Taxidermy and Zoological Collecting. W. J. Holland

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СКАЧАТЬ untouched. Pare away the membrane which adheres to the inside of the eyelids, and turn the ear wrong side out at the base, in order to cut away the flesh around it. If the ears have hair upon them, they must be skinned up from the inside and turned wrong side out quite to the tip, in order to separate the outside skin, which holds the hair, from the cartilage which supports the ear.

       Fig. 3.—Skinning a squirrel's head.

      For a full description of ear skinning, see another chapter.

      The great principle which is the foundation of all valuable field work on mammal skins is this: A skin must be so taken off, cleaned of flesh, and preserved that the preservative powder or fluid can act directly upon the roots of the hair from the inner side of the skin, and over every portion of its surface. Neither alum, nor salt, nor alcohol (unless it be of great strength) can strike through a thick layer of flesh and penetrate through the skin to the epidermis quickly enough to save it from decomposition. The epidermis of most animals is of such a close and oily nature that preservatives cannot strike through it from without, and therefore when a skin is removed it must be cleaned of flesh and fat, so that the preservative liquid or dry powder can come immediately in contact with the cutis.

      The skin is now off. If the lips have been opened out, the ears skinned to the tip (if they be haired), and the feet well skinned down, we are ready to go on. But first we must clean the skull. Cut the flesh all off, or the most of it at least, for it is not possible to get it all away at the base; cut out the eyes and tongue, and with your brain-hook, or a piece of wire hammered flat at the end and bent up at a right angle, patiently draw out the brain through the occipital opening at the base of the skull. By this time, perhaps, the skin will be bloody in places, or possibly it was dirty to start with. Now is the time to wash it thoroughly in clear water. Remember that a skin which has been dried with blood upon it is damaged forever. It stains the hair, and very often forms a hard, gummy mass which nothing will dissolve.

      Preservation of the Skin.—The next step depends upon what you propose to do with the skin, or it may depend upon the conditions under which you are collecting. 1. If you are in your laboratory preparing skins to mount, preserve them all (except quite young specimens and certain others) in a soft, or wet state, in a salt-and-alum bath. 2. If you are in the field (especially the tropics), making a large collection of mammal skins for mounting, by all means do the same if possible. 3. If the skins are for purposes of study as skins, during which frequent handling and examination is absolutely necessary, make them up as dry skins. 4. If you lack facilities for preserving them wet, then make dry skins of them. 5. If the necessities of travel and transportation make it necessary to reduce the weight to the lowest possible limit, and to divide it up for carriage overland, make up all skins dry, both little and big. 6. If you have only one or two skins to preserve, it will be less trouble to you to make them up dry at once.

      Here are the two methods:

      A. The Salt-and-Alum Bath.—This is the finest solution ever discovered for the preservation of the skins of quadrupeds that are destined to be mounted. It is inexpensive, simple, and easy to make; its action is perfect; its strength can be regulated to suit any kind of a skin; it never gets stale; and if properly handled will preserve a skin for a hundred years in the same pliable and elastic condition as when it leaves the animal's back. In only two or three instances have I ever known it to change the color of the hair in the least. Every taxidermist knows that it is far easier to mount a fresh specimen in fine style than an old, dry skin which has lost all its elasticity. The work on a soft skin (i.e., one which has never been dried) can be done more easily, more quickly, and vastly better. With a dry skin you can make only what it will let you; but with a wet skin you can make just as fine a mount as your skill is capable of producing. And with the latter it makes no difference whether the skin came off the animal last week or ten years ago, except in the case of very young animals. Of these the bath softens the leg bones. For years it has been my custom to preserve all skins that I expect to mount (except the young of the smaller species) in this salt-and-alum bath, and it is almost superfluous to add that I strongly advise all others to do the same. In many ways it is a great economy to do so.

      Directions for Making It.—For every gallon of water put in three-quarters of a pound of alum (one pint) and a pound and three-quarters of salt (about one quart), and heat the liquid to the boiling-point, stirring occasionally, so that the salt and alum will dissolve. Then pour it into a wooden, earthen, or glass vessel, or a tank lined with lead (for zinc or galvanized iron will not answer), and when it is cool, or even milk warm, it is ready for use. Test it with your salometer (which you can procure for fifty cents of Bahmann & Hoehn, 21 Park Place, New York), and see that it stands at 15°. This is the normal strength. If stronger than that, e.g., 16° or 17°, the skin will be hardened too much. It can go as low as 13° with safety, but that is the limit. At 12° skins are liable to lose their hair.

      Directions for Use.—If the hair is tight on the skin everywhere, simply immerse it in the bath, leg bones and all, giving it plenty of room at first. Move it up and down, and leave it as much spread out and free from folds as possible. Remember that the fluid must act upon the inside of the skin, for the epidermis is often almost impervious to it. If you allow the skin to lie upon itself in thick folds, stuck together on the inside, those spots are liable to lose their hair in a most unaccountable and aggravating way. If the skin is small and thin, the bath soon does its work; but if it is a large skin, move it up and down, and all about, every day for the first two or three days. By the end of that time its preservation will be complete.

      Half-spoiled Specimens.—Very often a subject will be brought to you in the flesh, several days old, green on the abdomen, and the hair starting to slip off between the hind legs. If the hair pulls out readily on various parts of the body and limbs, it is a gone case; but if it starts only a little on the lower part of the abdomen, and is firm everywhere else, put some bath, with a little extra alum in it, on the fire to get warm, snatch that skin off in a hurry, and without stopping for any fancy touches whisk it into the warm bath. The bath should not be so hot that you cannot bear your hand in it. It will act like magic. Then you can gradually finish your work on the skin, so as to keep it safe from harm. Very often quick work, and a warm bath with plenty of alum in it, will save a skin in fine, mountable shape, when nothing else will. The alum acts as a powerful astringent, drawing together the fibres of the epidermis around the root of each individual hair, and likewise binding together the cutis and epidermis.

      Cleanliness.—You will observe that as fresh skins are put into a bath it gradually loses its strength, and it is also liable to become, in time, so dirty with blood and grease that it must be thrown away. Keep skins that are greasy (bear, seal, etc.) carefully by themselves, and never put the skin of a deer, cat, or any animal with a fine coat in a greasy or dirty bath. If a bath is clean, but of too low strength, make some extra strong bath, say 20°, and add to it and bring it up to 15°. Keep all your bath receptacles tightly closed, or the liquid will evaporate very rapidly.

      Testing the Bath.—If you have no salometer, and are not overparticular, you can test your bath by tasting it; but unless the bath is new and untouched, I prefer the little salometer. By tasting the bath when first made in the proportions given above, and remembering the degree of its astringency upon the tongue, you can make that a standard for comparison—if it suits your taste!

      Skulls and Leg Bones.—The leg bones of all small and medium sized mammals, even up to the deer, can just as well go into the bath, after they have been thoroughly cleaned of all flesh and tendons. The skulls, however, had better not go into the solution. Clean them carefully, anoint them all over with thin arsenical soap, put a tag on each to show to what skin it belongs, and let it dry. Don't lay it aside without poisoning, or it will be swarming with dermestes before you know it.

      As before stated, a skin must have room while it СКАЧАТЬ