c^ /-.y ^-^<.%.*,-,.r £l4Ae^. r.i.;.i>0>i PALEFS THEOLOGY, WITH ILLUSTRATIONS. NATURAIi THEOLiOGY: OR, EVIDENCES OF THE EXISTENCE AND ATTRIBUTES OF THE DEITY, COLLECTED FROM THE APPEARANCES OF NATURE. BY WILLIAM PALEY, D. D. ARCH-DEACON OF CARLISLE. AND BY A SELECTION FROM THE NOTES OF JAMES PAXTON, Member of the Royal College of Surgeons, London. WITH ADDITIONAL NOTES, ORIGINAL AND SELECTED, FOR THIS EDITION. And a Vocabulary of Scientific Terms. fronton: PRINTED AND PUBLISHED BY LINCOLN U EDIJIAKDS, No. 59 Washington-Street. ' / 1829. , ' ,.;'::"' .^ Jf LIBRARY 155852 MTTOR, LENOX AND 7EDEN FOUNDATIONS. DIsAlCT OF mI^SAcHUSETTS, to vnt: District ClerVa office. BE IT REMEMBERED, That on the fourteenth day of March, A. D. 1 829, in the fifty-third year of the Independence of the United States of America, Lincoln & Edmands, of the ».»id district, have deposited in this office the title of a Book, the light whereof they claim as Proprietors, in the words following, to ivit : " Paley's Theology, with Illustrations. Natural Theology : or, Evidences of the Existence and Attributes of the Deity, collected from the Appearances of Nature. By William Paley, D. D. Arch-Deacon of Carlisle. Illustrated by the Plates, and by a Selection from the Notes of James Paxton, Member of the Royal College of Surgeons, London. With additional Notes, Original and Selected, for this Edition. And a Vocabulary of Scientific Terms.'' In Conformity to the Act of the Congress of the United States, entitled, "An Act for the encouragement of Learning, by securing the copies of Maps, Charts and Books, to the Author* ind Proprietors of suchcopies during the times therein mentioned ;" and also to an Actentitled, •'An Act supplementary to an Act, entitled, An Act for the Encouragement of Learning, by se- curing the Copies of Maps, Charts and Books to the Authors and Proprietors of such Copies during the times therein mentioned: and extending the Benefits thereof to the Arts of Designing, En- grating and Etching. Histarical, and other Prints." JNO. W. DAVIS, Cleric of the District of Massachusetts. PUBLISHERS' NOTICE. To give this valuable work a more extended circulation in our Col- leges and High Schools, the Publishers engaged a competent profes- sional gentleman of Boston, to superintend this edition. And they feel confident that his Notes, and those he has selected — the references to the Plates — and his Vocabulary, will be found greatly to enhance the value of the book. They have been at much expense to procure the Il- lustrations ; but as these plates are as necessary to facilitate the scholar in his study of this work, as an atlas is to aid the pupil's progress in geography, they believe they shall be remunerated by the patronage which a discerning public will bestow upon their endeavours to pre- sent a complete edition of this standard work of acknowledged merit. -•^©®®-"~ NOTE. The reader will please to supply the following references to plates, which were omitted in the text. p. 112, after the wovH package, insert (PI. xxii. Fig. 1.) 115, after mesentery, insert (PI. xxii. Fig. 2.) 130, after hill, insert (PI. xxiii. Fig. 1.) 132, dXiQT place,* insert (PI. xxiii. Fig. 2.) ' . ', ,16?, aftei"OHj2wi,^eon, insert (PI. xxxi. Fig. 1.)' . .' '.' 163-,aft8r s^^'(w, insert (PI. xxxi. Fig. 2, 3.) PREFACE TO THIS EDITION. The present edition of the Natural Theology of Dr. Paley was undertaken with the view of making this admirable work more ex- tensively useful than it could ever be under the form in which it has been usually circulated. A great proportion of those who have read it must have sensibly felt the disadvantage under which they labour in comprehending the descriptions ; and of course the arguments of the author, from the want of a knowledge of the subjects to which they relate. No man could so well supply the want of this knowl- edge, by clearness of statement and description, as Dr. Paley ; and it is probable that few other writers would have made a book so intelligible, which relates to subjects remote from common observation, without the aid of plates and illustrations. Still it must be imperfectly com- prehended in many important parts, except by those acquainted with the sciences from which his illustrations are drawn. Enough it is true may be understood by all, to carry them along with the argument, and produce a general conviction of its truth. But the conceptions even of professional readers would be much more clear, definite, and satisfactory, were the description aided by visible representations. It was the original design of the publishers to have merely attached the plates and references of Paxton, which have been published in England and in this country in a separate volume, to the text of Dr. Paley. It was, however, suggested to them that the value of their edition might be increased by the addition of Notes, and they had made arrangements for this purpose and were going on with the work, when Mr. Paxton's edition of the Natural Theology fell into their hands, containing, beside the plates, a considerable number of Notes. From these Notes a selection has been made of such as seemed most valuable and interesting. A number of Notes have also been made up of quotations from the excellent treatise of Mr. Charles Bell on Animal Mechanics, published in the Library of Useful Knowledge ; a tract which cannot be too highly recommended to the perusal of those who take pleasure in studying the indications of a wise and be- nevolent Providence in the works of creation. A few additional Notes have also been subjoined, which have not been before published. It seems to be supposed by some, that the progress made in science since the writing of this work must have furnished ample materials for valuable additions to it. It will readily appear, however, upon re- IT PREFACE. flection, that this is not Ukely to be the case, and that no particular ad- vantage to tlie argument is to be expected from bringing it down, as it is often expressed, to the present state of science. The object of the work is, not to tcacli science in its connexion with Natural Theol- ogy, a plan entirely different, and one upon which distinct works may, and have been written, but to gather materials from the knowledge communicated by science, where with to construct an argument for the existence and attributes of God. The excellence of such a work, then, will not consist in the number of illustrations, or in the copious- ness and completeness of the materials, but in the judgment with which they are selected, and the aptness with which they are made to bear upon the question at issue. So far, therefore, as the argument is concerned, no additional strength will be given to it by new discoveries in science. As Dr. Paley has himself admitted, a single case thoroughly made out, proves all that can be proved, and, generally speaking, the most familiar in- stances which can be selected and made intelligible are the best for this purpose, and will have the greatest influence upon men's minds. All the knowledge, therefore, which is necessary for the complete- ness and strength of the argument was possessed long ago. Still there is an advantage in selecting and arguing from a variety of examples, arising out of the different constitutions of men's minds, or their different habits of thinking and reasoning. Some are more af- fected by examples of one kind, and some by those of another. In this way much more might be done in the way of illustrating and en- forcing the argument, and holding it up in every possible light, than has been attempted in the present edition. The principal object here had in view, has been to make such additions, as with the help of the engraved views, would bring the argument, as stated by the author, clearly within reach of all readers. To give a correct edition, various English and AmenVan copies have been consulted, in which variations have been found ; but those read- ings have been adopted, which appeared best to comport with that familiarity, and originality of expression, which gives its principal charm, and its great force and clearness to Dr. Paley's style. J. w. Boston, March, 1829. RIGHT HONOURABLE AND RIGHT REVEREND SHUTE BARRINGTON, LL. D. LORD BISHOP OF DURHAM. My Lord, The following work was undertaken at your Lordship's recommen- dation ; and amongst other motives, for the purpose of making the most acceptable return I could make for a great and important benefit conferred upon me. It may be unnecessary, yet not perhaps, quite impertinent, to state to your Lordship and to the reader, the several inducements that have led me once more to the press. The favour of my first and ever honoured patron had put me in possession of so liberal a provision in the church, as abundantly to satisfy my wants, and much to exceed my pretensions. Your Lordship's munificence, in conjunction with that of some other excellent Prelates, who regarded my services with the partiality with which your Lordship was pleased to consider them, hath since placed me in ecclesiastical situations, more than adequate to every object of reasonable ambition. In the mean time, a weak, and, of late, a painful state of health, deprived me of the power of discharg- ing the duties of my station, in a manner at all suitable, either to my sense of those duties, or to my most anxious wishes concerning them. My inability for the public functions of my profession, amongst other consequences, left me much at leisure. That leisure was not to be l(S8t. It was only in my study that I could repair ray deficiencies in the church. It was only through the press that I could speak. These circumstances, in particular, entitled your Lordship to call upon me for the only species of exertion of which I was capable, and disposed me, without hesitation, to obey the call in the best manner that I could. In the choice of a subject I had no place left for doubt : in saying which, I do not so much refer, either to the supreme impor- tance of the subject, or to any scepticism concerning it with which the present times are charged, as I do, to its connexion with the sub- jects treated of in my former publications. The following discussion alone was wanted to make up my works into a system : in which VI DEDICATION. works, such as they are, the public have now before them, the evi- dences of natural religion, the evidences of revealed religion, and an account of the duties that result from both. It is of small importance, tJuit tliey have been written in an order, the very reverse of that in which they ought to be read. I commend therefore the present vol- ume to your Lordship's protection, not only as, in all probability, my last labour, but as the completion of a consistent and comprehensive design. Hitherto, my Lord, I have been speaking of myself and not of my Patron. Your Lordship wants not the testimonyof a dedication, nor any testimony trom me : I consult therefore the impulse of my own mind alone when I declare, that in no respect has my intercourse with your Lordship been more gratifying to me, than in the opportunities, which it has afforded me, of observing your earnest, active, and unwearied solicitude, for the advancement of substantial Christianity : a solici- tude, nevertheless, accompanied wuth that candour of mind, which suf- fers no subordinate differences of opinion, when there is a coincidence in the main intention and object, to produce an alienation of esteem, or diminution of favour. It is fortunate for a country, and honourable to its government, when qualities and dispositions like these are placed in high and influential stations. Such is the sincere judgment which I have formed of your Lordship's character, and of its pubUc value: my personal obligations I can never forget. Under a due sense of both these considerations, I beg leave to subscribe myself, with great respect and gratitude, My Lord, Your Lordship's faithful ^ And most devoted servant, WILLIAM PALEY. BishojJ- Wearmoiith, July, 1802. HONOURABLE AND RIGHT REVEREND SHUTE BARRINGTON, LL. D. LORD BISHOP OF DURHAM. My Lord, To your suggestion the world is indebted for the existence of Dr. Paiey's valuable work on Natural Theology. The universal and permanent esteem in which it has been held in this country, and its favourable reception in France, even after the desolating influence of the Revolution, have abundantly approved your Lordship's selec- tion both of the subject and of the person to whom you intrusted it. In looking round, then, for a patron lor these Illustrations, it was natural to have recourse to him who was the original sug- gestor of the work which it is their object to explain. Nor was I disappointed in my wish ; your Lordship not only condescending to approve of the design, but to encourage me in its prosecution, by your very liberal support. For this distinguished honour you will believe me deeply sensible ; and if I may indulge the hope that my humble efforts will increase the utility of so eminent a writer, I shall consider it the highest gratification. I am, my Lord, With great veneration, Your Lordship's most obliged. And obedient servant, JAMES PAXTON, Oxford, January 1, 1826. CONTENTS. CHAP. Page 1. State of the Argument, ------ 5 2. State of the Argument, continued, ----- 8 3. Application of the Argument, ----- 13 4. Of the succession of plants and animals, - - - - SO 5. Application of the Argument, continued, - - - 34 6. The Argument cumulative, ------ 43 7. Of the mechanical and immechanical parts and functions of Animals and Vegetables, ------ 45 8. Of mechanical Arrangement in the human Frame — Of the Bones, 52 9. Of the Muscles, 74 10. Of the Vessels of animal Bodies, 91 11. Of the animal Structure, regarded as a Mass, - - 110 12. Comparative Anatomy, 123 13. Peculiar Organizations, - 139 14. Prospective Contrivances, ------ 146 15. Relations, 151 16. Compensation, --- 159 17. The Relation of animated Bodies to inanimate Nature, - 168 18. Instincts, - - - 172 19. Of Insects, - 182 20. Of Plants, 196 21. Of the Elements, 210 22. Astronomy, 215 23. Personality of the Deity, 233 24. Of the Natural Attiibutes of the Deity, - - - - 249 25. The Unity of the Deity, 253 26. The Goodness of the Deity, 256 27. Conclusion, 295 Vocabulary, 303 NATURAIi THEOIiOGY. CHAPTER I. STATE OF THE ARGUMENT IN crossing a heath, suppose I pitched my foot agaiiisi 'i stone, and were asked how the stone came to be there, { might possibly answer, that, for any thing I knew to the xiontrary, it had lain there forever : nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place, I should hardly think of the answer which I had be- fore given, that, for any thing I knew, the watch might have always been there. Yet why should not this answer serve for the watch, as well as for the stone ? Why is it Hot as admissible in the second case, as in the first? For this reason, and for no other, viz. that, when we come to inspect the watch, we perceive (what we could not discov- er in the stone) that its several parts are framed and put together for a purpose, e. g. that they are so formed and ad- justed as to produce motion, and that motion so regulated as to point out the hour of the day ; that, if the several parts had been differently shaped from what they are, or of a different size from what they are, or placed after any oth- er manner, or in any other order, than that in which they are placed, either no motion at all would have been carried on in the machine, or none which would have answered the use* that is now served by it. To reckon up a few of the plainest of these parts, and of their offices, all tending to one result : [See Plate I.] — We see a cylindrical box containing a coiled elastic spring, which, by its endeavour to relax itself, turns round the box. We next observe a flexible chain (artifi- cially wrought for the sake of flexure) communicating the ac- tion of the spring from the box to the fusee. We then find a B 0 STATE OF THE ARGUMENT. series of wheels, the teeth of which, catch in, and apply io^ each other, conductinjrthe motion from the fusee to the bal- ance,and from the balance to the pointer ; and at the same time, by the size and shape of those wheels, so regulating that motion, as to terminatf- in causing an index, by an oquable and measured j»rogression, to pass over a given space in a given time. We take notice that the wheels are made of brass, in order to keep them from rust ; the springs of steel, no otlier metal being so elastic ; tliat over the face of tlie watch tlx^re is placed a glass, a material employed in no other part of the work ; but in the room of which, if there had been any other than a transparent substary^e, the hour could not be seen without opening the case. This mechanism being observed (it requires indeed an exami- nation of the instrument, and perhaps some previous knowl- edge of the subject, to perceive and understand it; but be- ing once, as we have said, observed and understood,) the inference, we think, is inevitable; that the watch must have had a maker ; that there must have existed, at some time and at some place or other, an artificer or artifi- cers, who formed it for the purpose which we find it actu- ally to answer ; who comprehended its construction, and designed its use. I. Nor would it, I apprehend, weaken tlie conclusion, that we had never seen a watch made : that we had never known an artist capable of making one ; that we were alto- gether inctpalle of executing such a piece of workman- ship ourselves, or of understanding in what manner it was performed ; all this being no more than what is true of some exquisite remains of ancient art, of some lost arts, and, to the generility of mankind, of the more curious produc- tions of modern manufacture. Does one man in a million know how oval frames are turned ? Ignorance of this kind exalts our opinion of the unseen and unknown artist's skill, if he be unseen and unknown, but raises no doubt in our mind of the existence and agency of such an artist, at some former time, and in some place or otlier. Nor can I perceive that it varies at all the inference, whether 'the question arise concerning a human agent, or concerning an agent of a diflerent species, or an agent possessing, in some respects, a diflerent nature. II. Neither, secondly, would it invalidate our conclu- sion, that the watch sometimes went wrong, or that it sel- dom went exactly right. The purpose of the machinery, the design, and the designer, might be evident, and in tli* STATE OF THE ARGUMENT. 7 case supposed would be evident, in whatever way we ac- counted for the irregularity of the movement, or whether we could account for it or not. It is not necessary that a machine be perfect, in order to show with what design it was made ; still less necessary, where the only question is, whether it were made with any design at all. III. Nor, thirdly, would it bring any uncertainty into the argument, if there were a few parts of the watch, concern- ing which we could not discover, or had not yet discovered, in what manner they conduced to the general effect ; or even some parts, concerning which we could not ascer- tain whether they conduced to that effect in any manner whatever. For, as to the first branch of the case ; if, by the loss, or disorder, or decay of the parts ia question, the movement of the watch were found in fact to be stopped, or disturbed, or retarded, no doubt would remain in our minds as to the utility or intention of these parts, although we should be unable to investigate the manner according to which, or thf; connexion by which, the ultimate effect depended upon their action or assistance ; and the more complex is the machine, the more likely is this obscurity to arise. Then, as to the second thing supposed, namely, that there were parts, which might be spared without prej- udice to the movement of the watch, and that we had prov- ed this by experiment — these superfluous parts, even if we were completely assured that they were such, would not vacate the reasoning which we had instituted concerning other parts. The indication of contrivance remained, with respect to them, nearly as it was before. IV. Nor, fourthly, would any man in his senses think the existence of the watch, with its various machinery, ac- counted for, by being told that it was one out of possible combinations of material forms ; that whatever he had found in the place where he found the watch, must have contained some internal configuration or other ; and that this configuration might be the structure now exhibited ; viz. of the works of a watch, as well as a different struc- ture. V. Nor, fifthly, would it yield his inquiry more satisfac- tion to be answered, that there existed in things a principle of order, which had disposed the parts of the watch into their present form and situation. He never knew a watch made by the principle of order ; nor can he even form to himself an idea of what is meant by a principle of order, 4jstinct from the intelligence of the watch-maker. C> STATE OF THE ARGUJIENT, VI. Sixthly, he would be surprised to hear, that the mechanism of the watch was no proof of contrivance, only a motive to induce the mind to think so. VII. And not less surprised to be informed, that tli( watch in his hand was nothing more than the result of the. laws 0^ metallic nature. It is a perversion of language to assign any law, as the efficient, operative cause of any thing. A law presupposes an agent; for it is only the mode, ac- cording to which an agent proceeds ; it implies a power ; for it is the order, according to which that power acts. Without this agent, without this power, which are both dis- tinct from itself, the laiv does aothing, is nothing. The expression, '' the law of metallic nature," may sound strange^ and harsh to a philosophic ear, but it seems quite as justi- fiable as some others which are more familiar to him ; such as *' the law of vegetable nature" — " the law of animal na- ^ture,'"' or indeed as " the law of nature" in general, when assigned as the cause of phenomena, in exclusion of agen- cy and power ; or when it is substituted into the place of these. VIII. Neither, lastly, would our observer be driven out of his conclusion, or from his confidence in its truth, by being told that he knew nothing at all about the matter. He knows enough for his argument. He knows the utility of the end : he knows the subserviency and adaptation of the means to the end. These points being known, his igno- rance of other points, his doubts concerning other points,, affects not the certainty of his reasoning. The conscious- ness of knowing little, need not beget a distrust of that which he does know. CHAPTER II. STATE OF THE ARGUMENT CONTINUED. Suppose, in the next place, that the person who found the watch, should, after some time, discover, that, in ad- dition to all the properties which he had hitherto observed in it, it possessed the unexpected property of producing, in the course of its movement, another watch like itself (the thing is conceivable;) that it contained within it a mechanism, a system of parts, a mould for instance, or a complex adjustment of lathes, files, and other tools, evident - STATE OF THE ARGUMENT. \f \y and separately calculated for this purpose ; let us in- i{uire, what effect ought such a discovery to have upon his former conclusion. I. The first effect would be to increase his admiration of the contrivance, and his conviction of the consummate skill of the contriver. Whether he regarded the ob- ject of the contrivance, the distinct apparatus, the intri- cate, yet in many parts intelligible meclianisin by which it was carried on, he would perceive, in this new observa- tion, nothing but an additional reason for doing what he had already done ; for referring the construction of the watch to design, and to supreme art. If that construction without this property, or, which is the same thing, before this property had been noticed, proved intention and art to have been employed about it, still more strong would the proof appear, when he came to the knowledge of this further property, the crown and perfection of all the rest. II. He would reflect, that though the watch before him were, 171 some sense, the maker of the watch, which was fabricated in the course of its movements, yet it was in a very different sense irom that, in which a carpenter, for instance, is the maker of a chair , the author of its con- trivance, the cause of the relation of its parts to their use. With respect to these, the first watch was no cause at all to the second , in no such sense as this, was it the author of the constitution and order, either of the parts 'which the new watch contained, or of the parts by the aid and instrumentality of which it was produced. We uiight pos- sibly say, but with great latitude of expression, that a stream of water ground corn ; but no latitude of expres- sion would allow us to say, no stretch of conjecture could lead us to think, tiiat the stream of water built the mill, though it were too ancient for us to know who the builder was. What the stream of water does in the affair is nei- ther more nor If^ss than this ; by the application of an in- telligent impulse to a mechanism previously arranged, arranged independently of it, and arranged by intelligence, an effect is produced ; viz. the corn is ground. But the effect results from the arrangement. The force of the stream cannot be said to be the cause or author of the effect, still less of the arrangement. Understanding and plan in the formation of the mill were not the less neces^ .sarv, for any share which the water has in grinding the B 2 10 STATE OF THE ARGUMENT, corn : yet is this share the same, as that which the watcli would have contriDuted to the production of the new watch., upon the supposition assumed in the last section. There- fore, III. Though it be now no longer probable, that the individual watch which our observer had found was made immediately by the hand of an artificer, yet doth not this alteration in any wise affect the inference, that an artificer had been originally employed