only to preserve the
interior network of vessels.
The following are the attentions which this operation exacts: The
injected part is consigned to a vessel of pure water for two or three
days, which is occasionally to be renewed, in order the better to
disgorge the vessels of any blood they may contain. It is afterwards to
be solidly fixed on a piece of wax at the bottom of a porcelain vase,
pierced with holes near the base, through which the liquor used to wash
them may flow off without deranging the vessels. This corrosive liquor
is the muriatic acid, or spirit of salt; the aquafortis of engravers,
or nitric acid, may be used for the same purpose.
The first time, the preparation is to remain two or three hours in
this acid, which is then drawn off and replaced by the same quantity
of water, which is allowed to flow on it in small streams. This water
is left for four or five days, according to the season, until the
water begins to be covered with a scum, and the preparation begins to
be cottony at its surface; the liquor is poured off a second time,
and the pot or vase is placed beneath the cock of a fountain, from
which escapes a delicate stream of water, which will carry off slowly
and without shocks, any detached parts; when it is perceived that the
washing carries off no more animal matter, the acid is poured into the
pot, of which the opening is to be reclosed with a stopper of glass
or porcelain, warmed and endued with wax. This operation is to be
repeated every four or eight days, until the tunics of the vessels are
altogether denuded, and the injected matter is seen throughout.[9]
[9] These details on maceration and corrosion, are extracted from a
work full of interest of Professor Dumèril: Essay on the means of
perfecting and extending the anatomical art.--(_Paris_, 1803.)
_c._ _Injections._--These are _evacuative_, _repletive_, _antiseptic_,
or _preservative_. The first have for object, as their name indicates,
to disembarrass the vessels or hollow organs, of the matters and fluids
which they contain; they consist of water, of acids very much reduced,
of diluted alcohol, &c. Thus it is serviceable to inject water or
alcohol into the bloodvessels to prepare them for the reception of the
repletive and preserving injections. The second are either definite or
temporary.
The substances employed in these injections are vehicles for colouring
matter. The nature of the vehicles determines that of the colours,
which ought to be as far as possible, analogous to those of the humors,
which the vessels contained during life.
As vehicles, those fluids which always retain their fluidity are rarely
employed, for parts thus injected cannot be dissected, and they are,
besides, apt to allow the colouring matters which they contain in
suspension, to be deposited.
Liquids saturated with glue or gelatine, made use of in ordinary
injections, have the inconvenience of not being equally solidifiable
at different degrees of temperature, or harden too rapidly by cooling;
they are made with the glue of commerce, either simple, or mixed with
gummy or saccharine matter; that commonly used, is called Flanders
glue, although it is manufactured in Paris, and that called mouth
glue, which only differs from the other in containing a little gum
or sugar. That which succeeds best, because it melts with the heat
of the hand, and which nevertheless coagulates at a temperature of
twenty-five or twenty-six degrees of Reaumer’s thermometer, which is
one of the highest points to which our atmosphere attains, is made of
the membranes of fishes, or icthyocolla. An ounce is to be melted in
a sand-bath, in double its weight of water, and mixed afterwards with
two ounces of alcohol, previously warmed. In these sorts of gelatinous
injections, there is much choice in the colouring matters. All those
that are ground like gum, and which are used in miniature painting, and
in painting “a la gouache,”[M] may be employed; they remain very well
suspended.
[M] Paintings where colours are employed diluted with water or
gum.--_Tr._
The sticks of carmine of Delafosse, and the carmine lacks of Hubert,
may then be used with advantage for the arteries; for the veins,
Prussian blue, ground in vinegar, and the white of zinc of Antheaume,
or that of oyster shells well porphyrized, for the colour of metallic
oxide is subject to change in animal matter; they are also subject to
the inconvenience of becoming precipitated by repose before the vehicle
cools, and thus obstruct the smaller vessels.
Liquors which can be made solid by the effect of certain re-actives,
offer, on this account, some advantage. It is thus, that it is
serviceable to soak for a day or two in a solution of nut-galls or
of tannin, those parts injected with gelatine, when it is intended to
preserve them dry. In partial injections of lymphatic vessels, and
particularly of the chyliferous, cow’s or goat’s milk, may be made use
of. When, after having tied the thoracic duct, injections of milk have
been made into all the vessels in which can be introduced the beak of a
glass syringe, or of the syringe used for injecting the lacrymal ducts,
pour on the surface of the injected parts strong vinegar, or a diluted
acid, which will coagulate the milk, so that the chyliferous vessels
will be found filled with a solid, white, and flexible.[10]
[10] There are some specimens in the museum of Natural History prepared
by this process.
The most common, the most solid, and the most convenient injections,
are made of fatty and resinous matter. Volatile oils, balsams, resins
dissolved in alcohol, fats, wax, and the most ordinary fixed oils,
are principally used. These different substances are combined, and
the compositions of them are varied according to the nature of the
injections, which it is desirable to prepare, and above all, according
to the manner which it is proposed to preserve them.
The nature and the preparation of the colouring matters, ought also to
vary according to the kind of fatty medium which is used.
The volatile oils being nearly equally penetrating, turpentine is
generally chosen, because it is cheaper. Nevertheless, for small
objects, the citron, or that of a species of lavender (aspie of the
shops) is preferred, on account of their odour, which are besides
not very expensive. When it is intended to inject only with one of
these oils, which makes a liquid matter extremely penetrating, after
having dissolved a colouring matter previously ground in a fixed oil,
the mixture is slightly heated. This liquor is generally employed to
render perceptible the small vessels of membranes, which are not to be
dissected, but well preserved in their integrity. If it is intended
to inject the large trunk which supplies these membranes towards the
end of the operation, it is necessary to inject a little essence of
varnish, charged with much resin, and before drying the piece, let
it soak a day or two in an aqueous solution of the deuto-chloride of
mercury, according to the process of Chaussier.
The matters with which the volatile oils are to be coloured, should be
previously ground with the greatest care. It is easy to procure those
which are prepared with nut oil, and which are sold in little bladders
to be employed upon palettes.
Colours, thus prepared and intimately amalgamated with fixed oils,
remain much better suspended; the heaviest oxides, even those of lead
and mercury, are not then subject to become deposited.
Resins, dissolved in spirits of wine, are also sold by the pint, all
prepared, under the name of varnish, and in general are not costly.
Those which the anatomist can turn from the ordinary arts to his own
profits, are employed principally in pieces which it is intended to
preserve dry. Perfect success attends the varnish, named in the shops
_fat_, _wood-red_, _à la copale_, and with some others which remain a
long time flexible.
These fluids are difficult to colour; it is necessary, for the first,
to grind the colouring matter with essence, and for the others with
alcohol; and to incorporate them afterwards with varnish after having
slightly heated them. The carmined lakes, thus suspended in fat
varnish, produce absolutely the effect of arterial blood; this colour
preserves very well, and with such like injections it is unnecessary to
colour the surface of the arteries.
The mixture of mutton fat or of suet, of white or yellow wax, of the
fixed oils of olives, nuts, or flax seed, are the ordinary matters
of injections, even for those destined for corrosions. The different
degrees of solidity or softness are determined by the calculated
proportions of wax and oil, and by the amalgam of resinous and
colouring matters.
In general, in this sort of injections it is advantageous to introduce
beforehand, a small quantity of volatile oil mixed with the fatty
matter which is to serve for filling the vessels; by this preliminary
process a liquid more fluid, more penetrating, higher coloured, and
susceptible of cooling more slowly, is driven before into the smaller
ramifications.
I could here transcribe several receipts proper to indicate the
proportion of fatty matters among themselves; but the season during
which the pieces are made, the nature of the ingredients employed
on them, will occasion the proportional quantities to vary, so that
a sketch only can be given for obtaining a matter which may be made
more solid or more fluid after having tried it by cooling some drops
separately. Nevertheless, here is one of those receipts:
℞. Of suet, 5 parts.
