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that he has seen them in the agonies of death, and struggling convulsively (!) with all the appearance of animal life.'
In the fifth order, Characee, the chambered threads of Chara contain an abundance of little spiral bodies having an active
motion when discharged into water, and resembling entirely 'the so-called animalcules in mosses, &c. M. Thuret, who finds tentacula in the spores of Confervas, ascribes a similar moving apparatus to these bodies.'
These latter instances are taken from natural orders, all belonging to the first alliance, that of Algales, including those vegetable forms which are of the simplest structure and the lowest organization; besides their bearing on the present subject, they illustrate our former statement, that at the bottom of the scale of organization occurs the most apparent commingling of animal and vegetable characteristics.
The faculty of Sensation is so entirely an animal endowment, that the animal nature of any being which could be proved its possessor must be acknowledged by all. Linnæus made this his ground of distinction in the brief general definition which he propounded between the three kingdoms of Nature; • Lapides crescunt; vegetabilia crescunt et vivant; animalia crescunt, vivunt et sentiant. But the difficulty lies in the proof either of its presence or absence; and this difficulty is much greater than might be supposed without some consideration. In dumb animals, amongst the Vertebrata, or such as possess a brain and spinal cord, this proof is of two kinds: the possession of those structures which we know from various observations to be the agents of this function in man; and the movements or cries produced upon the application of stimuli, such as would cause sensation or pain in man. In those inferior animals which are not constructed with a cerebro-spinal axis, and still more in such as present no evident nervous structure whatever, the former of these proofs is, of course, quite wanting; and the latter, by itself, is insufficient; the physician finds that in the paralysed limb of a patient, (of which the nervous communication with the brain is cut off by disease or accident,) movements may be produced by external impressions, which communicate no sensation to the patient, either of the impression or the consequent movement. In like manner the body of a dead frog, or other animal, is convulsed when galvanised; or the tail of a lizard, accidentally separated from its body, twists and wriggles when pricked, as though in pain. Such instances sufficiently prove that, even in animal bodies, movements following external impressions are no proof of the faculty of sensation. The philosopher, Des Cartes, drew a very unjustifiable conclusion, when he maintained that all the movements of brutes are without con
sciousness; that animals are mere organized machines; and that when a horse quickens its speed on applying the spur, or a hound yelps, on the touch of the whip, this is no more than when the movements of a steam engine are accelerated on the turning of a tap, or an organ sounds on pressing down the keys. But if movements alone were sufficient proof of sensation, then is the Catch-fly plant conscious of the touch of the fly upon which it folds its leaf. The conclusion seems inevitable, that, in the descending series of organizations, we are unable to say where sensation terminates and irritability alone remains.
The nutritive apparatus and functions in plants and animals present remarkable differences. The plant expands in the media from which it directly imbibes its food. Its roots ramify in the earth, from which it absorbs moisture, holding in solution various nutritive principles; the leaves unfold in the atmosphere, from which they derive large supplies of carbonic acid and watery vapour. The animal is not so constantly supplied with nutriment; it takes in supplies of food only at considerable intervals, and hence it requires to be provided with some internal cavity for its reception.
The presence of a stomach, therefore, in animals, and its absence from plants, is frequently stated as one of their most exact distinctions. But an hydatid is an animal being, in its simplest form, consisting of a hollow membranous sac; the nutriment
' absorbed by its external surface is digested in the cavity within. In like manner, there are vegetable forms consisting only of isolated, independent cells. If the cavity of an animal hydatid be dignified by the title of a stomach, so must the cavities of vegetable cells. It is impossible to say, remarks Dr. Lindley,
• • that the whole interior of a living and independent cell is not sa stomach.'
If we consider the nature of their food, we shall find that, in this respect, there is a marked general distinction between plants and animals Animals feed merely upon organized substances, or organic principles; mineral, or inorganic matter, they are incapable of assimilating; it affords them no support. We may read of savage tribes who sometimes appease the cravings of hunger by filling their stomachs with unctuous earth or clay; but this can merely serve to relieve the sensation of vacuity; unless organic matter be commingled with it, it can afford no support; and though the earth worm, or the echinus, passes earth or sand through its body as food, it is only the small insects, or other particles of organic matter, which this contains, from which it can derive any nutriment. This rule, with regard to animals, is not, however, quite without exception; water, and some saline
matters, as phosphate of lime, and particularly common salt, form an essential part of their food; the broad statement must therefore be taken, literally cum grano salis, and with some limitation.
Plants, on the other hand, derive the materials of their growth only from mineral, or inorganic matters, or such as have been reduced, by the process of decomposition, to the state of inorganic compounds, such as water, carbonic acid and ammonia. If there were no other instance, on the part of vegetables, of a deviation in this particular from the general rule observed in vegetable life, yet the class of Fungi, -anomalous, as we have seen, in other respects,-are so in this, that they seem quite to resemble animal beings in the nature of their food. These singular plants grow chiefly upon organic substances in a state of commencing decomposition; and from these they imbibe for their food organic principles in a state of solution.
Connected with this anomaly in the chemical nature of their food, and likewise with an anomalous chemical constitution of their substance, which we before noticed,—is a striking anomaly in the action of the fungi upon the surrounding atmosphere; and in which respect, likewise, they imitate the phenomena of animal beings.