and concerned in the pro- duction. The argument from design remains as it was, Marks of design and contrivance are no more accounted for now, than they were before. In the same thing, we may ask for the cause of different properties. We may ask for the cause of the colour of a body, of its hardness, of its heat ; and these causes may be all different. We are now asking for the cause of that subserviency to an use^ that relation to an end, which we have remarked in the watch before us. No answer is given to this question by telling us that a preceding watch produced it. There can- not be design without a designer ; contrivance without a contriver ; order v.ithout choice ; arrangement, without any thing capable of arranging; subserviency and relation to a purpose, without that which could intend a purpose ; means suitable to an end, and, executing their office in accomplishing that end, without the end ever having been contemplated, or the means accommodated to it. Arrange- ment, disposition of parts, subserviency of means to an end, relation of instruments to an use, imply the presence of in- telligence and mind. No one, therefore can rationally be- lieve, that the insensible, inanimate watch, from which the watch before us issued, Vv'as the proper cause of the me- chanism we so much admire in it ; could be truly said to have constructed the instrument, disposed its parts, assign- ed their office, determined their order, action, and mutual dependency, combined their several motions into one re- sult, and that also a result connected with the utilities of other beings. All these properties, therefore, are as much miaccounted for, as they were before. IV. Nor is any thing gained by running the difficulty farther back, i, e. by supposing the watch before us to have been produced from another watch, that from a former, and so on indefinitely. Our going back ever so far brings us no nearer to the least degree of satisfaction upon the subject. Contrivance is still unaccounted for. We still want a contriver. A designing mind is neither supplied STA.TE OF TflE ARGUMENT. U by this supposition, nor dispensed with. If the difficulty- were diminished the furtlier we went back, by going back indefinitely we might exhaust it. And this is the only case to which this sort of reasoning applies. Where there is a tendency, or, as we increase the number of terms, a continual approach towards a limit, there, by supposincr the number of terms to be what is called infinite, we may con- ceive the limit to be attained : but where there is no sucli tendency or approach, nothing is affected by lengthening the series. There is no difference as to the point in ques- tion, (whatever there may be as to many points) between one series and another ; between a series which is finite and a series which is infinite. A chain, composed of an infinite number of linKs, can no more support itself, than a chain composed of a finite number of links. And of this we are assured, (though we never can have tried the ex- periment) because, by increasing the number of links, from ten, for instance, to a hundred, from a hundred to a thousand, &c. we make not the smallest approach, we ob- serve not the smallest tendency, towards self-support. There is no difference in this respect (yet there may be a great difference in several respects) between a chain of a greater or less length, between one chain and another, between one that is finite and one that is infinite. This very much rec^embles the case before us. The ma- chine, which we are insp(5cting, demonstrates, by its construction, contrivance and design. Contrivance must have had a contriver , design, a designer ; whether the machine immediately proceeded from another machine or not. That circu instance alters not the case. That other machine may, in like manner, have proceeded from a for- mer machine ; nor does that alter the case ; contrivance must have had a contriver. That former one from one preceding it ; no alteration still ; a contriver is still neces- sary. No tendency is perceived, no approach towards a diminution of this necessity. It is the same with any and every succession of these machines; a succession of ten, of a hundred, of a thousand ; with one series as with an- other ; a series which is finite, as with a series which is infinite. In whatever other respects they may diiier, in ihis they do not. In all equally, contrivance and design are unaccounted for. The question is not simply, How came the first watch into existence ? which question, it may be pretended, is done away by supposing the series of watches thus pro- 1:1 STATE OP THE ARGUMENT. fliiced from one another to have been infinite, and consc- «iuently to liave had no such /?r.s^, for which it was neces- >«ary to provide a cause. This, perhaps, would have been nearly the stateof the question if nothing had been before us, but an unorganized, unmechanized substance, without mark or indication of contrivance. It might be difficult to .>^how that such substance could not have existed from eter- nity, either in succession (if it were possible, which I think it is not, for unorganized bodies to spring from one another,) or by individual perpetuity. But that is not the question now. To suppose it to be so, is to suppose timt it made no difference whether we had found a watch or a stone. As it is, the metaphysics of that question have no place ; for, in the watch which we are examining, are seen con- trivance, design ; an end, a purpose , means for the end, adaptation to the purpose. And the question, which irresistibl} presses upon our thoughts, is, whence this con- trivance and design ? The thing required is the intending mind, the adapting hand, the intelligence by which that hand was directed. This question, this demand, is not shaken off, by increasing a number of succession of sub- stances, destitute of these properties; nor the more, by in- creasing that number to infinity. If it be said, that, upon the sup})osition of one watch being produced from another in the course of that other's movements, and by means of the mechanism within it, we have a cause for the watch in my hand, viz. tlie watch from which it proceeded, I deny, that for the design, the contrivance, the suitableness of means to an end, the adaptation of instruments to an use (all which we discover in a watch,) we have any cause what- ever. It is in vain, therefore, to assign a series of such causes, or to allege that a series may be carried back to infinity ; fvir I do not admit tiiat we have yet any cause at all for the phenomena, still less any series of causes either finite or infinite. Here is contrivance, but no contriver; proofs of design, but no designer. V. Our observpr would further also reflect, that the mak- er of the watch before him, was, in truth and reality, the maker of every watch produced from it; there being no difference, (except that the latter manifests a more ex- quisite skill,) between the making of another watch with his own hands by the mediation of files, lathes, chisels, &c. and the disposinj, fixing, and inserting, of these instru* ments, or of others equivalent to them, in the body of the watch already mn.de, in such a manner, as to form a new APPLICATION OF THE ARGUMENT, W watch in the course of the movements which he had giveis to the old one. It is only working by one set of tools, in- stead of another. The conclusion which the Jirst examination of the watch^ of its works, construction, and movement suggested, was, that it must have had, for the cause and author of that con- struction, an artificer, who understood its mechanism, and designed its use. This conclusion is invincible. A second examination presents us with a new discovery. The watch is found, in the course of its movement, to produce anoth- er watch, similar to itself- and not only so, but we perceive in it a system of organization, separately calculated for that purpose. What effect would this discovery have, or ought. it to have, upon our former inference 1 What, as hath al- ready been said, but to increase, beyond measure, our ad- miration of the skill, which had been employed in the for- mation of such a machine ? Or shall it, instead of this, all at once, turn us round to an opposite conclusion, viz. that no art or skill whatever has been concerned in the business, although all other evidences of art and skill re- main as they were, and this last and supreme piece of art be now added to the rest 1 Can this be maintained with- out absurdity 1 Yet this is atheism, CHAPTER III. APPLICATION OF THE ARGUMENT. This is atheism ; for every indication of contrivance, ev- ery manifestation of design, which existed in the watch, ex- ists in the works of nature ; with the difference, on the side of nature, of being greater and more, and that in a degree which exceeds all computation. I mean that the contriv- ances of nature surpass the contrivances of art, in the com- plexity, subtlety, and curiosity of the mechanism ; and still more, if possibly, do they go beyond them in number and variety : yet in a multitude of cases, are not less evidently mechanical, not less evidently contrivances, not less evi- dently accommodated to their end, or suited to their office, than are the most perfect productions of human ingenuity. I know no better method of introducing so large a sub- ject, than of comparing a single thing with a single thing; an eye, for example, with a telescope. As far as the ex- 14 APPLICATION OF THE ARGUMENT. umination of the instrument goes, there is precisely the same proof that the eye was made for vision, as there is that the telescope was made for assisting it. They are made upon the same principles; both bemgj adjusted to the laws by which the transmission and retraction of rays of light are regulated. I speak not of the origin of the laws themselves; but, such laws being fixed, the construction, in both cases, is adapted to them. For instance ; these laws require, in order to produce the same effect, that the rays of light, in passing from water into the eye, should be refracted by a more convex surface than when they passed out of air into the eye. Accordingly we find, that the eye of a fish, in that part of it called the crystdliine lens, is much rounder than the eye of terrestrial animals. [Plate II. fig. 1.] What plainer manifestation of design c^n there be than this difference ? What could a mathematical instrument maker have done more, to show his knowledge of his prmciple, his application of that knowledge, his suiting of his means to his end ; I will not say to display the compass or excel- lency of his skill and art, for in these all comparison is indecorous, but to testify counsel, choice, or consideration, purpose ? To some it may appear a difference sufficient to destroy all similitude between the eye and the telescope, that the one is a perceiving organ, the other an unperceiving instru- ment. The fact is, that they are both instruments. And, lis to the mechanism, at least as to mecimnism being em- ployed, and even as to the kind of it, this circumstance va- ries not the analogy at all. For observe, what the constitu- tion of the eye is. [Plate II. fig. '2, 3, 4.] It is necessary, in order to produce distinct vision, that an image or picture of the object be formed at the bottom of the eye. Whence this necessity arises, or how the picture is connected with the sensation, or contributes to it, it may be difficult, nay we will confess, if you please, impossible for us to search out. But the present question is not concerned in the inquiry. It may be true, that in this, and in other instances, we trace mechanical contrivance a certain way; and that then we come to something which is not mechanical, or which is in- scrutable. But this affects not the certainty of our inves- tigation, as far as we have gone. The difference between an animal and an automatic statue, consists in this, — that, in the animal, we trace the mechanism to a certain point, and then we are stopped ; either the mechanism becoming foo subtile for our discernment, or something else b^sido APPLICATION OP THE ARGtJ3IENT. !/> the known laws of mechanism taking place ; whereas, ii^ the automaton, for the comparatively few motions of which it is capable, we trace the mechanism throughout. But, up to the limit, the reasoning is as clear and certain in the one case as the other. In the example before us, it is a matter of certainty, because it is a matter which experience and observation demonstrate, that the formation of an im- age at the bottom of the eye is necessary to perfect vision. The image itself can be shown. Whatever affects the dis- tinctness of the image, affects the distinctness of the vision. The formation then of^ such an image being necessary, (no matter how,) to the sense of sight, and to the exercise of that sense, the apparatus by which it is formed is con- structed and put together, not only with infinitely more art, but upon the selfsame principles of art, as in the telescope or the camera ol-scura. The perception arising from the inaage may be laid out of the question ; for the production of the image, these are instruments of the same kind. The end is the same; the means are the same. The pur- pose in both is alike , the contrivance for accomplishing that purpose is- in both alike. The lenses of the telescope, and the humours of the eye, bear a complete resemblance to one another, in their figure, their position, and in their power over the rays of light, viz. in bringing each pen- cil to a point at the right distance from the lens ; name- ly, in the eye, at the exact place where the membrane is spread to receive it. How is it possible, under circum- stances of such close affinity, and under the operation of equal evidence, to exclude contrivance from the one, yet to acknowledge tlie proof of contrivance having been em- ployed, as the plainest and clearest of all propositions, in the other ? The resemblance between the two cases is still more accu- rate, and obtains in more points than we have yet represented, or than we are, on the first view of the subject, aware of. In dioptric telescopes there is an imperfection of this na- ture.— Pencils of light, in passing through glass lenses, are separated into different colours, thereby tinging the ob- ject, especially edges of it, as if it were viewed through a prism. To correct this inconvenience had been long a desideratum in the art. At last it came into the mind of a sagacious optician, to inquire how this matter was man- aged in the eye ; in which there was exactly the same diffi- culty to contend with as in the telescope. His observation '^iglil him, that, in the eye, the evil was cured by com- 16 APPLICATION OF THE ARGUMENT. billing t05;ether lenses composed of different substances. i. e of substances which possessed different refracting powers. Our artist borrowed from thence his hint ; and produced a correction of the defect by imitating, in glasses inadc from different materials, the effects of the different humours through which the rays of light pass before they reac'i the bottom of the eye. Could this be in the eye without purpose, which suggested to the optician the only effectual means of attaining that purpose ?* But further ; there are other points, not so much perhaps of strict resemblance between the two, as of superiority of the eye over the telescope, which being found in the laws that regi^iate both, may furnish topics of fair and just com- parison. Two things were wanted, to the eye, which were not 'vanted, at least in the same degree, to the teles- cope ; and these were the adaptation of the organ, first, ^o different degrees of light ; and, secondly, to the vast diversity of distance at which objects are viewed by the naked eye, viz. from a few inches to as many miles. These difBcuities present not themselves to the maker of the telescope. He wants all the light he can get ; and he nsver directs his instrument to objects near at hand. In '•'The hint taken from the eye, and applied by Mr. Dollond in the construction of achromatic telescopes, has been since carried still far- ther, and illustrates more strongly, if possible, the point so admi- rably inp".sted upon by Dr. Paley, namely, the resemblance between the eye and our optical instruments. In the best achromatic tele- scopes, composed of the different kinds of glass, according to the dis- covery of Mr. Dollond, white or luminous objects are not shown per- fectly fiee from colour, their edges being tinged on one side with a claret coloured, and on the other with .i greenish fringe. This remain- ing imperfection has been got rid of by" the combination of solid and fluid lenses in the object and eye-glasses of telescopes. For this beau- tiful discovery science is indebted to Dr. Blair of Edinburgh, who found that by placing a concave lens of muriatic acid with a metallic solution, between two convex lenses of glass, a combined lens was formed which refracted rays with perfect regularity and equality. A lens like this has been used with great advantage. The most impor- tant point is, however, to consider this improvement in its application to the argument, and it will be seen how" much nearer this construc- tion brings the telescope to the eye. In Dollond's telescope there is a combination of solid lenses of different substances. — In Blair's, a com- bination ol fluid and solid ; which is exactly the case in the human eye. The only difference is, that in the eye there is a solid lens be- tween tvvo fluid ones; and in the telescope a fluid between two solid. The combination is closely similar, and the final cause in both proba- bly the same, namely, to correct the unequal refraction of light." — See Ediiiburs^h Journal of Science, No. viii, p. 212 : and Library of Useful Knowledge, No. 1 & 12. [Ed, APPLICATION OF THE ARGUMENT, 17 <,ne eye, both these cases were to be provided for ; and for the purpose of providing for them a subtile and appropriate mechanism is introduced. I. In order to exclude excess of light, vi?hen it is ex- cessive, and to render objects visible under obscurer degrees of it, when no more can be had : the hole or aperture in the eye, through which the light enters, is so formed, as to contract or dilate itself for the purpose of admitting a great- er or less number of rays at the same time. The cham- ber of the eye is a camera obscura, which, when the light is too sniiiU, can enlarge its opening ; when too strong, can again contract it; and that without any other assist- ance than that of its own exquisite machinery. It is fur- ther also, in the human subject to be observed, that this hole in the eye, which we call the pupil, under all its dif- ferent dimensions, retains its exact circular shape. This is a structure extremely artificial. Let an artist only try to execute the same. He will find that his threads and strings must be disposed with great consideration and con- trivance, to make a circle, which shall continudlly change its diameter, yet preserve its form. This is done in the eye by an application of fibres, i. e. of strings, similar, in their position and action to what an artist would and must employ, if he had the same piece of workmanship to per- form. [Plate II. Fig. 5 6l 6.]* II. The second difficulty which has been stated, was the suiting of the same organ to the perception of objects that * There is a curious circumstance in the way in which light pro- duces the contraction of the opening of the iris, which strengthens very- much the argument derived from design manifested in its structure and adaptation to its purpose. The object of the iris, it is to be observ- ed, has reference to the quantity of light to be admitted upon the re- tina or expansion of the optic nerve. It is the state of the retina then which regulates the motions of the iris, and it is the action of the hght on the retina which causes those motions and not its action upon the iris itself. This has been shown by a very delicate experiment. If a ray of light be accurately thrown in such a direction, that it shall fall upon the circle of the iris itself, and not pass through its aperture, no con- traction of the aperture takes place ; but if it be so thrown as to pass through the aperture, and fall upon the retina without touching the iris at all, still a contraction of the iris immediately takes place. So that light upon the iris alone occasions no contraction, although it is the part which really contracts when the same light falls upon a dis- tant part. The design here is too obvious to need being enlarged upon. How could the iris acquire the power of contracting when light falls on another membrane, for the protection of that membrane ? although it does not contract when the light falls upon itself alone ? [Ed. c 18 APPLICATION OF THE ARGUMENT. lie near at hand, within a few inches, we will suppose, oi the eye, and of objects which were placed at a considerable distance from it, that, for example, of as many furlongs, (I speak in both cases of the distance at which distinct vision can be exercised.) Now, this, according to the principles of optics, that is, according to the laws by which the transmission of light is regulated, (and these laws are fixed,) could not be done, without the organ itself under- going an alteration, and receiving an adjustment, that might correspond witn the exigency of the case, that is to say, with the different inclination to one another under which the rays of light reached it. Rays issuing from points placed at a small distance from the eye, and which conse- quently nmst enter the eye in a spreading or diverging order, cannot, by the same optical instrument in the same state, be brought to a point, i. e. be made to form an image, in the same place with rays proceeding from objects situat- ed at a much greater distance, and which rays arrive at the eye in directions nearly, and, physically speaking,, parallel. It requires a rounder lens to do it. The point of concourse behind the lens must fall critically upon the retina, or the vision is confused ; yet this point, by the im- mutable properties of light, is carried further back, when the rays proceed from a near object, than when they are sent from one that is remote. A person, who was using an optical instrument, would manage this matter by chang- ing, as the occasion required, his lens or his telescope ; or by adjusting the distance of his glasses with his hand or his screw ; but how is it to be managed in*the eye? What the alteration was, or in what part of the eye it took place, by what means it was effected (for, if the known laws which govern the refraction of light be maintained, some alteration in the state of the organ there must be,) had long formed a subject of inquiry and conjecture. The change, though suiRcient for the purpose, is so minute as to elude ordinary observation. Some very late discove- ries, deduced from a laborious and most accurate inspection of the structure and operation of theorgaU; seem at length to have ascertained the mechanical alteration which the parts of the eye undergo. It is found, that by the action of certain muscles, [PI. II. fig. 7.] called the straight muscles, and which action is the most advantageous that could be imagined for the purpose, — it is found, I say, that whenever the eye is directed to a near object, three changes are produc- ed in it at the same time, all severally contributing to the ad-^ APPLICATION OF THE ARGUMENT. 10 justment required. The cornea, or outermost coat of the eye, is rendered more round and prominent ; the crystalline Jens underneath is pushed forwards ; and the axis of vision, as the depth of the eye is called, is elongated. These changes in the eye vary its power over the rays of light in such a manner and degree as to produce exactly the effect which is wanted, viz. the formation of an image upon the retina, whether the rays come to the eye in a state of divergency, which is the case when the object is near to the eye, or come parallel to one another, which is the case when the object is placed at a distance. Can any thing be more decisive of contrivance than this is ? The most secret laws of optics must have been known to the author of a structure endowed with such a capacity of change. It is, as though an optician, when he had a nearer object to view, should recti/}/ his instruaient by putting in another glass, at the same time drawing out also his tube to a different leiiojth. Observe a new born child first lifting up its eyelids. What does the opening of the curtain discover] Tlie an- terior part of two pellucid globes, which, when they come to be examined, are found to be constructed upon strict op- tical principles ; the selfsame principles upon which we ourselves construct optical instruments. We find them perfect for the purpose of forming an image by refraction : composed of parts executing different offices : one part having fuliilled its office upon the pencil of light, deliver- ing it over to the action of another part ; that to a third, and so onward ; the progressive action depending for its success upon the nicest and minutest adjustment of the parts concerned ; yet, these parts, so in fact adjusted as to produce, not by a simple action or effect, but by a combi- nation of actions and effects, the result which is ultimate- ly wanted. And forasmuch as this organ would have to operate under different circumstances, with strong degrees of light, and with weak degrees, upon near objects, and upon remote ones, and these differences demanded, accord- ing to the laws by which the transmission of light is regu- lated, a corresponding diversity of structure ; that the aperture, for example, through which the light passes, should be larger or less ; the lenses rounder or flatter, or that their distance from the tablet, upon which the picture is delineated, should be shortened or lengthened : this, I say, being the case and the difficulty, to which the eye was to he adapted, we find its several parts capable of being oc- 10 APPLICATION OF THE ARGUMENT. casionally changed, and a most artificial apparatus provid- ed to produce that change. This is far beyond the com- mon regulator of a watch, which requires the touch of a foreign hand to set it ; but is not altogether unlike Harri- son's contrivance for making a watch regulate itself, by in- serting within it a machinery, which, by the artful use ot the different expansion of metals, preserves the equability of the motion under all the various temperatures of heat and cold in which the instrument may happen to be placed. The ingenuity of this last contrivance has been justly prais- ed. Shall, therefore, a structure which differs from it chiefly by surpassing it, be accounted no contrivance at all? or, if it be a contrivance, that it is without a contriver ? But this, though much, is not the whole : by different species of animals the faculty we are describing is possess- ed, in degrees suited to the different range of vision which their mode of life, and of procuring their food, requires, Birds, for instance, in general, procure their food by means of their beak ; and the distance between the eye and the point of the beak being small, it becomes necessary that they should have the power of seeing very near objects dis- tinctly. On the other hand, from being often elevated much above the ground, living in air, and moving through it with great velocity, they require for their safety, as well as for assisting them in descrying their prey, a power of seeing at great distance ; a power, of which, in birds of rapine, surprising examples are given. The fact accordingly is^ that two peculiarities are found in the eyes of birds, both tending to facilitate the change upon which the adjustment of the eye to different distances depends. The one is a bony, yet, in most species, a flexible rim or hoop, [Plate III. fig. 1, 2.] surrounding the broadest part of the eye; which, confining the action of the muscles to that part, increases the effect of their lateral pressure upon the orb, by which pressure its axis is elongated for the purpose of looking at very near objects. The other is an additional muscle, call- ed the marsupiura, [Plate III. fig. 3,4, 6.] to draw, upon occasion, the crystalline lens back, and so fit the same eye for the viewing of very distant objects. By these means the eyes of birds can pass from one extreme to another of their scale of adjustment, with more ease and readiness than the eyes of other animals. The eyes of fishes also, compared with those of terres- trial animals, exhibit certain distinctions of structure, adapted to their state and element. We have already ob- APPLICATION OP THE ARGUMENT. 