in natural history, an organized and living body, which is also endowed with sensation: thus, minerals are said to grow or increase, plants to grow and live, but animals alone to have sensation.
It is this property of sensation alone that can be deemed the essential characteristic of an animal; and by which the animal and vegetable kingdoms seem to be so essentially separated, that we cannot even imagine the least approximation of the one to the other. Those naturalists, indeed, who have supposed the distinction between animals and vegetables to consist in anything else than what we have already mentioned, have found themselves greatly embarrassed; and have generally agreed, that it was extremely difficult, if not impossible, to settle the boundaries between the animal and vegetable kingdoms. But this difficulty will be easily seen to arise from their taking the characteristic marks of the animal kingdom, from something that was evidently common to both. Thus Boerhaave attempted to distinguish an animal from a vegetable, by the former having a mouth, which the latter has not; but here, as the mouth of an animal is only the instrument by which nourishment is conveyed to its body, it is evident that this can be no essential distinction, because vegetables also require nourishment, and have instruments proper for conveying it into their bodies; and where the end is the same, a difference in the means can never be essential. The fixing the difference in an animal's having a gula, stomach, and intestines, as is done by Dr Tyton, is as little to the purpose.
The power of moving from one place to another, hath by many been thought to constitute their difference; and indeed, in most cases, it is the obvious mark by which we distinguish an animal from a vegetable: but Lord Kames hath given several very curious instances of the locomotive power of plants; some of which, as he says, would do honour to an animal.—"Upon the slightest touch, the sensitive plant shrinks back and folds up its leaves, similar to a snail; which on the slightest touch retires within its shell. A new species of the sensitive plant hath been lately discovered. See Dionaea. If a fly perch upon one of its flower-leaves, it closes instantly, and crushes the insect to death. There is not an article in botany more admirable than a contrivance, visible in many plants, to take advantage of good weather, and to protect themselves against bad. They open and close their flowers and leaves in different circumstances: some close before sunset, some after: some open to receive rain, some close to avoid it. The petals of many flowers expand in the sun; but contract at night, or on the approach of rain. After the seeds are fecundated, the petals no longer contract. All the trefoils may serve as a barometer to the husbandman; they always contract their leaves on an impending storm. Some plants follow the sun, others turn from it. Many plants, on the sun's receipt, vary the position of their leaves, which is styled the sleep of plants. A singular plant was lately discovered in Bengal. Its leaves are in continual motion all day long; but when night approaches, they fall down from an erect posture to rest.
"A plant has a power of directing its roots for procuring food. The red whortle-berry, a low evergreen plant, grows naturally on the tops of our highest hills, among stones and gravel. This shrub was planted in an edging to a rich border, under a fruit-wall. In two or three years, it over-ran the adjoining deep-laid gravel-walk; and seemed to fly from the border, in which not a single runner appeared. An effort to come at food in a bad situation, is extremely remarkable in the following instance. Among the ruins of Newabbey, formerly a monastery in Galloway, there grows on the top of a wall a plane-tree about 20 feet high. Strengthened for nourishment in that barren situation, it several years ago directed roots down the side of the wall, till they reached the ground ten feet below; and now the nourishment it afforded to those roots during the time of their defending is amply repaid, having every year since that time made vigorous shoots. From the top of the wall to the surface of the earth, these roots have not thrown out a single fibre; but are now united in a single root.
"Plants, when forced from their natural position, are endowed with a power to restore themselves. A hop-plant, twisting round a stick, directs its course from south to west, as the sun does. Untwist it, and tie it in the opposite direction: it dies. Leave it loose in the wrong direction: it recovers its natural direction in a single night. Twist a branch of a tree so as to invert its leaves, and fix it in that position: if left in any degree loose, it untwists itself gradually, till the leaves be restored to their natural position. What better can an animal do for its welfare? A root of a tree meeting with a ditch in its progress, is laid open to the air. What follows? It alters its course like a rational being, dips into the ground, surrounds the ditch, rises on the opposite side to its wonted distance from the surface, and then proceeds in its original direction. Lay a wet sponge near a root laid open to the air; the root will direct its course to the sponge. Change the place of the sponge; the root varies its direction. Thrust a pole into the ground at a moderate distance from a scalding plant: the plant directs its course to the pole, lays hold of it, and rises on it to its natural height. A honeysuckle proceeds in its course, till it be too long for supporting its weight; and then strengthens itself by shooting into a spiral. If it meet with another plant of the same kind, they coalesce for mutual support; the one creeping to the right, the other to the left. If a honeysuckle twig meets with a dead branch, it screws from the right to the left. The clasps of briony shoot into a spiral, and lay hold of whatever comes in their way." Animal. for support. If, after completing a spiral of three rounds, they meet with nothing, they try again by altering their course."
