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all equally partake of the vivifying heat. Thus the wren, who lays from ten to eighteen eggs, constructs her little edifice with the greatest care, and of the warmest materials; while the plover and the eagle, whose eggs are so few that the body may easily cover them, build with little solicitude, and sometimes content themselves with the naked cleft of a rock. And thus, too, in very cold winters in Lapland, the fond water-fowl will occasionally strip the down off its breast to line its nest and protect its progeny.
When a wasp, in attempting to transport a dead companion from the nest, finds the load too heavy, he cuts off its head, and carries it out in two portions.*
A strawberry offset planted in a patch of sand will send forth almost the whole of its runners in the direction in which the proper soil lies nearest, and few, and sometimes none, in the line in which it lies most remote.
When a tree which requires much moisture (says Mr. Knight) has sprung up or been planted in a dry soil, in the vicinity of water, it has been observed that a much larger portion of its roots has been directed towards the water; and that when a tree of a different species, and which requires a dry soil, has been placed in a similar situation, it has appeared, in the direction given to its roots, to have avoided the water and moist soil.”+
“ When a tree (remarks Dr. Smith) happens to grow from seed on a wall (and he particularly alludes to an ash in which the fact actually occurred), it has been observed, on arriving at a certain size, to stop for a while and send down a root to the ground. As soon as this root was established in the soil, the tree continued increasing to a large magnitude."I
The best means, perhaps, that a plant can possess of resisting the effects of drought, is a tuberous or bulbous root. The grass called phleum pratense, or common catstail, when growing in pastures that are uniformly moist, has a fibrous root, for it is locally supplied with a sufficiency of water; but in dry situations, or such as are only occasionally wet, its root acquires a bul. bous form, and thus instinctively accommodates the plant with a natural reservoir.
And there are various other grasses, as the alopecurus geniculatus, or geniculate foxtail, that exhibit the same curious adaptation.g
There are some philosophers and physiologists who have endeavoured to ascribe the whole of these very extraordinary phenomena to the mechanical powers of gravitation and centrifugal force: among whom I may especially mention Mr. Knight, who has altempted it in a very ingenious paper to which I have just alluded. There are others who ascribe them to the operation of an intelligent principle, among whom, more especially, as I have already observed, is Dr. Darwin. Of these two causes the instances just submitted to you, and thousands more might be added to them, sufficiently prove that the first is inadequate and that the second does not always exist; at least that the phenomena are often found in organized forms in which, to a certainty, the precise organs do not exist which are the only known seats of intelligence and sensation in the visible world. They are hence to be resolved into another cause, equally remote from either, more complex in its operations than that of gravity, but less so, perhaps, than those of intelligence and feeling; embracing a distinct family of well-defined and cognate actions, always aiming at the same common end, the perfection, preservation, or reproduction of the system in which they exist; and constituting what we should denominate instinct, the general property of the living principle or the law of organized life in a state of action.
But the subject is too important to be closed here. It remains yet to point out the difference between instinct and sensation or feeling, as well as between instinct and reason. It remains yet for me to show you that all these are equally distinct principles; that they may exist separately or conjointly;
*Smellie, vol. ii. 151. Reaumur, tom. II. 241. For an account of other curious instances of instincts, in Insects, see the Swedish Amanitates Academicæ, vol. iii. art. 45. Nosa Insectorum, by M. A. Bøchner 1752 ; and compare with
these the younger Hüber's Recherches sur les Maure des Fourmis Ladigenes t Phil. Trans. 1811, p. 210.
1 Introd. to Botany, p. 114. See Smith, Introd. to Bot. p. 113, and p. 41.
and it remains also for me to offer examples from among the more curious or striking instances of each of these recondite powers, both under a more simple and a more complicated modification. This shall form the basis of our ensuing study. At present I shall only farther observe that instinct may be defined the operation of the principle of organized life by the exercise of certain natural powers directed to the present or future good of the individual; and reason the operation of the principle of intellectual life, by the exercise of certain acquired powers directed to the same end. Both equally answer their object, are equally perfect in their kind, and equally display their common origin.