21 stirved upon the figure of the crystalline compensating by its roundness the density of the medium through which their light passes : to which we have to add, that the eyes of fishes, in their natural and indolent state, appear to be ad- justed to near objects, in this respect differing from the hu- man eye, as well as those of quadrupeds and birds. The ordinary shape of the fish's eye being in a much higher de- gree convex than that of land animals, a corresponding diflference attends its muscular conformation, viz. that it is throughout calculated ioY fiattening the eye. The iris also in the eyes of fish does not admit of con- traction. This is a great difference, of which the proba- ble reason is, that the diminished light in water is never too strong for the retina. In the eel, [Plate III. fig. 5.] which has to work its head through sand and gravel, the roughest and harshest sub- stances, there is placed before the eye, and at some distance from it, a transparent, horny, convex case or covering, which, without obstructing the sight, defends the organ. To such an animal, could any thing be more wanted, or more useful? Thus, in comparing together the eyes of different kinds of animals, we see, in their resemblances and distinction, one general plan laid down, and that plan varied with the varying exigencies to which it is to be applied. There is one property, however, comaion, I believe, to all eyes, at least to all which have been examined,* namely, that the optic nerve enters the bottom of the eye, not in the ceutre or middle, but a little on one side; not in the point wlsere the axis of the eye meets the retina, but between that point and the nose. — The difference which this makes is, that no part of an object is unperceiv- ed by both evf^s at the same time. In considorinor vision as achieved by the means of an image formed u the bottom of the eye, we can never re- flect, without wonder, upon the smallness, yet correct'jess^ of the picture, the subtlety of the touch, the fineness of the lines. A 1 mdscape of five or six square leagues is hroujjht into a space of half an inch diameter ; yet the multitude of objects which it contains are all preserved ; are all discrim- inated in their magnitudes, positions, figures, colours. The * The eye of the seal or sea-calf, I understand, is an exception,-— Mem. Acad. Paris, 1701, p. 123. C2 22 APPLICATION OF THE ARGUMENT. prospect from Hampstead-Hill is compressed into the com- pass of a sixpense, yet circumstaniially represented. A stage coach, tiavelling at its ordinary speed for half an hour, passes, in the eye, only over one-twelfth of an inch, yet is this change of place in the image distinctly per- ceived throughout its whole progress; for it is only by means of that perception that the motion of the coach it- self is made sensible to the eye. If any thing can abate our admiiation of the smallness of the visual tablet compar- ed with the extent of vision, it is a reflection, which the view of nature leads us, every hour, to make, viz. that in the hands of the Creator, great and little are nothing. Sturmius held, that the examination of the eye was a cure for atheism. Beside that conformity to optical principles, which its internal constitution displays, and which alone amounts to a manifestation of intelligence hav- ing been exerted in its structure ; besides this, which forms, no doubt, the leading character of the organ, there is to be, seen, in every thing belonging to it and about it, an ex-' traordmary degree of care and anxiety for its preservation, due, if we may so speak, to its value and tenderness. It is lodged in a strong, deep, bony socket, composed by the junction of seven different bones,* hollowed out at their edges. In some few species, as that of the coatimondi,t the orbit is not bone throughout ; but whenever this is the ca^e, the upper, which is the deficient part, is supplied by a cartilaginous licrament . a substitution which shows the same care. Within this socket it is imbedded in fat of all animal substances the best adapted both .to its repose and motion. It is sheltered by the eyebrows, and arch of hair, which, like a thatched pent-house, prevent the sweat and moisture of the forehead from running down into it. But it is >till better protected by its lid Of the super- ficial parts of the animal frame, I know none which, in its ofii -e and structure, is more deserving of attention than the eyelid. It »lefends the eye ; it wipes it; it closes it in sleep. Are there, in any work of art whatever, purposes more evident than those which this organ fulfils : or an apparatus for executinsr those purposes more intelligible, more appropriate, or more mechanical '\ If it oe overlooked by the observer of nature, it can only be because it is ob- vious and familiar. — This is a tendency to be guarded against. We pass by the plainest instances, whilst we are * Heister, sect. 89. t Mem. of the R. Ac. Paris, p. 117. APPLICATION OF THE ARGUMENT. 23 exploring those which are rare and curious ; by which con- duct of the understanding, we sometimes neglect the strongest observations, being taken up with others, which, though more recondite and scientific, are, as solid argu- jnents, entitled to much less consideration. In order to keep the eye moist and clean, which qualities are necessary to its brightness and its use, a wash is con- stantly supplied by a secretion for the purpose ; and the superfluous brine is conveyed to the nose through a perfora- tion in the bone as large as a goose quiil. [Plate IV. fig. 1.] When once the fluid has entered the nose, it spreads itself upon the inside of the nostril, and is evaporated by the cur- rent of warm air, which, in the course of respiration, is con- tinually passing over it. Can any pipe or outlet for carry- ing off the waste liquor from a dye-house or distillery, be more mechanical than this is? It is easily perceived that the eye must want moisture : but could the want of the eye generate the gland which produces the tear, or bore the hole by which it is discharged — a hole through a bone ? It is observable that this provision is not found in fish ; the element in which they live supplying a constant lotion .to the eye. It were, however, injustice to dismiss the eye as a piece of mechanism, without noticing thrt most exquisite of all contrivances, the nictitating membrane, which is found in the eyes of birds and of many quadrupeds. [Plate IV fig. 2, 3, 4, 5.] Its use is to sweep the eye, which it does in an instant ; to spread over it the lachrymal humour ; to defend it also from sudden injuries ; yei: not totally, when drawn upon the puuil, to shut out the light. The commodiousness with which it lies folded up in the upper corner of the eye, ready for use and action, and the quickness with which it executes its purpose, are properties known and obvious to every observer ; but, what is equally admirable, though not quite so obvious, is the combination, of two different kinds of substance, muscular and elastic, and of two different kinds of ac- tion, by which the motion of this mem^rance is performed. It is not, as in ordinary cases, by the action of two antagonist muscles, one pulling forward and the other backward, that a reciprocal change it; effected ; but it is thus : the membrance itself is an elastic substance, ca- pable of being drawn out by force like a piece of elastic gum, and hy its own elasticity returning, when the force is removed, to its former position. Such being its nature. 24 APPLICATION OF THE ARGUMENT* in order to fit it up for its office it is connected by a ten- don or thread with a muscle in the back part of the eye ; this tendon or thread, though strong, is so fine, as not to obstruct the sight, even when it passes across it ; and the muscle itself being placed in the hack part of the eye, de- rives from its situation the advantage, not only of being secure, but of being out of the way ; which it could hard- ly have been in any position that could be assigned to it in the anterior part of the orb, where its function lies. When the muscle behind the eye contracts, the membrance, by means of the communicating thread, is instantly drawn over the forepart of it. When the muscular contraction (which is a positive, and, most probably a voluntary effort,) ceases to be exerted, the elasticity alone of the membrance brings it back again to its position.* Does not this, if any thing can do it, bespeak an artist, master of his work, ac- quainted with his materials? "Of a thousand other things," say the French Academicians, " we perceive not the contrivance, because we understand them only by the effects of which we know not the causes ; but we here treat of a machine, all the parts whereof are visible ; and which needs only to be looked upon to discover the rea- sons of its motion and action."! In the configuration of the muscle, which, though placed behind the eye, draws the nictitating membrane over the eye, there is, what the authors, just now quoted, deserved- ly call a marvellous mechanism. I suppose this structure to be found in other animals ; but, in the Memoirs from which this account is taken, it is anatomically demonstrat- ed only in liie cassowary. The muscle is passed through a loop f >rmfd hif another muscle; and is tliere inflected, as if it were round a pulley. This is a peculiarity; and observe the advantage of it. A single ruuscle with a straight tendon, whi h is the common muscular form, would have been sufficient, if it had had the power to draw far enough. But the contraction, necessary to draw the mem- brane over the whole eye, required a longer muscle than couH lie straight at the bottom of the eye. Therefore, in order to have a greater length in a less compass, the cord of the main muscle makes an angle. This, so far. « Phil. Tran. 1796. t Memoirs for a Natural History of Animals by the Royal Academy of Sciences at Paris, done into English by order of the Royal Society.- 1701, p. 249. APPLICATION OF THE ARGUxMENT, 2h answered the end ; but, still further, it makes an angle^ Hot round a fixed pivot, but round a loop formed by anoth- er muscle ; which second muscle, whenever it contracts, of course twitches the first muscle at the point of inflec- tion, and thereby assists the action designed by both. One question may possibly have dwelt in the reader's mind during the perusal of these observations, namely, Why should not the Deity have given to the animal the faculty of vision at once ? Why this circuitous perception ; the ministry of so many means ; an element provided for the purpose ; reflected from opaque substances, refracted through transparent ones ; and both according to precise laws ; then, a complex organ, an intricate and artificial ap- paratus, in order, by the operation of this element, and in conformity to the restrictions of these laws, to produce an image upon a membrane coi imunicating with the brain ? Wherefore all this ? Why make the difficulty in order on- ly to surmount it ? If to perceive objects by some other mode than that of touch, or objects which lay out of the reach of that sense, wt^re the thing purposed, could not a simple volition of the Creator have communicated the ca- pacity ? Why resort to contrivance where power is omnip- otent ? Contrivance, by its very definition and nature, is the refuge of imperfection. To have recourse to expedi- ents, implies difficulty, impediment, restraint, defect of power. This question belongs to the other senses, as well as to sights ; to the general functions of animal life, as nu- trition, secretion, respiration ; to the economy of vegeta- bles ; and indeed to almost all the operations of nature. The question therefore is of a very wide extent ; and, a- mongst other answers which may be given to it, beside rea- sons of which probably we are ignorant, one answer is this : It is only by the display of contrivance, that the existence, the agency, the wisdom of the Deity, cmld be testified to his rational creatures. This is the scale by which we as- cend to all the knowledge of our Creator which we possess, so far as it depends upon the phenomena, or the works of na- ture. Take away this, and you take away from us every sub- ject of observation, and ground of reasoning ; I mean as our rational faculties are formed at present. Whatever is done, God could have done, without the intervention of instru- ments or means : but it is in the construction of instru- ments, in the choice and adaptation of means, that a crea- tive intelligence is seen. It is this which constitutes the order and beauty of the universe. God, therefore, has i26 APPLICATION OF THE ARGUMENT. been pleased to prescribe limits to his own power, and to work his ends within those limits. The •:i;eneral laws of matter have perhaps the nature of these limits , its inertia, its re-action ; the laws which govern the communication of motion, the retraction and reflection of liglit, the constitu- tion of fluids non-elastic and elastic, the transmission of sound through the latter ; the laws of magnetism, of elec- tricity ; and probably others yet undiscovered. These are general laws ; and when a particular purpose is to be ef- fected, it is not by making a new law, nor by tiie suspen- sion of the old ones, nor by making them wind and bend and yield to the occasion (for nature with great steadiness adheres to, and sup)x>rts them,) but it is, as we have seen in the eye, by the interposition of an apparatus, correspond- ing with these laws, and suited to the exigency which re- sults from them, that the purpose is at length attained. As we have said, therefore, God prescribes limits to his power, that he may let in the exercise, and thereby exhibit demon- strations of his wisdom. For then, i. e. such laws and lim- itations being laid down, it is as though one Being should have fixed certain rules ; and, if we may so speak, provid- ed certain materials ; and afterwards, have cojnmitted to another bemg out of these materials, and in subordination to these rules, the task of drawing forth a creation : a sup- position which evidently leaves room, and induces indeed a necessity for contrivance. Nay, there may be many such agents, and many ranks of these. We do not advance this as a doctrine either of philosophy or of religion ; but we say that the suoject may safely be represented under this view, because the Deity, acting himself by general laws, will have the same consequences upon our reasoning, as if he had prescribed thesv^ laws to another. It has been said, that the problem of creation, was ** attraction and matter being given, to make a world out of them :" and, as above explained, this statement perhaps does not convey a false idea. We have made choice of the eye as an instance upon which to rest the argument of this chapter. Some single example was to be proposed : and the eye offered itself un- der the advantage of admitting of a strict comparison with optical instruments. The ear, it is probable, is no less artificially and mechanically adapted to its office than the eye; but we know less about it: we do not so well un- APPLICATION OF THE ARGUMENT. 27 i PLANTS AND ANIMALS. 31 lion ? Whether a latent plantule with the means of tem- porary nutrition, or whatever else it be, it encloses an or- ganization suited to the germination of a new plant. Has the plant which produced the seed any thing more to do with that organization, than the watch would have had to do with the structure of the watch which was produced in the course of its mechanical movement ? I mean, Has it any thing at all to do with the contrivance ? The maker and con- triver of one watch when he inserted within it a mechanism suited to the production of another watch, was, in truth, the maker and contriver of that other watch. All the prop- erties of the new watch were to be referred to his agency ; the design manifested in it, to his intention ; the art, to him, as the artist ; the collocation of each part, to his placing ; the action, effect, and use, to his counr^el, intelligence, and Avorkmanship. In producing it by the intervention of a formiCr v/atch, he was only working by one set of tools in- stead of another. So it is with the plant, and the seed produced by it. Can any distmction be assigned between the two cases; between the producing watch, and the pro- ducing plant? Both passive, unconscious substances; both, by the organization which was given to them, pro- ducing their like without understanding or design ; both, that is, instruments. II. From plants we may proceed to oviparous animals; from seeds to Ci^gs. Now, I say, that the bird has the same concern in the formation of the egg which she lays, as the plant has m that of the seed which it drops; and no other, nor greater. The internal constitution of the egg is as much a secret to the hen, as if the hen were inan- imate. Her will cannot alter it, or change a single feather of the chick. 8he can neither foresee nor determine of which sex her brood shall be, or how many of either ; yet the thing produced shall be, from the first, very different in its make, according to the sex which it bears So far, therefore, from adapting the means, she is not beforehand apprized of the effect. If there be concealed within that ' smooth shell a provision and a preparation for the produc- tion and nourishment of a new animal, they are not of her providing or preparing ; if there be contrivance, it is none of hers. Although, therefore, there be the difference of life and perceptivity between the animal and the plant, it is a difference which enters not into the account. It is a for- eign circumstance. It is a difference of properties not employed. The animal function and the vegetable func- 32 ON THE SUCCESSION OF tion are alike destitute of any design which can operate up- on the form of the thing produced. The plant has no de- sign in producing the seed, no comprehension of tiie na- ture or use of what it produces : the bird with respect to its egg, is not above the plant with respect to its seed. Neith- er the one nor the other bears that sort of relation to wltat proceeds from them, which a joiner does to the chair w hich he makes. Now a cause, which bears this relation to the effect, is what we want, in order to account for the suita- bleness of means to an end, the fitness and fitting of one thing to another : and this cause the parent plant or ani- mal does not suppl}'. It is further observable, concerning the propagation of plants and animals, that the apparatus employed exhibits no resemblance to the thing produced ; in this respect holding an analogy with instrument? and tools of art. The filaments, antherae, and stiamata of fiiowers bear no more resemblance to the young plant, or even to the seed, which is formed by their inter v^ention, than a chisel or a plane does to a table or a chair. What then are the filaments, antherae, and stigmata of plants, but instruments, strictly so calle;! ?* Ill We may advance from animals which bring forth eggs, to animals which bring forth their young alive ; and., of this latter case, from the lowest to the highest : from " Nearly akin to the reproduction of plants and animak by genera- tion, is the reproduction of parts of animal bodie-; which have been destroyed, and the reparation of those which have been injured. To say nothing of the reproduction of limbs in crustaceou^ animals, the wonderful but well attested fact, of the formation of a new eye in an animal of the lizard kind, in the place of one, which had been cut out of the socket, is one which no atheistical theory can approach, in the way of explanation. In the process by which a new eye is formed^ the apparatus, instruments and materials, employed, bear no resem- blance to the organ to be formed. The small capillary vessels ot the root of the eye, construct anew eye, out of the blood which circulates in them. To use a mode of expression like that of our author — the vessels which thus construct a new eye, bea:- no more resemblance to it, than a chisel or a plane, to a table or a chair ; and the blood out of which it is made, no more resemblance to it when made, than the metallic ores when taken out of the mine, to a complete and perfectly constructed watch. In this ca>je, we find a contrivance existing in a whole race of animals, for the accomplishment of a purpose which it is not called upon to accomplish in one instance out of a thousand. If the reader will examine the several atheistical modes of evading the force of the arguments for the existence of God, referred to in the next Chapter, as well as in various other parts of this volume, he will lind that they signally fail in their application to this case. Ed. PLANTS AND ANIMALS. 33 irrational to rational life, from brutes to the human species ; without perceiving, as we proceed, any alteration whatever in the terms of the comparison. The rational animal does not produce its offspring with more certainty or success than the irrational animal ; a man than a quadruped, a quadruped than a bird ; nor (for we may follow the grada- tion through its whole scale) a bird than a plant ; nor a plant than a watch, a piece of dead mechanism, would do upon the supposition which has already so olten been re- peated. Rationality therefore has nothing to do in the business. If an account must be given of the contrivance which Vi'e observe ; if it be demanded, whence arose either the contrivance by which the young animal is produced, or the contrivance manifested in the young animal itself, it is not from the reason of the parent that any such account can be drawn. He is the cause of his offspring in the same sense as that in which a gardener is the cause of the tulip which grows upon his parterre, and in no other. We ad- mire the flower ; we examine the plant ; we perceive the conduciveness of many of its parts to their end and office ; we observe a provision for its nourishment, growth, pro- tection, and fecundity : but we never think of the gardener in all this. We attribute nothing of this to his agency ; yet it may still be true, that, without the gardener, we should not have had the tulip Just so it is with the suc- cession of animals even of the highest order. For the contrivance discovered in the structure of the thing pro- duced, we want a contriver. The parent is not that contri- ver. His consciousness decides that question. He is in total ignorance, why that which is produced took its present form rather than any other. It is for him only to be astonished by the effect. We can no more look therefore to the intel- ligence of the parent animal for what we are in search of, a cause of relation and of subserviency of parts to their use, which relation and subserviency we see in the procreated body, than we can refer the internal confirmation of an acorn to the intelligence of the oak from which it dropped, or the structure of the watch to the intelligence of the watch which produced it ; there being no difference, as far as argument is concerned, between an intelligence which is not exerted, and an intelligence which does not exist, D2 34 APPLICATION OF THE CHAP. V. APPLICATION OP THE ARGUMENT CONTINUED. Every observation which was made, in our first chap- ter concerning the watch, may be repeated with strict pro- priety concerning the eye ; concernmg animals ; concern- ing plants ; concerning, indeed, all the organized parts of the works of nature. As, ■> I. When we are inquiring simply after the existence of an intelligent Creator, imperfection, inaccuracy, liability to disorder, occasional irregularities, may subsist, in a con- siderable degree, without inducing any doubt into the question : just as a watch may frequently go wrong, seldom perhaps exactly right, may be faulty in some parts, defec- tive in some, without the smallest ground of suspicion from thence arising, that it was not a watch ; not madCj or not made for the purpose ascribed to it. When faults are pointed out, and when a question is started concerning the skill of the artist, or the dexterity with which the work is executed, then, indeed, in order to defend these qualities from accusation, we must be able, either to expose some intractableness and imperfection in the materials, or point out some invincible difficulty in the execution, into which imperfection and difficulty the matter of complaint may be resolved ; or, if we cannot do this, we must adduce such specimens of consummate art and contrivance proceeding from the same hand, as may convince the inquirer of the existence, in the case before him, of impediments like those which we have mentioned, although, what from the nature of the case is very likely to happen, they be unknown and unperceived by him. This we must do in order to vindi- cate the artist's skill, or, at least, the perfection of it ; as we must also judge of his intention, and of the provisions employed in fulhlling that intention, not from an instance in which they fail, but from the great plurality of instances in which they succeed. But, after all, these are diifereiit questions from the question uf the artist s existence ; or, which is the same, whether the thing before us be a work of art or not ; and the question ought always to be kept sepa- rate in the mind. So likewise it is in the works of nature. Irregularities and imperfections are of little or no weight in the consideration, when that consideration relates sim- ply to the existence of a Creator. WHien the argument re- spects his attributes, they are of weight . but are then to ARGUMENT CONTINUED. 