gains the ascendant; and loading the tree with | to their situation. For as their ground, if I may a verdure not its own, keeps away that nourishment designed to feed the trunk; and, at last, entirely destroys its supporter. As all animals are ultimately supported upon vegetables, so vegetables are greatly propagated by being made a part of animal food. Birds distribute the seeds wherever they fly, and quadrupeds prune them into greater luxuriance. By these means the quantity of food, in a state of nature, is kept equal to the number of the consumers; and, lest some of the weaker ranks of animals should find nothing for their support, but all the provisions be devoured by the strong, different vegetables are appropriated to different appetites. If, transgressing this rule, the stronger rank should invade the rights of the weak, and, breaking through all re- | gard to appetite, should make an indiscriminate use of every vegetable, nature then punishes the transgression, and poison marks the crime as capital. If, again, we compare vegetables and animals, with respect to the places where they are found, we shall find them bearing a still stronger similitude. The vegetables that grow in a dry and sunny soil, are strong and vigorous, though not luxuriant; so also are the animals of such a climate. Those, on the contrary, that are the joint product of heat and moisture, are luxuriant and tender; and the animals assimilating to the vegetable food, on which they ultimately subsist, are much larger in such places than in others. Thus, in the internal parts of South America and Africa, where the sun usually scorches all above, while inundations cover all below, the insects, reptiles, and other animals, grow to a prodigious size: the earth-worm of America is often a yard in length, and as thick as a walking cane; the boiguacu, which is the largest of the serpent kind, is sometimes forty feet in length; the bats in those countries are as big as a rabbit; the toads are bigger than a duck; and their spiders are as large as a sparrow. On the contrary, in the cold frozen regions of the north, where vegetable nature is stinted of its growth, the few animals in those climates partake of the diminution; all the wild animals, except the bear, are much smaller than in milder countries; and such of the domestic kinds as are carried thither, quickly degenerate, and grow less. Their very insects are of the minute kinds, their bees and spiders being not half so large as those in the temperate zone. The similitude between vegetables and animals is nowhere more obvious than in those that belong to the ocean, where the nature of one is admirably adapted to the necessities of the other. This element, it is well known, has its vegetables, and its insects that feed upon them, in great abundance. Over many tracts of the sea, a weed is seen floating, which covers the surface, and gives the resemblance of a green and extensive meadow. On the under side of these unstable plants, millions of little animals are found adapted so express it, lies over their heads, their feet are placed upon their backs; and as land animals have their legs below their bodies, these have them above. At land also, most animals are furnished with eyes to see their food; but at sea, almost all the reptile kinds are without eyes, which might only give them prospects of danger at a time when unprovided with the means of escaping it.1 Thus, in all places, we perceive an obvious similitude between the animals and the vegetables of every region. In general, however, the ¦most perfect races have the least similitude to the vegetable productions on which they are ultimately fed; while, on the contrary, the meaner the animal, the more local it is found to be, and the more it is influenced by the varieties of the || soil where it resides. Many of the more humble reptile kinds are not only confined to one country, but also to a plant; nay, even to a leaf. Upon that they subsist; increase with its vegetation, and seem to decay as it declines. They are merely the circumscribed inhabitants of a single vegetable: take them from that and they instantly die; being entirely assimilated to the plant they feed on, assuming its colour, and even its medicinal properties. For this reason there are infinite numbers of the meaner animals that we have never an opportunity of seeing in this part of the world; they are incapable of living separate from their kindred vegetables, which grow only in a certain climate. Such animals as are formed more perfect, lead a life of less dependence; and some kinds are found to subsist in many parts of the world at the same time. But, of all the races of animated nature, man is the least affected by the soil where he resides, and least influenced by the variations of vegetable sustenance: equally unaffected by the luxuriance of the warm climates, or the sterility of the poles, he has spread his habitations over the whole earth; and finds subsistence as well amidst the ice of the north as the burning deserts under the Line. All creatures of an inferior nature, as has been said, have peculiar propensities