nous, masses which serve to separate or change any peculiar liquor.

ABSORBENTS are a set of small colourless vessels which pervade the whole surface of the body both externally and internally. Their office is to take up whatever fluids are effused into the different cavities, and to pour out their contents for particular uses. For the purpose of absorption they are highly irritable at their extremities, and are very replete with valves to prevent the escape or return of their contents. Their number, when compared with other vessels, is four times greater, and they are divided into lymphatics and lacteals, according to their respective offices.

FLESH is a fibrous part of an animal body, soft and bloody; it is that of which most of the other parts are composed, and by which they are connected toge ther. The ancients made five different kinds of flesh, the first muscular, as the heart and muscles, the second parenchymous, as that of the lungs, liver, spleet; the third viscerous, as the flesh of the sto mach and intestines; the fourth glandulous, as that of the breast, &c. and the fifth spurious, as the gums, lips, &c. The moderns, however, admit only of one kind, viz. the muscular, consisting of little tubes or vessels with blood therein; so that fleshy and muscular parts of the body are with them the same. In the flesh the blood vessels are so small as only to retain blood enough to preserve their colour red.

The BRAIN is a soft, whitish mass, inclosed in the cranium or skull; in which all the organs of sense ter minate, and the soul is supposed by some principally to reside. The brain is encompassed with two membranes called dura and pia mater. Its figure is roundish, oblong, and flat on the sides: it is divided into three principal parts, viz. the cerebrum or brain strictly so called, the cerebellum, and the medulla oblongata..

The CEREBRUM, or brain strictly so called, consists of two kinds of substance: the exterior one, called the cortex is ash coloured, soft and moist; the other, or inner part, is white, more solid and more dry; this is called the marrow or medullary, and sometimes the fibrous part, in contradistinction to the other,

which is also called the glandulous part. Most authors suppose the exterior part to consist of innumerable minute glands, destined for the secretion of animal spirits from the blood; and that the inner or medullary part is composed of infinitely fine fibres, which communicate with the nerves. Perhaps, then, to young readers it will be more intelligible to say that by the brain, the fine animal spirits are filtered or secreted from the blood; that their fine fluids or animal spirits, thus separated, pass through the fine fibres to the nerves, while the remaining blood is conveyed back through the veins. By turning up the brain, the origin of the nerves proceeding from it are distinctly seen. are in number nine pair, among which are the olfactory, optic, eye-movers, auditory, lingual, and sympathetic

nerves.

These

There are great diversities in respect of figure, structure, bulk, &c. in the brains of different animals

CEREBELLUM; the hind part of the brain-it is esteemed a kind of little brain by itself. Its colour is yellowish, and its figure somewhat resembles a flat bowl. Its substance is harder and more solid than that of the brain, but of the same nature.

MEDULLA OBLONGATA is the medullary part and the cerebellum joined in one. The medulla spinalis, or spinal marrow is also but a continuation of the me dulla oblongata, through the centre of the spine; and as the spine is an assemblage or series of bones of the back, which support the rest of the body, so the spinal marrow is the origin of most of the nerves of the trunk of the body.

The HEART is that part of the animal body, in which all veins terminate; and from which all the arteries arise. It is the chief instrument of the circulation of the blood. The heart is of a strong muscular substance. The figure of a heart is a cone, or pyramid reversed. Its size is various, ordinarily in length about six inches, its breadth at the basis four or five. younger the subject, the larger is the heart in proportion to the body. It is often smaller in tall and strong men than in others. It is immediately connected with the great blood-vessels. Some consider the heart as a

The

double muscle or as two muscles tied together by numerous fibres. It has an alternate motion of contraction and dilation, called systole and diastole, for the purpose of circulating the blood throughout the whole body. Some say there have been two hearts found in one man. Many insects have naturally several hearts; and silk worms have a chain of hearts running the whole length of their bodies.

The weight of the human heart, when removed from the body, with its pericardium, is from 10 to 15

ounces.

The LUNGS are the organs of respiration; a process which brings the atmospheric air in contact with the blood in the lungs, where it absorbs oxygen sufficient to give it a red colour, and whence carbonic and nitrogen gas are expelled. The cavity of the chest contains two distinct membranous bags, called the right and left bags of the pleura: each of these holds the lung of its own side, and is entirely separated from the opposite one. The pleure may be compared to two bladders placed laterally with respect to each other. The right bag of the pleura is larger than the left, as is also the right lung. The lung follows all the motions of the sides of the chest. It is distended by the influx of air, when the chest is enlarged; and the air is expelled from the lung, when the chest is diminished.

