nated, as it flows over a soil composed either wholly or in part of the earth called magnesia; it evinces a peculiar attraction for this substance, separates it from the bed on which it has been quietly reposing, and so minutely dissolves it, as still to retain its transparency. But the attraction of the sulphuric acid for the magnesia is much less than its attraction for the fixed alkalis, potash and soda and hence, if, to the water thus impregnated, we add a certain quantity of either of the two latter substances, the connexion between the acid and the magnesia will immediately cease: the former will evince its perference for the alkali employed; and the magnesia no longer laid hold of by the sulphuric acid, will be precipitated, or in other words, fall by its own weight to the bottom of the water in the form of a white powder, and may be easily collected and dried. And this, in reality, is the usual inode by which this valuable earth is obtained in its pure state. But the sulphuric acid having thus shown a stronger attraction for an alkali than for an earth, is there no substance for which it discovers a stronger attraction than for an alkali? There are various it may be sufficient to mention caloric or the matter of heat. And hence, exposed to the action of heat, it soon becomes volatile, unites itself to the heat, flies off with it in vapour, and now leaves the alkali behind as it before left the megnesian earth. Glass-manufacturers take advantage of this superior attraction of the mineral acids for heat compared with their attraction for alkalis, and employ, in their formation of glass, common sea-salt, which is a combination of an acid and an alkali; drive off the former from the latter by the aid of a very powerful fire, and then obtain a substance which is absolutely necessary for the production of this material. These curious and altogether inexplicable properties and preferences we call chemical affinities and chemical elections; and there are numerous instances in which the substances, thus uniting themselves together, evince an order and regularity of the most wonderful precision, and which is nowhere exceeded, in the developement of the most elegant organ of animated nature. And I now particularly allude to the phænomena of crystallization; the different kinds of which, produced by the consolidation of different substances, uniformly maintain so exact an arrangement in the peculiar shape of the minute and central nucleus, or the two or three elementary particles that first unite into a particular figure, and follow up with so much nicety the same precise and geometrical arrangement through every stage of their growth, that we are able, in all common cases, to distinguish one kind of crystal from another by its geometrical figure alone; and with the same ease and in the same manner as we distinguish one kind of animal from another by its general make or generic structure. The form of these elementary particles we can no more trace to a certainty than the bond of their union; but there is great reason for believing them to be spheres or spheroids, as first conjectured by that most acute and indefatigable philosopher Dr. Hooke, and since attempted to be explained by Dr. Wollaston in a late Bakerian lecture.* Such are the most striking powers that occur to us on a contemplation of the unorganized world. From unorganized let us ascend to organized nature. And here the first peculiar property that astonishes us is the principle of life itself;-that wonderful principle equally common to plants and animals, which maintains the individuality, connects organ with organ, * Phil. Trans. 1813. p. 51. resists the laws of chemical change or putrefaction, which instantly commence their operation as soon as this agent or endowment ceases; and which, with the nicest skill and harmony, perpetuates the lineaments of the different kinds and species through innumerable generations. It is an agency which exists as completely in the seed or the egg as in the mature plant or animal for as long as it is present, the seed of the egg is capable of specific developement and growth; but the moment it quits its connexion, they can no more grow than a grain of gunpowder. What now is this wonderful principle that so strikingly separates organized from inorganized matter? that, as I have observed on a former occasion, from the first moment it begins to act infuses energy into the lifeless clod; draws forth form and order, and individual being from unshapen matter, and stamps with organization and beauty the common dust we tread upon ?* I have called it an agent or endowment: is it nothing more than these? is it a distinct essence? and if so, is this essence refined, etherealized matter, freed from the more obvious properties of grosser matter, or is it strictly immaterial? It has been said by different physiologists to be oxygene, caloric, the electric or the galvanic gas; but all this is mere conjecture; and even of several of these powers we know almost as little as we do of the vital principle itself, and are incapable of tracing them in the vegetable system. The next curious energy we meet with in organized nature, and which also equally belongs to animals and vegetables, is instinct. This I have defined to be "the operation of the vital principle, or the principle of organized life by the exercise of certain natural powers directed to the present or future good of the individual, or of its progeny." But what are these powers, with which the vital principle is thus marvellously gifted, and which enables it, under different circumstances, to avail itself of different means to produce the same end?