By comparing these and other instances of seeming voluntary motion in plants, with that share of life wherever some of the inferior kinds of animals are endowed, we can scarce hesitate at ascribing the superiority to the former; that is, putting sensation out of the question. Muscles, for instance, are fixed to one place as much as plants are; nor have they any power of motion, besides that of opening and shutting their shells; and in this respect they have no superiority over the motion of the sensitive plant; nor doth their action discover more sagacity, or even so much, as the roots of the plane-tree mentioned by Lord Kames.
Mr Buffon, who seems to be delirious of confounding the animal and vegetable kingdoms, denies sensation to be any essential distinction. "Sensation (says he) more essentially distinguishes animals from vegetables: but sensation is a complex idea, and requires some explication. For if sensation implied no more than motion consequent upon a stroke or an impulse, the sensitive plant enjoys this power. But if, by sensation, we mean the faculty of perceiving and comparing ideas, it is uncertain whether brute animals are endowed with it. If it should be allowed to dogs, elephants, &c., whose actions seem to proceed from motives similar to those by which men are actuated, it must be denied to many species of animals, particularly to those which appear not to possess the faculty of progressive motion. If the sensation of an oyster, for example, differed only in degree from that of a dog; why do we not ascribe the same sensation to vegetables, though in a degree still inferior? This distinction, therefore, between the animal and vegetable, is neither sufficiently general nor determined.
"From this investigation, we are led to conclude, that there is no absolute and essential distinction between the animal and vegetable kingdoms; but that nature proceeds, by imperceptible degrees, from the most perfect to the most imperfect animal, and from that to the vegetables; and the fresh-water polypus may be regarded as the last of animals and the first of plants."
It were to be wished, that philosophers would on some occasions consider, that a subject may be dark as well on account of their inability to see, as when it really affords no light. Our author boldly concludes, that there is no essential difference between a plant and an animal, because we ascribe sensation to an oyster, and none to the sensitive plant; but we ought to remember, that though we cannot perceive a distinction, it may nevertheless exist. Before Mr Buffon, therefore, had concluded in this manner, he ought to have proved that some vegetables were endowed with sensation.
It is no doubt, however, as much incumbent on those who take the contrary side of the question, to prove that vegetables are not endowed with sensation, as it was incumbent on Mr Buffon to have proved that they are. But a little attention will show us, that the difficulty here proceeds entirely from our inability to see the principle of sensation. We perceive this principle in ourselves, but no man can perceive it in another. Why then does every individual of mankind conclude, that his neighbour has the same sensations with himself? It can only be from analogy. Every man perceives his neighbour formed in a manner similar to himself; he acts in a similar manner on similar occasions, &c. Just so it is with brute animals. It is no more doubtful that they have sensations, than that we have them ourselves. If a man is wounded with a knife, for instance, he expresses a sense of pain, and endeavours to avoid a repetition of the injury. Wound a dog in the same manner, he will also express a sense of pain; and, if you offer to strike him again, will endeavour to escape, before he feels the stroke. To conclude here, that the action of the dog proceeded from a principle different from that of the man, would be absurd and unphilosophical to the last degree.
