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 mass 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 shellac. 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 brass 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.