--that directs plants to sprout forth from the soil, and expand themselves to the reviving atmosphere; fishes to deposite their eggs in the sands; birds in nests, of the nicest and most skilful contrivance; and the wilder quadrupeds to accomplish the same purpose in lairs or subterraneous caverns; that guides the young of every kind to its proper food, and, whenever necessary, teaches it how to suck? Are these powers also material, or are they immaterial? Are they simple properties issuing out of a peculiar modification of matter, or something superadded to the material frame? In the confused language and confused ideas of various metaphysical hypotheses, and even of one or two that pretend to great exactness in these respects, instinct is made a part or faculty of the mind: and hence we hear of a moral instinct. But has the polype, then, or the hydatid a mind? Are we to look for a mind in the midst of sponges, corals, and funguses?—in the spawn of frogs, or the seeds of mushrooms? Instinct, however, the operation of the principle of life, equally superintending the entire frame, and every separate part of it, guiding it to its perfect developement, exciting its peculiar energies, remedying its occasional evils, and providing for a future progeny, is equally to be traced in all of them? Are instinct, then, and mind the same thing? or is the vocabulary of the hypotheses I now advert to, and shall have occasion to examine more at large hereafter, so meagre and limited that it is necessary to employ the same term to express ideas that have no connexion with each other, and which cannot, therefore, be thus expressed without the grossest confusion? Ser. II. Lect. IV. * Ser. I. Lect. IX. It is high time to be more accurate, and to have both determinate words and determinate ideas; and it has been one object of this course of instruction to define what ought to be the real distinction between instinct, sensation, and intelligence. But let us ascend a step higher in the great scale of life; let us quit the vegetable for the animal kingdom. If I take the egg or grain of a mustard-seed, and the egg of a silkworm, where is the chemist or physiologist that will point out to me the diversity of their structure, or unfold the cause of those different faculties which they are to evince on future developement and growth? At present, so far as they appear to us, they are equally common matter, actuated by the same common living principle, directed to different ends. To give them developement and mature form, we equally expose them to the operation of the sun and the atmosphere, and, in the case of the mustard-seed, of moisture and we are not conscious of exposing them to any thing else; all which, again, so far as we are acquainted with them, are nothing but matter in different states of modification. Yet the animal egg produces a new and a much higher power, which we denominate sensation, while the vegetable egg produces nothing of the kind. What is sensation, and from what quarter has it been derived? Is it a mere property, or a distinct essence? Is it material, or is it immaterial? This, also, has occasionally been called instinct, and been contemplated as of instinctive energy. With equal confusion it has also been called or contemplated as a property of mind. It is neither the one nor the other: it is equally different from both. We trace, indeed, its immediate seat of residence; for we behold in the silk-worm a peculiar organ which does not exist in the mustard-plant, and to which, and which alone, sensation always attaches itself; and to this organ we give the name of a nervous system. But to become acquainted with the organ, in which sensation resides, is no more to become acquainted with the essence of sensation itself, than to know the principle of life because we know the general figure of the individual animal or vegetable in which it inheres; or than to know what gravitation is because we see the matter which it actuates. As simple nerves, or a nervous cord, such as that of the spinal marrow, is the proper organ of sensation or feeling, the gland of a brain, from which the nervous cord usually, though not always, shoots, is the proper organ of intelligence; and as I had occasion to observe in a former study, when lecturing upon the subject of the senses, the degree of intelligence appears, in every instance we are acquainted with, to be proportioned, not, indeed, to the size of the brain as compared with that of the animal to which it belongs, as was conjectured by Aristotle, and has been the general belief almost to the present day, but as compared with the aggregate bulk of nerves that issue from it.* The larger the brain and the less the nerves, the higher and more comprehensive the intelligence: the smaller the brain and the larger the nerve, the duller and more contracted. In man, of all animals whatever, the brain is the largest, and the nerves comparatively with its bulk the smallest: in the monkey tribes it makes an approach to this proportion, but there is still a considerable difference; in birds a somewhat greater difference; in amphibials the brain is very small in proportion to the size of the nervous cord; in fishes it is a bulb not much larger than the nervous cord itself; in insects there is no proper brain whatever; the nervous cord that runs down the back Ser. I. Lect. XV. originating near the mouth; sometimes of an uniform diameter with the cord itself. and sometimes rather larger; and in infusory and zoophytic worms we have no trace either of nerves or brain. In these last, therefore, it is possible, and indeed probable, as I have already observed, that there is no sensation: the vital principle, and the instinctive faculty, which is the operation of the vital principle, by the exercise of certain natural powers constantly appertaining to such principle, alone producing all the phænomena of life as in plants. In most insects, for the same reason, it is possible, and indeed probable, that though there is sensation, there is little or no intelligence: the brain, which is the sole seat or organ of intelligence, being totally destitute, in most of them, and of very minute compass in the rest. In fishes we have reason to apprehend different degrees of intelligence; in many amphibials somewhat more; more still in birds and quadrupeds, and most of all in man. But what is intelligence, which is a distinct principle from sensation, and to which, as in the case of sensation, a distinct