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necessary to enable them properly to fix themselves, somewhat analogous to those mechanical contrivances by which the seeds of numerous plants, as those of the dandelion and cranesbill, are transported to a distance and enabled to enter the soil and fix themselves in it.
That any creature should begin life as an animal and end it as a plant seems to contradict the general analogy of creation, and requires much stronger proofs than appear to have been adduced in the present case, before it can be admitted. The motions of the oscillating plants are not very different from those of the stamina of some, and of the leaves of others, as the Hedysarum gyrans; yet Adanson has proved that the vibrations of the filaments are the same both in hot and cold weather, and that the aquatic species are equally sensible with the terrestrial, therefore the movement can scarcely be caused by the temperature. But as analogous motions were observed by Mr. Brown in spherical and other molecules obtained from vegetables, it is evident that such motions do not necessarily indicate an animal, but only a kind of attraction and repulsion produced by an uncertain cause. Another argument proves their vegetable nature, these plants give out oxygen, whereas if they were animals they would absorb oxygen and give out azote.
Professor Agardh illustrates his opinion just stated by the following fanciful allusion. When thus fixed he considers these beings as no longer having any animal life, but as preserving the appearance of it, “ Like those men of Plato,” adds he, “ agitated by eternal regret with which the remembrance of a happy life, the sweets of which they formerly tasted, inspires them ; always oscillating, never tranquil, they seem aiming at the recovery of that happy life which they have lost.” The locomotions, however, of the germes of these Hydrophytes, and their oscillatory movements when fixed, indicate at least a semblance of animality, and an approach to the confines of the animal kingdom.
Leaving, therefore, these doubtful forms, as having no just claim to be considered as animals, I shall now proceed to those whose right to that title is generally acknowledged. And here two very different tribes start up and prefer their claim to be first considered; the Infusories, namely, and those which have been called Polypes and Zoophytes. But since the first of these two classes, by means of one of its tribes, as its great oracle, Ehrenberg, remarks, approaches the oscillating plants, I shall consider it as the basis on which the Deity has built the animal kingdom. Indeed, though the Polypes at first sight appear most to resemble the higher plants, in their general configuration, the Infusories, as well as coming nearer to the lowest by some of
their members, in others exhibit no slight analogy to seeds.
Of all the groups of animals those of the least consequence, one would think, must be those that for the most part escape the inquiring eye unless aided by a microscope. The infusories, or as they have been also called animalcules, microscopic animals, acrita or indiscernibles, amorpha or without form, are of this description. These wonderful little creatures, though they are every where dispersed, remain like seeds, without apparent life or motion, perhaps after animation has been suspended for years, till they come in contact with some fluid, when they are immediately reanimated, move about in various directions, absorb their proper nutriment, and exercise their reproductive powers according to the law of their several natures. Yet these little animals, though in some respects they exhibit no slight analogy to vegetables, are not only distinguished from them by their irritability, but likewise by their organization, and powers of locomotion and voluntary action. Their mode of reproduction, however, is not far removed from that of some vegetables; they are spontaneously divisible, some longitudinally and others transversely, and these cuttings, if they may be so called, as in the Hydra or common Polype, become separate animals. They are also propagated by germes, and some appear to be viviparous. The species of. Vibrio found in diseased wheat by M. Bauer is oviparous, as is evident from his observations and admirable figures. Lamarck indeed regards them as having no volition, as taking their food by absorption like plants; as being without any mouth, or internal organ; in a word, as transparent gelatinous masses, whose motions are determined not by their will, but by the action of the medium in which they move. That they have neither head, eyes, muscles, vessels, nerves, nor indeed any particular determinable organ, whether for respiration, generation, or even digestion. On account of these supposed negative characters, they were called by De Blainville, Agasiria, or stomachless, as having no intestines; but Ehrenberg, who has studied them in almost every climate, has discovered, by keeping them in coloured waters, that they are not the simple animals that Lamarck and others supposed, and that almost all have a mouth and digestive organs, and that numbers of them have many stomachs. Spallanzani, and other writers that preceded Lamarck, had observed that their motions evidently indicated volition : this appeared from their avoiding each other and obstacles in their way; from their changing their direction and going faster or slower as occasion required ; from their passing suddenly from a state of rest to motion without any external impulse ; from their darting eagerly at particles of infused substances; from their incessantly revolving on themselves without a change of place; from their course against the current; and from their crowding to shallow places of the fluid in which they are: each species seems also to exhibit a peculiar kind of instinct. Lamarck thinks all this delusion proceeding from errors in judgment, and the result of prejudices inducing people readily to believe what accords with their persuasions. But to apply this remark to such observers as Spallanzani, &c., is drawing rather largely on the credulity of his readers, who might very justly change the tables and apply it to himself, who is certainly as much chained by system as any one can be. Admitting that the observations of Spallanzani just stated record facts, it appears clearly to follow from them that these animals have volition, and therefore cannot properly be denominated apathetic, or insensible. The fact that they almost all have a mouth and a digestive system; many of them eyes, and some rudiments of a nervous one, implies a degree, more or less, of sensation in them all, and consequently that they have all, whether it be molecular and diffused in their substance, or confined to particular organs, I say that they have all a nervous influence and excitement sufficient for their several wants, corresponding with their several natures.