10. Mix a proper quant.i.ty of plaster, pour it into the mould and let it harden.

Lay the mould (with the cast inside) on a cushion, or on your lap; take a half-inch chisel and a light mallet, and, beginning at the end nearest your left hand, chisel away the case of the mould, bit by bit, until you come down to the pink lining coat, which shows that you are close to the cast.

Great care is necessary to avoid breaking the cast, which of course is very easily cut or broken. In cutting off the pink lining be exceedingly careful not to go too deep (Fig. 65). The purpose of this lining is to show you when you are close to the cast. If the case of the mould is quite thick, hold the chisel on a slant of about fifty degrees from a perpendicular, and pare off the upper surface gradually.

[Ill.u.s.tration: FIG. 65.--Chiseling off the Waste Mould.]

MAKING GELATINE MOULDS.--There are many objects which can not be copied in plaster by either of the above methods without great difficulty. These are hard substances, the surfaces of which are extremely irregular and full of little hollows, such as meteorites, statuettes, sculptured rocks, or models such as those of the Aztec calendar stone and sacrificial stone. When a number of copies are required, the making of a waste mould for each copy is out of the question, and the manufacture of a piece mould that will draw off is also a long task, to say nothing of making the casts themselves and cleaning them up. The solution of all such difficulties is the gelatine or "glue" mould, which is elastic, pliant, and yet keeps its shape perfectly.

This is how to make it:

Let us suppose we are to make a gelatine mould of a flattened meteorite, eight inches in diameter and about three inches thick. Take some potter's clay, or modeling clay, which has been nicely worked up in a square lump, and is not wet enough to be too sticky. With a small wire, cut it into slabs about three-quarters of an inch thick, and with these cover the entire object to the depth mentioned. Put the clay on everywhere the same thickness, making it conform to the irregularities of the surface. This clay will presently be exactly replaced with gelatine.

Having coated the object as described, make a plaster Paris mould of the whole of it, in two parts, which separate horizontally around the outermost edge. When you make a plaster mould of the upper half, erect a high cone of clay over the centre of the meteorite as it lies flat upon the table, so that it will make a funnel-shaped hole in the upper half of the mould, through which you can pour in the gelatine. Of course the two pieces of this plaster mould must fit nicely together, with countersunk holes. This plaster mould of the clay-covered object is called the "jacket," and its use will soon be apparent. Now for the gelatine.

_Recipe for Gelatine Moulds._--The gelatine compound is made by taking glue and glycerine in the following proportions, varying the quant.i.ty to suit the size of the object: Of best Irish glue, 3 pounds; glycerine, 1-1/4 pounds; and about 1-1/2 ounces of white-wax. Dip the glue in water, and then roll it up overnight in several thicknesses of wet cloth, so as to soften it without soaking it in water, which is an element to be kept out.

In the morning the glue will be soft. Procure a large-sized gluepot, or improvise one by putting a small tin pail in a larger one, with water between, and in this put the glue and glycerine and cook it up. Melt the wax separately, and pour it in after the other is well mixed and hot. A gelatine mould can be made of any degree of hardness by adding dry white zinc which has been carefully ground in a mortar, but ordinarily none is necessary.

To make the gelatine mould the clay must all be taken off the object, and the latter washed clean. Lay the lower half of the "jacket" upon the table, inside uppermost, and drive four small wire nails into it at different points, allowing each one to project just three-fourths of an inch, for the meteorite to rest upon, and give s.p.a.ce for the gelatine to flow underneath and form that part of the mould. Now put the meteorite carefully in place, resting on these nail-heads, and then put on the upper half of the "jacket." Cord the jacket tightly together without disturbing the position of the object inside. If there are any cracks at the edges, fill them up with clay. Now pour in the hot gelatine at the funnel-shaped hole in the upper half of the jacket, until the mould is quite full. Let the mould stand two hours to cool and harden; then remove the upper half of the "jacket." To get the object out, take a sharp knife and slit the coating of gelatine fully half-way round, so that the two halves can be opened like an oyster, and the object lifted out. The inside of the gelatine mould must now have a coating to make it impervious to the water in the plaster Paris.

Mix up the following:

1 teacupful of spirits of turpentine.

About 4 level teaspoonfuls of white lead.

About 1 teaspoonful of lightning dryer.

Mix this well, paint the inside of the mould with it, two coats, which makes the gelatine waterproof.

To make a cast, oil the inside of the mould with lard oil, put the plaster jacket around it, so that it fits perfectly, and tie the two pieces of the jacket firmly together to prevent a disaster when the plaster begins to heat in the mould.

Mix your plaster with ice-water for the same reason, and you will have no trouble. For irregular objects, the working of a gelatine mould is perfection itself. It yields gracefully in coming out of the undercuts and around corners, takes every detail perfectly, and in the jacket its shape is always the same. A careful operator can make from twenty to fifty copies of a cast in a single mould before its loss of sharpness necessitates its abandonment.