Whether with Reason or with Instinct blest,
And find the means proportion'd to their end.
Cares not for service, or but serves when press'd;
ON THE DISTINCTIVE CHARACTERS OF INSTINCT, SENSATION, AND INTELLIGENCE.
We closed our last study by observing that instinct is the operation of the principle of organized life by the exercise of certain natural powers directed to the present or future good of the individual, while reason is the operation of the principle of intellectual life by the exercise of certain acquired powers directed to the same end. Hence reason demands discipline and attains maturity; instinct, on the contrary, neither demands the one nor is capable of attaining the other; it is disciplined and mature from the first, and is as perfect in the infant as in the man.
Instinct, however, has as often been confounded with FEELING OF SENSATION as it has with PERCEPTION, which is the outline or foundation of reason: and hence another source of those perplexities and errors in distinguishing between animal and vegetable life which we noticed in the preceding lecture: perplexities and errors which have been productive of the most absurd and disgusting consequences, and especially in regard to the delicate and elegant science of botany.
Instinct, sensation, and perception are all principles essentially different; they may, indeed, exist conjointly, but each of them is capable of existing separately. Instinct is the common law or property of organized matter, as gravitation is of unorganized; and the former bears the same analogy to sensation and perception as the latter does to crystallization and chemical affinity. Instinct is the general faculty of the organized mass, as gravitation is of the unorganized mass; sensation and perception are peculiar powers or faculties appertaining to the first, as crystallization and affinity are apper taining to the second: they can only exist under certain circumstances of the organized or unorganized matter to which they respectively belong.
This parallel, indeed, may be carried much farther. Gravitation discovers itself under different modifications, different degrees of power, and, conse
quently, different effects. Instinct evinces an equal diversity in all these instances. Gravitation belongs equally to the smallest and to the largest por. tions of unorganized matter : instinct, in like manner, belongs equally to the smallest and to the largest portions of organized matter; it exists alike in solids and in fluids ; in the whole frame and in every part of the frame; in every organ, and in every part of every organ, so long as the principle of life continues. Sir Isaac Newton established the doctrine of gravitation, and overcame all objections to it chiefly by the modesty with which he propounded and illustrated it. Without inquiring into the nature of its essence, he contented himself with recognising it by its operations and laws. It is the aim of the present study to follow this great example ; and leaving all discussions concerning the essence of instinct or of organized life, on which instinct is dependent, and which constitutes its sphere, as matter constitutes the sphere of gravitation, to point out nothing more than the nature of its action, and occasionally to catch a glance at the laws by which it is regulated.
From what has been already said, we see clearly that the power of instinct runs' equally through the limits of vegetable and animal life, and consequently, that instinct, sensation and perception, whatever they consist in, are powers or principles essentially different. Instinct is the common property of organized life in all its forms, but life itself is not necessarily connected either with reason or sensation; and it is of no small consequence that we attend to this curious and extraordinary fact, the proofs of which are abundantly in our own possession. The blood is alive, and has all the common properties of life, as was very satisfactorily shown in an antecedent lecture, from the experiments of Mr. John Hunter; but we all know that it possesses neither feeling nor intelligence: the bones, the cartilages, the cellular membrane, and the cuticle are alive; but, in a state of health, they are equally destitute of both these properties, and whether in health or disease, are always destitute of the latter.