We must further take notice, that there are sensations essentially distinct from one another; and in proportion as an animal is endowed with more or fewer of these different species, it is more or less perfect as an animal; but, as long as one of them remains, it makes not the least approach to the vegetable kingdom; and, when they are all taken away, is so far from becoming a vegetable, that it is only a mass of dead matter. The senses of a perfect animal, for instance, are five in number. Take away one of them, suppose sight, he becomes then a less perfect animal; but is as unlike a vegetable as before. Suppose him next deprived of hearing, his resemblance to a vegetable would be as little as before; because a vegetable can neither feel, taste, nor smell; and we suppose him still to enjoy these three senses. Let us, lastly, suppose him endowed only with the sense of feeling; which, however, seems to include that of taste, and he is no more a vegetable than formerly, but only an imperfect animal. If this sense is then taken away, we connect him, not with the vegetable kingdom, but with what Mr Buffon calls brute-matter. It is to this kingdom, and not to the vegetable, that animals plainly approximate as they descend. Indeed, to suppose an approximation between the vegetable and animal kingdoms, is very absurd: for, at that rate, the most imperfect animal ought to be the most perfect plant; but we observe no such thing. All animals, from the highest to the lowest, are possessed of vegetable life; and that, as far as we can perceive, in an equal degree, whether the animal life is perfect or imperfect: nor doth there seem to be the smallest connection between the highest degree of vegetation and the lowest degree of sensation. Though all animals, therefore, are possessed of vegetable life, these two seem to be as perfectly distinct and incommensurate to one another as any two things we can possibly imagine.
The power of vegetation, for instance, is as perfect in an onion or leek, as in a dog, an elephant, or a man: and yet, though you threaten a leek or an onion ever so much, it pays no regard to your words, as a dog would do; nor, though you wound it, does it avoid a second stroke. It is this principle of self-preservation in all animals, which, being the most powerful one in their nature, is generally taken, and with very good reason, as the true characteristic of animal life. This principle is undoubtedly a consequence of sensation; and as it is never observed to take place in vegetables, we have a right to say that the foundation of it, namely sensation, belongs not to them. There is no animal, which makes any motion in consequence of external impulse where danger is threatened, but what puts itself in a posture of defense; but no vegetable whatever Animal ever does so. A muscle, when it is touched, immediately shuts its shell; and as this action puts it in a state of defense, we conclude that it proceeded from the principle of self-preservation. When the sensitive plant contracts from a touch, it is no more in a state of defense than before; for whatever would have destroyed it in its expanded state, will also do it in its contracted state. We conclude, therefore, that the motion of the sensitive plant proceeds only from a certain property called by physicians irritability; and which, though our bodies possess it in an eminent degree, is a characteristic neither of animal nor vegetable life, but belongs to us in common with brute-matter. It is certain, that an electrified silk-thread shows a much greater variety of motions than any sensitive plant. If a bit of silk-thread is dropped on an electrified metal-plate, it immediately erects itself; spreads out the small fibres like arms; and, if not detained, will fly off. If a finger is brought near it, the thread seems greedily to catch at it. If a candle approaches, it claps close to the plate, as if afraid of it.—Why do we not conclude that the thread in this case is really afraid of the candle? For this plain reason, That its seeming flight is not to get away from the candle, but to get towards the electrified metal; and, if allowed to remain there, will suffer itself to be burnt without offering to stir.—The sensitive plant, in like manner, after it has contracted, will suffer itself to be cut in pieces, without making the least effort to escape. The case is not so with the meanest animal. An hedge-hog, when alarmed, draws its body together, and expands its prickers, thereby putting itself in a posture of defense. Throw it into water, and the same principle of self-preservation prompts it to expand its body and swim. A snail, when touched, withdraws itself into its shell; but if a little quicklime is sprinkled upon it, so that its shell is no longer a place of safety, it is thrown into agonies, and endeavours to avail itself of its locomotive power in order to escape the danger. In muscles and oysters, indeed, we cannot observe this principle of self-preservation strongly, as nature has deprived them of the power of progressive motion; but, as we observe them constantly to use the means which nature has given them for self-preservation, we can have no reason to think that they are defective of that principle upon which it is founded.
But there is no need of arguments drawn from the inferior creation. We ourselves are possessed both of the animal and vegetable life, and certainly must know whether there is any connection between vegetation and sensation or not.—We are conscious that we exist; that we hear, feel, &c.: but of our vegetation we are absolutely unconscious. We feel a pleasure, for instance, in gratifying the calls of hunger and thirst; but of the process by which our aliment is formed into chyle, the chyle mixed with the blood, the circulation of that fluid, and the separation of all the humours from it, we are altogether ignorant. If we, then, who are more perfect than other vegetables, are utterly insensible of our own vegetable life, why should we imagine that the less perfect vegetables are sensible of it?