to peculiar climates; they are circumscribed to zones, and confined to territories, where their proper food is found in greatest abundance; but !! man may be called the animal of every climate, and suffers but very gradual alterations from the nature of any situation. As to animals of a meaner rank, whom man compels to attend him in his migrations, these being obliged to live in a kind of constraint, and upon vegetable food often different from that of their native soil, they very soon alter their natures with the nature of their nourishment, assimilate to the vegetables upon which they are fed, and thus assume very different habits as well as appearances. Thus man, unaffected himself, alters 1 Linnæi Amænitates, vol. v. p. 68. and directs the nature of other animals at his pleasure; increases their strength for his delight, or their patience for his necessities. This power of altering the appearances of things, seems to have been given him for very wise purposes. The Deity, when he made the earth, was willing to give his favoured creature many opponents, that might at once exercise his virtues, and call forth his latent abilities. Hence we find, in those wide uncultivated wildernesses, where man, in his savage state, owns inferior strength, and the beasts claim divided dominion, | that the whole forest swarms with noxious animals and vegetables; animals as yet undescribed, and vegetables which want a name. In those recesses, nature seems rather lavish than magnificent in bestowing life. The trees are usually of the largest kind, covered round with parasite plants, and interwoven at the tops with each other. The boughs, both above and below, are peopled with various generations; some of which have never been upon the ground, and others have nover stirred from the branches on which they were produced. In this manner millions of minute and loathsome creatures pursue a round of uninterrupted existence, and enjoy a life scarcely superior to vegetation. At the same time, the vegetables in those places are of the larger kinds, while the animal race is of the smaller; but man has altered this disposition of nature; having, in a great measure, levelled the extensive forests, cultivated the softer and finer vegetables, destroyed the numberless tribes of minute and noxious animals, and taken every method to increase a numerous breed of the larger kinds. He thus has exercised a severe control; unpeopled nature, to embellish it, and diminished the size of the vegetable, in order to improve that of the animal kingdom. same food; as, to make use of a similar instance, a greater number of people may be crowded into the same space, if each is made to bear his fellow upon his shoulders." To diminish the number of animals and increase that of vegetables, has been the general scope of human industry; and if we compare the utility of the kinds, with respect to man, we shall find, that of the vast variety in the animal kingdom, but very few are serviceable to him; and, in the vegetable, but very few are entirely noxious. How small a part of the insect tribes, for instance, are beneficial to mankind, and what numbers are injurious! In some countries they almost darken the air: a candle cannot be lighted without their instantly flying upon it, and putting out the flame." The closest recesses are no safeguard from their annoyance; and the most beautiful landscapes of nature only serve to invite their rapacity. As these are injurious, from their multitudes, so most of the larger kinds are equally dreadful to him from their courage and ferocity. In the most uncultivated parts of the forest these maintain an undisputed empire; and man invades their retreats with terror. These are dreadful; and there are still more which are utterly useless to him, that serve to take up the room which more beneficial creatures might possess; and incommode him rather with their numbers than their enmities. Thus, in a catalogue of landanimals, that amounts to more than twenty thousand, we can scarcely reckon up a hundred that are any way useful to him; the rest being either all his open or his secret enemies, immediately attacking him in person, or intruding upon that food he has appropriated to himself. Vegetables, on the contrary, though existing in greater variety, are but few of them noxious. The most deadly poisons are often of great use in medicine; and even those plants that only seem to cumber the ground, serve for food to that race of animals which he has taken into friendship or protection. The smaller tribes of vegetables, in particular, are cultivated, as contributing either to his necessities or amusement; so that vegetable life is as much promoted by human industry, as animal life is controlled and diminished. 2 See Supplementary Note to this chapter, p. 186. 