organ is appropriated? An organ, moreover, which, like that of simple sensation, may be also produced out of an insentient egg by the mere application, so far as we are able to trace the different substances in nature, of a certain proportion of heat; for the egg of the hen, unquestionably insentient when first laid, becomes equally hatched and endowed with the organs and properties both of sensation and intelligence, by the application of a certain portion of warmth, whether that warmth be derived from the body of the hen, of a dung-hill, an oven, or the sun. But though we know the organ, what information does this give us of the thing itself? In what respect is intelligence connected with the brain? Does it result from its mere peculiarity of structure, secreted, like the blood, but of a finer and more attenuate crasis, or is it a something superadded to the organ? Is it matter in its most active, elaborate, and etherealized form, or is it something more than matter of any kind? and, if so, how has this superadded essence been communicated? To this point we can proceed safely, and see our way before us: but shadows, clouds, and darkness rest on all beyond, while the gulf on which we sail is unfathomable to the plummet of mortals. It is something more than matter, observes one class of philosophers, for matter itself is essentially unintelligent, and is utterly incapable of thought. But this is to speak with more confidence than we are warranted, and unbecomingly to limit the power of the Creator. It has already appeared that we know nothing of the essential properties of matter. If it be capable of gravitation, of elective attractions, of life, of instinct, of sensation, there does not seem to be any absurdity in supposing it may be capable of thought and if all these powers or endowments result from something more than matter, then is the visible world as much an immaterial as a material system. On the other hand, it is as strongly contended by an opposite class of philosophers, and the same train of arguments has been continued, almost without variation, from the days of Epicurus, that the principle of thought or the human mind must be material; for otherwise the frame of man, we are told, will be made to consist of two distinct and adverse essences, possessing no common property or harmony of action. But this is to speak with as unbecoming confidence as in the former case. The great visible frame of the world seems to point out to us in every part of it a co-exist ence either of different essences or of different natures-of matter and something which is not matter; or of common matter and matter possessed of properties that it does not discover in its common form. Yet all these, so far from being adverse to each other, subsist in the strictest union, and evince the completest harmony of action. And hence the soul, or intelligent principle, though combined with matter, though directly operating from a material organ, may be a something distinct from matter, and more than matter, even in its most active, ethereal, and spiritualized forms : though, whatever be its actual essence, it undoubtedly makes the nearest approach to it under such a modification. In reality, under some such kind of ethereal or shadowy make, under some such refined or spiritualized and evanescent texture, it seems in almost all ages and nations to have been handed down by universal tradition, and contemplated by the great mass of the people, whatever may have been the opinion of the philosophers, as soon as it has become separated from the body. And the opinion derives some strength from the manner in which it is stated to have been first formed in the Mosaic records, which intimate it to be a kind of divine breath, vapour, or aura, or to have proceeded from such a substance; for " God," we are told, "breathed into man's nostrils THE breath of life, (” )) and he became a living soul."* Opposed as the two hypotheses of materialism and of immaterialism are to each other, in the sense in which they are commonly understood, it is curious to observe how directly and equally they tend to one common result, with respect to a point upon which they are conceived to differ diametrically; I mean an assimilation of the human soul to that of brutes. The materialist, who traces the origin of sensation and thought from a mere modification of common matter, refers the perception and reflection of brutes to the very principle which produces them in man; and believing that this modification is equally, in both instances, destroyed by death, maintains that "as the one dieth, so dieth the other; so that a man hath no pre-eminence above a beast ;"t whence his hope of future existence, apparently like that of Solomon, who was without the light of the Christian Scriptures, depends exclusively upon a resurrection of the body. The immaterialist, on the contrary, who conceives that mere matter is incapable, under any modification, of producing sensation and thought, is under the necessity of supplying to every rank of being possessing these powers, the existence of another and of a very different substance combined with it; a substance not subject to the changes and infirmities of matter, and altogether impalpable and incorruptible. For if sensation and ideas can only result from such a substance in man, they can only result from such a substance in brutes; and hence the level between the two is equally maintained by both parties; the common materialist lowering the man to the brute, and the immaterialist exalting the brute to the The immaterialist, however, on the approach of dissolution, finds one difficulty peculiar to himself, for he knows not, at that period, how to "dispose of the brutal soul: he cannot destroy an incorruptible substance, and yet he cannot bring himself to a belief that it is immortal. This difficulty seems to have been peculiarly felt by the very excellent Bishop Butler. He was too cautious a reasoner, indeed, to enlist the term IMMATERIAL into any part of his argument; not pretending to determine, as man. |