Sensation and perception, so far as we are capable of witnessing, can only exist in appropriate organs, as nerves, or modifications of nerves, which are the only known seat of the one, and the brain, or some modification of brain, which is the only known seat of the other. In the higher classes of animals, as mammals, birds, amphibials, and fishes, the nerves take their rise from the brain, or rather from some particular part of it. But this is not an indispensable law of life; for, in insects, we meet with nerves, but no brain; and in most zoophytic and many other tribes of worms, with neither brain nor nerves. And hence, wherever these organs or either of them are discoverable, it is consistent with right reason to infer, that the faculty also exists to which they respectively give rise. But, on the contrary, where neither of these organs exists, as in plants, and a multitude of the lowest tribes of aninals, which in the zoological system of Lamarck are on this account denoini. nated apathic or insentient,* we have the same reason for inferring that, though life is present, and, indeed, in many instances, peculiarly tenacious and vigorous, there is neither intelligence nos sensation; and that the whole of the vital functions and operations are performned, like the semblances of intelligence in the preceding case, by the common law of instinct; which, operating in different ways, in different organs, and beings of different structures, appertains to living matter of every kind.
These observations will apply to the vegetable as well as to the animal kingdom; for plants have a close analogy to the senseless tribes, the tubipores, madrepores, sponges, and infusory worms, we are now contemplating in their structure and origin, as well as in the limited range of their powers; these animals being in many instances equally simple in their make, and equally destitute of locomotion, and equally propagating their kinds by the generation of buds or bulbs, instead of by that of seeds or eggs. Like these low kinds of animals, plants, moreover, are altogether without organs either of sense or intelligence; and it is consequently correct to infer, that they are
• Philosophie Zoologique.
equally without the faculties which it is the sole property of such organs to develope. And hence, again, however curious and astonishing the powers they occasionally evince, they are powers that can only be resolved, as in the case of zoophytic worms, into the ever present and ever active law of instinct or organized life. We hear, indeed, at times, of the ascription of mental or corporeal passions to vegetables; of general feeling and ideas; of love and languishment, and desire and aversion. But all this is fancy, and proceeds from an erroneous and contracted view of the general nature of the law of instinct, and its extraordinary power of supplying the place of sense and reason, where these, or the organs in which they reside, are not present. We hear, in like manner, occasionally, of the brain, stomach, lungs, and nerves of vegetables; but all this is still more imaginary than the preceding; it is a mere fancy built upon a mere fancy: nobody has ever been capable of pointing out the probable or even possible seat of such organs, and they have only been idly conjectured because the faculties to which they give rise have been conjectured antecedently.
Is there, then, no such thing as instinctive feeling ?-a term in every one's mouth, and which every one, till he tries, supposes he comprehends ?' What but an instinctive feeling is the love of life, the dread of death, the economy of pairing, and the desire of progeny ?
Wherever feeling exists, these, in a certain sense, may unquestionably be called instinctive feelings; but it should be remembered that ihe expression is, in every instance, of a compound character, and involves two distinct ideas, which may exist either separately or conjointly: and we have the same reason for using the phrase instinctive intelligence as instinctive feeling : for we can only mean, or ought only to mean, instinct combined with intelligence, or instinct combined with feeling, according to the nature of the case before us.
Combinations of this kind, indeed, are not unfrequent; and I shall presently proceed to produce examples of them: but it becomes necessary to observe, in the present place, that all the operations we are now adverting to, and which are usually characterized as instinctive feelings, as self-preservation, attachment to life, resistance of destruction, reproduction of the whole or of separate parts of the system, and even the economy of pairing, though often united with feeling, and not unfrequently with intelligence as well, occur, nevertheless, in a multiplicity of instances in which we have either direct proofs, or the most cogent reasons for believing, that there is neither feeling nor intelligence whatever; and that every thing is the result of pure, unintelligent, insentient instinct.
I have just observed that the blood is alive: it has all the common properties of life; irritability, contractility, and a power of maintaining its natural scale of heat, whatever be the temperature of the atmosphere by which it is surrounded : and it is perpetually showing its attachment to life by the due and discretionary exercise of these properties with a view of preserving life. It equally resists every excess of cold or of heat that may be injurious to it, and hence sometimes raises the thermometer and sometimes depresses it: it contracts itself, like the muscular fibre, upon the application of an appropriate stimulus, and conveys the principle of life, and powerfully assists in applying that principle to parts in which the vital action is languid, or has altogether ceased. There is no part of the animal system that evinces in a more eminent degree the faculty of self-preservation, or self-production, of attachment to life, or of resistance to whatever is injurious, than the blood; and yet every one knows that this faculty is pure, unmixed instinct, equally destitute of feeling or intelligence: it is, as I have already defined instinct to be in every instance, a “simple operation of the principle of organized life by the exercise of certain natural powers directed to the present or future good of the individual."