To illustrate our reasoning here by an example.—The direction of the roots of the plane-tree mentioned by Lord Kames, shows as much sagacity, if we are to look only to the outward action, as can be observed in any motion of the most perfect animal whatever; nevertheless, we have not the least suspicion, either that the tree saw the ground at a distance, or that it was informed of its being there by the root of its roots. If a wound is made in the body of a man, and a loss of substance is to be repaired, the same sagacity will be observed in the arrangement of the fibres, not only as if they were animated, but they will dispose of themselves seemingly with a degree of wisdom far superior to what we have any idea of; yet this is done without our having the least knowledge either how it is done, or of its being done at all. We have therefore in ourselves a demonstration, that vegetable life acts without knowing what it does: and if vegetables are ignorant of their most sagacious actions, why should we suspect that they have a sensation, let it be ever so obscure, of any of their inferior ones, such as contracting from a touch, turning towards the sun, or advancing to meet a pole?
Thus we may easily give Mr Buffon a reason why we ascribe sensation to an oyster, and none to a vegetable; namely, because we perceive the vegetable do nothing but what is also performed in our own bodies, without our having the least sensation of it; whereas an oyster puts itself in a defensive posture on the approach of danger; and this being an action similar to our own upon a like occasion, we conclude that it proceeds from the same principle of sensation. Here it may also be observed, that though the inferior animals are deficient in the number, they are by no means so in the acuteness of their sensations; on the contrary, though a muscle or an oyster is probably endowed with no other sense than that of feeling, yet this sense is so exquisite, that it will contract upon the slightest touch, such as we would be altogether insensible of.
As to that power of contractility, or irritability, which is observed in some plants; our fools have it, when deprived both of vegetable and animal life: for a muscle, cut out of a living body, will continue to contract, if it is irritated by pricking it, after it has neither sensation nor vegetation.
A very good moral reason may also be adduced why we do not believe vegetables to be endowed with sensation.—Had they been so, we must suppose them to suffer pain when they are cut or destroyed; and if so, what an unhappy state must they be in, who have not the least power to avoid the injuries daily offered them? In fact, the goodness of the Deity is very conspicuous in not giving to vegetables the same sensations as to animals; and as he hath given them no means of defense, though we had not been told it by himself, we might have known that he gave them for food to animals; and, in this case, to have endowed them with sensation would have been a piece of cruelty. Tho' animals without number prey upon one another, yet all of them have some means of defense; from whence we may justly conclude, that their mutual destruction was not an original appointment of the Creator, but what he foreflew would happen in a course of time, and which he therefore gave every one of them some means of guarding against. It may no doubt be here objected, that the giving some means of self-defense to every animal cannot be reckoned a sufficient proof that it was not the original design of the Creator that they should be destroyed, seeing these means are not always effectual for their preservation.—This objection, how- ever, cannot be completely abated without a solution of the question concerning the origin of evil among the works of a perfectly good Being. But whatever difficulty there may be in solving this question, it is certain, that, as some means of self-defence is given to every animal, it has been the original design of the Creator, that in all cases one species of animals should not be destroyed at the pleasure of any other species; and as no means of self-defence is given to any vegetable, it is plain that they have been destined for a prey to every species of animals that had access to them. Philosophers have insisted much on the necessity of one animal's devouring another, that there might be room sufficient for all; but this, so far from being a system worthy of the divine wisdom, seems to us to be a reflection upon it, as if the author of nature could not have found means to preserve the life of one part of his creatures, without the destruction and misery of the rest.
The sacred writings leave us at no loss to see how this carnivorous disposition came in; and in the next world, this piece of perfection (as the sanguinary philosophers abovementioned would have it to be) seems to be left out; for there, it is said, "They shall not hurt nor destroy; the lion shall eat straw like the ox, and there shall be no more pain."