The lungs are two in number, one being contained in each bag of the pleura. They are loose and unconnected in these bags, except where the great vessels enter them. Their colour varies. It is always verging more to a red, in proportion as the subject is younger; in the adult it has more of a spotted and livid cast.

The lungs are subdivided into lobes; of which the right contains three, and the left two. Their substance is composed of a congeries of minute membranous cells, about equal in size to a pin's head, and as these are more or less filled with air, they give the lung a peculiar spongy feel.

These cells communicate with the ultimate ramifications of the air vessels, and receive air from that source. The pulmonary vessels-ramify minutely in them, and

thereby expose the blood to the effects of the contained air, and in this exposure the object of respiration is effected.

Diemerbroeck observes, that the vesicles admit not only of air, but also of other gross matters; and he instances two asthmatic persons which he opened; the one a stone-cutter, the vesicula of whose lungs were so stuffed with dust, that, in cutting, his knife went as through a heap of sand; and the other a feather-dresser, in whom the vesicles were full of the fine dust or down of feathers.

The WIND-PIPE, is the tube which conveys the external air into the lungs; it may be divided into three parts; the larynx, the trachea, and the bronchi.

The LARYNX is a hollow cartilaginous organ, placed at the top of the trachea. The air which passes through this from the lungs, in expiration, produces the voice. The cavity of the larynx opens above, at the root of the tongue, and below, in the trachea.

The TRACHEA, lies between the larynx and the bronchi: it is a cylindrical tube, about 3-4ths of an inch in diameter, and containing 16 or 18 cartilaginous rings. It runs along the middle of the fore-part of the neck, having the large blood-vessels of the neck on each side.

The BRONCHI are two branches, into which the trachea divides for the two lungs. They ramify through the lungs, dividing into smaller and smaller branches; and ultimately communicate with the air-cells.

The LIVER is a collection of glands, wherein the bile is separated; or, it is a large glandulous mass, of a red sanguine colour. It stretches itself over the right side of the stomach. Its figure is somewhat approaching to round. Its size is greater in proportion as the animal is younger. Its weight in an adult man, is about three pounds. The liver has a motion which depends on the diaphragm or midriff, to which it is very firmly connected, and must needs obey. Hence, in expiration, it is drawn up, and in inspiration let down again. The liver serves to purify the mass of blood, by making a secretion of the bilious humour it contains. The blood conveyed into the liver by the porta, after

the manner of the arteries, is received again, after having been purged of its bile in the glands of the liver, into innumerable veins, which empty themselves into the cava, which is the common channel by which the blood returns to the heart. The liver also delivers part of its bile unto the gall bladder, by the cystic and hepatic ducts, first discovered by Dr. Glisson. Besides these gall-vessels which are peculiar to the liver, it abounds with blood-vessels, especially veins. The French call the liver foye from foyer, focus, or fire-place, agree. able to the doctrine of the ancients, who believed the blood to be boiled and prepared in it.

The GALL BLADDER is a bag, serving as a reservoir for the bile. Its shape is that of a pear. The broad end is called the fundus, and the smaller part the neck of the viscus. It is firmly connected to the liver. The offices of bile are not satisfactorily known, but it is ascertained that it contributes to the separation of the chyle, exciting the peristaltic motion, carrying off gross matter from the blood, &c. It has been considered as animal soap, of a yellow green colour in healthy subjects, and according to Thenard, 800 parts contained. 700 water, 43 oily or resinous matter, 41 saccharine, and 4 animal substance, besides muriat, sulphat, and phosphat of soda, phosphat of lime, and oxyd of

iron.

The SPLEEN is a soft vascular body or mass of vesicles full of blood; it is spongy, of a darkish red, or rather livid colour, somewhat resembling the figure of a tongue, though sometimes triangular, and at other times approaching to round. It is usually single, though sometimes there are two; and even three have been found. It is situate between the spurious ribs and the stomach. Its ordinary length is six inches ; breadth three, and one thick. It is connected by the blood-vessels to the stomach and left kidney. It is covered by two tunics, or coats, the inner one consists of fibres very curiously interwoven. From this, probably, are derived those innumerable cells or little bladders, which make up the main bulk of the spleen, though Malpighi thinks otherwise. The use of the spleen has been disputed in all ages, both, as no imme.