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Swarming, they pour : of all the varied hues,
511. Animalcules are shaped like fish, reptiles, eels, stars, hexagons, triangles, ovals, and circles; they have horns, probosces, &c. and although the eyes of many species are not discernible, yet they move about with inconceivable relative velocity in the fluids they inhabit, without interfering with each other.
512. Hunter divided all animated nature into single and complicated animals. The single, are those which possess only feeling or the powers of muscular contraction, and the power of absorbing food, as chalk absorbs moisture, and appropriating it to nourishment.
The Hydatid, found in sheep, consists only of a bag filled with water, and has no appearance of animal powers; but, when excited or pricked, contracts and shews its irratibility; while this vital power is supported by the nourishment which it receives through its coat.
513. From such simple animals, we ascend, through all the degrees, up to the complicated and combined powers of body and mind, in Man!
The links are kept up, by the addition of muscles, for additional motions; by other senses, for hearing, seeing, &c. and by various degrees of irratibility in those senses.
The blood for renovation circulates through the lungs; and for action through the muscles of the heart; secretions take place by the various glands; the contraction of the muscles moves the bones; the nerves convey the effect of the mental secretions to the brain; and there produce the inscrutable powers of sensation, will, and judgment.
514. Although animals, in general, are sufficiently distinct from vegetables, yet the gradations of nature are so minute, that many animals are but slightly removed from vegetables, having not more than one or two senses; and, as in some shell-fish, have not even the power of loco-motion.
Between these and man, there is a regular succession of that cunning and sagacity which are necessary to preserve and sustain life; yet between man and most other animals, there is, in mental capacity, as great'a difference as between some of those and vegetables.
Far as creation's ample range extends,
Obs.-In Art. 127 and 128, are described the transformations of insects, from the egg to the worm-the worm to the chrysalis--and the chrysalis to the butterfly.
The following cut represents those four states in the common catterpillar.
THE EGGS, THE CATERPILLAR, CHRYSALIS,
XXI. Chemistry 515. By Chemistry we ascertain the ingredients, component parts, or first principles of which all kinds of matter are composed.
DEFINITIONS. 1. Decomposition implies the separation of the elementary substances of which any compound substance is formed.
2. Pulverisation signifies the mere mechanical separation of bodies into smaller ones, without being decomposed into its elementary ingredients.
3. Chemical affinity affords proof that atoms are compounded in different forms, which coalesce and dovetail together with more or less facility.
4. The sensible atoms appear attracted or repelled accordingly as they, or those of the media in which they are placed, are more or less mutually affected.
5. The substance which decomposes another, is called a chemical test or re-agent.
6. If a salt be dissolved in water, it is said to be in solution, and the water is oalled the menstruum.
7. When water will dissolve no more of any substance, the water is said to be saturated.
8. If we would extract the salt, we must evaporate the water by heat, with a still, a retort or alembic; and if the va. por from either of these pass through a spiral tube or worm,