THIRTEENTH WEEK-SATURDAY.

THE BALANCE PRESERVED IN THE ANIMAL AND VEGETABLE CREATION.

EVERY naturalist must have observed, that there is a tendency, in the reproductive powers bestowed by the Creator, to overstock the world, so that, if any one species of animals were permitted to produce its kind without check, the whole earth would, in process of time, be entirely over-run by that species alone, to such an extent, that, by-and-by, there would not be room for the vegetable to spread, or the animal to move. Among living creatures, a remarkable example of this power may be taken from the rabbit. This animal breeds seven times in a year, and produces eight young ones each time. On the supposition, therefore, that this happens regularly, at the end of four years, a couple of rabbits would have peopled the land with a progeny of nearly a million and a half. The common grass is an example of a similar kind among vegetables, a single plant of which would, in a very few years, under favourable circumstances, clothe a whole island such as ours. These are extreme cases; but, if any person would take the trouble of estimating the productive powers of any one kind of plant or animal, even the least remarkable for fecundity, he would soon satisfy himself, that the fact is not overstated.

This excessive power of reproduction, as in one sense it may be called, seems to be a necessary part of the wise economy of Nature; because it always enables organized existences to propagate their species, up to the extent in which provision is made for their subsistence; but then it would have occasioned the most injurious consequences, were not checks provided, by which each kind might be kept within its proper bounds. These checks are numerous and effectual. The most remarkable of

them, among the living tribes, is the existence of predacious animals. One creature preys upon another, and thus provision is made, by a remarkable contrivance, which, at first sight, appears cruel, for the existence of more numerous species, and for the more easy death of individuals, which would otherwise so press upon the means of subsistence, as to drag out a lingering and miserable life, till they perished by famine; while another instance of providential care, in this provision, is, that dead bodies are consumed and removed, which would otherwise infest the air with noisome and pestilential effluvia, in the process of decomposition.

But what has led me at present to advert to this subject, is the effect which winter also produces in checking an over production of organized beings. To what extent its severity, and the scanty subsistence it affords, are destructive of animal and vegetable life, I shall not attempt to estimate; but that it is considerable, cannot be denied. Notwithstanding the various and astonishing means made use of by a wise Creator, for the preservation of organized beings during the inclemency of winter, it is certainly true, that this season does not pass without a great expense of life. Violent storms, severe frosts, sudden inundations, deep snows, scarcity of food, the tracks of animals in the new-fallen snow, which guide the hunter to their lair,—all these are so many means of destruction to numerous individuals of various tribes of animals, and some of them means of destruction to different kinds of vegetables also.

Now, that the checks we have mentioned, combined with others, are most wisely adapted for promoting the benevolent intentions of Providence, in preserving a due 'balance in Nature, may be inferred from various considerations. Of these, I shall mention one, which is sufficiently striking. Man has frequently attempted, for his own purposes, to interfere with the balance which Providence has thus established, and often not with impunity. The following examples of this, which I ex

tract from a note in Mr Sharon Turner's History of the Creation, may suffice as an illustration. "Farmers destroy moles, because the hillocks they make break the level surface; but they have found worms increase so much, when the moles were gone, as to wish they had not molested them. Moles live on worms, insects, snails, frogs, and larvæ. The farmers on a nobleman's estate in France, found the moles' disturbances of the earth such a good husbandry to it, as to solicit their landlords not to have them killed.-(Bull. Un., 1829, p. 334.) So toads are found to keep down the ants. Mice have increased in barns where owls have been shot. The blue jay was destroyed in America for eating the pease; but the pea-grub, which it fed on, became more destructive afterward. A gentleman shot a magpie, to save his cherries, but found its craw as full as it could be crammed with the large blue-bottle flies, that lay their eggs in meat. The fox renders considerable service to man, by the quantity of rats, field-mice, frogs, toads, lizards, and snakes, which he destroys."