3 Ulloa's Description of Guayaquil. To subdue the earth to his own use, was, and ought to be, the aim of man; which was only to be done by increasing the number of plants, and diminishing that of animals: to multiply existence alone, was that of the Deity. For this reason, we find in a state of nature, that animal life is increased to the greatest quantity possible; and we can scarcely form a system that could add to its numbers. First, plants, or trees, are provided by nature of the largest kinds; and, consequently, the nourishing surface is thus ex--Ed. tended. In the second place, there are animals peculiar to every part of the vegetable, so that no part of it is lost. But the greatest possible increase of life would still be deficient, were there not other animals that lived upon animals; and these are, themselves, in turn, food for some other greater and stronger set of creatures. Were all animals to live upon vegetables alone, thousands would be extinct that now have existence, as the quantity of their provision would shortly fail. But, as things are wisely constituted, one animal now supports another; and thus, all take up less room than they would by living on the 4 This is not correct. Mr. Loudon, in his 'Encyclo pedia of Agriculture,' says: "On a superficial view, vegetables seem more abundant than animals; so contrary, however, is this to fact, that the species of animals, when compared with those of plants, may be considered in the proportion of 10 to 1. Hence it follows that botany, when compared with zoology, is a very limited study: plants, when considered in relation to insects alone, bear no proportion in the number of the species. The phanogamous plants of Britain have been estimated in round numbers at 1,500, while the insects that have already been discovered in this country (and probably many hundreds still remain unknown) amount to 10,000, which is more than six insects to one plant."-ED. Hence it was not without a long struggle, and various combinations of experience and art, that man acquired his present dominion. Almost every good that he possesses was the result of the contest; for, every day, as he was contending, he was growing more wise: and patience and fortitude were the fruits of his industry. Hence, also, we see the necessity of some animals living upon each other, to fill up the plan of Providence; and we may, consequently, infer the expediency of man's living upon all. Both animals and vegetables seem equally fitted to his appetites; and, were any religious or moral motives to restrain him from taking away life, upon any account, he would only thus give existence to a variety of beings made to prey upon each other; and, instead of preventing, multiply mutual destruction,5 5 NOTE.-The Law of Prey. The law of prey is the existing law of nature; of organized matter. It is the law whereby the balance of creation appears to be preserved, one class preying on another, and also individuals of the same class preying on each other,-vegetables as well as animals. Throughout organic creation, nature has provided, that every race, animal and vegetable, shall produce more offspring than is required to fill the spaces the parents occupy. For this there seems to be two reasons; first, to colonize the uninhabited spaces at the outset, and secondly, to supply casualties. To prevent too great accumulations, where casualties do not occur, the law of prey comes in force. In natural forests, the trees tower upwards, side by side, each striving to out-top its neighbour, till all alike become weak, lose all developinent of lateral branches, and possess only an unnatural tuft at their top in the likeness of a broom, the timbers of their long thin trunks being of most inferior quality. Nor does either grass or brushwood grow in the spaces between their roots. In their competitive struggle, the sun-light is shut out from between their stems, they have destroyed all races of plants except themselves, and they have degenerated in the process. But when a river or a mountain ravine breaks in upon the monotonous level, or where the agency of man, or fire, has opened up space, then, the trees exposed to air and light, and thinned in their numbers, become strong and healthy, develop lateral branches, and produce strong timber. So also, in the process of natural decay, as the weakest dry up and fall the remainder flourish. But it is under the care of man, where the process of thinning is judiciously performed, that trees attain their greatest perfection, when the competitive process is at an end. There is also another process of thinning which nature has provided, in the vegetable-eating tribes of animals, which in some cases carry the process so far that the forests are actually extirpated, as in the steppes of Tartary, and the pampas and savannahs of Southern America. Forests thus extirpated cannot rise again, the young trees are bitten off like grass as fast as they shoot, and grasses and herbs become the sole occupants of the land; grass, which becomes a matted turf, and loses the characteristics of a seed-bearing plant, remaining a mass of imperfect vegetation. Yet, select from amongst this mass individual plants, cultivate them carefully through a series of years, and seed will be developed. Replant this seed, and select the finest seeds for the next crop, and one may, perhaps, become a plant of wheat, another of barley, another of oats, another of rye. And when the