Burgundy pitch, 2 "
Oil of olives, or of nuts, 2 "
Of fluid turpentine and colouring
matter, dissolved in volatile oil, 1 "
This latter part should not be mixed until the liquor is well melted
and ready to be put into the syringe, as the heat will volatilize the
volatile oils, which will become disengaged in the form of gas, and
cause the mass to occupy a very great volume.
As a matter of injection, the dissolved gum elastic or caoutchouc
may be employed; it becomes gelatinized in losing a portion of its
menstruum by desiccation. After leaving this matter in a moist place,
and having well washed it, in order to clean it of the clayey matter
which generally impregnates it, it may be dissolved in volatile oils
by heating it in a sand bath, with a moderate fire in a matrass with a
long neck; adding by degrees, a sufficient quantity of oil to render
the mass very fluid, incorporating with it the colouring matters which
have been previously ground in an essential oil. The gum elastic may
also be dissolved in ether, but this process is too expensive; and as
a matter for injecting this liquor is not preferable to the other. The
elastic injections are only advantageous in the preparation of parts
which are not to be exposed to cutting instruments, and to which it
is desirable to preserve a certain degree of suppleness, as in the
injection of the cotyledons, or the placenta of women. This liquor, it
must be confessed, has the great inconvenience of retaining its odour
a long time, assuming its solid form with difficulty, and of rendering
the preparations pitchy, and rebellious to varnish, and becoming loaded
with dust.
There are certain organs which may be injected with solid matters,
in order to obtain, in relief, resisting, but coarse, the forms
of interior cavities. Such is the injection with the matter which
forms the stucco paste, or of fine plaster diluted with gelatinous
water, which gives to this salt a greater solidity when it takes its
consistency. This gross matter is employed with advantage to render
more solid the membranes of certain cavities, in the thickness of which
it is desired to search for the nerves. Pure wax does not present
the same advantage, because it exacts more heat, and contracts more
by cooling, although it is more applicable in case it is proposed to
corrode with acids all the fleshy or osseous parts, in order to become
acquainted with the real form of their interior capacity: in fine,
the fusible metallic mixture of Darcet is employed under different
circumstances, but it is not more useful.[11]
[11] M. Dumèril, work cited.
Preservative injections, which may also be applied to vessels and to
hollow organs, are composed of materials to which have been attributed
preservative properties to the tissues: such are the solutions of
mercurial salts, arsenical, ferruginous, &c., and different aromatic
and spirituous liquors.
_d._ _Ablutions_.--These vary according to the end proposed: acids;
these serve to give whiteness to some tissues and resistance to
others: alkaline; these clean the preparations, divesting them of
the mucilage and grease which they contain. In one word, the action
of aqueous liquids, of oily, alkaline, saline, acid, alcoholic,
is necessary before, as well as after dissection to preserve the
preparations.
When these preparations are left a longer or shorter time in water,
they are subjected to what is called a _degorgement_; the bath ought to
be renewed until it will no longer receive any colouring matter.
The removal of _grease_ is included under dissection, maceration, and
ablution.
_e._ _Ligature of the vessels._--This is made with a flat silk, or silk
very slightly twisted, during the dissection, or immediately after,
on the extremity of the vessel which contains the injection; it is
necessary in order to prevent the escape of the injected matter.
_f._ _Separation and distention of parts._--These offer the whole
surface of the prepared pieces to those agents of preservation which
ought to be applied to them; they sustain them, and preserve them from
being deformed. Besides, it is well known, that the means of separation
and distension ought to vary according to the form of the organs;
atmospheric air suffices for hollow and thin organs, the stomach, the
intestines, the bladder, &c. Under other circumstances, wool, hair
cotton, plaster, &c., serve better.
SECT. 2.--_Means of Preservation._
The means of preservation may be arranged under two principal heads,
as we have said, according as the anatomist intends to expose his
preparations to the open air, or to preserve them from insects and
render them more transparent by the aid of certain liquors, in which it
is intended to keep them continually.
_Preservation by desiccation._--When applied to soft parts is only
applicable to anatomy, properly so called, and to natural history; it
cannot be employed for specimens of pathological anatomy.
Desiccation is preceded by a more or less prolonged immersion,
according to the thickness of the organs in acid or saline solutions,
&c.; that which presents the greatest advantage for the nerves,
according to Dumèril, is diluted nitric acid. The salts commonly
employed present some inconveniences. Corrosive sublimate hardens
too much, and causes the parts to contract on each other; the triple
sulphate of alumine, (alum,) often chrystalizes in drying, which
produces in the interior of the piece, which ought to be pellucid,
saline vegetations, which not only elevate the organic lamina, often
rendering the surface tuberculous, but further deprive the part of the
transparency necessary to see the texture of it; the muriate of soda,
(white kitchen salt,) attracts the humidity of the air, and causes the
varnish to scale off, which can have no hold upon the preparation.
Diluted nitric acid, with which the parts are washed, does not expose
them to these inconveniences: the preparation preserves, it is true, a
certain degree of suppleness; it tarnishes a little, but is never humid.
The numerous means used for disposing the preparations to desiccation,
may be reported under four series:
Alcohol, where expense is no object, is preferable to all the others;
its affinity for water gives it the property of absorbing humidity from
anatomical pieces.
The deuto-chloride of mercury, the proto-nitrate of the same base,
the solutions of acetate of lead, and of the proto-nitrate, merit the
preference among metallic substances.
Marine salt and alum are nearly those alone among the earthy salts
which have been employed for this object. M. Breschet advises that,
according to the method followed by the tanners, the piece be permitted
to remain for several days in powdered sea salt, and to immerge it
afterwards in a strong solution of alum for fifteen days, when it is to
be withdrawn and dried.
In fine, tanning is still a preparatory method for desiccation.
_Desiccation._--Anatomical pieces may, says M. Doct. Patissier, be
dried in the open air, in a stove, in a vacuum, and by employing
substances very avaricious of water, and in a bath of sand, or of
absorbing powders; but desiccation by means of an oven is the best
process: the heat of the oven must be neither too weak nor too strong;
the most convenient temperature is that of 45° to 55° of centigrade.
When the parts have been dried by one of the processes just mentioned,
if they be abandoned to themselves, they would become injured in a
little time by humidity and insects. There remains, then, some care to
be taken before depositing them in a cabinet; they should be washed
in a liquid containing a preparation of arsenic, or of sublimate, or
rather by applying to them a varnish containing one or both of these
substances. We shall not reconsider here the compositions of varnishes,
having already given several formulæ for them when speaking of Swan’s
method, and we shall have occasion to refer to them again when passing
in review the different methods of preparing objects of natural history.
_Preservation in liquids._--Anatomical parts are also preserved, and
more advantageously, in liquids. We shall now consider the acids, or
acidulated waters, alkalies, salts, oils, spirituous or alcoholic
liquors; expose their advantages under certain circumstances, their
inconveniences under others.
When acids are employed for preserving anatomical parts in their
natural state of suppleness, caution must be used to dilute them,
with a sufficient quantity of water, so that they may not corrode or
harden the parts. In general, it is advantageous to allow them to
remain for the first few days, in a very weak acid, and not place them
in the prepared liquor, until they have ceased to make any deposit.
The objections against muriatic acid are, that it renders the surface
of the parts gelatinous, gluey, and transparent; of nitric acid, to
tarnish and contract them; of sulphuric acid, to bleach them. All
these acids decompose the parts when they are not sufficiently diluted
with water; they allow the liquor to putrefy or to freeze, and break
the vessel when they are too weak. The proportions are indicated by
experience, and depend upon the nature of the part which it is intended
to preserve. It is those parts in particular which are loaded with fat,
that are best preserved in acid liquors.
In general, little use is made of liquors which hold alkalies in
solution: the carbonates of commerce are preferable; and these are used
with advantage, when it is necessary to keep for several days, before
dissection, animal parts in which corruption has already commenced.
