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its solution in iron pans or pots, is commonly known under the name of potash.

That other alkali of commerce, called soda is derived from a similar, though indeed a much more humble source; for, in this case, the alkali does not result from the combustion of stately and aboriginal forests, but from the combustion of heaps of seaweed; which, in various parts of the coast of Europe, has been collected from the surfaces of the adjoining rocks. *

CHAPTER IX.

ADAPTATION OF ANIMALS TO THE PHYSICAL CONDITION OF MAN.

SECTION I.
General Observations on the Animal Kingdom.

THE same remark may be made with regard to the general utility of animals, which has been made in the case of vegetables: for we have sufficient reason for believing, that, among the myriads of species of animals which exist upon the face of the earth, there is not one which does not act an important part in the economy of nature.t And yet, if it be correctly stated that out of about a hundred thousand species of animals, the number supposed to have been hitherto discovered, eighty thousand are of the class of insects:* it will be evident that the mass of mankind is ignorant of the very existence of nearly four-fifths of the whole animal kingdom: for, with the exception of the fly, the bee, the wasp, the ant, and perhaps ten or twelve more species, few but professed naturalists are acquainted with the specific differences of this class of animals; so small are they in size, and so apparently insignificant to a common observer. But, if we have reason for believing that not a single animal species exists without its use in the general economy of nature, we have a certainty that there are many, the absence of which would be almost incompatible with the continuance of the existence of the human race. If, for instance, the duties of the shepherd and herdsman could no longer be exercised, in consequence of the extinction of the two species of which they have now respectively the care, into what misery would not the population of a great part of the world be plunged, cut off at once from some of the most substantial forms of animal food, and the most general and effectual sources of clothing ! And, if we consider the subject in another point of view, how fitly are the natures of these species, from the individuals of which such immense advantage accrues to man, accommodated to that end If, for instance, the sheep and the ox were carnivorous, instead of herbivorous, how could the species be preserved : or, supposing for a moment that a sufficient quantity of animal food could be procured for them, under that supposition how could it be conveniently distributed to the flocks and herds scattered over a thousand hills; which now, without any con

* In some instances loose stones are intentionally placed on the sea-beach for the purpose of affording a substratum for the growth of various sea-plants, which attach themselves to the stones so placed.

# It is the opinion of Mr. Scoresby, (Account of the Arctic Regions, vol. i. p. 179, 180,) that the olive-green colour of the water, observable in many parts of the Greenland sea, is owing to the presence of numberless quantities of very small medusae and other minute animals. “These small animals,” he says, “apparently afford nourishment to the sepia, actiniae, and other

mollusca which constitute the food of the whale: thus producing

a dependent chain of animal life, one particular link of which

being destroyed, the whole must necessarily perish. * The number is probably greater.

sequent trouble to the shepherd or the herdsman, leisurely crop the grass, as they slowly traverse the surface from their morning to their evening range of pasture. , Let us suppose, again, that the horse were to become extinct. In that event how greatly would be in a moment altered the condition of the whole civilized world! for by what other means could there be kept up that general communication, between distant parts of the same empire, the rapidity and facility of which contribute at the same time to national prosperity, and to individual wealth and comfort; since that recent invention, the steam carriage, though capable of supplying the place of horses along the course of regular roads, would be inapplicable in most other situations? Consider, again, the position of contending armies, whose fate often is determined by the evolutions of united squadrons of this noblest of all the inferior animals; and sometimes even by the speed of the individual charger whose rider conveys the command which is to determine those evolutions: or, to descend into the less important though not less interesting scenes of domestic life, let us imagine, what we may perhaps have witnessed, the ecstasy of an afflicted parent, who has been enabled by the speed of this all but friend of man to reach the couch, and to receive the dying embraces of a beloved child; or to obtain those means of human aid, which haply may have averted the stroke of impending death. But in this, as in many similar instances, we can at once perceive (what we may always in reasoning presume) that an alteration in the constitution of any department of nature would be incompatible with that harmony of the whole, the existence of which is evident to all those who are capable of observing and interrogating philosophically the phenomena of creation. And if it should be said that some species of animals have actually become extinct, and others are gradually becoming more and more rare; yet, in such instances, we shall find the fact to be either the result of a providential adjustment, if the expression may be permitted; or, of the original rarity of the species themselves, as in the case of that uncouth bird the dodo;* or, as might possibly happen, with respect to that still more remarkable animal of New Holland, the ornithorhynchus paradoxus: in each of which instances the locality of the species appears to have been always extremely limited. On the other hand there are species of animals, which, though so minute, and so far removed from common observation, as to be scarcely known to mankind at large, much less employed for any useful purpose, would yet be productive of great inconvenience were they permitted to increase indefinitely: and hence, although they may perhaps previously accomplish some important end in the scheme of nature, they are destined to be the food of other animals, which, being much larger than themselves, necessarily consume them in great quantity. There is hardly a bird, or a reptile, or a fish, the contents of whose stomach would not bear witness to the truth of the assertion just made: and even among quadrupeds there are many species, as the mole, the hedgehog, the manis, and the ant-eater, which, from the nature of their food, are grouped into a distinct family, called insectivorous.

* It is not without reason that the epithet uncouth has been applied to the dodo; for two distinguished naturalists, in their day, maintained for many years that such a form had never existed, but in the imagination of the painter. One of these individuals however at length had an opportunity of inspecting the well-known specimen of the head of the dodo, which is preserved in the Ashmolean Museum at Oxford; and was then convinced that such a bird had existed. But so far was he from producing the same conviction in the mind of his friend, by the description of the specimen, that he incurred the charge of an intentional deception; and the result was, that an interminable feud arose between them: for though they were attached to the same institution, and lived within its walls, (not indeed without other companions, or absolutely under the same roof, as their prototypes in the Eddystone light-house,) they never again spoke to each other.

SECTION II.
Geographical Distribution of Animals.

AMong the strongest evidences of an intentional adaptation of the external world to the physical condition of man, may be classed the geographical distribution of animals, taken in connexion with certain points in their general history. Thus the elephant, which lives exclusively on vegetable food, is found naturally in those climates only, where vegetation is so luxuriantly abundant as easily to meet the large supply, which numerous individuals of such enormous bulk require: and then the tractability and docility of the animal are such, that its amazing strength may be easily directed to forward the purposes of man; and often is so directed, in the conduct of military operations, as well as on various ordinary occasions: and lastly, the increase of the species advances slowly; for, in by far the greater number of instances, only one individual is produced at a birth. Now had the elephant been equally adapted to colder climates, where vegetation is comparatively scant, the difficulty of supporting the individual animals in such climates would have diminished the value of the species: or, were elephants as intractable and indocile, as they are the reverse, what destruction would they not be continually dealing around them; witness the scene which took place a few years since in a public menagerie of London; where a company of musketeers was introduced, in order to subdue a single individual of this species, which had become infuriated from accidental circumstances ! Or, lastly, had the elephant been as prolific as the swine, (and it should be observed that they are branches of the same natural order,) how could the increased numbers of individuals have been maintained, in the case of a species which is not naturally capable of emigrating to a different climate?

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