Anatomy (Gr.Anatomy 100293 dissection), the science which treats of the structure of organized bodies as learned from dissection. During the primitive ages of the world anatomy was little cultivated as a science, and hence the art of surgery was undeveloped. In later ages religious scruples forbade the opening of the human body to inspect the viscera; and students of anatomy were limited to the dissection of animals, to gain a knowledge of internal organs and their functions. The first branch of this science which was studied from nature was therefore animal anatomy, now called "comparative anatomy," from the fact of different types of the animal kingdom differing in their internal structure as much as in their external form. Aristotle was the first to give accurate descriptions of the internal organs of different, species of animals, and for many centuries after him little was done to advance the science by actual dissection and observation. Hippocrates had some accurate views of osteology, but his descriptions of the brain and the heart, and their respective functions, show that he knew little of anatomy.

The first important development of human anatomy, of which we have any authentic record, took place at Alexandria in Egypt during the reign of the Ptolemies. Erasistratus of Ceos and Herophilus of Chalcedon are mentioned by Galen as eminent anatomists of the Alexandrian school; and Herophilus is said to have obtained permission to open and inspect the bodies of living criminals, to gain a knowledge of internal organs and their modes of action. The writings of Oelsus show that he cultivated anatomy, but the next great steps in advance were made by Claudius Galenus, the celebrated physician of Pergamus. Galen was born at Pergamus, A. D. 130. He collected the works of his predecessors and pursued the study of anatomy, as far as he was able, by dissecting animals. He first showed that arteries in the living animal contain blood, and not air alone, as had been supposed by Erasistratus; but it did not occur to him to notice the circulatory movement of the blood in the vessels. This was reserved for Harvey, many centuries later; before which time the blood was supposed to move, in the veins as well as in the arteries, from within outward.

During the middle ages the natural sciences, neglected by the Christians, were mainly cultivated by the Arabs; but, as the Mohammedan religion forbade the dissection of human bodies, their physicians were obliged to rely on the knowledge transmitted to them by the school of Alexandria, and chiefly on the works of Galen. Their writings add little or nothing to the science of anatomy, unless it be the names of certain organs translated from the Greek into the Arabic, and afterward to some extent adopted by Italian and Spanish writers on anatomy. The spirit of religious liberty and commercial enterprise revived the cultivation of the arts and sciences in Italy during the 14th century; and Mondino da Luzzi, professor of anatomy at the university of Bologna, first publicly dissected two human bodies in the presence of medical students in 1306 and 1315, and shortly afterward published a description of the organs from direct observation and dissection. This, with the works of Galen, served as a text book for the schools till the 16th century, when the study of human anatomy from actual dissection became general in the medical schools of Italy. From this time forward human anatomy has been constantly studied from actual dissection and observation, in those countries of Europe where religious considerations offered least resistance to this mode of proceeding.

First Italy, then Holland, Denmark, Sweden, Germany, France, England, and America, have furnished names of eminence in the cultivation and advancement of the science of anatomy; but popular prejudices have hindered the free dissection of human bodies in medical schools, until a very recent date, in many states of Europe, and also in this country. Anatomy is now one of the most important branches of natural science, and its various departments have become so extensive as to require separate divisions and distinct methods of analysis. We have thus comparative anatomy, including every type of animal organization, not excepting man, as one of the types of the animal kingdom; and human anatomy as a distinct branch of study, in connection with physiology, pathology, surgery, and therapeutics. These again are subdivided into distinct branches, under the names of regional or surgical anatomy, descriptive or special anatomy, histological or general anatomy, and microscopical or minute anatomy. - Surgical anatomy treats of the relations of organs to each other, in each region of the body, such as the positions, forms, dimensions, structure, and peculiarities of nerves and vessels, muscles, glands, and membranes, in the head, the trunk, and the limbs, a proper knowledge of which is necessary to guide the surgeon in his delicate and difficult operations.

He must know where to cut and what to avoid in operating on the living body: for the life of the patient might be jeoparded if the surgeon were not well acquainted with the relative anatomy of vital organs. Descriptive anatomy treats of the distinct systems which pervade the whole frame, or perform a certain class of functions in the organism; such as the bones of the skeleton, the muscles, the skin, and the nerves of the whole body; the digestive system; the blood vessels; the respiratory organs; the generative and the urinary apparatus; the blood and the secretions. General anatomy treats of the different tissues which compose the special organs or classes of organs in different parts of the body; such as the three distinct coats of the stomach, i. e., the mucous membrane, the muscular coat, and the serous membrane or peritoneal covering; the areolar or connective tissue, found between the mucous and muscular layers, and disseminated more or less extensively throughout the body. Minute anatomy investigates the elementary basis of organic nature, and by the aid of chem-istry and the microscope observes and analyzes the atomic and cell structure of the tissues which compose the organs of the body; the fluids and contents are also subjected to this minute analysis.