wheat has attained its greatest state of perfection, and the seed is produced in quantities at pleasure, let a field be thickly sown with it, and let the crop shed its seed into the ground and grow up the following year, the crops of straw will be large, and the seed reduced. Let this process be repeated through a sufficient period of years, and the wheat will return to the original state of grass from which it was developed. The peasantry of Chilé it becomes rye." It is the same with the wild express this known fact, by saying vuelve centeno, kale, which may be cultivated into every variety of cabbage by human care, but which, if neglected, will become kale again. Competition, with weeds and other plants, will reduce it to its original type. Had the forests been left to the operations of the law of prey, acting against them, and not for them, by their own competition, and by the rapacity of the vegetable-eating tribes, they must wholly have discarnivorous animals, who thin their numbers by the appeared. But nature provided a balance in the same law of prey, and by this reciprocal action and re-action, forests, grass, and animals, were kept in abundance to greet the advent of man, as fuel, implements, houses, and food, to supply the wants of his savage state. Man, as a hunter, was little more than instinctive, as a wild beast. While his numbers were few, and birds, beasts, and other animals were in surplus, he would not quarrel; but as they became scarce with man's increase of numbers, the law of prey came again into operation, man against man. Rival claims to hunting-grounds begat strife, and the numbers of men were kept thinned, till the balance was adjusted between mouths and food. And, in this mode, the finest and strongest trees, animals, and men, were preserved to keep up the races, while the weaker were destroyed; a law of nature to prevent deterioration. It must be sufficiently obvious that the law of prey was essential to progress, in the merely instinctive state. Every organized being, plant, or animal, had its food prepared for it by nature, throughout a series of gradations. But with the advent of man, provision was made for the development of a new law, gradually to abrogate the law of prey, viz. The law of human reason. The cultivation of the earth, for the production of improved vegetation, is amongst its earliest efforts. The competition for hunting - grounds les-ened, when, from a limited space, the amount of food could be insured, till such time as the consequent increase of population restored the rivalry. And the history of all nations called civilized, is that of a constant struggle between population and food, skill and industry increasing the quantity of food, and population, thus excited, growing beyond the quantity, till the application of fresh skill again changed their relative proportions. The same has been the case with fuel. Trees disappeared under dense population, and then the stores of coal, hived up by nature, were dug from the surface and near the surface, and, as exhaustion took place, man's growing skill pierced deeper and deeper still. Had not fuel been thus provided, the numbers of mankind must have been very limited, and great parts of the earth left uninhabited. It is an established fact, that vegetable-eating animals are far inferior in energy to the carnivorous tribes; but the omnivorous are the most generally intelligent, amongst the lower animals, as well as amongst mankind. The Bramins of India and the Celts of Ireland are dominated over by the omnivorous English. Rammohun Roy was accustomed to say that when the Eastern Indians should begin to eat meat with their rice, they would take part with the English in governing. The bean-eating peasantry of Chilé are quiet and submissive; the flesheating wanderers of Paraguay and La Plata are ferocious and intractable."-From a paper in the Illuminated Magazine. CHAP. II. OF THE GENERATION OF ANIMAIS. BEFORE We survey animals in their state of maturity, and performing the functions adapted to their respective natures, method requires that we should consider them in the more early periods of their existence. There has been a time when the proudest and the noblest animal was a partaker of the same imbecility with the meanest reptile; and, while yet a candidate for existence, equally helpless and contemptible. In their incipient state, all are upon a footing; the insect and the philosopher being equally insensible, clogged with matter, and unconscious of existence. Where, then, are we to begin with the history of those beings, that make such a distinguished figure in the creation? Or, where lie those peculiar characters in the parts that go to make up animated nature-that mark one animal as destined to creep in the dust, and another to glitter on a throne? This has been a subject that has employed the curiosity of all ages, and the philosophers of every age have attempted the solution. In tracing Nature to her most hidden recesses, she becomes too minute or obscure for our inspection; so that we find it impossible to mark her first differences, to discover the point where