When speaking of the food of plants, we took occasion to mention a certain power, totally different from that of attraction or repulsion, by which the food of a plant, after it was attracted, or otherwise brought to it, was assimilated to its substance. This power which we there distinguish by the name of transmutation, belongs in a more eminent degree to animals. The alimentary substance is changed into two kinds of matter. (1.) An excrementitious one, which passes off through the intestines; and (2.) A fluid, which is the direct pabulum of the animal. Different substances, however, are not equally changeable by this process. The human stomach is not capable of acting upon any animal substance till it has lost its vital principle: the stomachs of some animals cannot act upon creatures of their own species: some have an apparatus for grinding their food after it is swallowed, &c. and there are no animals but what are subject to death by taking certain substances into their stomach. Some substances also, though they resist the action of the stomach, and pass unchanged into the system, produce no bad effects. Thus, madder will turn the bones of animals red; rhubarb will communicate its purgative nature to the milk, and its deep yellow colour to the urine.—All these changes, however, seem to belong to the vegetative part of our system: for as every one of them are performed without our knowledge of the manner how; and not only so, but while we are absolutely unconscious of their being done; we can have no reason to suppose, that the animal life, properly so called, is at all connected with them, any farther than as they are at present the means of preserving the creature alive, and making the connection betwixt the principle of life and this visible creation.
The description and classing of animals make a considerable part of Natural History, known by the name of Zoology. See the article Zoology.
For particulars relating to different animals, their analogous structure, sagacity, instinct, peculiarities, &c. see Comparative Anatomy, Instinct, Migration, No. 21.
Amphibious, Quadruped, Singing, Ornithology, Viviparous, Oviparous, Ichthyology, Entomology, &c.
Animal, used adjectively, denotes anything belonging to, or partaking of, the nature of animals. Thus, animal actions, those that are peculiar to animals; such are sensation and muscular motion.
Animal-Flower, in zoology, a name given to several species of animals belonging to the genus of Actinia of Linnaeus. They have likewise been distinguished by the names of Urtica Marina, or Sea-nettle, from their supposed property of stinging; and Sea-anemone, from their claws or tentacles being disposed in regular circles, and tinged with a variety of bright lively colours, resembling the petals of some of our most beautiful flowers. As to one species particularly, mentioned by Abbé Dieuemerre, (Phil. Trans. for 1773, art. 37.) the purest white, carmine, and ultramarine, are said to be scarce sufficient to express their brilliancy. The bodies of some of them are hemispherical, of others cylindrical, and of others shaped like a fig. Their substance likewise differs; some are stiff and gelatinous, others fleecy and mucilaginous; but all of them are capable of altering their figure when they extend their bodies and claws in search of food. They are found in many of the rocky coasts of the West India islands, and likewise on some parts of the coast of England.
They have only one opening, which is in the centre of the uppermost part of the animal; round this are placed rows of fleecy claws; this opening is the mouth of the animal, and is capable of great extension. The animals themselves, though exceedingly voracious, will bear long fasting. They may be preserved alive a whole year, or perhaps longer, in a vessel of sea-water, without any visible food; but, when food is presented, one of them will successively devour two mucles in their shells, or even swallow a whole crab as large as a hen's egg. In a day or two the crab-shell is voided at the mouth, perfectly cleared of all the meat. The mucle-shells are likewise discharged whole, with the two shells joined together, but entirely empty, so that not the least particle of fish is to be perceived on opening them.
An anemone of one species will even swallow an individual of another species; but, after retaining it ten or twelve hours, will throw it up alive and uninjured. Through this opening also it produces its young ones alive, already furnished with little claws, which, as soon as they fix themselves, they begin to extend in search of food.
One of the extremities of the sea-anemone resembles, as we have said, the outward leaves of that flower; while its limbs are not unlike the frag or inner part of it. By the other extremity it fixes itself, as by a sucker, to the rocks or stones lying in the sand; but it is not totally deprived of the power of progressive motion, as it can shift its situation, though very slowly.
A particular species of animal-flowers has been found in some of the islands ceded to Britain at the last treaty of peace with France; and the following account of them was published in the Philosophical Transactions, vol. 57. by Mr Ellis, in a letter to Lord Hillsborough.
"This compound animal, which is of a tender fleecy substance, consists of many tubular bodies, swelling gently towards the upper part, and ending like a bulb..." or very small onion; on the top of each is its mouth, surrounded by one or two rows of tentacles, or claws, which when contracted look like circles of beads.