35 he taken in conjunction (the attention is not to rest upon them, but they are to be taken in conjunction) with the unexceptionable evidences which we possess, of skill, power, and benevolence, displayed in other instances ; which evidences may, in strengtn, number, and variety, be such ; and may so overpower apparent blemishes, as to in- duce us, upon the most reasonaule ground, to believe, that these last ought to be referred to some cause, though we be ignorant of it, other than defect of knowledge or of be- nevolence in the author. 11. There may be also parts of plants and animals, as there were supposed to be of the watch of which, in some instances, the operation, in others, the use is unknown, These form different cases ; for the operation may be un- known, yet the use be certain. Thus it is with the lungs of animals It does not, I think, appear, that we are acquainted with the action of the air upon the blood, or in what man* ner that action is comiiiunicated by the lungs ; yet we tind that a very short suspension of their office destroys the life of the anirnal. In this case, therefore, we may be said to know the use, nay, we experience the necessity of the organ, though we be ignorant of its operation. Nearly the same thing may be observed of what is called the lympha- tic system. We suffer grievous inconveniences from its dis- order, without being informed of the office which it sus- tains in the economy of our bodies. There may possibly also be some few examples of the second class, in which, not only tiie operation is unknown, but in Vv'hich experi- ments may seem to prove that the part is not necessary ; or may leave a doubt, how far it is even useful to the plant or animal m which it is found. This is said to be the case with the spleen ; which has been extracted from dogs, with- out any sensible injury to their vital functions. Instances of the former kind, namely, in which we cannot explain the operation, may be numerous ; for they v.ili be so in proportion to our ignorance. They will be more or fewer to different persons, and in different stages of science. Every improvement of knowledge diminishes their number. There is hardly, peihaps, a year passes, that does not, in the works of nature, bring some operation, or some mode of operation, to light, which was before undiscovered, pro- bably unsuspected instances of the second kind, namely, where tne part appears to be totally useless, I believe to be extremely rare ; compared with the number of those, of which the use is evident, they are beneath any assignable 36 APPLICATION OF THE proportion ; and perhaps, have never been submitted to a trial and examination, sufficiently accurate, long enough continued, or often enough repeated. No accounts, which I have seen, are satisfactory. The mutilated animal may live and grow fat, as was the case of the dog deprived of its spleen, yet may be defective in some other of its func- tions ; which, whether they can all, or in what degree of vigour and perfection, be performed, or how long preserv- ed, without the extirpated organ, does not seem to be as- certained by experiment. But to this case, even were it fully made out, may be applied the consideration which we sug- gested concernmg the watch, viz. that these superfluous parts do not negative the reasoning which v/e instituted concerning those parts which are useful, and of which we know the use. The indication of contrivance, with re- spect to them, remains as it was before. III. One atheistic way of replynig to our observations upon the works of nature, and to the proofs of a Deity which we thnik that we perceive in them, is to tell us, that all which we see must necessarily have had some form, and that it might as well be its present torm, as any other. Let us now ap;)ly this answer to the eye, as we did before to the watch. Something or other must have occupied that place in the animal's head ; must have filled up, we will say, that socket : we will say also, that it must have been of that sort of substance which we call animal substance; as flesh, bono, membrane, cartilage, &c. ; but that it should have been an eye, knowing, as we do, what an eye com- prehends, viz. that it should have consisted, first, of a se- ries of transparent lenses (very different, by the by, even in their substance, from opaque materials of which the rest of the body is, in general, at least, composed ; and with which the whole of its surface, this single portion of it ex- cepted, is covered :) secondly, of a black cloth or canvass (the only membrane of the body which is black) spread out behind these lenses, so as to receive the image, formed by pencils of light, transmitted through them ; and placed at the precise geometrical distance, at which, and at which alone, a distinct image could be formed, namely, at the concourse of the refracted rays : thirdly, of a large nerve, communicating between this membrane and the brain ; without which the action of light upon the membrane, however modified by the organ, would be lost to the pur- poses of sensation. That this fortunate conformation of parts should have been the lot, not of one individual out ARGUMENT CONTINUED. 37 ©f many thousand individuals, like the great prize in a lot- tery, or like some singularity in nature, but the happy chance of a whole species ; nor of one species out of many thousand species, with which we are acquainted, but of by far the greatest number of all that exist ; and that under varieties, not casual or capricious, but bearing marks of being suited to their respective exigencies : that all this should have taken place, merely because something must have occupied those points in every animal's fore- head ; or, that all this should be thought to be accounted for, by the short answer " that whatever was there must have had some form or other," is too absurd to be made more so by any argumentation. We are not contented with this answer, we find no satisfaction in it, by way of accounting for appearances of organization far short of those of the eye, such as we observe in fossil shells, petri- fied bones, or other substances which bear the vestiges of animal or vegetable recrements, but which, either in re- spect of utility, or of the situation in which they are dis- covered, may seem accidental enough. It is no way of accounting even for these things, to say that the stone, for instance, which is shown to us, (sup».x)8ing the question to be concerning a petrification,) must have contained some internal conformation or other. Nor does it mend the an- swer to add, with respect to the singularity of the confor- mation, that, after the event, it is no longer to be comput- ed what the chances were against it. This is always to be computed, v/hen the question is, whether an useful or imi- tative conformation be the produce of chance or not. I desire no greater certainty in reasoning, than that by which chance is excluded from the present disposition of the nat- ural world. Universal experience is against it. What does chance ever do for us? In the human body, for in- stance, chance, i. e. the operation of causes without design, may produce a wen, a wart, a mole, a pimple, but never an eye. Amongst inanimate substances, a clod, a pebble, a liquid drop might be ; but never was a watch, a telescope, an organized body of any kind, answering a valuable pur- pose by a complicated mechanism, the effect of chance. In no assignable instance hath such a thing existed without intention somewhere. IV. There is another answer, which has the same ef- fect as the resolving of things into chance ; which answer would persuade us to believe, that the eye, the animal to which it belongs, every other animal, every plant, indeed 38 APLLICATION OP THE every organized body which we see, are only so many ouf of the possible varieties and combinations of being, which the lapse of infinite ages has brought into existence ; that the present world is the relic of that variety ; millions of other bodily forms and other species having perished, be- ing by the defect of their constitutions incapable of preser- vation, or of continuance by generation. Now there is no foundation whcitever for this conjecture in any thing which we observe in the works of nature ; no such experiments are going on at present ; no such energy operates as that which is here suppossible life and propagation, we might, at least, have nations of human beings without nails upon their fin- gers, with more or fewer fingers and toes than ten, some with one eye, others with one ear, with one nostril, or with- out the sense of smelling at all. All these, and a thousand other imaginable varieties, might live and propagate. We may modify any one species many different ways, all con- sistent with life, and with the actions necessary to preserva- tion, although affording different degrees of conveniency and enjoyment to the animal And if we carry tiiese mod- ifications through the different species which are known to subsist, their number would be incalculable. No reason can be given why ; if these deperdits ever existed, they have now disappeared. Yet, if all possible existences have been tried, they must have formed part of the catalogue. But, moreover, the division of organized substances into animals and vegetables, and the distribution and sub-distri- bution of each into general and species, which distribution is not an arbitrary act of the mind, but is founded in the order which prevails in external nature, appear to me to contradict the supposition of the present world being the ARGUMENT CONTINUED. 39 remains of an indefinite variety of existences ; of variety which rejects all plan. The hypothesis teaches, that every possible variety of being hath, at one time or other, found its way into existence (by what cause or in what manner is not said,) and that those which were badly formed, perish- ed ; but how or why those which survived should be cast, as we see that plants and animals are cast, into regular classes, the hypothesis does not explain ; or rather the hy- pothesis is inconsistent with this phenomenon. The hypothesis, indeed, is hardly deserving of the con- sideration which we have given to it. What should we think of the man, who, because we had never ourselves seen watches, telescopes, stocking-mills, steam-engines, &c. made ; knew not how they were made ; or could prove by testimony when they were made, or by whom ; — would have us believe that these machines, instead of deriving their curious structures from the thought and design of their inventors and contrivers, in truth, derive them from no other origin than this ; that a mass of metals and oth- er materials having run, when melted, into all possible fig- ures, and combined themselves in all possible forms, and shapes, and proportions ; these things which we see, are what were left from the accident, as best worth preserving ; and, as such, are become the remaining stock of a maga- zine, which at one time or other, has, by this means, con- tained every mechanism, useful and useless, convenient and inconvenient, .into which such like materials could be thrown ? I cannot distinguish the hypothesis as applied to the works of nature, from this solution, which no one would accept, as applied to a collection of machines. V. To the marks of contrivance discoverable in animal bodies, and to the argument deduced from them in proof of design, and of a designing Creator, this turn is sometimes attempted to be given, viz. that the parts were not intended for the use, but that the use arose out of the parts. This distinction is intelligible. A cabinet-maker rubs his ma- hogany with fish-skin ; yet it would be too much to assert that the skin of the dog-fish was made rough and granulated on purpose for the polishing of wood, and the use of cabinet- makers. Therefore the distinction is intelligible. But I think that there is very little place for it in the works of nature. When roundly and generally aflirmed of them, as it hath sometimes been, it amounts to such another stretch of assertion, as it would be to say, that all the implements of the cabinet-maker's workshop, as well as his fish-skin, 40 APPLICATION OF THE were substances accidentally configurated, which he had picked up, and converted to his use ; that his adzes, saws, planes and gimlets, were not made, as we suppose, to hew, cut, smooth, shape out, or bore wood with ; but that these things being made, no matter with what design, or whether with any, the cabinet-maker perceived that they were ap- plicable to his purpose, and turned them to account. But, again ; so far as this solution is attempted to be ap- plied to those parts of animals, the action of which does not depend upon the will of the animal, it is fraught with still more evident absurdity. Is it possible to believe that the eye was formed without any regard to vision ; that it was the animal itself Vvhich found out, that, though formed Avith no such intention, it would serve to see with ; and that the use of the eye, as an organ of t^ight, resulted from this discovery, and the animal's application of it? The same question may be asked of the ear ; the same of all the senses. None of the senses, fundamentally, depend upon the election of the animal ; consequently, neither upon his sagacity nor his experience. It is the impression which objects make upon them that constitutes their use. Under that impression he is passive. He may bring objects to the sense, or w ithin its reach ; he may select these objects ; but over the impression itself he has no power, or very little ; and that properly is the sense. Secondly, there are many parts of animal bodies which seem to depend upon the will of the animal in a greater degree than the senses do, and yet with respect to which this solution is equally unsatisfactory. If we apply the so- lution to the human body for instance, it forms itself into questions upon which no reasonable mind can doubt : such as, w^hether the teeth were made expressly for the mastica- tion of food, the feet for w^alking, the hands for holding ; or w hether, these things being as they are, being in fact in the animal's possession, his own ingenuity taught him that they were convertible to these purposes, though no such purposes w^ere contemplated in their formation. " All that there is of the appearance of reason in this way of considering the subject is, that, in some cases, the organization seems to determine the habits of the ani- mal, and its choice, to a partictilar mode of life ; which, in a certain sert.se, may be called " the use arising cut of the part." Now to all the instances, in wliich there is any place for this suggestion, it may be replied, that the organ- ization determines the animal to habits beneficial and salu- ARGUMENT CONTIUED. 41 tavy to itself; and that this effect would not be seen so regularly to follow, if the several organizations did not bear a concerted and contrived relation to the substances by which the animal was surrounded. They would, other- wise, be capacities without objects ; powers without em- ployment. TiiS web foot determines, you say, the duck to swim : but what would that avail, if there vrere no water to swim in? The strong, hooked bill, and sharp talons, of one species of bird, determine it to prey upon animals; the soft straight bil), and weak claws of another species, determine it to pick up seeds : but neither determination could take elfect in providing for the sustenance of the birds, if animal bodies and vegetable seeds did not lie v/ith- in their reach. The peculiar conformation of the bill, and tongue, and claws of the woodpecker, determines that bird to search for his food amongst the insects lodcred behind the bark, or in the wood, of decayed trees ; but what would this profit him if there were no trees, no decayed trees, no insects lodged under their bark, or in their trunk 1 The proboscis with which the bee is furnished, determines him to seek for honey ; but what would that signify, if flowers supplied none? Faculties thrown down upon animals at random, and without reference to the objects amidst which they are placed, v^ould not produce to them the services and benefits which we see ; and if there be that reference, then there is intention. Lastly, the solution fails entirely when applied to plants. The parts of plants answer their uses, without any concur- rence from the will or choice of the plant. VI. Others have chosen to refer every thing to a prin- ciple of order in nature. A principle of order is the word ; but what is meant by a principle of order, as different from an intelligent Creator, has not been explained either by definition or example ; and, without such explanation, it should seem to be a mere substitution of words for rea- sons, names for causes. Order itself is only the adaptation of means to an end ; a principle of order, therefore, can only signify the mind and intention which so adapts them. Or were it capable of being explained in any other sense, is there any experience, any analogy to sustain it? Was a watch ever produced by a principle of order ? and why might not a watch be so produced as well as an eye ? Furthermore, a principle of order, acting blindly and without choice, is negatived by the observation, that order E 42 APPLICATION OF THE ARGUMENT CONTINUED, is not universal ; \vhich it would be, if it issued from a con- stant and necessary principle; nor indiscriminate, which iti would be, if it issued from an unintelligent principle. Where order is wanted, there we find it ; where order is not want- ed, i. e. where, if it prevailed, it would be useless, there we do not find it. In the structure of the eye (for we adhere to our example,) in the figure and position of its several parts, the most exact order is maintained. In the forms of rocks and m.ountains, in the lines which bound the coasts of con- tinents and islands, in the shape of bays and promontories^ no order "hatever is perceived, because it wotdd have been superflu as. No useful purpose would have arisen from moulding rocks and mountains into regular solids, bound- ing the channel of the ocean by geometrical curves, or from the map of the world resembling a table of diagrams in Euclid's Elements, or Simpson's Conic Sections VII. Lastly, the confidence which we place in our ob- servations upon the works of nature, in the marks which we discover of contrivance, choice, and design, and in our reasoning upon the proofs afforded us, ought not to be sha- ken, as it is sometimes attempted to he done by bringing forward to our view our own ignorance, or rather, the gen- eral imperfection of our knowledge of nature. Nor, in many cases, ought this consideration to affect us, even when it respects some parts of the subject immediately un- der our notice. True fortitude of understanding consists in not suffering what v;e know to be disturbed by what we do not know. If we perceive an useful end, and means adapted to that end, we perceive enough for our conclusion. If these things be clear, no matter what is obscure. The argument is finished. For instance ; if the utility of vision to the animal which enjoys it, and the adaptation of the rye to this office be evident and certain (and I can mention nothing that is more so,) ought it to prejudice the inference ^vhich we draw from these premises, that we cannot ex- plain the use of the spleen 1 Nay more ; if there be parts of the eye, viz. the cornea, the crystalline, the retina, in their substance, figure, and position, manifestly suited to the formation of an image by the refraction of rays of light, at least as manifestly as the glasses and tubes of a dioptric telescope are suited to that purpose, it concerns not the proof which these afford of design and of a designer, that there may perhaps be other parts, certain muscles, for in- stance, or nerves, in the same eye, of the agency or effect of which we can give no account: any more than we THE ARGUMENT CUMULATIVE. 43 should be inclined to doubt, or ought to doubt, about the construction of a telescope, viz. for what purpose it was constructed, or whether it were constructed at all, because there belonged to it certain screws and pins, the use or action of which we did not comprehend. I take it to be a general way of infusing doubts and scruples into the mind, to recall to it its own ignorance, its own imbecility ; to tell us that upon these subjects we know little , that little im- perfectly ; or rather, that we know nothing properly about the matter. Tliese suggestions so fall in with our con- sciousnesses, as sometimes to produce a general distrust of our faculties and our conclusions. But this is an unfound- ed jealousy. The uncertainty of one thing, does not necessarily affect the certainty of another thing. Our ig- norance of many points need not suspend our assurance of a few. Before we yield, in any particular instance, to the scepticism which this sort of insinuation would induce, we ought accurately to ascertain, whether our ignorance or doubt concern those precise points upon which our conclu- sion rests. Other points are nothing. Our ignorance of other points may be of no consequence to these ; though they be points, in various respects, of sjreat importance. A just reasoner removes from his consideration, not only what he knows, but what he does not know, touching mat- ters not strictly connected with his argument, i. e. not forming the very steps of his deduction ; beyond these, his knowledge and his ignorance are alike irrelative. CHAPTER VT. THE ARGUMENT CUMULATIVE. Were there no example in the world of contrivance ex- cept that of the ei/e, it would be alone sufficient to support the conclusion which we draw from it, as to the necessity of an intelligent Creator. It could never be got rid of ; because it could not be accounted for by any other suppo- sition, which did not contradict all the principles we pos- sess of knowledge : the principles according to which, things do, as often as they can be brought to the test of ex- perience, turn out to be true or false. Its coats and hu- mours, constructed, as the lenses of a telescope are con-. Biructed; for the refraction of rays of light to a point, which 14 THE ARGUMENT CUMULATIVE, forms the proper action of the organ ; the provision in ii> muscular tendons for turning its pupil to the object, sim- ilar to that which is given to the telescope by screws, and upon which power of direction in the eye, the exercise of its office as an optical instrument depends ; the further provision for its defence, for its constant lubricity and moisture, which we see in its sockets and its lids, in its glands for the secretion of the matter of tears, its outlet or communication with the nose tor carrying off the liquid after the eye is washed with it ; these provisions compose altogether an apparatus, a system of parts, a preparation of means, so manifest in their design, so exquisite in their contrivance, so successful in their issue, so precious, and so infinitely beneficial in their use, as, in my opinion, to bear down all doubt that can be raised upon the subject. And what I wish, under the title of the present chapter, to obser\e is, that, if other parts of nature were inaccessi- ble to our inquiries, or even if other parts of nature present- ed nothing to our examination but disorder and confusion, the validity of this example would remain the same. If there were but one watch in the world, it would not be less certain that it had a maker. If we had never in our lives seen but one single kind of hydraulic machine; yet, if of that one kind we understood the mechanism and use, we should be as perfectly assured that it proceeded from the hand, and thought, and skill of a workman, as if we visited a museum of the arts, and saw collected there twenty dif- ferent kinds of machines for drawing water, or a thousand different kinds for other purposes. Oi this point each ma- chine is a proof, independently of the rest. So it is with the evidences of a divine agency. The proof is not a conclusion, which lies at the end of a chain of