Those salts derived from the combination of acids and earths, the
alkalies or metals, may be employed like the acids diluted with
water. They are not subject to the same objections. The nitrate of
potash, the muriate of ammonia, those of lime, or of soda, are very
proper for preserving pieces of myology; they appear even to reclaim
the red colour of the muscles, when these solutions are strongly
saturated; but, then, they are liable, some of them, to liquify,
others, to effervesce or to chrystalize upon the sides of the jars,
and even on the surface of the parts themselves, which is a very great
inconvenience when it is wished to expose the parts to view.
The solution of the triple sulphate of alumine, (alum of commerce)
is employed with the same advantages; it must be confessed, however,
that they are more proper to preserve membranous parts which have been
previously allowed to macerate a long time. In general, this liquor
discolours the parts, and deposits at length on the sides of the jar
and the surface of the piece which it bleaches, the white earthy
matter with which it is charged; this is a great objection, and exacts
great care when the atmosphere freezes suddenly.
Chaussier has latterly proposed the solution of the deuto-chloride
of mercury, in distilled water. This liquor is very useful, but it
bleaches the surface of the parts, particularly the muscles; it
hardens, and attacks the instruments when new researches are attempted,
upon parts already prepared. This discovery, however, is very valuable
to obtain the mummification of certain parts, which it is intended to
preserve in the open air. In order to obtain a solution always equally
saturated, Chaussier,[12] has proposed to keep at the bottom of the
liquor two or three knots of fine linen enclosing a certain quantity of
this metallic salt, in order that the saturation may always be complete.
[12] See Bulletin des Sciences, by the Philomatic Society, Vol. 3, 6th
year, No. 3.
In general, we repeat, these preservative liquors are attended with the
great inconvenience of leaving suspended, after frosts, the albuminous
matters which the cooling has caused to precipitate; so that the fluid
of the vessel which contains the preparation becomes clouded, and no
longer permits the object so be clearly seen. Besides, the liquor
freezes, and breaks the jar, when the temperature is very low.
The volatile oils, from whatever vegetable they may have been
extracted, are very proper for the preservation of anatomical objects;
they lose at length, it is true, their transparency; they thicken,
precipitate to the bottom of the vessel, the animal fluids which
exude from the object, which exposes them to corruption. But all these
changes are sensible to the eye, and the fault is easily repaired
when perceived in time to renew the liquor, which may be afterwards
re-distilled.
It is never useful to employ these liquids for the preservation
of objects loaded with fat, for they dissolve these at length and
penetrate them entirely, changing their form and colour.
Volatile oils, and particularly turpentine, which is the best, are
employed to preserve with the greatest success certain injections, the
vehicles of which would be dissolved in alcohol, and all the parts
whose vessels have been injected with coloured gelatine; finally,
these oils are used in all cases where it is desirable to preserve the
transparency of certain membranes, which have been previously dried.
Alcoholic liquors are most generally used for the preservation of
animal substances, if they are more costly, they are liable to fewer
objections. Brandy, rum, tafea, are coloured by a resinous substance,
which clouds their transparency, and which is liable to be deposited.
The alcohol of cherries, of grain, of cider, or of wine, is preferred
at present, which can be procured well rectified and transparent, and
which may be afterwards weakened with distilled water, so as to obtain
alcohol very limpid, marking from 22° to 30° of Baumè’s areometer.
Some years since, alcohol was still employed, in which was dissolved
certain transparent resins; such as camphor, but it has since been
ascertained, that animal substances which have remained in this
liquor, contract such a disagreeable and nauseous odour, that it
becomes very painful to keep them long uncovered for examination,
consequently, pure alcohol is preferred.
Nevertheless, when it is desirable to preserve the preparations of
the nerves, it is better to put a few drops of muriatic acid into the
jar along with the spirits of wine: this mixture bleaches and renders
more visible the nervous fibres, on which the acid appears to act more
specially. The yellow tinge, which the parts sometimes assume in the
end, may sometimes be removed by pouring a small quantity of muriatic
acid into the jar which contains them: this precaution occasionally
gives a new aspect to the parts.
We have chosen this passage of M. Dumèril’s pamphlet, because it
gives with sufficient accuracy all the liquids employed by preparors,
and because it indicates a part of the inconveniences which we have
experienced from them.
We shall see to what extent the more recent additions made to
sublimated alcohol, of hydrochlorate of soda, (chloride of sodium,) of
the hydrochlorate of ammonia, of the muriate and nitrate of alumine,
can contribute to the wants of the collector of pathological anatomy.
Before entering into this critical examination, it remains for us to
describe the processes employed by naturalists for preserving the
different species of animals. The excellent manual of M. Boitard, so
useful to preparors, will furnish us with this information.
_Means of preparing and preserving practised by naturalists._--The
soap of Bècoeur enjoys with naturalists a great reputation as a
preservative. It is this preservative, then, that we should recommend
as the most approved by experience: the following is the receipt:
℞. Arsenic pulverized, 2 ℔.
Salt of tartar, 12 ℥.
Camphor, 5 ℥.
White soap, 2 ℔.
Powdered lime, 8 ℥.
In the original, four ounces of lime is recommended, and we have given
this dose in our first edition; but it has since been found by doubling
it, the preservative is less pasty, and less difficult to use, more
abundant and equally good.
M. Simon thus composes the preservative, but he adds to it a certain
quantity of corrosive sublimate, and of camphor dissolved in spirits of
wine. The camphor, thus incorporated with the preservative, does not
volatilize so easily as when used in powder.
When used, a sufficient quantity is placed in a small vessel, and, with
the aid of a hair pencil, it is moistened with water and spread upon
the piece to be preserved.
Some naturalists, fearful of the danger of the daily use of arsenic,
have endeavoured to replace this preservative by another composition,
but have never succeeded in obtaining results equally advantageous;
but, nevertheless, in order to render this work as complete as
possible, and to facilitate new researches, we thought that we should
at least, indicate here, the different processes which have by turns
been imagined.
In my cabinet of natural history, I have indicated, under the name of
_soapy pomatum_, the following composition:
℞. White soap, 1 ℔.
Potash, 1/2 ℔.
Powdered alum, 4 ℥.
Common water, 2 ℔.
Oil of petroleum, 4 ℥.
Camphor, 4 ℥.
M. Mouton de Fontenille proposes a tanning liquor thus composed:
℞. Quinquina, 1 ℥.
Grenada bark, 1 ℥.
Oak bark, 1 ℥.
Gentian root, 1 ℥.
Absynthium, 1 ℥.
Tobacco, 1 ℥.
Powdered alum, 1 ℥.
Common water, 2 ℔.
Boil the whole, except the alum, which is not to be added to the liquor
until withdrawn from the fire; it is to be put into a well corked vial
for use.
M. Mouton thus uses his liquor: when an animal is skinned, and the skin
divested of grease as well as possible, the internal surface is to be
moistened with the tanning liquor until it is perfectly impregnated; if
it be a dry skin, it is to be moistened in the same manner until it is
softened.
An author has recommended, under the name of _antiseptic powder_, the
following composition:
℞. Arsenic, 1 ℔.
Calcined alum, 1-1/2 ℔.
Purified sea salt, 1/2 ℔.
The whole to be reduced to a fine powder and well mixed.
We advise that powdered arsenic never be used, because, by
volatilizing, it might penetrate the lungs and cause mortal ravages.[N]
[N] In this country, powdered arsenic is almost exclusively used by
preparors--and is alone sufficient for this purpose--the arsenical
soap is not sufficiently strong; no fatal effects have been known to
follow its use; care should be taken to wash frequently.--_Tr._
The preparor Nicholas recommends, in certain cases, a composition
which ought to be here mentioned, not to advise the use of it, on the
contrary, to advise the rejection of it; for far from driving off the
insects, it attracts them; he calls it _gummy paste_.
℞. Colocynth, 2 ℥.
Gum Arabic, 4 ℥.
Amidon, 6 ℥.
Cotton, hashed fine, 1 ℥.
Other preparors, without passing any thing over the skin, confine
themselves to the use of the following powder:
℞. Calcined alum, 3 ℥.
Flour of sulphur, 1 ℥.
Black pepper, 1/2 ℥.
Powdered tobacco, 1/2 ℥.
Powdered sabine, 1/2 ℥.