"The lower part of all these bodies have a communication with a firm fleshy wrinkled tube, which sticks fast to the rocks, and sends forth other fleshy tubes, which creep along them in various directions. These are full of different sizes of these remarkable animals, which rise up irregularly, in groups near to one another.
"This adhering tube, that secures them fast to the rock, or shelly bottom, is worthy of our notice. The knobs that we observe, are formed in several parts of it by its infusing itself into the inequalities of the coral rock, or by grasping pieces of shells, part of which still remain in it, with the fleshy substance grown over them.
"This shows us the instinct of nature, that directs these animals to preserve themselves from the violence of the waves, not unlike the anchoring of muscles, by their fine filken filaments that end in suckers; or rather like the shelly basis of the serpula, or worm-shell, the tree-oyster, and the slipper barnacle, &c. whose bases conform to the shape of whatever substance they fix themselves to, grasping it fast with their tellaceous-claws, to withstand the fury of a storm.
"When we view the inside of this animal dissected lengthwise, we find like a little tube leading from the mouth to the stomach, from whence there rise eight wrinkled small guts, in a circular order, with a yellowish soft substance in them; these bend over in the form of arches towards the lower part of the bulb, from whence they may be traced downwards, to the narrow part of the upright tube, till they come to the fleshy adhering tube, where some of them may be perceived entering into a papilla, or the beginning of an animal of the like kind, most probably to convey its nourishment till it is provided with claws: the remaining part of these slender guts are continued on in the fleshy tube, without doubt for the same purpose of producing and supporting more young ones from the same common parent.
"The many longitudinal fibres that we discover lying parallel to each other, on the inside of the semi-transparent skin, are all interlaid in the several claws round the animal's mouth, and are plainly the tendons of the muscles for moving and directing the claws at the will of the animal: these may be likewise traced down to the adhering tube.
"As this specimen has been preserved in spirits, the colour of the animal, when living, cannot be certainly known; it is at present of a pale yellowish brown.
"With regard to its name, it may be called Actinia sociata, or the Clyster Animal-flower."
The Abbé Dicquemarre, by many curious, though cruel, experiments related in the Phil. Trans. for 1773, has shown that these animals possess, in a most extraordinary degree, the power of reproduction; so that scarce anything more is necessary to produce as many sea-anemonies as we please, than to cut a single one into as many pieces. A sea-anemone being cut in two by a section through the body, that part, where the limbs and mouth are placed, eat a piece of a muscle offered to it soon after the operation, and continued to feed and grow daily for three months after. The food sometimes passed through the animal; but was generally thrown up again, considerably changed; as in the perfect sea-anemone. In about two months, two rows of limbs were perceived growing out of the part where the incision was made. On offering food to this new mouth, it was laid hold of and eaten; and the limbs continually increasing, the animal gradually became as perfect as those which had never been cut. In some instances, however, he found, that, when one of these creatures was cut through, new limbs would be produced from the cut place, those at the mouth remaining as before; so that a monstrous animal was the consequence, having two mouths, and feeding at both ends. Having put some of them into a pan of water, set over a slow fire, he found that they lost their life at 50 degrees of Reaumur's thermometer. To avoid the imputation of cruelty in these experiments, the author argues the favourable consequences that have attended his operations on the sea-anemonies which have been so fortunate as to fall into his hands; as he hath not only multiplied their existence, but also renewed their youth; which last, he adds, "is surely no small advantage."
In Hughes's Natural History of Barbadoes an account is also given of several species of animal-flowers. They are there described as only found in a basin in one particular cave; and of the most remarkable species mentioned by him we have the following description:
"In the middle of the basin, there is a fixed stone, or rock, which is always under water. Round its sides, at different depths, seldom exceeding 18 inches, are seen, at all times of the year, issuing out of little holes, certain substances that have the appearance of fine radiated flowers, of a pale yellow, or a bright straw colour, slightly tinged with green, having a circular border of thick-set petals, about the size of, and much resembling, those of a single garden-marigold, except that the whole of this seeming flower is narrower at the discus, or setting on of the leaves, than any flower of that kind.