reasoning, of which chain each instance of contrivance is only a link, and of which, if one link fail, the whole fails : but it is an argument separately supplied by every separate example. An error in stating an example affects only that example. The argument is cumulative in the fullest sense of that term. The eye proves it without the ear ; the ear without the eye. The proof in each example is complete ; for when the design of the part, and the conduciveness of its structure to that design, is shown, the mind may set itself at rest ; no future consideration can detract any thing from the force of the example. MECHANICAL AND IMMfiCHANICAL, &C. 45 CHAPTER VII. ♦?P THE MECHANICAL AND IMMECHANICAL PARTS AND FUNC- TIONS OF ANIMALS AND VEGETABLES. It is not that every part of an animal or vegetable has not proceeded from a contriving mind; or that every part is not constructed with a view to its proper end and pur- pose, according to the laws belonging to, and governing, the substance or the action made use of in that part ; or that each part is not so constructed, as to effectuate its purpose whilst it operates according to these laws ; but it is, because the laws themselves are not in all cases equal- ly understood ; or, what amounts to nearly the same thing, or not equally exemplified in more simple processes, and more simple machines ; that we lay down the distinction, here proposed, between the mechanical parts, and other parts, of animals and vegetables. For instance; the principle of muscular motion, viz. upon what cause the swelling of the belly of the muscle, and consequent contraction of its tendons, either by an act of the will or by involuntary irritation, depends, is wholly unknown to us. The substance employed, whether it be fluid, gaseous, elastic, electrical, or none of these, or nothing resembling ttiese, is also unknown to us ; of course the laws belonging to that substance, and which regulate its acti(tn, are unknown to us. We see nothing similar to this contraction in any machine which we can make, or any process which we can execute. So far (it is con- fessed) we are in ignorance; but no farther. This power and principle, from whatever cause it proceeds, being as- sumed, the collocation of the fibres to receive the princi- ple, the disposition of the muscle for the use and applica- tion of the power, is mechanical; and is as intelligible as the adjustment of the wires and strings b} which a puppet is moved. We see, therefore, as far as respects the sub- ject before us, what is not mechanical in the animal frame^ and what is. The nervous influence (for we are often obliged to give names to things which we know little about) — I say the nervous influence, by which the belly or middle of the muscle is swelled, is not mechanical. The utility of the effect we perceive : the means, or the preparation of means, by which it is produced, we do not. But obscurity as to the origin of muscular motion brings £ 3 46 MECHANICAL AND IMMECANICAL PARTS no doubtfulness into our observations upon the sequel of the process. Which observations relate, 1st, to the con- stitution of the muscle ; in consequence of which consti- tution, the swelling of the belly or middle part is neces- sarily and mechanically followed by a contraction of the tendons : 2dly, to the number and variety of the muscles, and the corresponding number and variety of useful powers which they supply to the animal ; which is astonishingly crreat; 3dly, to the judicious (if we may be permitted to use that term, in speaking of the author, or of the works, of nature,) to the wise and well-contrived disposition of each muscle for its specific purpose ; for moving the joint this way, and that way, and the other way ; for pulling and drawing the part, to which it is attached, in a determi- nate and particular direction ; which is a mechanical oper- ation, exemplified in a multitude of instances. To mention only one ; the tendon of the trochlear muscle of the eye, to the end that it may draw in the line required, is passed throuLrh a cartilaginous ring, at which it is reverted, exactly in the same manner as a rope in a ship is carried over a block or round a stay, in order to make it pull in the direction which is wanted. [PI. v. fig. L] All this, as we have said^ is mechanical ; and is as accessible to inspection, as capa- ble of bein^ ascertained, as the mechanism of the automa- ton in the Strand. Suppose the automaton to be put in motion by a snagnet (which is probable,) it will supply us with a comparison very apt lor our present pur[)Ose. Of the magnetic effluvium we know perhaps as little as we do of the nervous fluid. But magnetic attraction being as- sumed (it signifies nothing from what cause it proceeds,) we can trace, or there can be pointed out to us, with per- fect clearness and certainty, the mechanism, viz. the steel bars, the wheels^ the joints, the wires, by which the motion so much admired is communicated to the fingers of tiie im- ac/e ; and to make any obscurity, or difli -ulty, or contro- versy in the doctrine of magnetism, an objection to our knowledge or our certainty concerning the contrivance, or the marks of contrivance, displayed in the antomaton, would be exactly the same thing, as it is to make our ig- norance (which we acknowledge) of the cause of nervous agency, or even of the substance and structure of the nerves themselves, a ground of question or susj)icion as to the reasoning which we institute concerning the mechani- cal part of our frame. That an animal is a machine, is a proposition, neither correctly true, nor wholly false. ThQ AND FUNCTIONS OF ANIMALS, &C. 47 distinction which we have been discussing will serve to show how far the comparison, which this expression im- plies, holds ; and vv^herein it fails. And, whether the dis- tinction be thought of importance or not, it is certainly of importance to remember, that there is neither truth nor justice in endeavouring to bring a cloud over our under- standmgs, or a distrust into our reasonings upon this sub- ject, by suggesting that we know nothing of voluntary motion, of irritability, of the principle of life, of sensation, of animal heat, upon all which the animal functions de- pend ; for our ignorance of these parts of the animal frame concerns not at all our knowledge of the mechanical parts of the same frame. I contend, therefore, that there is mechanism in animals ; that this mechanism is as proper- ly such, as it is in machines made by art ; that this me- chanism is intelligible and certain ; that it is not the less so, because it often begins or terminates with something which is not mechanical ; that, whenever it is intelligible and certain, it demonstrates intention and contrivance, as well in the works of nature as in those of art ; and that it is the best demonstration which either can afford. But, whilst I contend for these propositions, I do not exclude myself from asserting that there may be, and that there are otiier cases, in which, although we cannot ex- hibit mechanism, or prove indeed, that mechanism is em- ployed, we want not sufficient evidence to conduct us to the same conclusion. There is what may be called the chemical part of our frame ; of which, by reason of the imperfection of our chemistry, we can attain to no distinct knowledge ; I mean, not to a knowledge, either in degree or kind, similar to that which we possess of the mechanical part of our frame. It does not, therefore, afford the same species of argument as that which mechanism affjrds; and yet it may afford an argument in a high degree satisfactory. The gas- tric juice ^ or the liquor which digests the ff)und ingredients, so as to form a solvent, which will act in the manner in which the gastric juice acts, we may be able to ascertain the chemical principles upon which its efficacy depends, as well as from what part, and by what concoction, in the human body, these principles are generated and derived. In the meantime, ought that, which is in truth the de- fect of our chemistry, to hinder us from acquiescing in the inference, which a production of nature, by its place, its properties, its action, its surprising efficacy, its invaluable use, authoris'^s us to draw in ret^pect of a creative design? Another most subtle and curious function of animal bod- ies is secretion. Tiiis function is secni-chemical and semi- mechanical ; exceedingly important and diversified in its effects, but obscure in its process and in its apparatus. The importance of the secretory organs is but too well at- tested by the diseases, which an excessive, a deficient, or a vitiated secretion is almost sure oi producing. A single secretion being wrong, is enough to make life miserable ; or sometimes to destroy it. Nor is the variety less than the importance. From one and the same blood (I speak of the human body) about twenty different fluids are sepa- rated ; in their sensible properties, in taste, smell, colour, and consistency, the most unlike one another that is possi- AND FUNCTIONS OP ANIMALS, &-C. 49 ble ; thick, thin, salt, bitter, sweet : And if from our own we pass to other species of animals, we find amongst theii secretions not only the most various, but the most opposite properties ; the most nutritious aUment, the deadliest poi- son; the sweetest perfumes, the most fetid odours. Of these the greater part, as the gastric juice, the saliva, the bile, the slippery mucillage which lubricates the joints, the tears which moisten the eye, the wax which defends the ear, are, after they an^ secreted, made use of in the animal economy ; are evidently subservient, and are actually con- tributing to the utilities of the animal itself Other fluids seem to be separated only to be rejected. That this also is necessary (though why it was originally necessary, we cannot tell) is shown by the consequence of the separation being long suspended ; which consequence is disease and death. Akin to secretion, if not the same thing, is assim- ilation, by which one and the same blood is converted into bone, muscular flesh, nerves, membranes, tendons ; things as different as the wood and iron, canvass and cordage, of which a snip with ijs furniture is composed. We have no operation of art wherewith exactly to compare all this, for no other reason perhaps than that all operations ot art are ex- ceeded by it. No chemical election, no chemical analysis oi- resolution of a substance into its constituent parts, no me- chanical sifting or division, that we are acquainted with, in perfection or viriety, come up to animal secretion. Never- theless, the apparatus and process are obscure : not to say, absolutely concealed from our inquiries. In a few, and only a few instances, we can discern a little of the constitution of a gland. In the kidneys of large animals we can trace the emulgent artery dividing itself into an infinite number of branches ; their extremities every where communicating with little round bodies, in the substance of wbich bodies the secret of the machinery seems to reside, for there the change is made. We can discern pipes laid from these round bodies towards the pelvis, which is a basin within the solid of the kidney. (PI. VI. fig. 2.) We can discern these pipes joining and collecting together into larger pipes; and when so collected, ending in innumerable papillae, through which the secreted fluid is continually oozing into its receptacle. This is all we know of the mechanism of a gland, even in the case in which it seems most capable of being investigated. Yet to pronounce that w^e know noth- ing of animal secretion, or nothing satisfactorily, and with Jliat concise remark to dismiss the article from our argii- 50 MECHANICAL AND IMMECHANICAL PARTS ment, would be to dispose of the subject very hastily and very irrationally. For the purpose of which we want, that of evincing intention, we know a great deal. And what wo know is this. We see the blood carried by a pipe, conduit, or duct, to the gland. We see an organized apparatus, be its construction or action what it will, which we call that gland. We see the blood, or part of the blood, after it has passed through and undergone the action of the gland, coming from it by an emulgent vein or artery, i. e. by an- other pipe or conduit. And we see also at the same time a new and specific fluid issuing from the same gland by its excretory duct, i. e by a third pipe or conduit ; which new fluid is in some cases discharged out of the body, in more cases retained within it, and there executing some impor- tant and intelligible office. Now supposing, or admitting, that we know nothing of the proper internal constitution of a gland, or of the mode of its acting upon the blood; then our situation is precisely like that of an unmechani- cal looker-on, who stands by a stocking-loom a corn-mill, a cardingr-machine, or a threshing-machine at work, the fabric and mechanism of which, as well as all that passes within, is hidden from his sight by the outside case; or, if seen, would be too complicated for his uninformed, unin- structed understanding to comprehend. And what is that situation? — This spectator, ignorant as he is, sees at one end a material enter the machine, as unground grain the mill, raw cotton the carding-machine, sheaves of unthresh- ed corn the threshing-machine : and when he casts his eye to the other end of the apparatus, he sees the material is- suing from it in a new state; and, what is more, m a state manifestly adapted to future uses ; the grain in meal fit for the making of bread, the wool in rovings ready for spinning into threads, the sheaf in corn dressed for the mill. Is it necessary that this man, in order to be convinced that de- sign, that intention, that contrivance has been employed about the machine, should be allowed to pull it in pieces ; should be enabled to examine the parts separately ; explore their action upon one another, or their operation, whether simultaneous or successive, upon the material which is pre- sented to them ? He may long to do this to gratify his curiosity ; he may desire to do it to improve his theoretic knowledge ; or he may have a more substantial reason for requesting it, if he happen, instead of a common visitor, to be a mill-wright by profession, or a person sometimes call- ed in to repair such-like machines when out of order ; but^, AND FUNCTIONS OP ANIMALS, &C. 51 for the purpose of ascertaining the existence of counsel und design in the formation of the machine, he wants no such intromission or privity. What he sees is sufficient. The effect upon the material, the change produced in it, the utility of that change for future applications, abundant- ly testify, be the concealed part of the machine or of its construction what it may, the hand and agency of a con- triver. If any confirmation were wanting to the evidence which the animal secretions afford of design, it may be de- rived, as hath been already hinted, from their variety, and from their appropriation to their place and use. They all come from the same blood ; they are all drawn off by glands ; yet th?; produce is very different, and the differ- ence exactly adapted to the work which is to be done, or the end to be answered. No account can be given of this without resorting to appointment. Why, for instance, is the saliva, which is diffused over the seat of taste insipid, whilst so many others of the secretions, the urine, the tears, and the sweat, are salt ? Why does the gland within the ear separate a viscid substance, which defends that passage: the gland in the upper angle of the eye, a thin brine, which washes the ball? Why is the synovia of the joints muci- laginous ; the bile bitter, stimulating, and soapy ? Why does the juice, which flows into the stomach, contain pow- ers which make that bowel the great laboratory, as it is by its situation the recipient, of the materials of future nu- trition 1 These are all fair questions ; and no answer can be given to them, but what calls in intelligence and inten- tion. My object in the present chapter has been to teach three things : first, that it is a mistake to suppose, that, in rea- soning from the appearances of nature, the imperfection of our knowledge proportionably affects the certainty of our conclusion . for in many cases it does not affect it at all : secondly, that the different parts of the animal frame may be classed and distributed, according to the degree of ex- actness with which we can compare them with works of art : thirdly, that the mechanical parts of our frame, or, those in which this comparison is most complete, although constituting, probably the coarsest portions of nature's workmanship, are the properest to be alleged as proofs and specimens of design. 52 OF MECHANICAL ARRANGEMENT CHAPTER VIII. OF MECHANICAL ARRANGEMENT IN THE HUMAN FRAME. We proceed, therefore, to propose certain examples ta- :.en out of this class; making choice of such, as amongst those which have come to our knowledge, appear to be the most striking, and the best understood ; but obliged, per- haps to postpone both these recommendations to a third, that of the example being capable of explanation without plates or figures, or technical language. OF THE BONES. I. I challenge any man to produce, in the joints and pivots of the most complicated, or the most flexible, ma- chine, that was ever contrived, a construction more artifi- cial, or more evidently artificial, than that which is seen in the vertebrae of the human neck. [PI. VII. fig. 1.] Two things were to be done. The head v.as to have the power of bending forward and backward, as in the act of nodding, stooping, looking upward or downward ; and, at the same time, of turning itself round upon the body to a certain extent, the quadrant, we will say, or rather, perhaps, a hun- dred and twenty degrees of a circle. For these two pur- poses, two distinct contrivances are em.ployed. [PI. VII. fig. 2, 3, 4.] First, the head rests immediately upon the !ippermost of the vertebras, and is united to it by a hinge, joint; upon which joint the head plays freely forward and backward, as far either way as is necessary, or as the liga- ments allow ; which was the first thing required. But then the rotatory motion is unprovided for. Therefore secondly, to make the head capable of this, a further me- chanism is introduced , not between the head and the up- permost bone of the neck, where the hinge is, but between that bone, and the bone next underneath it. It is a me- chanism resembling a tenon and mortice. This second, or uppermost bone but one, has what anatomists call a pro- cess, viz. a projection, somewhat similar, in size and shape, to a tooth ; which tooth, entering a corresponding hole or socket in the bone above it, forms a pivot or axle, upon which that upper bone, together with the head which it supports, turns freely in a circle ; and as far in the circle, as the attached muscles permit the head to turn. Thus are both motions perfect, without interfering with each IN THE HUMAN FRAME. 53 Other. When we nod the head we use the hinge joint, which lies between the head and the first bone of the neck. When we turn the head round, we use the tenon and mor- tice, which runs between the first bone of the neck and the second. We see the same contrivance, and the same prin- ciple, employed in the frame or mounting of a telescope. It is occasionally requisite, that the object-end of the in- strument be moved up and down, as well as horizontally, or equatorially. For the vertical motion there is a hinge upon which the telescope plays ; for the horizontal or equatorial motion, an axis upon which the telescope and the hinge turn round together. And this is exactly the mechanism which is applied to the motion of the head : nor will any one here doubt of the existence of counsel and design, except it be by that debility of mind, which can trust to its own reasonings in nothincr. We may add, that it was, on another account also, ex- pedient, that the motion of the head backward and for- ward should be performed upon the upper surface of the first vertebrae; for if the first vertebrae itself had bent for- ward, it would have brought the spinal marrow, at the very beginning of its course upon the point of the tooth. II. Another mechanical contrivance, not unlike the last in its object, but different and original in its means, is seen in what anatomists call the fore-arm ; that is, in the arm from ' the elbow to the wrist. [PI. VIII. fig. 1, 2.] Here, for the perfect use of the limb, two motions are wanted ; a motion at the elbow backward and forward, which is called a reciprocal motion ; and a rotatory motion by which the palm of the hand, as occasion requires, may be turned upward. How is this managed 1 The fore-arm, it is well known, consists of two bones, lying along-side each other, but touching only towards the ends. One, and only one, of these bones, is joined to the cubit, or upper part of the arm, at the elbow ; the other alone, to the hand at the wrist. The first, by means, at the elbow, of a hinge joint (which allows only of motion in the same plane,) swings backward and forward, carrying along with it the other bone, and the whole fore^arm. In the meantime, as often as there is occasion to turn the palm upward, that other bone, to which the hand is attached, rolls upon the first, by the help of a groove or hollow near each end of one bone, to which is fitted a corresponding prominence in the other. If both bones had been joined to the cubit F M OF MECHAXICAL ARRANGEMENT or upper arm at the elbow, or both to the hand at the wrisfi^ the thing could not have been done. The first was to be at liberty at one end, and the second at the other : by which means the two actions may be performed together. The great bone, which carries tlie fore-arm, may be swinging upon its hinge at the elbow, at the very same time, that the lesser bone, which carries the hand, may be turning round it in the grooves. The management also of these grooves, or rather of the tubercles and grooves, is very ob- servable. The two bones are called the radius and the ulna. Above, i. e. towards the elbow, a tubercle of the radius plays into a socket of the ulna ; whilst below, i. e. towards the wrist, the radius finds the socket, and the ulna the tubercle. A single bone in the fore-arm, with a ball and socket joint at the elbow, which admits of motion in all directions, might, in some degree, have answered the purpose, of both moving the arm, and turning the hand. But how much better it is accomplished by the present me- chanism, any person may convince himself, who puts the ease and quickness, with which he can shake his hand at the wrist circularly (moving likewise, if he pleases, his arm at the elbow at the same time,) in competition with the comparatively slow and laborious motion, with which his arm can be made to turn round at the shoulder, by the aid of a ball and socket joint. III. The spine or back bone is a chain of joints of very wonderful construction. (PI. IX. fig. 1, 2.) Various, diffi- cult, and almost inconsistent offices were to be executed by the same instrument. It was to be firm, yet flexible, (now I know no chain made by art, which is both these ; for by firmness I mean not only strength, but stability ; frrn, to support the erect position of the body ; flexible, to allow of the bending of the trunk in all degrees of curvature. It was further also, which is another, and quite a distinct purpose from the rest, to become a pipe or conduit for the safe con- veyance from the brain of the most important fluid* of the animal frame, that, namely, upon which all voluntary mo- tion depends, the spinal marrow ; a substance not only of * It seems proper to remark here, that the form of expression made use of in this case implies what is not strictly true. The spinal mar- row, or more properly the Spinal nerve, is not a fluid but a solid cord extending Irom the brain down through the canal of the spine, from which branches are distributed to all parts of the body. Dr. Paley in this instance probably had in view the animal spirits, a subtle fluid, which was formerly believed to be seated in the brain, and carried tlirough the nerves to the different parts. -E*^- IN THE HUMAN FRAME. 