Powdered camphor, 3 ʒ.
The whole to be finely powdered and well mixed.
Some amateurs content themselves in passing over the internal surface
of the skin they wish to preserve, a good layer of melted suet mixed
with a small quantity of corrosive sublimate; it appears that they
have obtained some advantageous results, which authorises further
experiments; it has been remarked, that suet is never attacked by
insects; perhaps, if it were combined with some mineral matter less
dangerous than the sublimate, results as satisfactory as those from the
arsenical soap of Bècoeur might be obtained.
Such are the preservatives which have been employed in France, but
which do not possess, to any extent, the efficacy of the arsenical soap
of Bècoeur. It appears that the Germans employ others to which they
attribute the same qualities, which appears to us very doubtful in all
cases: they may be mentioned here.
Naumann, in the first place, gives a method which appears to us
vicious, although he invokes in its favour his own experience.
After having said that the best method of preserving is to close
hermetically, stuffed animals in boxes, he adds: “I do no more for
skins which are to travel in boxes, than powder them with the following
composition:
“Of lime decomposed in the air, and finely sifted, two parts; of saxony
tobacco, also sifted, one part.”
Hoffman approves of, and recommends the following powder:
℞. Sal ammoniac, 1 ℥.
Calcined alum, 1/2 ℥.
Saxony tobacco, 3 ℥.
Aloes, 1 ʒ.
The librarian of Jena, M. Theodore Thon, proposes the following
powder, as better for preserving animals in the open air.
Cobalt, 1 ℥.
Alum, 2 ℥.
To be powdered and mixed. Before employing this powder, give a layer
of essence of pine, (turpentine,) in order that it may adhere better to
the interior of the skin. If the latter be very greasy, add an ounce
and a half of lime decomposed in the air and sifted.
Among the preservatives which this naturalist has investigated, we
find a very simple one, which he says, is very effectual for mammifera:
the following is its composition:
Cobalt in very fine powder, 4 ℥.
Alum, 4 ℥.
The same naturalist recommends another composition as very good, and
which I think would be worth making a trial of for large animals, which
would be very expensive done with arsenical soap. Very fat bitumen is
to be melted, in a strong solution of soap-water, until the whole forms
a sort of clear broth; the interior of the skin is to be endued with
this mixture, which costs very little.
_Preservatives in Liquors._
Liquors are employed in baths, in lotion, in friction, in injection,
and finally, in permanent baths, in which certain objects are always to
remain; we shall now treat of these four methods of preservation.
_Of the Bath._
In many animals, and particularly in the mammifera, the skin has such
a thickness, such a degree of intensity, that the arsenical soap can
not penetrate it sufficiently in order to preserve it perfectly; it is
then that the bath becomes an indispensable operation. In penetrating
the skin which is left to macerate a longer or shorter time, the
preservative molecules with which it is saturated enters all its pores,
and preserves it for ever from the attacks of insects.
The following is the composition of the bath employed by the
naturalists--preparors of Paris.
℞. Common water, 5 ℔. {pints}
Alum, 1 ℔.
Sea-salt, 1/2 ℔.
This mixture must be boiled until it is all entirely dissolved, and
when the liquor has cooled, plunge the skins into it; those of the size
of a hare, or thereabouts, need not remain longer than twenty-four
hours; those of the larger animals must macerate a longer or shorter
time, according to their thickness; from eight to fifteen days would
not be too long for a buffalo or a zebra. At the museum of Natural
History of Paris, they very rarely make use of this composition; they
are satisfied to macerate the skins in spirits of wine, which they
keep in hogsheads for that purpose. Without attempting to criticise
this method, which may have its advantages, we think that they might,
perhaps, in this particular, follow the English naturalists, and add,
like them, a small quantity of corrosive sublimate dissolved in
spirits of wine.
Nevertheless, as we ought to be impartial, we should mention here the
dangers attendant on the use of this terrible mineral, so much boasted
by Sir S. Smith, president of the Linnean Society of London. When there
is occasion to mount a subject prepared with sublimate, whether it has
been employed in powder or in solution, in arranging the animal there
arises a dust, which penetrates the nostrils, and may cause serious
accidents. Arsenic, though much less energetic, is not even free from
this inconvenience. Thus it is only with much precaution that preparors
should handle preparations in skins which they receive from foreign
countries, the substances used in the preparation of which they are
ignorant.
Let us now pass to the other preservatives in liquor, less generally
employed, at the present time, although some of them may be very
useful. The following is the tanning liquor which I have proposed in
the Cabinet of Natural History:
Tan, or oak bark, 1 ℔.
Powdered alum, 4 ℥.
Common water, 20 ℔.
An ancient author, the Abbe Manesse, composed his bath in the
following manner:
Alum, 1 ℔.
Sea-salt, 2 ℥.
Cream of tartar, 1 ℥.
Common water, 4 ℔.
_Liquors employed externally as lotion._
When an animal has been mounted or prepared, and fears exist less the
insect should attack it, this may be prevented by washing its feathers,
its hairs, or its naked skin, with one of the liquors which we are
about to indicate. Animals exposed to the open air have, above all,
need of being thus treated, and yet, by an inconceivable negligence,
many amateurs permit their collections to be devoured, for the want of
employment of a means both simple and easy.
1. _The essence of wild thyme_, has been recently advantageously
employed; in using it the feathers or hairs of an animal are to be
raised every little distance by a long needle, and at their bases, that
is to say, the skin, is to be touched by means of a hair pencil with a
drop or two of the essence, and when this has been well imbibed, the
hairs or feathers are to be replaced, their extremities, never being in
contact with the liquor, cannot become tarnished.
2. _Essence of turpentine_ has been recommended by almost all authors,
and yet, when made use of it is perceived with astonishment that great
inconveniences result; it never dries upon the feathers, which it
greases and soils in spite of every precaution, the spots spreading and
enlarging like oil; besides this, it forms a species of glue, which
arrests and fixes the dust in such a manner that no subsequent effort
can remove.
3. _Liquor of Sir S. Smith._--This intelligent English naturalist,
president of the Linnean Society of London, having turned his
attention to the preservation of prepared objects, already classed in
collections, has concluded that there cannot be a more efficacious
means employed than the following liquor.
℞. Corrosive sublimate, 2 ʒ.
Camphor, 2 ʒ.
Spirits of wine, 1 ℔. {pint}
In large animals it is applied by means of a sponge, which is passed
at different times over the whole exterior of the animal, until it is
perfectly impregnated, and the liquor has penetrated to the skin. In
small animals a hair pencil is used, and the operation is performed in
the same manner. Whether the individual submitted to this practice be
recently prepared, or whether it has long remained in a collection, it
must be permitted to dry perfectly before placing it in a cabinet.
In France this dangerous composition is replaced by the preservative
in very small quantities diluted with water.
4. _The bitter spirituous liquor_, recommended by other authors, is
thus composed:
℞. White soap, 1 ℥.
Camphor, 2 ℥.
Colocynth, 2 ℥.
Spirits of wine, 2 ℔.
The whole is to be subjected to cold infusion for several days in a
vessel hermetically sealed, frequently shaking the vessel during this
interval, and allowed to strain through unglazed gray paper; when it is
thought that the infusion is done, it must be put into bottles equally
well corked, and used after the same manner as the preceding.
5. _Varnish_ is employed only on the naked skin of reptiles and
fishes, to which it restores a portion of its splendour; it must be
absolutely colourless, and perfectly transparent. In order to obtain
it thus, it must be prepared by dissolving fine and new turpentine in
spirits of wine, which must themselves possess the qualities above
mentioned. It is to be applied with a pencil of squirrel’s tail, or the
tail of a martin, and the object is left exposed to the air, sheltered
from the dust, if it be wished to hasten its desiccation.
_Liquors employed in Injections._
Injections are more generally employed for the preparation of the eggs
of birds, for which it is desirable to secure a long preservation;
although by a very bad method, they have also been used for the
desiccation of very small animals.
In order to decompose the flesh of a fœtus already formed in an egg,
recourse is had to a strong solution of a fixed alkali, of soda, of
tartar, or to ether.