animal life begins, or the cause that conduces to set it in motion. We know little more than that the greatest number of animals require the concurrence of a male and female to reproduce their kind; and that these distinctly and invariably are found to beget creatures of their own species. Curiosity has, therefore, been active in trying to discover the immediate result of this union; how far either sex contributes to the bestowing animal life, and whether it be to the male or female, that we are most indebted for the privilege of our existence. Hippocrates has supposed that fecundity proceeded from the mixture of the seminal liquor of both sexes, each of which equally contributes to the formation of the incipient animal. Aristotle, on the other hand, would have the seminal liquor in the male alone to contribute to this purpose, while the female supplied the proper nourishment for its support. Such were the opinions of these fathers of philosophy; and these continued to be adopted by the naturalists and schoolmen of succeeding ages, with blind veneration. At length Steno and Harvey, taking anatomy for their guide, gave mankind a nearer view of nature just advancing into animation. These perceived, in all such animals as produced their young alive, two glandular bodies, near the womb, resembling that ovary, or cluster of small eggs, which is found in fowls; and from the analogy between both, they gave these also the name of ovaria. These, as they resembled eggs, they naturally concluded had the same offices; and, therefore, they were induced to think that all animals, of what kind soever, were produced from eggs. At first, however, there was some altercations raised against this system: for, as these ovaria were separated from the womb, it was objected that they could not be any way instrumental in replenishing that organ, with which they did not communicate. But, upon more minute inspection, Fallopius, the anatomist, perceived two tubular vessels depending from the womb, which, like the horns of a snail, had a power of erecting themselves, of embracing the ovaria, and of receiving the eggs, in order to be fecundated by the seminal liquor. This discovery seemed, for a long time after, to fix the opinions of philosophers. The doctrine of Hippocrates was re-established, and the chief business of generation was ascribed to the female. This was for a long time the established opinion of the schools; but Leuwenhoeck, once more, shook the whole system, and produced a new schism among the lovers of speculation. Upon examining the seminal liquor of a great variety of male animals with microscopes, which helped his sight more than that of any of his predecessors, he perceived therein infinite numbers of little living creatures, like tadpoles, very brisk, and floating in the fluid with a seeming voluntary motion. Each of these, therefore, was thought to be the rudiments of an animal, similar to that from which it was produced; and this only required a reception from the female, together with proper nourishment, to complete its growth. The business of generation was now, therefore, given back to the male a second time, by many; while others suspended their assent, and chose rather to confess ignorance than to embrace error.1 In this manner has the dispute continued for several ages, some accidental discovery serving, at intervals, to renew the debate, and revive curiosity. It was a subject where speculation could find much room to display itself; and Mr. Buffon, who loved to speculate, would not omit such an opportunity of giving scope to his propensity. According to this most pleasing of all naturalists, the microscope discovers that the seminal liquor, not only of males, but of females also, abounds in these moving little animals which have been mentioned above, and that they appear equally brisk in either fluid. These he takes not to be real animals, but organical particles, which being simple, cannot be said to be organized themselves, but go to the composition of all organized bodies whatsoever; in the same manner as a tooth, in the wheel of a watch, cannot be called either the wheel or the watch and yet contributes to the sum of the machine. These organical particles are, according to him, diffused throughout all nature, and to be found not only in the seminal liquor, but in most other fluids in the parts of vegetables, and all parts of 1 Bonet Considerations sur les Corps Organises. animated nature. As they happen, therefore, to | amusing, to begin with animal nature, from its be differently applied, they serve to contribute earliest retirements, and evanescent outlines, a part of the animal, or the vegetable, whose and pursue the incipient creature through all its growth they serve to increase, while the super- changes in the womb, till it arrives into open fluity is thrown off in the seminal liquor of both day. sexes, for the reproduction of other animals or vegetables of the same species. These particles assume different figures, according to the receptacle into which they enter; falling into the womb, they unite into a foetus; beneath the bark of a