55 the first necessity to action, if not to life, but of a nature so delicate and tender, so susceptible and so impatient of injury, as that any unusual pressure upon it, or any consid- erable obstruction of its course, is followed by paralysis or death. Now the spine was not only to famish the main trunk for the passage of the medullary substance from the bi-ain, but to give out, in the course of its progress, small pipes therefrom, which, being afterwards indefinitely sub- divided, might, under the name of nerves, distribute this exquisite supply to every part of the body. The same spine was also to serve another use not less wanted than the preceding, viz. to aflTord a fulcrum, stay, or basis (or more properly speaking a series of these) for the insertion of the muscles which are spread over the trunk of the body ; in which trunk there are not, as in the limbs, cylin- drical bones to which they can be fastened, and likewise, which is a similar use, to furnish a support for the ends of the ribs to rest upon. Bespeak of a workman a piece of mechanism which shall comprise all these purposes, and let him set about to contrive it ; let him try his skill upon it ; let him feel the difficulty of accomplishing the task, before he be told how the same thing is effected in the animal frame. Nothing will enable him to judge so well of the wisdom which has been employed; nothing will dispose him to think of it so truly. First, for the firmness, yet flexibility, of the spine, it is composed of a great number of bones (in the human subject of twenty-four) joined to one another, and compact- ed together, by broad bases. The breadth of the bases upon which the parts severally rest, and the closeness of the junction, give to the chain its firmness and stability ; the number of parts, and consequent frequency of joints, its flexibility. Which flexibility, we may also observe, varies in different parts of the chain : is least in the back, where strength more than flexure is wanted ; greater in the joins, which it is necessary should be more supple than the back ; and greatest of all in the neck, for the free motion of the head. Then, secondly, in order to afford a passage for the descent of the medullary substance, each of these bones is bored through the middle in such a manner, as that, when put together, the hole in one bone falls into a line, and corresponds with the holes in the two bones 4Jontiguous to it. By which means, the perforated pieces, when joined, form an entire, close, uninterrupted channel : ni leaat whilst the spi^ie is upright and at rest. But, as a qQ of mechanical arrangement settled posture is inconsistent with its use, a great difficul- ty still remained, which was to prevent the vertebrae shift- ing upon one another, so as to break the line of the canal as often as the body moves or twists ; or the joints gaping externally, whenever the body is bent forward, and the spine, thereupon, made to take the form of a bow. These dangers, which are mechanical, are mechanically provid- ed against. The vertebrae, by means of their processes and projections, and of the articulations which some of these form with one another, at their extremities, are so locked in and confined, as to maintain, in what are called the bodies or broad surfaces of the bones, the relative po- sition nearly unaltered ; and to throw the change and the pressure, produced by flexion, almost entirely upon the intervening cartilages, the springiness and yielding nature of whose substance admits of all the motion which is ne- cessary to be performed upon them, without any chasm beincr produced by a separation of the parts. I say of all the motion which is necessary ; for although we bend our backs to every degree almost of inclination, the motion of each vertebrae is very small ; such is the advantage which we receive from the chain being composed of so many links, the spine of so many bones. Had it consisted of three or four bones only, in bending the body the spinal marrow must have been bruised at every angle. The reader need not be told that these intervening cartilages are gristles ; and he may see them in perfection in a loin of veal. Their form also favours the same intention. They are thicker before than behind, so that when we stoop forward, the compressible substance of the cartilage, yielding in its thicker and anterior part to the force which squeezes it, brino-s the surfaces of the adjoining vertebrae nearer to the be- ing parallel with one another than they were before, instead of increaing the inclination of their planes, which must have occasioned a fissure or opening between them. Thirdly, for the medullary canal giving out in its course, and in a conve- nient order, a supply of nerves to different parts of the body, notches are made in the upper and lower edge of every vertebrae, two on each edge ; equi-distant on each side from the middle line of the back. When the vertebrae are put together, these notches,' exactly fitting, form small holes, throuo'h which the nerves at each articulation, issue out in pairs, in order to send their branches to every part of the body, and with an equal bounty to both sides of the body. The fourth purpose assigned to the same instrument, is the IN THE HUMAN FRAME. o7 insertion of the bases of the muscles, and the support of the ends of the ribs ; and for this fourth purpose, especial- ly the former part of it, a figure, specifically suited to the design, and unnecessary for the other purposes, is given to the constituent bones. Whilst they are plain, and round, and smooth towards the front, where any roughness or projection might have wounded the adjacent viscera, they run out, behind and on each side, into long processes, to which processes the muscles necessary to the motions of the trunk are fixed ; and fixed with such art, that, whilst the vertebrae supply a basis for the muscles, the muscles help to keep these bones in their position, or by their ten- dons to tie them together. That most important, however, and general property, viz. the strength of the compages, and the security against lux- ation, was to be still more specially consulted ; for where so many joints were concerned, and where, in every one, derangement would have been fatal, it became a subject of studious precaution. For this purpose, the vertebrse are articulated, that is, the moveable joints between them are formed, by means of those projections of their substance, which we have mentioned under the name of processes ; and these so lock in with, and overwrap, one another, as to secure the body of the vertebrcE, not only from accident- ally slipping, but even from being pushed out of its place by any violence short of that which would break the bone. I have often remarked and admired this structure in the chine of a hare. In this, as in many instances, a plain ob- server of the animal economy may spare himself the disgust of being present at human dissections, and yet learn enough for his information and satisfaction, by even examining the bones of the animals which come upon his table. Let him take, for example, into his hands, a piece of the clean-pick- ed bone of a hare's back ; consisting, we will suppose, of three vertebrae. He will find the middle bone of the three, so implicated by means of its projections or processes, with the bone on each side of it, that no pressure which he can use, will force it out of its place between them. It will give way neither forward, nor backward, nor on either side. In whichever direction he pushes, he perceives, in the form, or junction, or overlapping of the bones, an impedi- ment opposed to his attempt ; a check and guard against dislocation. In one part of the spine, he will find a still further fortifying expedient, in the mode according to F 3 5S ON MECHANICAL ARRANGEMENT which the ribs are annexed to the spine. Each rib rests upon two vertebrae. That is the thing to be remarked, and any one may remark it in carving a neck of mutton. The manner of it is this ; the end of the rib is divided by a middle ridge into two surfaces, which surfaces are join- ed to the bodies of two contiguous vertebrae, the ridge ap- plying itself to the intervening cartilage. Now this is the very contrivance which is employed in the famous iron bridge at my door at Bishop-Wearmouth ; and for the same purpose of stability ; viz. the cheeks of the bars, which pass between the arches, ride across the joints, by which the pieces composing each arch are united. Each cross bar rests upon two of these pieces at their place of junction ; and by that position resists, at least in one direction, any tendency in either piece to slip out of its place. Thus perfectly, by one means or the other, is the danger of slip- ping laterally, or of being drawn aside out of the line of the back provided against; and, to withstand the bones being pulled asunder longitudinally, or in the direction of the line, a strong membrane runs from one end of the chain to the other, sufficient to resist any force which is ever likely to act in the direction of the back, or parallel to it, and consequently to secure the whole combination in their places. The general result is, that not only the motions of the human body necessary for the ordinary offices of life are performed with safety, but that it is an accident hard- ly ever heard of, that even the gesticulations of a harlequin distort his spine. Upon the whole, and as a guide to those who may be in- clined to carry the consideration of this subject further, there are three views under which the spine ought to be regarded, and in all which it cannot fail to excite our ad- miration. These views relate to its articulations, its liga- ments and its perforation ; and to the corresponding advan- tages which the body derives from it, for action, for strength, and for that, which is essential to every part, a secure com- munication with the brain.* * It will be useful to append to the remarks of Dr. Paley upon the mechanism of the spine and of other parts of the body, some observa- tions by a very eminent anatomist and surgeon now living, who has lately considered the subject of Animal Mechanism in its connexion with Natural Theology, and has presented some striking and original views. These observations have been published as one of the trea- tises of the Society for the Diffusion of Useful Knowledge, which forms the ninth number of the series. These extracts will be the more in- structive^ as giving views of a professional observer in confirmation of IN THE HUMAN FRAME. 59 The Structure of the spine is not in general different in different animals. In the serpent tribe, however, it is con- those of our author ; and they will also serve as additional illustrations of the same great truths w^hich he has endeavoured to enforce. Ed. "The spinal column, as it is called, serves three purposes : it is the great bond of union betwixt all the parts of the skeleton ; it forms a tube for the lodgment of the spinal marrow, a part of the nervous sys- tem as important to life as the brain itself; and lastly, it is a column to sustain the head. We now see the importance of the spine, and we shall next explain how tlie various offices are provided for. If the protection of the spinal marrow had been the only object of this structure, it is natural to infer that it would have been a strong and unyielding tube of bone ; but, as it must yield to the inflexion of the body, it cannot be constituted in so strict an analogy with the skull. It must, therefore, bend ; but it must have no abrupt or considerable bending at one part ; for the spinal marrow within would in this way suffer. By this consideration we perceive why there are twenty-four bones in the spine, each bending a little ; each articulated or making a joint with its fellow ; all yielding in a slight degree, and, consequently, permitting in the whole spine that flexibility necessary to the motions of the body. It is next to be observed that, whilst the spine by this provision moves in every direction, it gains a property which it belongs more to our present purpose to understand. The bones of the spine are called vertebrs ; at each interstice between these bones, there is a peculiar gristly substance, wdiich is squeezed out from betwixt the bones, and, therefore, permits them to approach and play a little in the motions of the body. This gristly substance is enclosed in an elastic •binding, or membrane of great strength, which passes from the edge or border of one vertebra, to the border of the one next it. When a weight is upon the body, the soft gristle is pressed out, and the mem- brane yields : the mom.ent the weight is removed, the membranes re- coil by their elasticity, the gristle is pressed into its place, and the bones resume their position. We can readily understand how great the influence of these twenty- four joinings must be in giving elasticity to the whole column ; and how much this must tend to the protection of the brain. Were it not for this interposition of elastic material, every motion of the body would produce ajar to the delicate texture of the brain, and we should suffer almost as much in alighting on our feet, as in falling on our head. It is, as we have already remarked, necessary to interpose thin plates of lead or slate between the different pieces of a column to prevent the edges (technically called arrises) of the cylinders from coming in con- tact, as they would, in that case, chip or split off'. But there is another very curious provision for the protection of the brain ; we mean the curved form of the spine. If a steel spring, per- fectly straight, be pressed betwixt the hands from its extremities, it will resist, notwithstanding its elasticity, and when it does give way, it will be with a jerk. Such would be the effect on the spine if it stood upright, one bone perpendicular to another ; for then the weight would bear equally ; the spine would yield neither to one side nor to the other ; and, con- sequently, there would be a resistance from the pressure on all sides CO ON MECHANICAL ARRANGEMENT siderably varied ; but with a strict reference to the conveni- eiicy of the animal. (PI. IX. fig 3, 4, 5.) For, whereas in being balanced. We, therefore, see the great advantage resulting from the human spine being in the form of an italic/. It is prepared to yield in the direction of its curves ; the pressure is of necessity more upon one side of the column than on the other ; and its elasticity is immediately in operation without a jerk. It yields, recoils, and so forms the most perfect spring ; admirably <;alculated to carry the head with- out jar, or injury of any kind. The most unhappy illustration of all this is the condition of old age. The tables of the skull are then consolidated, and the spine is rigid : if an old man should fall with his head upon the carpet, the blow, which would be of no consequence to the elastic frame of a child, may to hiin prove fatal ; and the rigidity of the spine makes every step which he takes, vibrate to the interior of the head, and jar on the brain. We have hinted at a comparison betwixt the attachment of the spine to the pelvis and the insertion of the mast of a ship into the hull. The mast goes directly through the decks without touching them, and the heel of the mast goes into the step, which is formed of large ^solid pieces of oak timber laid across the keelson. The keelson is an inner keel resting upon the floor-timbers of the ship and directly over the proper keel. These are contrivances for enlarging the base on which the mast rests as a column ; for as, in proportion to the height and weight of a column, its base must be enlarged, or it would sink into the earth ; so, if the mast were to bear upon a point, it would break through the bottom of the ship. The mast is supported upright by the shrouds and stays. The shrouds secure it against the lateral or rolling motion, and the stays and backstays against the pitching of the ship. These form what is termed the standing rigging. The mast does not bear upon the deck or on the beams of the ship ; indeed there is a space covered with canvass betwixt the deck and the mast. We often hear of a new ship going to sea to stretch her rigging ; that is, to permit the shrouds and stays to be stretched by the motion of the ship, after which they are again braced tight ; for if she were overtak- en by a storm before this operation, and when the stays and shrouds were relaxed, the mast would lean against *^^he upper deck, by which it would be sprung or carried away. Indeed, the greater proportion of masts that are lost are lost in this manner. There are no boats which keep the sea in such storms as those which navigate the gulf of Finland. Their masts are not attached at all to the hull of the ship, but simply rest upon the step. Although the spine has not a strict resemblance to the mast, the contrivances of the ship-builder, however different from the provis- ions of nature, shows what object is to be attained ; and when we are thus made aware of what is necessary to the security of a column on a moveable base, we are prepared to appreciate the superior provis- ions of nature for giving security to the human spine. The human spine rests on what is called the pelvis, or basin ; — a circle of bones, of which the haunches are the extreme lateral parts ; and the sacrum (which is the keystone of the arch) may be felt at the lower part of the back. To this central bone of the arch of the pelvis the spine is connected ; and, taking the similitude of the mast, the sa- IN THE HUMAN FRAME. 61 quadrupeds the number of vertebrae is from thirty to forty, in the serpent it is nearly one hundred and fifty ; where- as in men and quadrupeds the surfaces of the bones are crum is as the stejy on which the base of the pillar, like the heel of the mast, is socketed or morticed. The spine is tied to the lateral parts of the pelvis by powerful ligaments, which may be compared to the shrouds. They secure the lower part of the spine against the shock of lateral motion or rolling ; but, instead of the stays to limit the play of the spine forwards and backwards in pitching, or to adjust the rake of the mast, there is a very beautiful contrivance in the lower part of the column. The spine forms here a semicircle which has this effect ; that wheth- er by the exertion of the lower extremities, the spine is to be carried forward upon the pelvis, or whether the body stops suddenly in run- ning, the jar which would necessarily take place at the lower part of the spine, if it stood upright like a mast, is distributed over several ot the bones of the spine ; and, therefore, the chance of injury at any particular part is diminished. For example, the sacrum, or centre bone of the pelvis, being car- ried forward, as when one is about to run, the force is communicated to the lowest bone of the spine. But, then, the surfaces of these bones stand with a very slight degree of obliquity to the line of mo- tion ; the shock communicated from the lower to the second bone of the vetebrae is still in a direction very nearly perpendicular to its sur- face of contact. The same takes place in the communication of force from the second to the third, and from the third to the fourth ; so that before the shock of the horizontal motion acts upon the perpendicular spine, it is distributed over four bones of that column, instead of the whole force being concentrated upon the joining of any two. If the column stood upright, it would be jarred at the lowest point of contact with its base. But by forming a semicircle, the motion would produce a jar on the very lowest part of the column, and which is distributed over a considerable portion of the column; and in point of fact, this part of the spine never gives way. Indeed, we should be inclined to offer this model to the consideration of nautical men, as fruitful in hints for improving naval architecture. Every one who has seen a ship pitching in a heavy sea, must have asked himself why the masts are not upright, or rather, why the fore- mast stands upright, whilst the main and mizen masts stand oblique to the deck, or, as the phrase is, rake aft or towards the stern of the ship. The main and mizen masts incline backwarks, because the strain is greatest in the forward pitch of the vessel ; for the mast having re- ceived an impulse forwards, it is suddenly checked as the head of the ship rises ; but the mast being set with an inclination backwards, the motion falls more in a perpendicular line from the head to the heel. This advantage is lost in the upright position of the foremast, but it is sacrificed to a superior advantage gained in working the ship ; the sails upon this mast act more powerfully in swaying the vessel round, and the perpendicular position causes the ship to tack or stay better ; but the perpendicular position, as we have seen, causes the strain in pitching to come at right angles to the mast, and is, therefore, more apt to spring. These considerations give an interest to the fact, that the human spine, from its utmost convexity near its base, inclines backwards, " Bell's Treatise on Animal Mechanics. 6^ OF MECHANICAL ARRANGEMENT flat, and these flat surfaces laid one against the other, and bound tight by sinews ; in the serpent the bones play one within another, like a ball and socket,* so that tliey have a free motion upon one another in every direction ; that is to say, in men and quadrupeds firmness is more consulted — in serpents, pliancy. Yet even pliancy is not obtained at the expense of safety. The backbone of a serpent, for coherence and flexibility, is one of the most curious pieces of animal mechanism, with which we are acquainted. The chain of a watch (I mean the chain which passes between the spring barrel and the fu- see,) which aims at the same properties, is but a bungling piece of workmanship in comparison with that of which we speak. t IV. The reciprocal enlargement and contraction of the chest to allow for the play of the lungs, depends upon a simple yet beautiful mechanical contrivance, referrible to the structure of the bones which enclose it. (PI. X. fig. 1.) The ribs are articulated to the back bone, or rather to its side projection, ohliquely : that is, in their natural position, they bend or slope from the place of articulation downwards. But the basis upon which they rest at this end being fixed, the consequence of the obliquity, or the inclination down- wards, is, that when they come to move, whatever pulls the ribs upwards, necessarily, at the same time, draws them out ; and that, whilst the ribs are brought to a right angle with the spine behind, the sternum, or part of the chest to which they are attached in front, is thrust forward. The simple action, therefore, of the elevating muscles, does the business ; whereas, if the ribs had been articulated with the bodies of the vertebrae at right angles, the cavity of the thorax could never have been further enlarged by a change of their position. If each rib had been a ridged bone, ar- ticulated at both ends to fixed bases, the whole chest had been immovable. Keill has observed, that the breast-bone in an easy inspiration, is thrust out one tenth of an inch ; and he calculates that this, added to what is gained to the *^Der. Phys. Theol. p. 396. i In fish, which have more elastic, but less flexible bodies, the etructure of the spine differs. The end of each vertebra is a cup con- taining a viscid fluid, which keeps the bones from approaching nearer to each other than the mean state of the elasticity of the lateral llga. ments ; the fluid js incompressible, therefore forms a ball round which the bony cups move ; the ball having no cohesion, the centre of mo- tion is always adapted to the change which the joint undergoes with- .out producing friction, " Paxton. IN THE HUMAN FRAME, 63 space within the chest by the flattening or descent of the diaphram, leaves room for forty-two cubic inches of air to enter at every drawing in of tlie breath. When there is a necessity for a deeper and more laborious inspiration, the enlargement of the capacity of the chest may be so increas- ed by effort, as that the lungs may be distended with seventy or a hundred such cubic inches,* The thorax, says Schel- hammer, forms a kind of bellows,'such as never have been^ nor probably will be made by any artificer.! *Anat. p. 229. t The thorax, or chest, is composed of bones and cartilages, so dis^ posed as to sustain and protect the most vital parts, the heart and lungs, and to turn and twist with perfect faciUty in every motion of the body ; and to be in incessant motion in the act of respiration, without a moment's interval during a whole life. In anatomical description, the thorax is formed of the vertebral column, or spine, on the back part, the ribs on either side, and the breast bone, or sternum, on the fore part. But the thing most to be admired is the manner in which these bones are united, and especially the manner in which the ribs are joined to the breast bone, by the interposition of cartilages, or gris- tle, of a substance softer than bone, and more elastic and yielding. By this quality they are fitted for protecting the chest against the effects of violence, and even for sustaining life after the muscular power of respiration has become too feeble to continue without this support. If the ribs were complete circles, formed of bone, and extending from the spine to the breast bone, life would be endangered by any accidental fracture ; and even the rubs and jolts to which the human frame is continually exposed, would be too much for their delicate and brittle texture. But these evils are avoided by the interposition of the elastic cartilage. On their forepart the ribs are eked out, and joined to the breast bone by means of cartilages, of a form corresponding to that of the ribs, being, as it were, a completion of the arch of the rib, by a substance more adapted to yield in every shock or motion of the body. The elasticity of this portion subdues those shocks which would occasion the breaking of the ribs. We lean forward, or to one side, and the ribs accommodate themselves, not by a change of form in the bones, but by the bending or elasticity of the cartilages. A severe blow upon the ribs does not break them, because their extremities re- coil and yield to the violence. It is only in youth, however, when the human frame is in perfection, that this pliancy and elasticity have full effect. When old age approaches, the cartilages of the ribs become bony. They attach themselves firmly to the breast-bone, and the extremities of the ribs are fixed, as if the whole arch were formed of bone unyielding and inelastic. Then every violent blow upon the side is attended with fracture of the rib, an accident seldom occurring in childhood, or in youth. But there is a purpose still more important to be accomplished by means of the elastic structure of the ribs, as partly formed of cartil- age. This is in the action of breathing, or respiration ; especially in the more highly-raised respiration which is necessary in great ex- ertions of bodily strength, and in>iolent exercise. There are two acts of breathing — expiration, or the sending forth of the breath ; and in- C4 OF MECHANICAL ARRANGEMENT V. The patella, or knee-pan is a curious little bone ; in its form and office unlike any other bone in the body. (PI. X. fig. 2, 3.) It is circular ; the size of a crown piece ; pretty thick ; a little convex on both sides, and covered with a smooth cartilage. It lies upon the front of the knee, and the powerful tendons, by which the leg is brought forward, pass through it (or rather it makes a part of their continu- ation ) from their origin in the thigh, to their insertion in the tibia. It protects both the tendon and the joint from any injury which either might suffer, by the rubbing of one against the other, or by the pressure of unequal surfaces. It also gives to