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4. Such are the principal parts of the thorax and abdomen; but besides these, there are several others which communicate with them. At the beginning of the neck, are the csophagus (gullet) and windpipe. The æsophagus is the canal, through which the food passes into the stomach: by the windpipe the air penetrates into the lungs. When the lungs send back the air through this channel, the voice is formed ;* and at the same time, the breast throws off its superfluous humours. At the top of the windpipe is a small valve or covering, which opens to give. passage to whatever is to come out by this tube. The lower orifice of the stomach is provided with a similar valve, which opens when it is pressed by the food; and shuts again to prevent it from returning in the upper part of the head, the brain is placed; which is capable of receiving impressions from external objects. Its whole inass is covered with two fine transparent membraness the outer of which is called the dura muter ; the inner, the piu mater. The former has a multitude of arteries and veins, interspersed over it: the latter closely invests thie substance of the brain.
5. Besides these parts, each of which occupies à determinate , place, there are others which are dispersed over the whole body, such as the bones, arteries, veins, lymphatics, and nerves. The bones, united together by joints, serve partly to support the body, and render it capable of motion; and partly to preserve and protect its nobler parts. The arteries and veins are diffused through the whole body, to nourish it by the blood that circulates in them. There are also many lymphatić vessels, which ordinarily join to certain glands, and receive a yellowish and transparent liquor, which they distribute afterwards to the whole body.
6. The nerves, of which ten principal pair are reckoned, are like little cords: they proceed from the brain, and disa tribute themselves over the whole body: they include a kind of medullary substance like that of the brain, and are the organs of sense and motion to the whole machine. All these parts are pierced with holes, in order that the light and subtle matter that superabounds may trans
* For a fuller account of the mechanism of the voice, see p. 2.
pire. These holes, which, by their extreme fineness, are invisible to the naked eye, are called pores. The same wisdom, so visible in the solid parts of our bodies, is found equally so in the fluid. The blood, chyle, lymph, bile, murrow, nervous juice, and the different kinds of viscous and glutinous humours, which innumerable glauds furnish; their several properties, ends, effects, the manner in which they are prepared, filtrated, and separated fienu each other ; their circulation, and reparation, all announce the most astonishing art, and the most profound wisdom.
7. Let us now recapitulate what we have said on the internal structure of the buman body. The bones, by their joints and solidiiy, form the ground-work, or frame, of this beautiful edifice. The liguments are the cords, which fasten all together. The muscles are fleshy substances, which execute their functions as elastic springs. The nerres, which extend to all parts of the body, establish buiween them the most intimate connexion. The arteries and reins, like rivers, convey health and life to every part.
8. The heurt, placed in the centre, is the focus, where the blood collects, and the primum mobile, from, and by means of which, it is circulated and preserved. The lungs, by another power, take in the external air, and expel noxious vapours. The stomach and intestines, are the magazines and laboratories, where those matters are prepared, which are necessary for daily supply. The bruin, the seat of the soul, is for ined in such a manner as is suitable to the dignity of its inhabitant. The senses, the servants of the soul, give it information of all that is necessary for it to know; and’minister to all its pleasures and wants.
ii. The Senses,
1. T'ision. See OPTICS.
2. Hearing. The undulations of the atmosphere, excited by the vibrations of sonorous bodies, are collected in the exiernal ear and auditory passage, as in the hearing trumpet, aud are conveyed to the meinbrana tympuni, or drum, which they cause to vibrate. The effect is transmitted through the small bones, to the watery fluid that fills the internal ear, in which the delicate filaments of the
auditory nerve float, and by this nerve the sensation is conveyed to the brain. See also ACOUSTICS.
3. Smelling. The cavily of the nose is divided into two parts, called the nostrils, by a partition, of which the upper part is bony, and the lower cartilaginous. The upper part of the cavity is covered with a thick glandulous membrane, above which the olfactory nerve is finely branched out and spread over the membrane of the spougy bones of the nose, and other sinuous cavities of the nostrils. The odorous efluvia of bodies being disseminated in the atmosphere, the latter fluid passes through the nose in respiration, and the odorous particles are thus brought into contact with the fibres of the nerves, which, by their communication with the brain, excite in the mind the sense of smell.
4. Tasting. The tongue is covered with two membranes: the external is thick and rugged, especially in quadrupeds; the internal membrane is thin and soft ; upon it appear several pupillæ, or small elevations, like the tops of the small horns of snails. These papillæ are composed of the extremities of the nerves of the tongue, and piercing the external membrane, are constantly affected by those qualities in bodies, which have their tastes excited in the quind hy means of these nervous papillæ, which are the immediate
organ of tasting. This organ bears a consider-able analogy to the sense of touch.