_Liquors, in which objects are preserved which do not admit of drying._
The qualities which a liquor ought to possess, in which objects of
natural history are placed, are, independently of that of preserving
from decomposition: 1. to be colourless, that they may not tarnish the
contained objects; 2. not to attack by corrosion the proper colours of
the object; 3. to be perfectly transparent, that the contained objects
may be visible through the vase which encloses them; 4. the power to
resist frost, in order that they may not break the jar which holds
them.
1. Spirits of wine, of from fourteen to eighteen degrees of the
areometer of Baume, appears to be the liquor which best fulfils all
these conditions; the other alcohols, such as those from potato,
from grain, from sugar, &c., have the same qualities; but a serious
inconvenience is the high price of all of them, and this reason alone
is an inducement to look for other compound liquors, capable of
replacing them with more or less advantage.
2. Nicholas recommends the following composition:
Very pure water, 2 ℔. {pints}
Alcohol, 1 ℔. {pint}
Sulphate of alumine, 6 ℥.
The English naturalist, George Graves, in a work published in London,
seven years ago, indicates a liquor which has much analogy with the
preceding:
Alum, 8 ℥.
Common water, 1 ℔. {pint}
Alcohol, 1/2 ℔. {1/4 pint}
The following is the method of preparing this mixture: the alum is
pulverised and put into a vessel capable of resisting heat; water
being heated to ebullition is poured upon the alum; when cool, it is
to be filtered through gray paper, and then mixed with alcohol. The
same author recommends another liquor, thus composed, but of which the
mixture is made cold.
Common water, 1 ℔. {pint}
Alcohol, 1 ℔. {pint}
Alum, 12 ℥.
4. The Abbe Manesse, after various trials, more or less successful,
has published the result of his experiments; he proposes as the best
liquor, one composed as follows:
Alum, 1 ℔.
Nitre, 1 ℔.
Sea salt, 1 ℔.
Common water, 4 ℔. {pints}
Alcohol, 1 ℔. {pint}
The water used should be distilled, so as to be freed of any foreign
matter; the alum should be the most transparent that could be obtained,
and the salt also should be purified before use. The liquor may be made
cold, but it is always better to boil it, with the precaution not to
add the spirits of wine until it has cooled.
All these liquors are inferior to spirits of wine, inasmuch as they
are liable to freeze.
After having given this long list of the known means of preserving, and
given in detail the representation of authors, it remains for us to
judge of them, to determine their merit, and the degree of confidence
that ought to be accorded to each, under the triple point of view of
the preservation of objects of _normal anatomy_, of _pathological
anatomy_, and of _natural history_.
1. _Process of desiccation._--It can be of no utility for pathological
anatomy, because it changes entirely the aspect and texture of parts,
and in most cases it leaves no traces of the alterations which it
is important to know. For normal anatomy, these preparations are,
and always must be, from the simple fact of desiccation, a feeble
resource, and really much inferior to the artificial subjects of M.
Azoux; for this ingenious preparation, if it has many of the faults
of dry anatomy, the objects are not so deformed as scarcely to be
recognised.
Further, each of the preparations which tend to desiccation has
its particular inconvenience: thus those of the deuto-chloride are
numerous, as we have seen in the preceding chapter, and as have
remarked in this the authors whom we have cited. We may add that the
salts of mercury, of copper, and of lead, which, in combining with
gelatine, form, it is true, an inalterable compound, have a great
affinity for hydrosulphuric acid, and that there results from this
affinity, a necessary deterioration of the objects, colouring them
black. Sea salt does not possess durable preservative properties; and
its affinity for water even facilitates the decomposition of the dried
subjects which contain it. Alcohol is, doubtless, a good means, but
it requires to be frequently renewed, until by its affinity for water
it absorbs all which the organs contain; but alcohol costs _forty
cents a quart, and loses always by evaporation_. Besides, parts thus
prepared, are not less deformed than other dried parts, when subjected
to desiccation.
The naturalist finds in the soap of Bècoeur, in other preparations
containing arsenic, the deuto-chloride of mercury, alum, &c.,
sufficiently good means of drying or of tanning the skin and other
animal tissues. But, as M. Boitard has remarked, these preparations are
not without their inconveniences.
What have I to offer the anatomist who believes in the utility of dried
preparations, to the naturalist whom a real necessity often forces to
recur to them? My liquid, employed as a bath or injection, without
either danger or inconvenience, and _which costs only two or four cents
the quart_.
I shall give here an example of injection; a corpse is injected by
the carotid with from five to seven quarts of the acetate of alumine
at 20°, and containing in solution about two ounces (fifty grammes)
of arsenic acid. Four days after this injection, if it is intended to
prepare the large and small vessels, inject by the aorta half a quart
of a mixture, equal parts, of the essence of turpentine and essence of
varnish; finally, make a single cast of a hot injection of a mixture
of suet and of rosin, in equal parts, coloured with cinabar for the
arteries, and with a black or blue colour for the veins. Then, the
corpse, or the part of the corpse which it is intended to preserve,
is prepared and dissected at leisure, according to the wish of the
operator.
When the body has been injected, as above described, the preparation
which is made of it easily dries in the open air from the month of
May to the month of October; during the winter it is necessary to
deposit it in an oven, or in a heated chamber. When the desiccation is
slow, or the moisture is excessive, the byssus sometimes develops on
its surface, but this may be washed off, and a layer of varnish will
prevent new vegetations. This preparation will be certainly superior to
any contained in cabinets of anatomy.
In support of this assertion, I will cite an authentic fact, that of a
woman whose body was submitted to the examination of the commissioners
of the Institute and of the Royal Academy of Medicine, appointed to
prove the value of my process.
On the 10th of May, 1834, a woman died in the wards of M. Majendie, at
the Hôtel-Dieu; the body was injected the next day with the acetate
of alumine; at the termination of this operation, it remained fresh
until the 15th of January, 1835, when it dried without experiencing any
alteration. The commissioners of the two Academies made experiments
upon this body, at different periods. On the 15th of January, 1836,
M. Guèneau de Mussy, to assure himself of the state of the cerebral
substance, demanded the head to be opened, I profited by this occasion
to _take off the hairy scalp_. The same day, M. Breschet, desiring to
know what would result from the exposure of this corpse to the open
air, it was suspended beneath the shed of the dissecting rooms (ècole
pratique.)
Ten months after, in the month of November of the same year, it had not
experienced any alteration. At this period, M. Gaucherant, inspecting
overseer of the ècole pratique, wishing to terminate the experiment,
the body was sent to the cemetery.
_The right arm and forearm_, the only parts remaining untouched,
after the experiments of MM. the commissioners, were _amputated by
myself_. I preserve this piece, as well as the hairy scalp; I can show
them to anatomists to be compared with all the preparations obtained
by other processes; none of them, I am convinced will be pronounced
comparable to mine. The hairs remain so firmly attached to the scalp,
that a strong pull will not detach them; I am quite sure that the
injection has penetrated even to the capillary tubes of these organs;
my experiments upon cats, dogs, and birds, have demonstrated the
penetration of my liquid into the horny organs, hairs, or feathers,
which clothe the skin of these animals. These facts will demonstrate
all the services which it is capable of rendering naturalists. Finally,
no process of tanning could give to the internal surface of the skin
an aspect more satisfactory than that which offer other preparations
deposited in my cabinet.
2. _Preservation in liquids._--The different preservative liquids
produce effects very different from the process of desiccation;
however, all those employed up to the present day, possess serious
inconveniences, as any one may be convinced by reading the very
commendable passages which we have extracted from the pamphlet of M.
Dumèril. We shall point out some others which he has omitted.
(_a._) _Nitric Acid_, the only one of all the acids, that can be of any
use to the anatomists, preserves well, it is true, the preparation of
the nerves, hardening their structure, and increasing their nacreous
white colour; but it deteriorates all the other structures, it
dissolves the gelatine, softens the muscles, and deprives the bones of
their calcareous salts; it cannot be other than deleterious to objects
of pathological anatomy, and natural history.