CHAPTER x.x.xV.

CASTS OF MAMMALS, FISHES, AND REPTILES.

CASTING PARTS OF MAMMALS IN THE FLESH.--Although it is usually impossible to carry more than ten or fifteen pounds of plaster into the field when you go off on a collecting trip, a quant.i.ty sufficient for a special purpose is often worth its weight in silver dollars. But many a fine subject comes entire to the laboratory, where the taxidermist can work his will upon it.

If I have never done any other good thing in my life, I believe I have at least taught some of our best American taxidermists the usefulness and value of plaster casts taken from the flesh. It is only a few hours' work to make a mould and cast of the entire side of an animal as large as a large dog, or even a lion, and still less to take half the head, or the nose, a fore leg, or hind leg. Once we had an opportunity to cast the entire head of an immense bull moose, and right greedily did we seize it.

The resultant cast has been of priceless value to us as an exact record of the form of a wonderful head. If you wish to do a fine piece of work, and have the animal in the flesh, by all means make a cast of one whole side of it. It will repay its cost ten times over. No record of form is equal to a cast, even though it be a poor one. I once made a mould of one entire side of the head of a large leopard in twenty minutes. It is about an hour's work to make a good mould of the entire head of a monkey, or two legs of a tiger.

The principles of this work have already been stated, and there is little more to be said. If the specimen is a large one, lay it upon the floor, build up around it with sand, or even wet sawdust, and arrange to take one side of the animal's head, or entire form, as the case may be. To take the two legs it will be necessary to first fill plaster under each one to make a separate piece. In order to keep the plaster from sticking to the hair, fill the hair full of thick clay-water, or thin clay, and plaster it down with the pasty ma.s.s so that the plaster Paris will not run into it. Coat the whiskers and eyelids with warm wax, or fill them full of clay. Do this thoroughly, to save the hair and save trouble. A little hair will stick in the mould anyway, but when you take the mould off, work the animal slowly and carefully from the mould, perhaps pouring in a little water to facilitate matters.

Always make a waste mould in these cases, to save time. If your cast breaks in two while you are chiseling the mould off, go ahead more carefully, and when you are done, chip the broken edges at the back, wet them with water, and stick them together with plaster. Small casts can be stuck together with sh.e.l.lac. If your mould breaks in pieces while you are taking it off, don't be discouraged, but simply put the pieces together, back them up with more plaster, and come up smiling for the next round.

It is often necessary to cast skulls or teeth, to put in skins that are being mounted, though it is better to carve a skull out of soft wood.

CASTING FISHES.--Fishes are easy and interesting subjects to cast.

Usually only one side is taken, and the cast is then mounted on a flat slab, or perhaps on two bra.s.s standards. The full method of procedure is as follows:

Wash off the mucus with alum-water. Put some dry alum on the side to be cast, to harden the soft edges of the fins, and make every scale stand out distinctly. Clean the fish carefully, close the mouth, adjust the eye and the gills. Lay the fish on its side, with the side to be cast uppermost.

Take some modeling clay, beat it out, and roll it into a smooth, square cake with parallel sides. With a small wire cut a section of this cake, and place it under each fin, so that the fin will be held in position as in life.

To make a piece mould, make it in three pieces, thus: Put up a wall of clay around the head from the base of the dorsal fin to the base of the a.n.a.l fin, keeping the clay wall a little distance away from the head and body.

With plaster Paris fill in the s.p.a.ce thus left, up to the median line of the fish, but no higher.

With a knife work the plaster under the edge of the fish, and let it harden; then put two countersinks in each side. For the main piece, mix some dry color in enough plaster to coat the fish one-eighth of an inch thick, make it thin, and pour over with a spoon. When covered thinly, blow hard upon it, all over, to make it take the scales sharply; then put on enough more to make the colored coat an eighth of an inch thick. Let this harden, then put on the thick coat of white plaster, which is to be chiseled off, as this is supposed to be a waste mould. In making the cast, if it be possible make it before the mould gets dry, so that the latter will chisel off easily. Pour the mould nearly full of plaster, then set a piece of wood in at the back to afford a means of s.c.r.e.w.i.n.g the cast to a panel, or inserting standards. After the cast is made it must, of course, be carefully painted, which is another matter, and is treated elsewhere.

CASTING REPTILES.--After all the detailed directions that have been already given on this subject it is not necessary to speak further of methods. Mr.

Joseph Palmer, of the National Museum, has produced such pleasing and artistic representations of reptiles of all sorts, especially serpents and tortoises, it would seem that perfection in this line has been reached. His serpents are all on imitation rocks, trees, or earth, and in about all the att.i.tudes they would a.s.sume in life. They are represented as crawling, sleeping, fighting, striking, and threatening. By the introduction of wires in the moulds while making the casts, they are made to act quite naturally.