These are instances of the kind of balance, which is preserved in the animal world, by means of predacious animals, and prove that, by removing one cause of annoyance, we may sometimes only give room to another of a more grievous nature; and that we ought therefore to be cautious how we do violence to Nature. There can be no doubt, however, that the judicious interference of man was taken into account in the establishment of the order of Nature; and that his employing his rational powers for this purpose, is one of the exercises by which Providence intended to call forth his ingenuity, and reward his industry. It is not merely as a curse, that, in the field of the sluggard, “thistles grow instead of wheat, and cockle instead of barley ;"-it is also as a warning against sloth, and as a stimulus to exertion. So it is with regard to industrious, intelligent, and virtuous habits of every kind; and, with reference to the agriculturist, * Turner, note, p. 350, quoting from Howit's Brit. Preserv. VOL. I.

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while the neglect of such habits is punished by an accumulation of noxious weeds and vermin, and a deficiency of useful produce, the very reverse is the case when these are cultivated ;—and, mutatis mutandis, the same observation may be made in relation to every other profession.

Of the salutary effect of a judicious use of the power which Providence has entrusted us with, of extirpating noxious animals, we have a remarkable instance in the total extinction of the wolf from Great Britain, chiefly through the energetic measures adopted by two of our kings, Edgar I, and Edward I. The importance which we ought to attach to the removal of this nuisance, will be better estimated on reading the official account which was given in the public papers, of the devastations committed by wolves, in the year 1823, in the province of Livonia alone. They are stated to have devoured 1841 horses, 1243 foals, 1807 horned cattle, 733 calves, 15,182 sheep, 726 lambs, 2545 goats, 183 kids, 4190 swine, 312 sucking pigs, 703 dogs, 673 geese.

This destruction is remarkable, and it is only a single example of the immense extent of the power by which the excess of the reproductive principle is restrained, in all the various races of living beings, from the microscopic insect to the huge elephant, and even to man himself, who, although he seldom devours his fellows, has yet his scenes of carnage, and wars of extermination. We may shudder to contemplate such violence and bloodshed, but still the proof thus afforded of the wisdom of the great Creator, is conspicuous and pre-eminent; the balance of Nature is preserved; one species, taken on the average, does not unduly encroach upon another; a greater quantity of living beings has the means of being nourished, and is therefore produced; and the good of the whole is most strikingly consulted.

One condition, which the due balance of the reproductive powers involves, is, that the most useful species shall be able not only to maintain their ground, but to

preponderate over all the rest. This is instanced in the case of vegetables, in the prolific power already noticed, as bestowed upon the common grasses on which so many animals, and especially those destined for the use of man, are formed to feed. It is in virtue of this quality, with which man, for his own purposes, finds it necessary frequently to war, that the soft green carpet is so universally spread over swelling hill and sweeping valley, on which our herds and flocks browse so luxuriously by day, and repose so comfortably by night. But then, it was the wise intention of Providence, that this mastery, gained by the prolific power, should not be of such extent as to annihilate any of the species of plants formed by His creative wisdom. There are, therefore, most surprising and ingenious contrivances, by which this power is so far counteracted as to serve the end in view. These will fall more properly to be considered in another season, and it is enough at present merely to advert to them.

In saying, however, that the most useful vegetable productions are usually the most prolific, I must not forget to make an exception, which embraces a great variety of those plants that are cultivated by the farmer and the gardener, for the use of man. All the cerial, leguminous, potato, and cabbage tribes are of this kind, and seem to be intended, along with many other means in the economy of Providence, to verify the sentence so early pronounced on our fallen race, that in the sweat of their face they must eat bread. It is indeed, in this view, a most remarkable provision, that while the means of subsistence is so amply provided for the lower animals, man is left to procure his food by the exercise of his own mental and bodily powers, in the labours of cultivation; and, for this purpose, finds it necessary to counteract the natural tendencies of vegetation, as well as to control the habits, and subdue the propensities of the brute creation.

Among animals, the balance which we have been con