(_b._) _Alcohol_, is more serviceable than any other liquor in use, but
its high price renders its employment almost impossible for objects of
normal anatomy; it hardens and sensibly alters objects of pathological
anatomy; and these alterations, however trifling they may be, and
unimportant to regular anatomy, are serious for the physician, who
cannot have too exact an idea of the progress of disorganization in the
living tissues. If alcohol is eminently useful for natural history, its
costliness renders it impossible to extend the use of it as far as the
interest of science demands.
(_c._) _Diluted Alcohol_, to which is added the deuto-chloride of
mercury, is a less expensive liquor; it preserves accurately enough the
labours of the naturalist and anatomist, but it is not sufficiently
faithful for a pathological anatomy. The same may be said of the
hydro-chlorate of soda, the hydro-chlorate of ammonia, the muriate and
nitrate of alumine added to alcohol.
(_d._) _Alum_, which we have seen figure in many of the adopted
formulæ, is, nevertheless an unprofitable means of preservation.
Extensively used in commerce, and employed from time immemorial in
dyeing, it has only recently attracted the attention of preparers. This
salt, to which the new chemical nomenclature has successively assigned
the names of _double sulphate_, _triple sulphate_, _acid sulphate of
alumine and potash_; has been experimented upon by myself, and has
not answered my expectations. I have investigated the cause of this
failure, and think I have found it; in analysing this compound, for
every hundred parts I have obtained
Sulphate of alumine, 36.85
Sulphate of potash, 18.15
Water, 45
----
100
One hundred parts of this salt contains 10.86 of alumine. At the
temperature of 12° centigrade, five hundred grammes of water dissolves
thirty grammes of salt, from whence it results that a pound of water
contains in solution only eighteen grains of alumine; from whence I
have suspected that the little efficacy of alum for the preservation
of animal matter, depends on the too small quantity of alumine in the
solution. A fact convinced me that I was right: twenty-four hours
after the immersion of a corpse in a bath containing the acid sulphate
of alumine, I have observed that all the alumine was absorbed by the
animal matter. Finally, the experiments which I have tried with the
salts of alum, more rich in alumine, and more soluble in water, and
the happy results I have attained, authorizes me to say: alum is a bad
means of preservation, _because it is not sufficiently soluble, and
does not contain enough alumine_. The reader will naturally again recur
to the subject when we come to the exposition of my researches.
SECT. 3.--_Means of preservation applied to each tissue._
In our first paragraph, we have passed in review the different
preparations which ought to precede the application of preservative
means; in the second, we have seen these numerous means, and we were
compelled to deliver an impartial judgment. It remains for us to
explain here how anatomists have applied them to the tissues taken
separately. We shall abstain from relating the preparations which
precede the application of preservative means, because they are
foreign to the subject which occupies us, and would uselessly prolong a
discussion already too much extended.
1. _Fibrous tissues._--_Articulations, aponeuroses, tendons, and
ligaments._--The process generally adopted is due to M. J. Cloquet, in
nearly following the method employed by the tanner, he has succeeded in
preserving the suppleness of these tissues.
“The following,” continues he, “is the process which I have adopted.
“Dissolve four pounds of muriate of soda and a pound of alum in ten
pints of water: the articulation, which has been carefully dissected,
must be allowed to macerate fifteen or twenty days in this lie; paying
attention to move it frequently in the solution, to press and twist
its ligaments, and, above all, to strike it lightly with a little mace
of light wood. These manœuvres are intended to render them pliable, to
separate the fibres, which permits the salts to penetrate more easily.
Withdraw the articulation from the solution, dry it for four or five
days, taking care to move it occasionally, and still to strike it with
the little mace; then put the articulation into a very concentrated
solution of soap, (a pound to three pints of water,) handle, and strike
it again for seven or eight days, the time necessary for divesting it
of salt, and permitting the soap to penetrate the ligamentous fibres,
to take the place of the salts. At the end of this time, that is to
say, thirty-six or forty days after the commencement of the operation,
wash the articulation in a weak lie of carbonate of soda, (an ounce to
two pounds of water,) after which it is to be dried.
“By this process, which may be modified in various ways, ligament
may be obtained perfectly supple, of a yellowish or grayish colour,
resembling chamois leather, very resisting, and permitting the joints
to execute their ordinary movements.
“I have prepared, in this manner, the articulations of the shoulder, of
the knee, of the fingers, and of the vertebral column. I repeated my
experiments with the intention of obtaining a more expeditious method.
“The articulations may also be preserved perfectly supple, by keeping
them immersed in a mixture of equal parts of olive oil and essence of
turpentine.
“2. _Osseous tissue._--The different preparations to which bones are
subjected in order to preserve them, are maceration or ebullition, and
then bleaching.
“_Maceration._--When it is desired to obtain the bones very white,
it is necessary to choose, as far as possible, a thin or infiltrated
corpse, of an individual of from thirty to forty-five years, or
thereabouts, dead of some chronic disease which has not altered the
structure of the bones. Consumptive bodies are the most proper for
this kind of preparation. The subject being chosen, it is roughly
stripped of its muscles and periosteum; the sternum is to be detached
by dividing the costal cartilages where they join the ribs; the members
are to be separated from the trunk, in order that these various parts
may be more conveniently placed in a trough, which is to be filled with
water, and disposed in some place where the putrid emanations cannot
produce any inconvenience; the bones must be constantly kept covered
with water, which must be renewed every four or five days in the
commencement, and at more prolonged intervals towards the end of the
maceration.
“The anatomist should watch over these macerations; and it is only
when all the fibrous parts separate easily from the bones, or the
inter-vertebral fibro-cartilages, and the yellow ligaments separate
readily from the vertebra, that the skeleton should be withdrawn from
the bath and cleaned. For this purpose, he collects with care all the
pieces, and places them in clean water; he cleans them by removing with
a scalpel the fibrous parts which may yet adhere, and by rubbing them
under water with a very coarse brush; he then places them on coarse
linen to dry them.
“_Ebullition._--Boiling water is often resorted to for preparing the
bones of the skeleton. After having roughly separated them from the
soft parts, they are placed in a kettle of water, and subjected to
ebullition for six or ten hours, according to the subject. The action
of the water is increased, and the fibrous parts more accurately
stripped from the bones, as well as the grease, by placing in the
kettle, an hour before the end of the operation, potash, or soda of
commerce, (sub-carbonate of potash, and of soda,) one pound to eighty
or a hundred pints of liquid. After having carefully removed the
grease which swims on the surface of the water, the bones are to be
withdrawn and plunged into a new alkaline lie, warm and very weak;
clean them with care, as in the preceding case, separating exactly
from the articular surfaces, the swollen and softened cartilages, which
remain adhering to them: the bones being clean, they are to be washed
frequently previously to drying.
“In employing ebullition, we have the advantage of preparing the bones
more promptly, and in a manner less insalubrious than by maceration.
Nevertheless, this mode of preparation has its inconvenience: 1. Bones
which are boiled, become, in general, less white than those which
are macerated; the blood coagulating in their pores, leaves a brown
tinge, which it is often impossible to remove; 2. They commonly retain
a greater quantity of medullary matter, which, by becoming rancid,
soon gives them a yellow colour and a very disagreeable odour; 3.
Ebullition is not applicable to the bones of young subjects, in which
the epiphyses are not yet adherent; it acts upon their gelatinous
texture, and despoils, in part, the short bones and the extremities of
the long bones of the compact layer which envelopes them. This last
inconvenience is manifested even in the bones of adults.