Animals, by the respiratory process, are constantly removing oxygen from the atmosphere, and replacing that gas with carbonic acid gas; on the other hand, the great effect of vegetable life upon the atmosphere is to absorb carbonic acid and effect its decomposition, the carbon being fixed in the tissues, and the oxygen returned in a free state to the air; the one action being counteractive of the other. This is a very general distinction, and an admirable provision for preserving the condition of our atmosphere unaltered, and maintaining the due proportion between animal and vegetable life. It is from the carbonic acid of the atmosphere, that plants obtain the carbon which enters so largely into their composition; it was from the dense atmosphere surrounding our planet, at an earlier period of its history, that the vegetation of that period removed those large supplies of carbon which are now stored up as coal in the superficial strata of the earth ; thus, purifying the air and fitting it for the respiration of man and all hot-blooded animals, and, at the same time, supplying a valuable fuel for the convenience of these beings, which, after the lapse of ages, should be called into existence.
With regard to fungi, we have stated that the materials of their nutrition are, as in other plants, not inorganic gases, but organic principles derived from decomposing organic substances. In this form they absorb the carbon they require, and need not, therefore, to extract it from the air as carbonic acid. They deviate, therefore, from the vegetable rule in this respect also; and as their nutrition is like that of animals, so is their respiration or action upon the atmosphere like that of animals; they absorb pure oxygen, and return it to the air combined with carbon, in the form of carbonic acid. On the other hand, the curious zoophyte, the Frustulia salina, which was before mentioned, presents a remarkable instance of an animal acting upon the atmosphere after the manner of a plant; the observation of its giving off pure oxygen gas being that which led to the analysis of its tissues, the results of which we noticed.
Some few other points of comparison or contrast between the animal and vegetable kingdoms might be gathered, but the subject has already extended to a greater length than we originally anticipated, and has included those particulars which would best serve to afford an exact definition, could such really be made out. On the contrary, our review of these particulars serves only to establish our original statement, that no exact limitations can be laid down as the boundaries of these kingdoms; that the characters of the one are imitated by beings belonging to the other; as the son of Sirach hath said, All things are double, one against another; and he hath made nothing imperfect.' Species alone are exactly defined in nature. All groups,
including several of these, arranged together for systematic purposes, insensibly glide into each other; in the words of Linnæus, * Natura non facit saltus.'
Our illustrations, we think, have fully established this with regard to the primary and most comprehensive groups, technically styled kingdoms; between which, if in any case, exact demarcations might have been expected to appear. far we have advanced to little more than the introductory matter of the work before us. Dismissing all consideration of animal life, we had intended now to bring under review the primary subdivisions of the • Vegetable Kingdom,' according to Dr. Lindley's systematic classification. This would again illustrate and confirm the truth of the principle. We should find Cryptogamic plants passing into Phanerogamic, by various intermediate forms; thus Fungi, shading into Endogens through the anomalous Rhizanths; and Ferns approaching Exogens through Cycadaceæ. And extending our observation to extinct species, we should find the fossil Calamites presenting a close external resemblance to recent Equisetacee, and yet pose sessing the wood and bark of Exogens; and fossil Lepidodendra presenting the central pith and medullary sheath, and the fistular
passages in its cortical integument, of a corniferous Exogen, though combined with the cellular stem, the dichotomous ramification, and the general appearance of gigantic Lycopodia. Or, considering merely the two principal types of structure amongst Phanerogamic plants, we should have found that Exogens passed into Endogens through the Dictyogens, a term by which Dr. Lindley designates his fifth class, derived from the reticulate venation of the leaves of these plants, in which respect, as well as in the structure of the stem, they approach to the character of Exogens; whilst in the ternary type upon which the flowers are constructed, and more especially in the monocotyledonous structure of their seeds, they resemble Endogens.
Particulars of this nature, had our space permitted, would have afforded matter for interesting contemplation; interesting, not merely to the man of science, or as items in the stock of general information, but likewise to the student of divine philosophy, as affording a long chain of decisive evidence of that unity of plan prevailing throughout the works of creation, the operation of one Mind pervading all matter and all space, and infinitely endowed with attributes of wisdom and benevolence.
Still may I note how all the agreeing parts
For ever rising, end in Deity.' . The more we study the works of the Creator,' says Sir J. E. Smith, the more wisdom, beauty, and harmony become manifest, 'even to our limited apprehensions; and while we admire, it is ' impossible not to adore.
• Soft roll your incense, herbs, and fruits, and flowers,
Whose breath perfumes you, and whose pencil paints.' Dr. Lindley's Vegetable Kingdom may be regarded as a new edition of his former work, "The Natural System of Botany,' only much enlarged, illustrated by numerous wood engravings, and presenting such modifications in the views of the author as have taken place during the interval between the publication of these works. These modifications are very considerable, both in classification and arrangement. The former work commences with the class of Exogens, and descends gradually to the lowest cellular Cryptogamic plants; the present work commences at the bottom of the scale, and ascends through the various orders and classes to Exogens, which are regarded as the class of vegetables