Of course they have been carefully and artistically painted, and half the credit for their beauty is therefore due to the colorist. Lizards of many species, large and small, and also tortoises and turtles of every American species, are thus represented with great success. This interesting collection is well worthy of study; but to the taxidermist who is not also a first-rate artist in oil colors, this method is beyond his powers.

PART IV.--OSTEOLOGY.

CHAPTER x.x.xVI.

COLLECTING SKELETONS.

It is really strange that so few American collectors are taught the scientific value of skeletons, and the need to collect them, especially when in the haunts of rare animals. While hundreds of collectors gather bird skins by the cord, perhaps not one out of the whole lot saves a rough skeleton. Any one who is wholly unaccustomed to the preparation of skeletons is apt to stand appalled at the thought of preparing one from the beginning; and, indeed, the _final_ work of cleaning and mounting is no child's play. But let me a.s.sure you that, so far as the field work is concerned, you can easily become a successful collector of skeletons of all kinds, even though you may never learn to clean and mount one. All you have to do in the field is to "rough out" skeletons from the flesh, and dry them in compact bundles for shipment.

A ROUGH SKELETON of a mammal, bird, reptile, or fish, is simply the complete bony framework of the body, from which the most of the flesh has been cut away with a common knife, after which the skeleton and remaining flesh has been dried preparatory to its being, at some indefinite time in the future, taken in hand by a professional osteologist. The work of preparation on such specimens is very simple, and when once learned is easily performed.

SELECTION OF SPECIMENS.--When a choice is possible, select large and perfect adult male specimens as subjects to be skeletonized. The skeletons of young animals are always imperfect in development, do not properly represent a species, and are seldom valuable except for comparison with other specimens of the same species. Very often a fine adult specimen has its skin so badly torn by shot or bullets, or the skin covering is in such a bad state of shedding, moulting, and the like, that the skin is totally unfit for preservation. In such a case the preservation of a fine perfect skeleton becomes a clear gain of one specimen to the collector and to science.

A perfect skeleton is one in which not a bone is missing, and in which no subst.i.tutions have been made. But it is by no means always possible to secure a wild animal without breaking some portion of its osteological anatomy. When a bone is broken, the best thing to do is to supply it with a corresponding bone from an animal of similar size and age. Sometimes the closet naturalist, who generally thinks that rare wild animals are gathered like berries, will grumble because a broken bone has thus been replaced, and find fault with the size of the subst.i.tute, but that need not trouble the collector's conscience in the least. I once shot a fine p.r.o.ng-horn antelope buck, skeletonized it carefully, cut up the skeleton, and carried the whole of it for three days attached to my saddle, while I rode a very restive and dangerous horse, and also carried two blankets and a Maynard rifle. That skeleton, thus earned, had some broken bones supplied from another specimen. It finally went to Europe, and fell into the hands of a closet naturalist, who blithely found fault with the collector because of the supplied bones. Again, when I once risked drowning in order to enter a cave on a dangerous sea-coast to collect guacharo birds, and got a goodly number, a German closet naturalist complained bitterly because a skin that was sent to him had two missing tail-feathers supplied by two other feathers that were a trifle smaller than the missing ones.

But I did once perform a feat in South America which filled the souls of my friends at Ward's with wonder, and even admiration. In collecting about half a dozen skeletons of capybara, each of which I took care should be absolutely perfect, by some brilliant manoeuvre I contrived to send home to the establishment one skeleton which was the happy possessor of two left forelegs and two left hind legs, but never a right one; and in the language of the Old Testament, "his bones are there to this day!"

SKELETONS OF MAMMALS: SMALL OBJECTS.--The smallest quadrupeds--such as bats, small rodents, shrews, and the like--should be eviscerated, and preserved in alcohol, without being skinned; but each specimen should be fully labeled. As a general thing it is best, for various reasons, not to dry such small carca.s.ses.

For all mammals below the size of the Virginia deer, proceed as follows:

1. Remove the skin as expeditiously as possible, in order to have a fair show at the skeleton.

2. If the skeleton is _smaller_ than a fox, leave the legs attached to the body, for convenience, until you have cut the flesh away from them with your scalpel or pocket-knife, without any disjointing. When all the legs have been thus roughly denuded of flesh, cut them loose from the body and lay aside for the moment.

3. If the specimen is larger than a fox, cut off the legs from the body, lay each one flat upon the ground, inside uppermost, divide the flesh all the way along it directly over the bones, and literally dissect the bones out of the ma.s.s of flesh, instead of cutting the flesh away piece by piece.

This is the quickest and neatest way. The scapula must come off with the fore leg, and be left attached to the humerus. Be sure you cut off all the ma.s.ses of flesh, _but don't cut off the knee-pan_, as you may easily do if you are not watchful.

4. Now for the carca.s.s. Hold it on its back, begin at the breastbone, flake off the flesh from the sides of the body close down to the ribs, until the backbone is reached. Cut off as much flesh as you can (hurriedly) from along the backbone.