In the new-laid egg we have an equal proof of the same faculty of self* Compare here Girtanner's Mémoires sur l'Irritabilité, considerée comme Principe de Vie dans la Nature organisée. - Journ. de Physique, 1790.
preservation, the same attachment to life, and resistance to destruction. For, like the blood of a healthy adult, the new-laid egg, the few and simple vessels of which are merely in a nascent and liquescent state, and which can scarcely be regarded otherwise than as a fluid, is capable equally of counteracting heat, cold, and putrefaction, and does forcibly counteract them for a considerable period longer than an egg that has been frozen or in any other way deprived of its vital and instinctive principle. It is this vital and instinctive principle that alone matures the egg, and shapes the matter of which it consists into distinct and specific lineaments, and calls forth the power which it does not yet possess, of sensation and perception. In what way these attributes are produced we know not; but we see them issuing froin the matter of the egg alone, when aided by the additional and cherishing power of simple heat. And, provided it be properly regulated and applied, it is of no importance from what quarter such heat is derived; for we have already had occasion to observe, that the warmth of a sand-bath or of an oven will answer as effectually as that of the mother's sitting over it.
But let us not rest here: let us proceed to examples of the renewal or propagation of life, from parent stocks; to examples of the reproduction of the whole, or of separate parts of the system, in cases in which there is as obvious a destitution of sensation or intelligence; and where, as in the preceding instances, the whole must be the result of pure insentient instinct.
There is not a single organ in the animal frame but what is perpetually reproducing itself, alternately dying and renewing; so that the same man of to-day has not an individual particle belonging to him of that which constituted his corporeal frame ten, fifteen, or twenty years ago. And yet the whole of this important change, this entire reproduction of the material system, though occurring in sentient and even in intelligent organs, occurs at the same time without any kind of feeling or consciousness in the individual, or the organs that constitute the individual.
This very curious fact is still more obvious in the generation of new matter of every kind,-muscular, glandular, bony, and even nervous, upon the death of a considerable portion of an organ in consequence of external injury or other violence. The nice and admirable law by which the dead substance is carried off, and its place supplied by the gradual reproduction of fresh matter of the very same nature and properties, I have already explained. In the separation of the dead from the living parts, there is gerterally, though not always, some degree of pain, from the increased local action that takes place, and more especially from the tension given to the skin by the secretion of sound and healthy pus, in order to effect its bursting ; but in the actual generation of the new material that is to fill up the cavity, and supply the place of what is lost, there is no pain or sensation whatever in a healthy process; while, as I have likewise already observed, the pointing of the abscess, like the pointing of the seeds of peas or beans, in what direction soever they are sown, will be uniformly towards the surface,t whatever be the obstacles that must be overcome in order to reach it.
The generation of life, then, no more necessarily demands or implies the existence of sensation, than attachment to lise, or a self-preserving principle: it may be combined with it, but it may also exist separately or without it. Monro, indeed, has distinctly proved by experiment, that the limb of a frog can live and be nourished, and its wounds healed, without any nerve whalever, and, consequently, without any source or known possibility of sensation.
Let us apply this reasoning, which I admit is thus far drawn from individual parts of the system alone, to a regeneration or reproduction of the entire system.
The lungs or gills of an animal are precisely analogous to the leaves of a plant. All these, as I have already observed, are perpetually changing by a nicely balanced alternation of decay and reproduction. In animals and ever. green plants, this change is so gradual as to elude all notice. In deciduous plants, on-the contrary, it is sudden and obvious to every one; yet the same
• Series 1. Lecture xiv.
Series 11. Lecture iv.