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XX. Of Animated Nature, 52. Auimals are a class of beings differently organized from vegetables; because they have different destinations, bave different habits, and have the power of moving from place to place, called the faculty of loco-motion,
See, thro' this air, this arran, and this earth,
From thee to nothing, Obs. - The principal object of the study of natural history, is to teach us the characteristics, or distinctive marks of each individual natural object, called classification. To distinguish a species from all others that exist in nature, it is necessary to express in its characters almost the whole of its properties. A number of species brought together, constitutes a gouue or tribe. Those pro. perties which are cominon to all gouern, compose a character that distinguishes this useimblage all group from all other groups, such an mweinblage is called an order, By bringing together such orders as are more nearly allied, we form a more grural assemblage, called a dass; and by the union of several classes, we obtain a higher division, to which naturalists have given the name of kingitom.
433, When the all-wise Creator determined on making beings which should be able to move from place to place, he contriver for them a'dit. ferent organization from that of beings which were fixed,
As moveable beings could not have their roots in the ground, he provided them with the cavity
of the stomach, in which they wero to carry about what should be equivalent to the soil for plants and the suckers of their nutriment erntermg in that cavity, were destined to act like the roots of plants in the soil.
154. Ilence, in all animals, exists the necessity of eating frequently, to fill the cavity of the stomach; hence the folly and mischief of filling it with heterogeneous and unnatural substances; it being the object of nature simply to extract from the matter in the stomach a single uniform milky substance called chyle; no other juies but chyle being admitted into the animal system, the rest being rejected and expelled.
455, As animals were intended to move about, the perfect are therefore provided with eyes, to see objects which might endanger their existence; with ears to hear, for a similar reason : with a voice to warn others, or to obtain assistance in danger.
Hence, also, they were provided with the senses of smelling and tasting, to discriminate the food which was proper for the stomach; and with the sense of feeling, or irritability, to secure their identities, and excite them to action.
And though things sensible be numberless,“
And in those tire, all things their forms express, Which we can touch, taste emell, or hear, or see, 450, The organs of sense and the powers of volition proceed from the head and brain, by the nerves, which direct the muscles and ten.. dows; but the functions of animal-life are sus
tained by simple, yet wonderful arrangement, in the stomach and cavities of the body.
The heart is the centre of a thousand tubes, called arteries ; and by its never-ceasing contractions, it carries the blood through them, tu alt parts of the frame, diffusing everywhere warmth and life
457. The blood of a man, thus driven by the contraction of the heart (a force like that by
wbich water is driven out of a syringe or blad. · der), weighs 30 pounds; and, as this is the
stock of the precious fluid possessed by each of us; and our lives depend on its constant circu
lation, it is not allowed to remain at the extre· mity of the arteries, but is there taken up by
awther set of tubes called veins, and by them brought back again to the heart.
468. Thus, there is a constant circulation, outward aud inward, of this same Blood, at the rate of an ounce to each contraction, from the heart through the arteries, and back to the heard by the reins. To warm, revive, nourish it, imd keep up its quantity, there are various other wonderfal, but very simple contrivances.
Were once the energy of air denys,
Noe back again pursue its curious way. 4:59. The heart consists of four cavities, from one of which called the left ventricle, the blood is driven into the arteries through the body; by another, called the right auricle, it is received back again by the veins': it then passes into the
right ventricle, whence it is forced into the lunan
Thaving there been revivified by coming into contact with the air, it is carried back by n set of wing into the left anricle, and, from thence, into the left tentricle, where it began its course; it is ten drain forced into the aricries, brought back by the veins, &c., till the end of life.
400. The lungs are a large spongy Nubstance filling nearly the whole cavily of the chest, wbich riscs as they till, and falls us they empty, in respiring nir ihrough the mouth and postrils.
The act of respiration is performed about 20 tuines in a minute; and about 40 cubic inches of air le respired every time; of which 2 inches of oxygen are absorbed by the blood on the lungs, producing, at the same instant, 98 degrees of vital beat, and restoring the veinous blood to its bright red colour.
(h. --The lights wned in families to ferd en is, are the lungs of wherp or oxen, and are exactly similar to the Inngs of man. On inspection, they will be found to be wonderfully adapted to their design of bringing the nir in contact with the blood. Any rupiure in this tende fabric, or defect in their action, tends to that final clan of diseases, culled consumptioni,
461. Four thousand times in overy hour, cuch cavity of the beart is called into action: and all the blood in the body passes througli the heart 14 times in
every The arteries, into which it is forced, branch in every direction through the body, like the roots, branches, and leaves of a tree, running througli the substance of the bones, and every
part of the animal substance, till they are lost in such fine tubes as to be wholly invisible. · 462. In this manirer, they distribute nourishimeut ; supply perspiration; and renew all the waste of the skin; and, by passing throug! glands in every part of the body, all the varie ous animal secretions are elaborated.
In the parts where the arteries are lost to the sight, tlie veins take their rise, and in their commencement are also imperceptible. The blood is then of a dark colour; and, as it roturns to the heart with a less impetus, there is always twice as much blood in the veins as in the arteries. · 463. As the blood, in this discoloured state, has lost some of its vital power, it is driven through the lungs, and its colour is restored , but on its passage hack to the heart, it also receives a supply of a new fluid extracted from the food of the animal in the stomach and intestines.
The loss of weight in a human body hy pers spiration in 24 hours is about four pounds; and what is gained by the inspiration of air into the lungs, is lost by the expulsion of moisture, and of gas generated in the lungs.
464. The motion of the lungs is preserved by that of the chest containing them; that of the heart, may be felt on the left breast; and the circulation of the blood, hy the action of the pulse in various parts of the body, and particularly at the wrist.
In children, the pulse gives 120 strokes in a