the tendons a very considerable mechani- cal advantage by altering the line of their direction, and by advancing it further out from the centre of motion ; and this upon the principles of the resolution of force, upon which principles all machinery is founded. These are its uses. But what is most observable in it is, that it appears to be supplemental, as it were, to the frame ; added as it should almost seem afterward ; not quite necessary, but very convenient. It is separate from the other bones ; that is, it is not connected with any other bones by the com- mon mode of union. It is soft, or hardly formed, in infan- cy ; and produced by an ossification, of the inception or progress of which, no account can be given from the struct- ure or exercise of the part. sjnration, or the drawing in of the breath. When the chest is at rest, it is neither in a state of expiration nor in that of inspiration ; it is in an intermediate condition between these two acts. And the mus- cular effort by which either inspiration or expiration is produced, is an act in opposition to the elastic property of the ribs. The property of the ribs is to preserve the breast in the intermediate state between expiration and inspiration. The muscles of respiration are excited al- ternately, to dilate or to contract the cavity of the chest, and, in do- ing so, to raise or to depress the ribs. Hence it is, that both in inspira- tion and in expiration the elasticity of the ribs is called into play; and, were it within our province, it would be easy to show, that the dead power of the cartilages of the ribs preserve life by respiration, after the vital muscular power would, without such assistance, be too weak to continue life. It will at once be understood, from what has now been explained, how, in age, violent exercise or exertion, is under restraint, in so far as it depends on respiration. The elasticity of the cartilages is gone, the circle of the ribs is now^ unyielding, and will not allow that high breathing, that sudden and great dilating and contracting of the cavity of the chest, which is required for circulating the blood through the lungs, and relieving the heart amidst the more tumultuous flowing of the blood which exercise and exertion produce. — Bell's Treatise on ■dnimul Mechanics. IN THE HUMAN FRAME, "65 VI. The shoulder-hladc is, in some material respects, a very singular bone ; it appearing to be made so expressly for its own purpose, and so independently of every other reason. (PI. X. fig. 4.) In such quadrupeds as have no collar bones, which are by far the greater number, the shoulder-blade has no bony communication w-ith the trunk, either by a joint, or process, or in any other way. It does not grow to, or out of, any other bone of the trunk. It does not apply to any other bone of the trunk — (I know not whether this be true of any second bone in the body, ex- cept perhaps the os hyoides.) In strictness, it forms no part of the skeleton. It is bedded in the flesh ; attached only to the muscles. It is no other than a foundation bone for the arm^ laid in^ separate, as it were, and distinct, from the general ossification. The lower limbs connect themselves at the hip with bones which form a part of the skeleton ; but, this connection^, in the upper limbs, being wanted, a basis whereupon the arm might be articulated was to be supplied by a detached ossification for the pur- pose, I. The above are a few examples of bones made re- markable by their configuration ; but to almost all the bones heXong joints ; and in these, still more clearly than in the form or shape of the bones themselves, are seen both contrivance and contriving wisdom. Every joint is a curiosity, and is also strictly mechanical. There is the hinge joint, and the mortice and tenon joint; each as manifestly such, and as accurately defined, as any which can be produced out of a cabinets-maker's shop. And one or the other prevails, as either is adapted to the motion which is wanted : e. g, a mortice and tenon, or ball and socket joint, is not required at th« knee, the leg standing in need only of a motion backward and forward in the same plane, for which a hinge joint is sufficient ; a mortice and tenon, or bail and socket joint, is wanted at the hip, that not only the progressive step may be provided for, but the interval between the limbs may be enlarged or contract- ed at pleasure. Now observe what would have been the inconveniency, i. e. both the superfluity and the defect of articulation, if the case had been inverted ; if the ball and socket joint had been at the knee, and the hinge joint at the hip. The thighs must have been kept constantly to- gether, and the legs have been loose and straddling. There would have been no use that we know of, in being able to turn G 6Q OF 3IECHAN1CAL ARRANGEMENT the calves of the legs before : and there would have been great confinement by restraining the motion of the thighs to one plane. The disadvantage would not have been less, if the joints at the hip and the knee had been both of the same sort ; both balls and sockets, or both hinges : yet wiiy, independently of utility, and of a Creator who con- sulted that utility, should the same bone (the thigh bone) be rounded at one end, and channelled at the other 1 The hinge joint is not formed by a bolt passing through the two parts of the hinge, and thus keeping them in their places ; but by a different expedient. A strong, tough, parchment-like membrane, rising from the receiving bones, and inserted all round the received bones a little below their heads, encloses the joint on every side. This mem- brane ties, confines, and holds the ends of the bones to- gether ; keeping the corresponding parts of the joint, i. e. the relative convexities and concavities in close application to each other.* For the hall and socket joint, beside the membrane al- ready described, there is in some important joints, as an additional security, a short, strong, yet flexible ligament, inserted, by one end into the head of the ball, by the oth- er into the bottom of the cup ; which ligament keeps the two parts of the joint so firmly in their place, that none of the motions which the limb naturally performs, none of the jerks and twists to which it is ordinarily liable, nothing less indeed than the utmost and the most unnatural vio- lence, can pull them asunder. [Plate XL fig. 1.] It is hardly indeed imaginable, how great a force is necessary, even to stretch, still more to break, this ligament; yet so flexible is it, as to oppose no impedient to the suppleness of the joint.f By its situation also, it is inaccessible to injury from sharp edges. As it cannot be ruptured such is its * This membrane is the capsular, or bursal ligament, common to every moveable joint. It certainly connects the bones together, but does not possess much strength : its chief use is to produce and pre- serve the synovia in the part where it is required. The security and strength of the hinge joint depends on certain ligaments called lateral ligaments, and the tendons of those muscles which pass over it. In the particular instance of the knee, from its being the largest joint in the body, there is, as we shall presently find, an additional contrivance to prevent dislocation. Paxton. t This ligament is also common to all quadrupeds, even in the more large and unwieldly, as the Hippopotamus and Rhinoceros — it is want- ing in the Elephant only, whose limbs, ill qualified for active move- ments, do not seem to require this se'^urity to the joint. Paxton. IN THE HUMAN FRAME. 67 strength ; so it cannot be cut, except by an accident which wouhi sever the limb. If I had been permitted to frame a proof of contrivance, such as might satisfy the most dis- trustful inquirer, I know not whether I could have chosen an example of mechanism more unequivocal, or more free from objection, than this ligament. Nothing can be more mechanical ; nothing, however subservient to the safety, less capable of being generated by the action of the joint. I would particularly solicit the reader's attention to this provision, as it is found in the head of the thigh bone ; to its strength, its structure, and its use. It is an instance upon which I lay my hand. One single fact, weighed by a mind in earnest, leaves oftentimes the deepest impres- sion. For the purpose of addressing different understand- ings and different apprehensions, for the purpose of senti- ment, for the purpose of exciting admiration of the Crea- tor's works, we diversify our views, we multiply examples ; but, for the purpose of strict argument, one clear instance is sufficient : and not only sufficient, but capable, perhaps, of generating a firmer assurance than what can arise from a divided attention. The ginglymuSj or hinge joint, does not, it is manifest, admit of a ligament of the same kind with that of the ball and socket joint, but it is always fortified by the species of ligament of which it does admit. The strong, firm, invest- ing membrane above described, accompanies it in every part j and, in particular joints, this membrane, which is properly a ligament, is considerably stronger on the sides than either before or behind, in order that the convexities may play true in their concavities, and not be subject to slip sideways, which is the chief danger ; for the muscular tendons generally restrain the parts from going further than they ought to go in the plane of their motion. In the knee^ which is a joint of this form and of great importance, there are superadded to the common provisions for the stability of the joint, two strong ligaments which cross each other, and cross each other in such a manner, as to secure the joint from being displaced in any assignable di- rection. [Plate XI. fig. 2, 3, 4.] " I think," says Che- selden, *' that the knee cannot be completely dislocated without breaking the cross ligaments."* We can hardly help comparing this with the binding up of a fracturd, * Ches. Anat. ed. 7th, p. 45. C8 OF MECHANICAL ARllANGLMlENT where the fillet is almost always strapped across, for the sake of giving firmness and strength to tlie bandage. Another no less important joint, and that also of the sin- gly mus sort, is the cuilde ; yet, though important, (in order perhaps, to preseive the symmetry and lightness of the limb) smallj and on that account, more liable to injury, (PI. XI. fig. 4.) Now this joint is strengthened, i. e. is defended from dislocation, by two remarkable processes or prolongations of the bones of the \eg^ which processes form the protuberances that we call the inner and outer ankle. It is part of each bone going down lower than the other part, and thereby overlapping the joint ; so that, if the joint be in danger of slipping outward, it is curbed by the inner projection, i. e. that of the tibia ; if inward, by the outer projection, i. e. that of the fibula. Between both, it is locked in its position. I know no account that can be given of this structure except its utility. Why should the tibia terminate at its lower extremity with a double end^ and the fibula the same, but to barricade the joint on both sides by a continuation of part of the thickness of the bone over it ? * * The most obvious proof of contrivance is the junction of the foot io the bones of the leg at the ankle joint. The two bones of the leg# called the tibia and the fibula, receive the great articulating bone of the foot (the astragalus) betwixt them. And the extremities of these bones of the leg project so as to form the outer and in- ner ankle. Now, when we step forward, and whilst the foot is raised^ it rolls easily upon the ends of these bones, so that the toe may be di- rected according to the inequalities of the ground we are to tread upon ; hut when the foot is planted, and the body is carried forward perpen- dicularly over the foot, the joint of the leg and foot becomes fixed, and we have a steady base to rest upon. We next observe, that, in walk- ing, the heel first touches the ground. If the banes of the log were perpendicular over the part which first touches the ground, we should come down with a sudden jolt, instead of which we descend in a semi- circle, the centre of which is the point of the heel. And when the toes have come to the ground we are far from losing the advantages of the structure of the foot, since we stand upon an elastic arch, tlie hinder extremity of which is the heel, and tiic anterior the balls of the toes, A finely formed foot should be high in the in- step. The walk of opera dancers is neither natural nor beautiful ; but the surprising exercises Avhich they perform give to the joints of the foot a freedom of motion almost like that of the hand. ^\'e have seen the dancers, in their morning exercises, stand for twenty minutes on the extremities of their toes, after which the effort is to bend the in- ner ankle down to the floor, in preparation for the Bolero step. By such unnatural postures and exercises the foot is made unfit for walk- ing, as may be observed in any of the retired dancers and old figuV' antes. By standing so much upou the toes, the human foot is convert- IN THE HUMAN FRAME. 69 The joint at the shoulder compared with the joint at the hip, though both ball and socket joints discover a differ- ence in their form and proportions, well suited to the dif- ferent offices which the limbs have to execute. The cup or socket at the shoulder is much shallower and flatter than it is at the hip, and is also in part formed of cartilage set round the rim of the cup. The socket, into which the head of the thigh bone is inserted, is deeper, and made of more solid materials.* This agrees with the duties as- signed to each part. The arm is an instrument of motion, principally, if not solely. Accordingly the shallowness of the socket at the shoulder, and the yieldingness of the car- ed to something more resembling that of a quadruped, where the heel never reaches the ground, and where the paw is nothing more than the phalanges of the toes. This arch of the foot, from the heel to the toe, has the astragalus, resembling the keystone of an arch ; but, instead of being iixed, as in masonry, it plays freely betwixt two bones, and from these two bones, a strong elastic ligament is extended, on which the bone rests, sinking or rising as the weight of the body bears upon it, or is taken off, and this it is enabled to do by the action of the ligament which runs under it. This is the same elastic ligament which runs extensively along the back of the horse's hind leg and foot, and gives the fine spring to it, but which is sometimes ruptured by the exertion of the animal in a leap, producing irrecoverable lameness. Having understood that the arch of the foot is perfect from the heel to the toe, we have next to observe, that there is an arch from side to side ; for when a transverse section is made of the bones of the foot, the exposed surface presents a perfect arch of wedges, regularly form- ed like the stones of an arch in masonry. If we look down upon the bones of the foot, we shall see that they form a complete circle hori- zontally, leaving a space in their centre. These bones thus form three different arches — forward ; across ; and horizontally : they are wedged together, and bound by ligaments, and this is what we alluded to Avhen we said that the foundations of the Eddystone were not laid on a better principle ; but our admiration is more excited in observing, that the bones of the foot are not only wedged together, like the courses of stone for resistance, but that solidity is combined with elasticity and lightness. Notwithstanding the mobility of the foot in some positions, yet when the weight of the body bears directly over it, it becomes immoveable, and the bones of the leg must be fractured before the foot yields. BelVs Treatise on Animal Mechanics. * The socket for the head of the thigh-bone is indeed deeper than that at the shoulder, but the " materials" which form the concavities are the same ; both are solid bone covered by cartilage, and both have a rim of a strong fibro-cartilaginous texture, not only for the purpose of rendering the socket deeper, but for preventing fractures of the rim in robust exercises, to which, were it bony, it would be very li- able. Faxton, G 2 70 OF MECflANiCAt AUUA^G^Mmt. tilaginous substance with which its edge is set round, and which in fact composes a considerable part of its concavi- ty, are excellently adapted for the allowance of a freer mo- tion and a wider range; both which the arm wants. Whereas the lower limb, forming a part of the column of the body • having to support the body, as well as to be the means of its locomotion ; firmness was to be consulted as well as action. With a capacity for motion, in all direc- tions indeed, as at the shoulder, but not in any direction to the same extent as in the arm, was to be united stabili- ty, or resistance to dislocation. Hence the deeper excava- tion of the socket, and the presence of a less proportion of cartilage upon the edge. The suppleness and pliability of the joints we every moment experience ; and the firmness of animal articu- lation, the property we have hitherto been considering, may be judged of from this single observation, that, at any given moment of time^ there are millions of animal joints in complete repair and use, for one that is dislo- cated ; and this, notwithstanding the contortions and wrenches to which the limbs of animals are continually subject. II. The joints, or rather, the ends of the bones which form them, display also, in their configuration, another use. The nerves, blood vessels, and tendons, which are neces- sary to the life, or for the motion, of the limbs, must, it is evident, in their way from the trunk of the body to the place of their destination, travel over the moveable joints; and it is no less evident, that, in this part of their course, they will have, from sudden motions and from abrupt changes of curvature, to encounter the danger of compres- sion, attrition, or laceration. To guard fibres so tender against consequences so injurious, their path is in those parts protected with peculiar care : and that by a provision in the figure of the bones themselves. The nerves which supply the fore-arm f especially the inferior cubital nerves, ajre at the elbow conducted, by a kind of covered way, be- tween the condyls, or rather under the inner extuberances of the bone, which composes the upper part of the arm.* At the knee the extremity of the thigh-bone is divided by a sinus or cliff into two heads or protuberances ; and these heads on the back part stand out beyond the cylinder of the bone. Through the hollow, which lies between the * Ches. An. p. 255, ed. 7th. IN THE HUMAN FRAME. 71 hind parts of these two heads, that is to say, under the ham, between the hamstrings, and within the concave re- cess of the bone formed by the extuberances on each side ; in a word, along a defile, between rocks, pass the great vessels and nerves which go the leg.* Who led these vessels by a road so defended and so secured ? In the joint at the slioul- der, in the edge of the cup which receives the head of the bone, is a notch which is joined or covered at the top with a ligament. Through this hole, thus guarded, the blood-ves- sels steal to their destination in the arm, instead of mount- ing over the edge of the concavity .t III. In all joints, the end of the bones, which work against each other, are tipped with gristle. In the ball and socket joint, the cup is lined, and the ball capped with it. The smooth surface, the elastic and unfriable nature of cartilage, render it of all substances the properest for the place and purpose. I should therefore have pointed this out amongst the foremost of the provisions which have been made in the joints for the facilitating of their action, had it not been alleged, that cartilage in truth is only nascent or imperfect bone ; and that the bone in these places is kept soft and imperfect, in consequence of a more complete and rigid ossification being prevented from taking place by the continual motion and rubbing of the surfaces. Which being so, what we represent as a designed advan- tage, is an unavoidable effect. I am far from being con- vinced that this is a true account of the fact ; or that, if it were so, it answers the argument. To me, the surmount- ing of the ends of the bones with gristle, looks more like a plating with a different metal, than like the same metal kept in a different state by the action to which it is exposed. At all events we have a great particular benefit, though arising from a general constitution ; but this last not being quite what my argument requires, lest I should seem by applying the instance, to overrate its value, I have thought it fair to state the question which attends it. IV. In some joints, very particularly in the knees, there are loose cartilages or gristles between the bones, and with- in the joint, so that the ends of the bones instead of work- ing upon one another, work upon the intermediate cartila- ges. Chesselden has observed,| that the contrivance of a loose ring is practised by mechanics, where the fric- tion of the joints of any of their machines is great; as be- ^ Ches. An, p. 35. t lb. 30, X lb. p. 13. 72 OF MECHANICAL ARRANGEMENT tween the parts of crooked hinges of large gates, or under the head of the male screw of large vices. The cartilages of which we speak have very much of the form of these rings. The comparison moreover shows the reason why we find them in the knees rather than in other joints. It is an expedient, we have seen, which a mechanic resorts to, only when some strong and heavy work is to be done. So here the thigh bone has to achieve its motion at the knee, with the whole weight of the body pressing upon it, and often, as in rising from our seat, with the whole weight of the body to lift. It should seem also from Ches- selden's account, that the slipping and sliding of the loose cartilages, though it be probably a small and obscure change, humoured the motion of the end of the thigh bone under the particular configuration which was necessary to be given to it for the commodious action of the tendons ; and which configuration requires what he calls a variable socket, that is, a concavity, the lines of which assume a different curvature in different inclinations of the bones. V. We have now done with the configuration ; but there is also in the joints, and that common to them all, another exquisite provision, manifestly adapted to their use, and concerning which, there can, I think, be no dispute ; namely, the regular supply of a mucilage, more emollient and slippery than oil itself, which is constantly softening and lubricating the parts that rub upon each other, and thereby diminishing the effect of attrition in the highest possible degree.* For the continual secretion of this im- portant linament, and for the feeding of the cavities of the joint with it, glands are fixed near each joint ; the excre- tory ducts of which glands, dripping with their balsamic contents, hang loose like fringes within the cavity of the joints. A late improvement in what are called friction wheels, which consists of a mechanism so ordered, as to be regularly dropping oil into a box, which encloses the axis, the nave, and certain balls upon which the nave revolves, may be said, in some sort, to represent the contrivance in the animal joint ; with this superiority, however, on the port of the joints, viz. that here, the oil is not only dropped, but made, t * This mucilage is termed synovia; vulgarly called joint oil, but it has no property of oil. It is very viscid, and at the same time smooth and slippery to the touch ; and therefore better adapted than any oil to lubricate the interior of the joints and prevent ill effects from friction. Farton, t A joint then consists of the union of two bon^s, of such a form as to permit the necessary motion ; but they are not in contact j each artic- IN THE HUMAN FRAME. 73 in considering the joints, there is nothing, perhaps, which ought to move our gratitude more than the reflection, lioio well they wear. A limb shall swing upon its hinge, or play in its socket, many hundred times in an hour, for six- ty years together, without diminution of its agility ; which is a long time for any thing to last ; for any thing so much worked and exercised as the joints are. This durabiUty I should attribute, in part, to the provision which is made for the preventing of wear and tear, first, by the polish of the cartilaginous surfaces, secondly, by the healing lubrication of the mucilage ; and, in part, to that astonishing property of animal constitutions, assimilation, by which, in every portion of the body, let it consist of what it will, substance is restored, and waste repaired. * ulating surface is covered with cartilage, to prevent the jar which would result from the contact of the bones. This cartilage is elastic, and the celebrated Dr. Hunter discovered that the elasticity was ia consequence of a number of filaments closely compacted, and extend- ing from the surface of the hone, so that each filament is perpendicu- lar to the pressure made upon it. The surface of the articulating car- tilage is perfectly smooth, and is lubricated by a fluid called synovia, signifying a mucilage, a viscous or thick liquor. This is vulgarly called joint oil, but it has no property of oil, although it ia better cal- culated than any oil to lubricate the interior of die joint When inflammation comes upon a joint, this fluid is not supplied, and the joint is stiff, and the surfaces creak upon one another Uke a hinge without oil. A delicate membrane extends from bone to bone, confin- ing this lubricating fluid, and forming the boundary of what is termed the cavity of the joint, although, in fact, there is no unoccupied space. External to this capsule of the joint, there are strong ligaments going from point to point of the bones, and so ordered as to bind them to- gether without preventing their proper motions. From this description of a single joint, we can easily conceive what a spring or elasticity is given to the foot, where thirty-six bones are joined together. BeWs Treatise on Animal Mechanics. * If the ingenious author's mind had been professionally called to contemplate this subject, he would have found another explanation. There is no resemblance betwixt the provisions against the wear and tear of machinery and those for the preservation of a living part. As the structure of the parts is originally perfected by the action of the vessels, the function or operation of the part is made the stimulus to tliose vessels. The cuticle on the hands wears away like a glove ; but the pressure stimulates tlie living surface to force successive lay- ers of skin under that which is wearing, or, as the Anatomists call it, desquamating ; by which they mean, that the cuticle does not change at once, but comes off in squamce, or scales. The teeth are subject to pressure in chewing or masticating, and they would, by this action, have been driven deeper in the jaw, and rendered useless, had there not been a provision against this mechanical effect. This provision is a disposition to grow, or rather to shoot out of their sockets ; and this dis- position to project, balances the pressure which they sustain ; and when one tooth is lost, its opposite rises, and is in danger of being lost also, for want of that very opposition. Ibid^ 74 OF THE MUSCLES. Moveable joints, I think, compose tiie curiosity of bones ; but their union, even where no motion is intended or want- ed carries marks of mechanism and of mechanical wis- dom. The teeth, especially the front teeth, are one bone fixed in another like a peg driven into a board. The sutures of the skull are like the edges of two saws clapp- ed together, in such a manner as that the teeth of one enter the intervals of the other.