“_Dealbation, or bleaching of bones._--In order to obtain macerated
bones perfectly white, several processes are employed: 1. The best
method consists in placing them upon the grass exposed to the united
action of the air, the sun, and the dew, as is practised in bleaching
linen, wax, &c.; care is to be taken to turn them every fifteen days,
in order that they may bleach equably; two or three months of such
exposure is sufficient, particularly during the spring, to give them
a brilliant whiteness. 2. The bones may be exposed to the action of
chlorine, either liquid or gaseous. In the first case, they are to
be plunged three or four times daily in a lie which holds chlorine
in solution, repeating this operation for ten or twelve days; in the
second, they must be steeped in water, placed on a hurdle and covered
with cere-cloth or gummed taffeta, they are then to be exposed over an
earthen pan, in which has been placed suitable proportions, of muriate
of soda, oxide of manganese, and sulphuric acid: from time to time this
mixture is to be slightly heated. 3. In place of gaseous chlorine, the
vapour of sulphuric acid may be advantageously employed, as is done
in the arts of bleaching wool, silk, &c.; sulphur is slowly burned
beneath the hurdle, upon which has been placed the moistened bones; the
alkaline lies may also be used for the bleaching of bones although they
do not appear to me so advantageous as the preceding means.
“3. _Cutaneous tissues._--Deprived of grease, and of subjacent cellular
tissue and exposed to the air, this tissue inclines to dry. The human
skin may be prepared by the aid of several processes analogous to those
of tanners and leather dressers. A lie has been recommended composed of
two pounds of common salt, four ounces of sulphate of iron, and eight
ounces of alum, melted in three pints of almost boiling water; the skin
divested of its grease, is plunged into this solution, agitated for
half an hour, and macerated for a day or two in this liquid; the lie
must be frequently renewed, then the skin is to be withdrawn from the
bath and dried in the shade.
“4. _Cellular tissue._--Authors have successively employed desiccation,
insufflation, tanning liquors and alcohol, for preparing the cellular
tissue; although the method given by them as preferable, is the
preservation in an aqueous solution of nitrate of alumine, to which is
added a small quantity of spirits of wine.
“5. _Synovial and serous tissues._--The first is much more easily
preserved than the other; an accurate dissection, expulsion of the
synovial liquor, kneading, and desiccation, are the means used; the
operation is finished by the application of a preservative varnish. The
same practice is applied to the serous tissues, but with less success;
its proximity to organs eminently putrescible, such as the brain, the
lungs, the liver, renders its dissolution more imminent, more difficult
to prevent.
“6. _Encephalon, spinal marrow, nerves._--We have already spoken of the
property of nitric acid, to give consistency to the nerves, without
causing them to lose any thing of their pearly whiteness. Anatomists
generally avail themselves, for the preservation of the whole nervous
system, of the alcoholic solution of corrosive sublimate. After twenty
or thirty days immersion in the bath, these organs are withdrawn and
exposed to dry. As communicating a remarkable density to the encephalic
mass, a solution of sugar in brandy is much praised: it is a method
recommended by Lobstein, chief of the anatomical department of the
Faculty of Strasbourg.
“7. _Arterial vessels, veins, and lymphatics._--The interesting details
which have been furnished to us by the pamphlets of M. Dumèril on the
subject of injections, will enable us to dispense with much further
developments; the vessels injected and preserved, as we have seen, are
dried and preserved in alcoholic liquors.
“When the object is to prepare the vessels of the bones, some care is
exacted to render visible their passage through the bony frame; after
having filled the vessel with a coloured injection, the piece is to be
placed in a diluted mineral acid, which, in dissolving the calcareous
phosphate, leaves the vessels in position, and clearly visible through
the gelatinous portion of the bone.
“In causing this mucous body to dry slowly and in the shade, it will
acquire the necessary transparency to manifest on its cut surface
(endued with volatile oil and varnished) the distribution of the
vessels which penetrate the bones. These pieces may be preserved in
a collection, either in the open air, after having been plunged into
an alcoholic solution of arsenical soap, which dries quickly without
bleaching; and to which essence varnish adheres very well; or if the
piece is small, it may be suspended in a jar of volatile oil, luted
with care; in this latter case, the injection must have been made with
gelatine, and not with fatty matter.
“8. _Muscular tissue._--The process of Swan, or rather the discoveries
of Chaussier, furnish the means of preserving the muscles by
desiccation. Nevertheless, another method is recommended by authors;
after having prepared the vessels and the muscles, the preparation
is to be placed in a mixture of alcohol, lavender, and essence of
turpentine; it is to be left for several days in this liquor, and then
exposed to a warm and dry air; when desiccation is complete, a layer of
varnish may be applied.
“9. The preservation of particular organs, such as the _heart_, the
_lungs_, the _eye_, &c., differ but little from that of the organs
which we have just mentioned; they are always to be either dried, or
deposited in an alcohol bath. The lacrymal ways, says M. Breschet in
his excellent thesis on the preservation of anatomical subjects (Paris,
1819,) are less easily preserved, although the lacrymal sac, nasal
canal, the lacrymal points and conducts, offer more difficulty in their
preparation than in their preservation, which may be accomplished by
liquors, or by desiccation. The lacrymal canal, and its excretory
canals, can only be seen on preparations in spirits of wine. Finally,
the following are some passages from the same work, upon the _means of
preserving the embryon and the fœtal envelopes_.
“It is useful to preserve the embryons and fœtuses at different periods
of gestation, in order to study the successive development of each
organ.
“The egg, considered in its various periods of incubation, can only be
preserved in alcohol somewhat weakened, in order that it may not harden
the membranes. Kirschwasser, in which has been dissolved the nitrate
of alumine, forms a limpid liquor, in which the egg may be preserved
without any alteration. In order to demonstrate the development of
these organs, many parts may be injected; thus, during the earlier
periods, the pedicle of the umbilical vesicle admits mercury, which is
introduced by a small glass syringe, the tube of which has been drawn
fine in the blow-pipe: this injection ought to be made on the side
of the vesicle, and sometimes the metal may be seen passing into the
intestines.
“The omphalo-mesenteric vessel ought also to be injected. The urachus
should be opened, and its communication with the bladder should be
shown on one part, and with the alantois on the other. All these parts
are to be kept separate from each other, and attached by means of small
pins to a plate of wax. In the fœtus, near the term of gestation, those
vessels which establish the communication between it and the mother,
are to be injected.
“The bones of the embryon, after having been injected, are to be placed
in oil of turpentine, without its being necessary previously to place
them in a weakened acid.
“As regards the envelopes of the fœtus, and the placenta which it may
be intended to preserve after an accouchment at full term, injections
of different colours are forced into the umbilical arteries and veins;
this injection should not be too delicate, or pushed with too much
force, otherwise it will pass from one of the vessels into the other.
These two parts should be allowed to soak some time in an aluminous
water, or, what is better, in a sublimated alcoholic solution, then
place a hog’s bladder in the cavity of the membranes, blow up the
bladder, and thus expose the parts to the air for desiccation; after
which the bladder is to be withdrawn. The membranes, with the placenta,
may thus be preserved, by placing the uterine face of the latter
sometimes within sometimes without the cavity of the membranes. These
same parts can be preserved in liquors. Finally, some persons make use
of the method of corrosion to prepare and preserve the placenta.”
It is useless to advance here new observations; those which have been
already presented on the occasion of preservation, considered in
general, are equally applicable to the present. It will be perceived in
the following chapter what means I propose to substitute for them, as
meriting the preference.
CHAPTER VIII.
GENERAL PROCESSES FOR THE PRESERVATION OF OBJECTS OF NORMAL ANATOMY,
PATHOLOGICAL ANATOMY, AND OF NATURAL HISTORY.
EMBALMING.
A portion of my researches has been submitted to the examination of
commissioners, appointed by the Institute, and by the Academy of
Medicine.
After long and repeated experiments, MM. the commissioners, have been
unanimous upon the utility of the processes of preservation which I
propose, and in particular my process for the preservation of subjects
for the amphitheatres, the only one for which it was important for me
to obtain a definite sanction, recommended by the Institute, is applied
to the dissecting rooms of Clamart, with a success that every one may
witness.
The faithful and complete exposition of the numerous trials which I
have attempted, will furnish me, in this chapter, the occasion of
indicating the most efficacious means of preservation for objects of
pathological anatomy and of natural history. And, as it is incumbent on
a man of study, disinterested in all that concerns science, I will give
publicity to the result of my labours, the composition of the different
liquids, and the mode of using them.
