We now proceed to a more particular description of The Curiosities of the Human Heart; and the Circulation of the Blood.

---------Though no shining sun, nor twinkling star

Bedeck'd the crimson curtains of the sky ;

Though neither vegetable, beast, nor bird,

Were extant on the surface of this ball.

Nor lurking gem beneath; though the great sea

Slept in profound stagnation, and the air

Had left no thunder to pronounce its Maker:

Yet Man at home, within himself might find

The Deity immense, and in that frame

So fearfully, so wonderfully made!

See and adore his providence and power. Smart.

With what admirable skill and inimitable structure is formed that muscular body, situated within the cavity of the chest, and called the human heart! Its figure is somewhat conical, and it is externally divided into two parts: the base, which is uppermost, and attached to vessels; and the apex, which is loose and pointing to the left side, against which it seems to beat. Its substance is muscular, being composed of fleshy fibres, interwoven with each other. It is divided internally into cavities, called auricles and ventricles; from which vessels proceed to convey the blood to the different parts of the body. The ventricles are situated in the substance of the heart, and are separated from each other by a thick muscular substance; they are divided into right and left, and each communicates with its adjoining auricle, one of which is situated on each side the base of the heart. The right auricle receives the blood from the head and superior parts of the body, by means of a large vein; and in the same manner the blood is returned to it from the inferior parts, by all the veins emptying their stores into one, which terminates in this cavity; which, having received a sufficient portion of blood, contracts, and by this motion empties itself into the right ventricle, which also contracting, propels the blood into an artery, which immediately conveys it into the lungs, where it undergoes certain changes, and then passes through veins into the left auricle of the heart, thence into the left ventricle, by the contraction of which it is forced into an artery, through whose ramifications it is dispersed to all parts of the body, from which it is again returned to the right auricle ; thus keeping up a perpetual circulation, for, whikst life remains, the action of the heart never ceases. In a state of health the heart contracts about seventy times in a minum, and as supposed, at each contraction, to propel about two ounces of blood; to do which, the force it exerts is very considerable, though neither the quantity of force exerted, nor of blood propelled, is accurately determined. The heart comprises within itself a world of wonders, and whilst we admire its admirable structure and properties, we are naturally led to consider the wisdom and power of Him who formed it, from whom first proceeded the circulation of the blood, and the pulsations of the heart; who commands it to be still, and the functions instantly cease to act.

This important secret of the circulation of blood in the human body was brought to light by William Harvey, an English physician, a little before the year 1600: and when it is considered thoroughly, it will appear to be one of the most stupendous works of Omnipotence.

The blood, the fountain whence the spirits flow, The generous stream that waters every part And motion, vigour, and warm life conveys To every particle that moves or lives,

---------------------through unnumber'd tube

Pour' d by the heart, and to the heart again

Refunded ----------------- Armstrong.

Who in the dark the vital flame illum'd, And from th' impulsive engine caused to flow Th' ejaculated streams through many a pipe Arterial with meand'ring lapse, then bring Refluent their purple tribute to their fount: Who spun the sinews' branchy thread, and twin'd The azure veins in spiral knots, to waft Life's tepid waves all o'er; or, who with bones Compacted, and with nerves the fabric strung : Their specious form, their fitness, which results From figure and arrangement, all declare Th' Artificer Divine! Bally.

Again:---------The nerves, with equal wisdom made.

Arising from the tender brain, pervade

And secret pass in pairs the channel'd bone.

And thence advance through paths and roads unknown.

Form'd of the finest complicated thread,

The num'rous cords are through the body spread.

These subtle channels, such is every nerve,

For vital functions, sense, and motion serve,They help to labour and concoet the food,

Refine the chyle, and animate tho blood. Blackmore.