"I have attempted to pluck one of these from the rock, to which they are always fixed; but never could effect it: for as soon as my fingers came within two or three inches of it, it would immediately contract close together its yellow border, and shrink back into the hole of the rock; but, if left undisturbed for about four minutes, it would come gradually in sight, expanding, though at first very cautiously, its seeming leaves, till at last it appeared in its former bloom. However, it would again recoil, with a surprising quickness, when my hand came within a small distance of it. Having tried the same experiment by attempting to touch it with my cane, and a small slender rod, the effect was the same.
"Though I could not by any means contrive to take or pluck from the rock one of these animals entire; yet I once cut off (with a knife which I had held for a long time out of sight, near the mouth of an hole out of which one of these animals appeared) two of these seeming leaves. These, when out of the water, retained their shape and colour; but, being composed of a membrane-like substance, surprisingly thin, it soon shrivelled up, and decayed."
The reproductive power of the Barbadoes animal-flower is prodigious. Many people coming to see these strange creatures, and occasioning some inconvenience. nience to a person through whose grounds they were obliged to pass, he resolved to destroy the objects of their curiosity; and, that he might do so effectually, caused all the holes out of which they appeared, to be carefully bored and drilled with an iron instrument, so that we cannot suppose but their bodies must have been entirely crushed to a pulp: nevertheless, they again appeared in a few weeks from the very same places.
Plate XXXI. fig. 1. represents the actinia socia, or clustered animal-flower, described by Mr Ellis, with its radical tube adhering to a rock: (a) One of the animals stretching out its claws. Fig. 2. A perpendicular dissection of one of the bodies, to show the gullet, intestines, stomach, and fibres or tendons that move the claws: (a) A young one arising out of the adhering tube. Fig. 3. The actinia after, or animal-flower of the newly ceded islands. Fig. 4. The actinia anemone, or sea anemone from the same place. Fig. 5. The under part of the same by which it adheres to the rocks. Fig. 6. The actinia helianthus, or the sea sunflower from ditto. Fig. 7. The under part of the same. Fig. 8. The actinia dianthus, or sea-carnation, from the rocks at Hastings in Sussex. This animal adheres by its tail, or sucker, to the under part of the projecting rocks opposite to the town; and, when the tide is out, has the appearance of a long white fig: this is the form of it when put into a glass of sea-water. It is introduced here as a new variety of this animal not yet described.
**Animal-Food.** See Food.
**Animal-Oeconomy.** This subject is explained under **Anatomy.**
**Animal-Magnetism.** See Magnetism.
**Animal Spirit.** See Nervous Fluid.
**Animal System** denotes the whole class of beings endowed with animal life, otherwise called **Animal Kingdom.**
**Animals,** the preparation of, for collections or museum. See Quadrupeds, Birds, Reptiles.
**Pairing of Animals.** See Pairing.
**ANIMALCULE,** in general, signifies a little animal which is considerably inferior in size to ourselves. It hath been customary, however, to distinguish by the name of *animalcules* only such animals as are of a size so diminutive, that their true figure cannot be discerned without the affluence of glasses; and more especially it is applied to such as are altogether invisible to the naked eye, and cannot even be perceived to exist but by the affluence of microscopes.
By the help of magnifying glasses, we are brought into a kind of new world; and numberless animals are discovered, which from their minuteness must otherwise for ever have escaped our observation: and how many kinds of these invisibles there may be, is still unknown; as they are discerned of all sizes, from those which are barely invisible to the naked eye, to such as reflect the action of the microscope, as the fixed stars do that of the telescope, and with the best magnifiers hitherto invented appear only as so many moving points.
The smallest living creatures our instruments can show are those that inhabit the waters: for though possibly animalcules equally minute, or perhaps more so, may fly in the air, or creep upon the earth, it is scarcely possible to bring such under our examination; but water being transparent, and confining the creatures in it, we are able, by applying a drop of it to our glasses, to discover, to a certain degree of fineness, all that it contains—Some of the most curious of these animalcules, which have been described by microscopic observers, we shall here give an account of.
