Anatomical Preparations, the skeleton and other portions of the dead body preserved from decomposition by various artificial methods, for the use of medical schools or science. The soft parts are usually separated from the skeleton by long-continued maceration in cold water, or by steaming or boiling; the bones are bleached, and the articulations held together by means of wires. This is called an artificial skeleton, and, when properly prepared, may be kept for an indefinite time. To preserve the natural articulations of the bones, the soft parts must be removed carefully by dissection, and many delicate sections and mechanical adaptations are required to display the internal structure, forms, and relative proportions of the skeleton and its component parts. The whole body of an animal, or any soft portion of the body, such as the heart or the intestines, may be preserved for a considerable time in alcohol or in spirits of turpentine; and such preparations are very useful in the study of comparative anatomy. Another method of anatomical preparation consists of injecting the vessels with some colored substance to distend them, and display their ramifications in the organs, that the shape and course and relative dimensions of the vessels may be seen with ease.

By means of a large syringe inserted into the main trunks of the arteries, these vessels are filled with a soft colored mass, which penetrates into the smallest branches, distends them, and makes them visible. The infused substance usually con-sists of a mixture of soap, pitch, oil, and turpentine, to which is added a coloring substance: red for the arteries, blue for the veins, and white for the absorbents or lymphatics. For the latter vessels quicksilver is preferred, on account of its extreme divisibility. - Dried preparations of the soft parts, such as muscles, nerves, and membranes, are preserved by covering them with a protecting coat of transparent varnish. The quicker they are dried, the better for this mode of preparation and conservation. Spirits of wine, distilled with pepper or a very strong pimento, and mixed with muriatic acid, is used for preserving them. Washing with pyroligneous acid gives firmness and whiteness to these anatomical preparations. Those which are preserved in liquids are usually kept in bottles of transparent glass, with accurately ground stoppers, to prevent evaporation, and secure them against the destructive influence of air, moisture, heat, dust, and insects. - Preparations of this kind are very necessary to preserve important specimens of normal and abnormal development in the animal economy, but they are difficult to preserve long in a comparative state of perfection.

Other means have therefore been devised as substitutes for common use. Instead of anatomical preparations properly so called, anatomical imitations are now used for purposes of general instruction, and great perfection has of late years been attained in the manufacture of these works of art. Imitations of organic form and structure were formerly made in wood, as those of the abbe Fontana in the museum at Florence; or in wax, as those made by Laumonier and others in France and Italy; card-board, as by Dr. Ameline of Caen; or in lithographic drawings, woodcuts, colored prints, etc. Drawings, however perfect, are not sufficient for all purposes; and though the anatomical imitations of organs were sometimes made with rare perfection and beauty in wax, they were too expensive for common use, and could neither be taken to pieces for detailed inspection, nor handled freely without risk of injury. In 1825 Dr. Auzoux of France conceived the idea of making imitations of all the organs of the human body; not only of their general external form and appearance, but also of their internal and minute details. For this purpose he composed a pasty mixture of a sort of papier mache which may be moulded to any form while liquid, and hardened in the form thus given.

Models of the organs were made in all their different layers and proportions, with the vessels and the nerves in each, as they are found in nature; the liquid substance was then poured upon the models and allowed to harden. A complete manikin of the human body and all the internal organs was thus formed, which could be taken to pieces and put together again at will and with the greatest ease; each part being colored in imitation of nature, and labelled with a number or the real name, by which it could be recognized at any time, either in or out of its natural position in the manikin. In 1830 this art, called clastic anatomy (Gr.Anatomical Preparations 100292 broken), was brought to great perfection; and a comparatively faultless model of the human body, 5 feet 6 inches in height, could be manufactured and sold for $600. This was still, however, too expensive for many persons, and complete manikins of a smaller size (3 feet 6 inches, in lieu of 5 feet 6 inches) were manufactured, and sold for $200 each. Each manikin contains 129 distinct pieces, forming different layers and organs or parts of organs.