5. Touching. The outside of the skin is covered by a thin pellicle, called the epidermis, cuticle, or scarf-skin. Under the cuticle, is a substance called the rê te mucosum. In negroes, this substance is of a black colour, but in Europeans, white, brown, or yellowish.
The cutis vera, or the skin, is a substance made up of fibres closely connected with each other, aud running in various directions, being composed of the extremities of numerous vessels and
The papilla of the fingers or inside of the hand, may become erect or elevated, and being gently pressed against a tangible body, receive an impression which is conveyed to the brain, and is called touch.
ANATOMY, which considers minutely thestructure and functions of the human body, is divided into, 1. Osteogeny, or the doctrine of the growth of bones. 2. Osteology, or the doctrine of the maiured bones. 3. Chondivlogy, which
treats of cartilages. 4. Syndosmology, which treats of ligaments. 5. Myology, or the doctrine of the muscles. 6. Bursulogy, which treats of the bursæ mucosæ. Splunchnology, or the doctrines of the viscera. 8. singiology, which treats of the vessels. 9. Adenology, of the glands. 10. Neurology, or the doctrine of the nerves, &c.
Select Books on the Animal Kingdom. Dr. Suaw's highly accurate and splendid work entitled, General Zoology, and his ralualle Lectures on this subject delivered at the Royal Institution. The General Zoology is unequalled for the elaborate fidelity of its descriptions, the beauty and accuracy of the plates : with which it is embellished, and for the splendour of its typography. The Zoological Leclures deserve to be generally read, and are an ado mirable introduction to the larger work, which is not yet brought to a conclusion. To both these works we are proud to confess our obligations.
Dr. Shaw's Naturalist's Pocket-Book, a pleasing and instructive an. val companion. Bingley's Animal Biography, 3 vols. &vo. British Zoology, and Memoirs of British Quadrupeds, svo. Bewick’s Quadrupeds, 8vo., and Birds, 2 vols. 8vo. Derham's Physico and AstroTheology, 2 vols, 8vo. a new edition, with notes. Lesser's InsectoTheology, with Lyonuet's notes, 8vo. Paley's Natural Theology, svo.
Natural Philosophy. 1. It is
is to the old alchemists, or to those who were engaged in whimsical and visionary attempts to discover the philosopher's stone, that we are ultimately indebted for philosophy. They engaged in various chemical processes or experiments, in order to effect this grand discovery; and from their patient and laborious endeavours, many useful inventions proceeded, though not the particular discovery they were in quest of. Our countrymai), Roger Bacon, a famous monk who resided at Oxford in the twelfth century, was one of these, but he was one of the most rational and sagacious of the whole sect. He was soon convinced of the difficulty of the research in which he was engaged, (that of transmuting or changing other metals er substances into gold;) but he saw that the mode of analyzing or dividing bodies or substances into their constituent parts, was the true mode of investigating nature.
2. To Lord Bacon philosophy is indebted for its nexi great improvement. He followed the footsteps of his name-sake arid predecessor; he reduced his principles to a system, and laid it down as a maxim, that it was by en periment alone, that any thing in philosophy could be known with certainty. He therefore traced out the way in which future experimentalists might proceed, and afforded a variety of hints, on which they afterwards improved.
3. The good and the illustrious Boyle, however, may justly be termed the father of modern philosophy. Ile made it a principle to conduct all his inquiries by experiment alone. He effected much in the analyzation of bodies, and the examination of the principles of which they were composed. He not only invented that curious and useful instrument, the air-pump, but his experiments on the nature of air, laid the foundation for all the modern doctrines concerning it. His discoveries on light and colours, were an excellent introduction to the grand theory of Newton on that subject, and, possibly, served as the basis or foundation of them. In short, there was scarcely a topic of natural philosophy to which he did not lend his attention, and there was scarcely one which he did not improve.
4. He proposed to substitute experiment for theory, and laid the foundation of a solid edifice of buman knowa ledge, which should rise in due proportion and regular order, from earth to heaven. In his · Advancement of Learning,' he laid down the principles of genuine philosophy. The design of the Novum Organun' was, to raise and enlarge the powers of the mind, by a useful application of reason to all the objects which philosophy considers. In order to preclude objections drawn from the supposed visionary nature or novelty of his system, Lord Bacon treats in the third part of his instauration on the Phenomena Universi. This is intended to form a collection of materials towards natural and experimental history.
5. Such was the state of philosophy when NEWTON appeared. He reduced into one grand system, all the scattered discoveries of his predecessors. He explained the inotions of the heavenly bodies, on a principle entirely new