1. **The Hair-like Insect.** This is so called by Mr Barker on account of its shape; being extremely slender, and frequently an hundred and fifty times as long as broad. The body or middle part, which is nearly straight, appears, in some, composed of such rings as the windpipe of land animals is made up of; but in others, seems rather scaled, or made up of rings that obliquely cross one another. Its two ends are hooked or bent, pretty nearly in the same degree, but in a direction opposite to one another; and as no eyes can be discerned, it is difficult to judge which is the head or tail. Its progressive motion is very singular, being performed by turning upon one end as a centre, and describing almost a quarter of a circle with the other, as represented in the figure. Its motions are very slow, and require much patience and attention in the observer. These creatures are so small, that millions of millions of them fineness, might be contained in an inch square. When viewed singly, they are exceedingly transparent, and of a beautiful green colour; but when numbers of them are brought together, they become opaque, lose their green colour, and grow entirely black.
Notwithstanding the extreme minuteness of these animalcules, they seem to be fond of society; for, after viewing for some time a parcel of them taken up at random, they will be seen disposing themselves in a kind of regular order. If a multitude of them are put into a jar of water, they will form themselves into a regular body, and ascend slowly to the top, where, after they have remained for some time exposed to the air, their green colour changes to a beautiful sky-blue. When they are weary of this situation, they form themselves into a kind of rope, which slowly descends as low as they intend; but if they happen to be close to the side of the jar, they will descend upon it. They are so nearly of the specific gravity of water itself, that they will either remain at the bottom, float on the surface, or be suspended in the middle, according as they are originally placed, or as they themselves have a mind.
A small quantity of the matter containing these animalcules having been put into a jar of water, it so happened, that one part went down immediately to the bottom, whilst the other continued floating on the top. When things had remained for some time in this condition, each of these swarms of animalcules began to grow weary of its situation, and had a mind to change its quarters. Both armies, therefore, set out at the same time, the one proceeding upwards, and the other downwards; so that, after some hours journey, they met in the middle. A desire of knowing how they would be received on this occasion, engaged the observer to watch, fed of a them carefully; and to his surprise he saw the army, able degree that was marching upwards, open to the right and left, to make room for those that were descending. Thus, without confusion or intermixture, each held on its way; the army that was going up, marching in two columns to the top, and the other proceeding in one column to the bottom, as if each had been under the direction of wise leaders.
The hair-like insect was first discovered in a ditch at Norwich. Norwich, one end of which communicates with the river there, and the other end with a second ditch, into which several kennels empty themselves. The length of this ditch, when Mr Baker wrote his account of this animalcule, was at least 100 yards, and its breadth nine. The bottom, for more than a foot thick, was covered with a blackish green substance, in appearance like mud, made up for the most part of these insects; but, supposing only half or a quarter part of it to be composed of them, according to the dimensions we have given, their numbers must exceed all imagination.
2. Eels in paste, &c. When paste is allowed to stand till it becomes four, it is then found to be the habitation of numberless animalcules, which may be discerned by the naked eye; and though their form cannot be perfectly distinguished, their motion is very perceptible, and the whole paste will seem to be animated. Fig. 4. represents one of these anguillae magnified.
The most remarkable property of these insects is, that viviparous they are viviparous. If one of them is cut through near the middle, several oval bodies of different sizes will be seen to issue forth. These are young anguillae, each of them coiled up and inclosed in its proper membrane, which is so exquisitely fine, as scarce to be discernible by the greatest magnifier, while it incloses the embryo animal. The largest and most forward immediately break through this covering, unfold themselves, and wriggle about in the water nimbly; others get out, uncoil, and move themselves about more slowly; and the least mature continue entirely without motion. The uterus, or vessel that contains all these oval bodies, is composed of many ringlets, not unlike the aspera arteria of land-animals, and seems to be considerably elastic; for as soon as the animalcule is cut in two, the oval bodies are thrust out with some degree of violence, from the springing back or action of this bowel. An hundred and upwards of the young ones have been seen to issue from the body of one single eel, whereby the prodigious increase of them may be accounted for; as probably several such numerous generations are produced in a short time. They seem to be all prolific; and unless trial happens to be made upon one that has brought forth all its young, or when the paste has been kept for a very long time, the experiment will always succeed.—This property of these eels being viviparous renders it highly improbable that they ever become flies.