tree they pullulate into branches; and, in short, the same particles that first formed the animal in the womb, contribute to increase its growth when brought forth.2 To this system it has been objected, that it is impossible to receive organical substances without being organized; and that, if divested of organization themselves, they could never make an organized body, as an infinity of circles could never make a triangle. It has been objected, | that it is more difficult to conceive the transformation of these organical particles, than even that of the animal, whose growth we are inquiring after; and this system, therefore, attempts to explain one obscure thing by another still more obscure. But an objection, still stronger than these, had been advanced by an ingenious countryman of our own; who asserts, that these little animals, which thus appear swimming and sporting in almost every fluid we examine with a microscope, are not real living particles, but some of the more opaque parts of the fluid that are thus increased in size, and seem to have a much greater motion than they have in reality. For the motion being magnified with the object, the smallest degree of it will seem considerable; and a being almost at rest, may, by these means, be apparently put into violent action. Thus, for instance, if we look upon the sails of a windmill moving at a distance, they appear to go very slow; but, if we approach them, and thus magnify their bulk to our eye, they go round with great rapidity. A microscope, in the same manner, serves to bring our eye close to the object, and thus to enlarge it; and not only increase the magnitude of its parts, but of its motion. Hence, therefore, it would follow, that these organical particles, that are said to constitute the bulk of living nature, are but mere optical illusions; and the system founded on them must, like them, be illusive. These, and many other objections, have been made to this system; which, instead of enlightening the rind, serve only to show, that too close a pursuit of nature very often leads to uncertainty. Happily, however, for mankind, the most intricate inquiries are generally the most useless. Instead, therefore, of balancing accounts between the sexes, and attempting to ascertain to which the business of generation most properly belongs, it will be more instructive, as well as 2 Mr. Buffon. The usual distinction of animals, with respect to their manner of generation, has been into the oviparous and viviparous kinds; or in other words, into those that bring forth an egg, which is afterwards hatched into life, and those that bring forth their young alive and perfect. In one of these two ways all animals were supposed to have been produced, and all other kinds of generation were supposed imaginary or erroneous. But later discoveries have taught us to be more cautious in making general conclusions, and have even induced many to doubt whether animal life may not be produced merely from putrefaction.3 Indeed the infinite number of creatures that putrid substances seem to give birth to, and the variety of little insects seen floating in liquors, by the microscope, appear to favour this opinion. But however this may be, the former method of classing animals can now by no means be admitted, as we find many animals that are produced neither from the womb nor from the shell, but merely from cuttings; so that to multiply life in some creatures, it is sufficient only to multiply the dissection. This being the simplest method of generation, and that in which life seems to require the smallest preparation for its existence, I will begin with it, and so proceed to the two other kinds, from the meanest to the most elaborate. The earth-worm, the millipedes, the sea-worm, and many marine insects, may be multiplied by being cut in pieces; but the polypus is noted for its amazing fertility; and from hence it will be proper to take the description. The structure of the polypus may be compared to the finger of a glove, open at one end, and closed at the other. The closed end represents the tail of the polypus, with which it serves to fix itself to any substance it happens to be upon; the open end may be compared to the mouth; and, if we conceive six or eight small strings issuing from this end, we shall have a proper idea of its arms, which it can erect, lengthen, and contract, at pleasure, like the horns of a snail. This creature is very voracious, and makes use of its arms as a fisherman does of his net, to catch and entangle such little animals as happen to come within its reach. It lengthens these arms several inches, keeps them separated from each other, and thus occupies a || a large space in the water in which it resides. These arms, when extended, are as fine as threads of silk, and have a most exquisite degree of feeling. If a small worm happens to get within the 3 Bonet Consid. p. 100.-The theory of equivocal generation was early exploded by men of science; but about the middle of the 18th century it was again revived. At present the opinion of English physiolo gists is pretty generally against the theory.-ED. |