As for my process of embalming, I have thought that it ought to remain
my property, and that one exclusively addicted to chemical studies was
more qualified than the physician to subject it to those modifications
which each particular case requires.
I have secured a patent of invention; for my method differs essentially
enough from the preparations which I indicate for the purposes of
anatomy.
It is necessary, in effect, to preserve to the tissues in embalming, a
freshness and suppleness which is lost by desiccation, at the end of
some months, in the subjects injected for the use of the anatomist; it
is necessary, above all, to secure to the body, in this latter case,
a more prolonged preservation: the facts which I can show, will prove
that I have attained my end.
1.--_Preservation of bodies for dissection._
My experiments upon gelatine have conducted me to the knowledge of
some one of the constituent parts of different animals. I had studied
the action of chemical agents habitually employed in the arts; the
labour of the tanner, or leather dresser, of the parchment maker, the
fabrication of glue, which I have practised on a large scale from 1819
to 1828, have equally furnished me with valuable data.
In 1826, my attention having been arrested by MM. Bègin and Serrulas,
on the preservation of objects of pathological anatomy, trials were
made at the Val-de-Grace.
In 1828, M. Alphonse Sanson, disposing himself to prepare a cabinet
of anatomy, at the request and for the use of some English gentlemen,
proposed to me to occupy myself with the question relative to
preservation, which obliged me to make some researches; but it was not
until 1831, and at the solicitation of M. Strauss, an anatomist of well
known merit, that I undertook serious and continued labours upon the
preservation of bodies. From this moment, I employed all my attention
and cares to resolve this question.
The researches on the preservation of bodies demanded the re-union of
different circumstances, without which it would have been impossible
for me to have attained a satisfactory solution. It is easy to
conceive, in effect, the great difference which ought to exist between
the action of any given liquid upon some scruples of animal matter, and
its action on an entire corpse; I ought to confess, also, that without
the extreme courtesy of M. Orfila, who placed at my disposition, at the
practical school of the faculty of medicine, all the objects of which I
might stand in need, it is probable that it would have been impossible
for me to have arrived at positive results. I encountered some
difficulties, some resistance, and even something more, on the part of
some scientific notables, and also of some ambitious subalterns; but I
have surmounted all.
This work on the preservation of bodies ought only to be considered
as the suit of that in which I have treated of the preservation of
alimentary meats. It is only the circumstances of which I have just
spoken, that have determined me to finish this work sooner.
It is well known that the study of medicine should be preceded by the
study of anatomy, which teaches the knowledge of the organization of
the human body; but this study is difficult and presents numerous
dangers. The study of the organs exacts time; their dissection is
tedious, especially if intended for demonstration. In this case it
almost always happens that putrefaction seizes the subject before the
preparation is finished; for, at a temperature above fifteen degrees,
it is impossible to preserve a subject more than six days; under this
temperature, that is to say, from 0 to 10 degrees, the longest time
one can dissect is twelve or fifteen days. But the corpse always
exhales mephitic miasmata before all the organs are putrefied, and
this emanation of gas is certainly the cause which most frequently
determines typhus fever, so destructive to a portion of our studious
youths.[13]
[13] Out of ten medical students lodging together, and frequently of
the same amphitheatre, nine were attacked by this grave malady in the
course of last year, and three of them died.
Before exposing my own researches upon the preservation of bodies, it
was necessary to examine the researches anterior to mine; it will have
been perceived by what precedes, that they were of no service to me.
Thus, in viewing all that has been effected on this matter, I can find
no indications excepting the processes employed in the arts.
In our works of chemistry applied to the arts, I have often been able
to prove, practically, that muscular flesh, perfectly isolated, easily
dries. When it is mixed with gelatine, it easily experiences, on the
contrary, putrid fermentation. Geline[14] is the animal matter, which,
all circumstances being equal, putrefies the easiest; and which,
forming the organs of animals, experiences an alteration more or less
prompt, according to the prevalence of a greater or less quantity
of water of composition present. Always, then, when we succeed in
preserving from putrefaction this animal part, the other parts will
be disposed to desiccation. My researches have conducted me to this
conclusion.
[14] Up to the present, certain animal substances have been considered
chemically identical, which are not so: 1, the proper matter of
gelatinous tissues not decomposed; 2, the product which results from
their decomposition by the action of heat and water; 3, this same
secondary product dried. These three compounds were designated by the
denomination of gelatine. As I have proved that there is not between
them any identity of character, I have named gelatine the animal matter
contained in the gelatinous tissues; I have reserved the name jelly to
the product of the decomposition of geline, and I have left the name
gelatine to glue, whatever may be its purity.
In order to find a method of preserving bodies, and animal matters
in general, it was essential to examine the action of chemical
substances to which may be attributed properties which produce upon
the constituent parts of these matters an immediate action; it is
necessary also, that they should be easily procured, and that they
be of a moderate price. I am satisfied that acids do not preserve
animal matters; they disorganize them more or less promptly, in direct
proportion to their concentration. Many weak acids, among others
hydrochloric acid, at five degrees, may be employed to dissolve the
calcareous salts from the bones; nitric acid also, at five degrees, may
be brought into use in some particular cases; for example, when it is
wished to study the nervous system; but then the bones are softened,
the geline is in part disorganized, the muscles are discolored, and
become flabby, as well as the viscera; the nerves only remain of a
pearly blue, strongly pronounced.
Arsenic acid has a very marked action on animal matters; I shall make
it known without delay in my second memoir upon gelatine. It preserves
bodies well, but appears to favour their desiccation. In the details of
experiments made under the surveillance of the commissioners of the two
academies, I shall cite the effects produced by the employment of this
substance. Acetic acid preserves flesh only by drying it. This acid
weakened, or vinegar, retards putrefaction, softens the bones, as well
as the muscles, which are discolored by its action.
Concentrated lies dissolve all animal matters; weak alkaline solutions
disorganize more or less promptly the same substances.
A very small quantity of alkali suffices, when warm, to decompose very
large masses of glue. This effect is often produced through ignorance
in the manufacture of strong glue.
Salts only preserve meats when employed dry, or in very concentrated
solutions; it is necessary that their affinity should be sufficiently
great to absorb all the water of combination of animal matters. It may
be then affirmed that salt only preserves meat by drying it; thus those
salts more soluble in warm than in cold water; may, when injected warm,
in a saturated solution, be considered as a good means of preservation,
but which cannot be employed for anatomical purposes, because of the
crystals which form in the organs during the cooling of the injected
liquor.
Salts with a metallic oxide base have in general little affinity for
geline, and do not preserve well; those which are poisonous being alone
excepted. The salts of copper, and above all those of mercury hinder
putrefaction; but many causes are opposed to their employment.
1. Their action is not sufficiently energetic to give them the
preference: 2. They are always dangerous when employed in large
quantities. 3. They are very injurious to dissecting instruments. 4. In
fine they are too costly.
The aluminous salts are those alone which I find possessed of the
property of preserving animal matters; their bases combine with geline
to form a particular compound, the acid being set free.
The vegetable kingdom furnishes but few products capable of preventing
or retarding putrefaction; alcohol is nearly the only substance
possessing the property. It preserves in the same manner as the salts,
by imbibing a portion of the water of composition; it bleaches,
discolours, and hardens the organs. Alcohol is the only substance
employed up to the present for preservation; but its action upon the
tissues, its extreme volatility, the difficulty of transporting it, and
its extreme dearness, makes another process desirable.
Tannin cannot be employed, because water does not contain enough of
it in solution to render an injection of it preservative; a corpse
immerged, even in a great mass of tannin, is no better preserved, the
skin is tanned, but the flesh decomposes.[O]
[O] Entire bodies of both men and horses have been found not
unfrequently, preserved for centuries in the English bogs--which
preservation has always been referred to the tannin in its fluid
portion. These instances probably occurred at a low temperature.
I have tried the experiment by immersing small quadrupeds
in a saturated solution of powdered nut-galls, during warm
weather, but always found it insufficient for preservation from
putrefaction.--_Tr._