Skeleton-making by maceration in cold water is, perhaps, one of the most sickening operations. I have been somewhat successful by trimming off all the flesh possible, wiring some parts together, tying others in cloths and boiling them gently for several hours in water changed from time to time, afterwards taking them out and picking off, with fingers and blunt tools, all the flesh remaining — whilst hot — then drilling and wiring all together with galvanised or copper fastenings in a proper manner, boiling again in plenty of water, and then allowing the bones to remain in cold water — constantly changed — for a week or so; finally laying out in the sun and air to bleach.
By this system I have lately "skeletonized" part of a horse, and the bones are free from grease and fairly white. Experience, however, in this as in everything else, will tell you what to do and how to piece one system into another to best advantage. Washing the bones with Hudson's "dry" soap, or soda and water, will often remove a great deal of the grease. Chloride of lime and water will assist the bleaching, but must be managed cautiously, or in careless hands it is likely to do more harm than good. The making of good and nicely bleached osteological preparations really depends on carefulness and neatness, supplemented by water, air, and sun; by the three latter aids, I have repeatedly improved in a wonderful manner "old bones" which were greasy and discoloured.
Should the sea be close at hand, the skeleton, shut in a box with holes, may be sunk, and exposed to the attacks of various "small deer," especially "bees" (Aega tridens), which swarm in some shallow waters to such an extent as to clear the flesh from a large animal in a few hours.
SKELETON LEAVES. -- Very beautiful objects may be made by placing the leaves of trees and shrubs, or such as are of a strong or woody texture, in a pan, pouring boiling soft or rain water over them, then exposing them to the atmosphere for a time varying from one to three or four months. They are then gently lifted out and held on a board, or on a plate, under running water, and the pulpy part, or epidermis, removed by gentle brushing with a camel-hair pencil or fine needle, to split the skin away from the mid-rib.
When nothing but the ligneous skeleton or woody fibre remains, it may be placed in a weak solution of chloride of lime, and exposed to the sun under glass to dry and bleach. To prevent them sticking to the paper on which you may wish to dry them, use either blotting-paper or oiled paper, after well washing the leaves. If skeletonizing in summer time, trust to sun alone, as chloride of lime has a tendency to make the leaves go brittle. The seed vessels of various plants, such as the poppies, thorn apples (Daturae), and campions, as also the leaves of laurel, holly, ivy, lime, sycamore, poplar, and a host of others, may be treated in this manner. When finished, they may be mounted on wires whipped with white silk, and placed on black velvet under a shade.
Some writers have advised the boiling of the leaves in a solution of caustic soda, or steeping them in a strong mixture of chloride of lime and water, but I have hitherto considered these plans not so practical as the foregoing, though, perhaps, quicker; as, however, I find two writers, in Science Gossip for 1867, very positive on the subject, I will give the following extracts:
"A solution of caustic soda is made by dissolving 3 oz. of washing soda in two pints of boiling water, and adding 1.5 oz. of quicklime, previously slacked; boil for ten minutes, decant the clear solution, and bring it to the boil. During ebullition add the leaves; boil briskly for some time — say, an hour — occasionally adding hot water to supply the place of that lost by evaporation. Take out a leaf and put into a vessel of water, rub it between the fingers under the water. If the epidermis and parenchyma separate easily, the rest of the leaves may be removed from the solution, and treated in the same way; but if not, then the boiling must be continued for some time longer.
To bleach the skeletons, mix about a drachm of chloride of lime with a pint of water, adding sufficient acetic acid to liberate the chlorine. Steep the leaves in this till they are whitened (about ten minutes), taking care not to let them stay in too long, otherwise they are apt to become brittle. Put them into clean water, and float them out on pieces of paper. Lastly, remove them from the paper before they are quite dry, and place them in a book or botanical press." — Dr. G. Dickson, Science Gossip, January, 1867.
"I once saw another way of managing skeleton leaves that interested me greatly. The leaves were boiled for two minutes, and then transferred to a strong solution of permanganate of potash and gently heated. In an hour or two the laxer tissues were easily removed by means of a brush. Sulphurous acid was used for bleaching them, and this liquid was also employed with much facility for the removing of the stains on the fingers caused by the permanganate of potash." — George Newlyn, Science Gossip, November, 1867.
The last-named gentleman appears to bleach his leaves by fastening them across a hat-box by means of strings, inserting a pan or tin cup containing sulphur, setting it on fire, and shutting down the lid (of course, out of doors). The whole article is very interesting, but too long for insertion here.