* We have sometimes one bone lapping over another, and planed down at the edges ; sometimes also the thin lamella of one bone received into a narrow furrow of another. In all which varieties we seem to discover the same design, viz. firmness of juncture, without clumsiness in the seam. CHAP. IX. OF THE MUSCLES. Muscles, with their tendons, are the instruments by which animal motion is performed. It will be our business to point out instances in which, and properties with respect to which, the disposition of these muscles is as strictly mechanical, as that of the wires and strings of a puppet.t * Most of the bones of the skull are composed of two plates or tob- lets, with an intermediate spongy, vascular substance ; the outer tablet is fibroua, having the edges curiously indented and united by a dove- tailed suture ; the inner from its brittleness is called vitreous, and therefore merely joined together in a straight line ; this mode of union is not accidental — not the result of chance, but design. The author of the treatise on "Animal Mechanics" gives the following admirable il- lusti-ation of the structure : — *' Suppose a carpenter employed upon his own material — he would join a box with regular indentations by dove-tailing, because he knows that the material on which he works, from its softness and toughness, admits of such adjustment of its edges. The processes of bone shoot into the opposite cavities with an exact resemblance to the fox-tail wedge of the carpenter. " But if a workman in glass or marble were to join these materials, he would smooth the edges and unite them by cement; for if he could succeed in indenting the line of union, he knows that his material would chip off on the slightest vibration. " Now apply this principle to the skull ; the outer table, which re- sembles wood, is indented and dove-tailed ; the inner glassy table has its edges simply laid in contact." Paxton. t Muscles are the fleshy parts of the body which surround the bones, having a fibrous texture j a muscle being composed of a number of OF THE MUSCLES. 75 I. We may observe, what I believe is universal, an ex- act relation between the joint and the muscles which move it. Whatever motion, the joint by its mechanical construc- tion, is capable of performing, that motion, the annexed muscles, by their position, are capable of producing. For example ; if there be, as at the knee and elbow, a hinge joint, capable of motion only in the same plane, the lead- ers, as they are called, i. e. the muscular tendons, are placed in directions parallel to the bone, so as, by the con- traction or relaxation of the muscles to which they beloncr, to produce that motion and no other. If these joints were capable of a freer motion there are no muscles to produce it. Whereas at the shoulder and the hip, where the ball and socket joint allows by its construction of rotatory or sweeping motion, tendons are placed in such a position, and pull in such a direction, as to produce the motion of which the joint admits. For instance, the sartorius or tailor's muscle, arising from the spine, running diagonally across the thigh, and taking hold of the inside of the main bone of the leg a little below the knee, enables us, by its contraction, to throw one leg and thigh over the other ; giving effect, at the same time, to the ball and socket joint at the hip, and the hinge joint at the knee. (PI. Ull. fig. 1.) There is, as we have seen, a specific mechanism in the bones for the rotatory motions of the head and hands ; there is also in the oblique direction of the muscles belonging to them, a specific provision for the putting of this mechanism of the bones into action. (PI. XII. fig. 2.) And mark the consent of uses. The oblique muscles would have been inefficient without the articulation ; the articulation would have been lost, without the oblique muscles. It may be proper however to observe with respect to the head, al- though I think it does not vary the case, that its oblique motions and inclination are often motions in a diagonal, produced by the joint action of muscles lying in straight directions. But, whether the pull be single or combined ; the articulation is always such, as to be capable of obeying the action of the muscles. The oblique muscles attached muscular faciculi, which are composed of fibres still smaller ; these result from fibres of a less volume, until by successive division we ar- rive at very small fibres no longer divisible. These muscular fibres are longer or shorter according to the muscles to which they be- long ; and every fibre is fixed by its two extremities to tendon or aponeurosis, which are the " wires and strings" which conduct the muscular power when they contract, Paxton, 70 OF THE MUSCLKS. to the head, arc likewise so disposed, as to be capable of steadying the jrlobe, as well as ofmovinj: it. The head ol' a new-born ini'ant is oitcn obliged to l>e lilietted up. After death the head drops and rolls in every direction. So that it is by the equilibre of the muscles, by the aid of a consid- erable and equipollent muscular force in constant exertion, that the liead maintains its erect posture. The muscles here supply, what would otherwise be a great defect in the articulation : for the joint in the neck, although admirably adapted to the motion of the head, is insufficient for its .support. It is not only by the means of a most curious structure of the bones that a man turns his head, but by virtue of an adjusted muscular power, that lie even holds it up. As another example of what we are illustrating, viz. con- formity of use between the bones and the muscles, it has beeji observed of the different vertebra;, that their proces- ses are exactly proportioned to the quantity of motion which the other bones allow of, and which the respective muscles are capable of producing. II. A muscle acts only by contraction. Its force is ex- erted in no otiier way. When the exertion ceases it relax- es itself; Uiat is, it returns by relaxation to its former state, but without energy. This is the nature of the muscular fibre ; and being so, it is evident that the reciprocal (ncr- ffdic motion of the limbs, by which we mean motion initk force in opj)Osite directions can only be produced by the instrumentality of oi)posite or antagonist muscles ; of fiexors and extensors answering to each other. For instance, the biceps and brachia-us rnfcrm/s muscles placed in the front part of the upper arm, by their contraction, bend the elbow ; and with such degree of force, as the case requires, or the strength admits of (IM. XIll. fig. 1.) The relaxation of these muscles, after tho effort, would merely let tho fore- arm drop down. For tlic bark stro/:e, therefore, and that the arm may not only bend at the elbow, but also extend and straighten itself with fcrcn, other muscles, tlie longus and brevis brachia-us r/frrnu.-i, and the ancon.rMis, placed on the hinder part of the arm, by their contractile twitch fctcii back the fore-arm into a straight line with the cubit, with no less force than that with which it was bent out of it. The same thing obtains in all the limbs, and in every move- able part of the body. A finger is not bent and straighten- ed, without the contraction of two muscles taking place, it is evident, therefore, that the ;inimal Junctions retpiire that OF THE MUSCLES, 77 particular disposition of the muscles which we describe by the name of antaijonist muscles. And they are according- ly so disposed. Every muscle is provided with an adversa- ry. They act like two sawers in a pit by an opposite pull; and nothing: surely can more strongly indicate design and attention to an end than their being thus stationed ; than this collocation. The nature of the muscular fibre being what it is, the purposes of the animal could be answered, by no other And not only the capacity for motion, but the aspect and symmetry of the body is preserved by the mus- cles being marshalled according to tliis order, e. g. the month is held in the middle of the face, and its angles kept in a state of exact correspondency, by two muscles drawing against, and balancing, each other. In a hemi- plegia, when the muscle on one side is weakened, the mus- cle on the other side draws the moutii awry. III. Another property of the muscles, which could only be the result of care, is their being almost universally so disposed, as not to obstruct or interfere with one another's ac- tion. I know but one instance in which this impediment is perceived. We cannot easily swallow whilst we gape. This, I understand, is owing to the muscles employed in the act of deglutition, being so implicated with the muscles of the lower jaw, that whilst these last are contracted, the former cannot act with freedom. The obstruction is, in this instance, attended with little inconveniency ; but it shows what the effect is, where it does exist ; and what loss of faculty there would be, if it were more frer^uent. Now when we reflect upon the number of muscles, not fewer than four hundred and forty-six in the human body, known and nanved,* how contiguous they lie to each other, in lay- ers, as it were, over one another, crossing one another, sometimes embedded in one anotlier, sometinjes perforating one another, an arrangement, which leaves to eacii its liberty and its full play, must necessarily require meditation and counsel. IV. The following is oftentimes the case with the mus- cles. Their action is wanted where their situation would be inconvenient. In which case the body of the muscle is placed in some commodious position at a distance, and made to communicate with the point of action, by slender strings or wires. If the muscles, which move the fingers, had been placed in the palm or back of the hand, they * KeiU's Anat. p. 295, edit. 3. There are. however, five hundred and twentv-seven muscles described by more modern anatomists. Paxton. H 78 OE THE MUSCLES. would have swelled that part to an awkward and clumsy thickness. The beauty, the proportions of the part, would have been destroyed. They are therefore disposed in the arm, and even up to the elbow ; and act by long tendons, strapped down at the wrist, and passing under the ligament to the fingers, and to the joints of the fingers, which they are severally to move. (PI. XIII. fig. 1, 2.) In like man- ner, the muscles which move the toes, and many of the joints of the foot, how gracefully are they disposed in the calf of the leg, instead of forming an unwieldly tumefaction in the foot itself? The observation may be repeated of the muscle which draws the nictitating membrane over the eye. Its ofiice is in the front of the eye ; but its body is lodged in the back part of the globe, where it lies safe, and where it encumbers nothing.* V. The great mechanical variety in the figure of the muscles may be thus stated. It appears to be a fixed law, that the contraction of a muscle shall be towards its centre. Therefore the subject for mechanism on each occasion is, so to modify the figure, and adjust the position, of the mus- cle, as to produce the motion required agreeably with this law. This can only be done by giving to different muscles, a diversity of configuration, suited to their several offices, and to their situation with respect to the work which they have to perform. On vrhich account we find them under a multiplicity of forms and attitudes ; sometimes with double, sometimes with treble tendons, sometimes with none ; sometimes one tendon to several muscles, at other times one muscle to several tendons. The shape of the organ is susceptible of an incalculable variety, whilst the original property of the muscle, the law and line of its con- traction, remains the same ; and is simple. Herein the muscular system may be said to bear a perfect resemblance to our works of art. An artist does not alter the native quality of his materials, or their laws of action. He takes * The convenience and beauty of the tendons seem only an ulterior object, their necessity and utility principally claim our attention. The force which a muscle possesses is as the number of the muscular fi- bres ; but a limited number of fibres only can be fixed to any certain point of bone destined to be moved, therefore the contrivance is, to attach them to a cord, called a sinew or tendon, which can be conve- niently conducted and fixed to the bone. If we are desirous of mov- ing a heavy weight, we tie a strong cord to it, that a greater number of men may apply their strength. Thus a similar effect is produced — the muscular fibres are the moving powers, the tendons are the cords attached to the point to be moved. Paxton. OF THE MUSCLES. 79 these as he finds them. His skill and ingenuity are em- ployed in turning them, such as they are to his account, by giving to the parts of his machine a form and relation, in which these unalterable properties may operate to the production of the effects intended. VI. The ejaculations can never too often be repeated. How many things must go right for us to be an hour at ease I How many more, to be vigorous and active ! Yet vigour and activity are, in a vast plurality of instances, pre- served in human bodies, notwithstanding that they depend upon so great a number of instruments of motion, and not- withstanding that the defect or disorder sometimes of a very small instrument, of a single pair, for instance, out of the four hundred and forty-six muscles which are employed, may be attended with grievous inconveniency. There is piety and good sense in the following observation taken out of the Religious Philosopher, " With much compas- sion," says this writer, " as well as astonishment at the goodness of our loving Creator, have I considered the sad state of a certain gentleman, who, as to the rest, was in pretty good health, but only wanted the use of these two little muscles that serve to lift up the eyelids, (PI. XIV. fig. I, 2.) and so had almost lost the use of his sight; being forced as long as this defect lasted, to shove up his eyelids every moment with his own hands !" In general we may remark how little those, who enjoy the perfect use of their organs, know the comprehensiveness of the blessing, the variety of their obligation. They [perceive a result, but they think little of the multitude of concurrences and rec- titudes which go to form it. Besides these observations, which belong to the muscu- lar organ as such, we may notice some advantages of struc- ture which are more conspicuous in muscles of a certain class or description than in others. Thus, The variety, quickness, and precision, of which mus- cular motion is capable, are seen, I think, in no part so remarkable as in the tongue. It is worth any man's while to watch the agility of his tongue ; the wonderful promptitude with which it executes changes of position, and the perfect exactness. Each syllable of articulated sound requires for its utterance a specific action of the tongue, and of the parts adjacent to it. The disposition and con- figuration of the mouth, appertaining to every letter and word, is not only peculiar, but, if nicely and accurately attended to, perceptible to the sight ; insomuch that curious 80 OF THE MUSCLES. persons have availed themselves of this circamstance to teach the deaf to speak, and to understand what is said by others. In the some person, and after his habit of speak- ing is formed, one, and only one, position of the parts, will produce a given articulate sound correctly. How instan- taneously are these positions assumed and dismissed ; how numerous are the permutations, how various, yet how infallible! Arbitrary and antic variety is not the thing we admire ; but variety obeying a rule, conducing to an effect, and commensurate with exigences infinitely diversified. I believe also that the anatomy of the tongue corresponds with these observations upon its activity. The muscles of the tongue are so numerous and so implicated with one another, that they cannot be traced by the nicest dissec- tion ; nevertheless, which is a great perfection of the organ, neither the number, nor the complexity, nor what might seem to be, the entanglement of its fibres, in any wise im- pedes its motion, or renders the determination or success of its efforts uncertain. I here entreat the reader's permission to step a little out of my way to consider the parts of the mouth in some of their other properties. It has been said, and that by an eminent physiologist, that, whenever nature attempts to work two or more purposes by one instrument, she does both or all imperfectly. Is this true of the tongue, regard- ed as an instrument of speech, and of taste ; or regarded as an instrument of speech, of taste and of deglutition? So much otherwise, that many persons, that is to say, nine hundred and ninety-nine persons out of a thousand, by the instrumentality of this one organ, talk, and taste, and swal- low, very well. In fact the constant warmth and moisture of the tongue, the thinness of the skin, the papillae upon its surface, qualify this organ for its office of tasting, as much as its inextricable multiplicity of fibres do for the rapid movements which are necessary to speech. Animals which feed upon grass, have their tongues covered with a, perforated skin so as to admit the dissolved food to the pa- pilliE underneath, which, in the mean time, remain defend- ed from the rough action of the unbruised spicula^.* ■ PapillcB are small bodies situated on the surface and sides of the tongue ; they are furnished by the extreme filaments of the gustatory nerve, through which medium we acquire tlie sense of tasting. In OP THE MUSCLES. 81 There are brought together within the cavity of the mouth more distinct uses, and parts executing more dis- tinct offices, than I think can be found lying so near to one another, or within the same compass, in any other por- tion of the body : viz. teeth of diiferent shape,* first for cutting, secondly for grinding : muscles, most artificially disposed for carrying on the compound motion of the low- er jaw, half lateral and half vertical, by which the mill is worked ; fountains of saliva, springing up in different parts of the cavity for the moistening of the food, whilst the mastication is going on : glands to feed the fountains : a muscular constriction of a very peculiar kind in the back part of the cavity, for the guidmg of the prepared aliment into its passage towards the stomach, and in many cases for carrying it along that passage : for, although we may imagine this to be done simply by the weight of the food itself, it in truth is not so, even in the upright posture of the human neck ; and most evidently is not the case with quadrupeds, with a horse, for instance, in which when pasturing, the food is thrust upward by muscular strength, instead of descending of its own accord. In the meantime, and within the same cavity, is going on another business, altogether different from what is here described, that of respiration and speech. In addition, therefore, to all that has been mentioned, we have a pas- sage opened, from this cavity to the lungs, for the admis- sion of air, exclusively of every other substance : we have muscles, some in the larnyx, and without number in the tongue, for the purpose of modulating that air in its passage, herbivorous animals the papillae are sharp pointed and directed back- wards to assist in laying hold of the grass. In the cat kind there is a horny or" prickly set covering the tongue, rendering it rough, and enabling it to take firmer hold of the prey. Birds also have a similar contrivance. In fish the tongue is covered by a number of teeth, serv- ing the same purpose. Paxton. * In each jaw there are four incisores, or cutting teeth, two canine which may be ranked with the former, only more pointed ; four small molar, and six large molar or grinding teeth. And as the teeth of an- imals indicate the food on which they are destined to subsist, so from analogy we may infer that man is called to use either animal or vege- table aliments, or both, i. e. keeps a mean between graminivorous and carnivorous animals, in the structure and complication of his digestive apparatus, without deserving on that account to be called omnivorous : for it is known, that, a great number of the substances upon which animals feed are of no use in the support of man. Paxton. H 2 ,c}o or THE MUSCLES. with a variety, a compass, and precision, of which no other musical instrument is capable. And, lastly, which in my opinion crowns the whole as a piece of machinery, we have a specific contrivance for dividing tlie pneumatic part from the mechanical, and for preventing one set of actions in- terfering with the other. Where various functions are united, the difficulty is to guard against the inconvenien- cies of a too great complexity. In no apparatus put togeth- er by art, and for the purposes of art, do I know such mul- tifarious uses so aptly combined, as in the natural organi- zation of the human mouth ; or where the structure, com- pared with the uses, is so simple. The mouth, with all these intentions to serve, is a single cavity ; is one machine; with its parts neither crowded nor confused, and each un- embarrassed by the rest ; each at least at liberty in a de- gree sufficient for the end to be attained. If we cannot eat and sing at the same moment, we can eat one moment and sing the next ; the respiration proceeding freely all the while. There is one case, however, of this double office, and that of the earliest necessity, which the mouth alone could not perform ; and that is, carrying on together the two ac- tions of sucking and breathing. Another rout, therefore, is opened for the air, namely, through the nose, which lets the breath pass backward and forward, whilst the lips, in the act of sucking, are necessarily shut close upon the body, from which the nutriment is drawn. This is a cir- cumstance, which always appeared to me worthy of notice. The nose would have been necessary, although it had not been the organ of smelling. The making it the seat of a sense, was superadding a new use to apart already wanted : was taking a vise advantage of an antecedent and a con- stitutional necessity. But to return to that which is the proper subject of the present section, the celerity and precision of muscular mo- tion. These qualities may be particularly observed in the execution of many species of instrumental music, in which the changes produced by the hand of the musician, are ex- ceedingly rapid ; are exactly measured, even when most minute; and display, on the part of the muscles, an obedi- ence of action, alike wonderful for its quickness and its correctness. OF THE MUSCLES. 83 Or let a person only observe his own hand whilst he is writing; the number of muscles, which are brought to bear upon the pen ; how the joint and adjusted operation of several tendons is concerned in every stroke, yet that five hundred such strokes, are drawn in a minute. Not a letter can be turned without more than one or two or three tendinous contractions, definite, both as to the choice of the tendon and as to the space through which the con- traction moves, yet how currently does the work proceed ' and when we look at it, how faithful have the muscles been to their duty, how true to the order which endeavour or habit hath inculcated ! For let it be remembered, that, whilst a man's hand writing is the same, an exactitude of order is preserved whether he write well or ill. These two instances of music and writing, show not only the quickness and precision of muscular action, but the do- cility. IL Regarding the particular configuration of muscles, spliincter or circular muscles appear to me admirable pieces of mechanism. (PL XIV. fig. 3.) It is the muscular pow- er most happily applied ; the same quality of the muscular substance, but under a new modification. The circular disposition of the fibres is strictly mechanical ; but, though the most mechanical, is not the only thing in sphincters which deserves our notice. The regulated degree of con- tractile force with which they are endowed, sufficient for retention, yet vincible when requisite ; together with their ordinary state of actual contraction, by means of which their dependence upon the will is not constant but occasion- al, gives to them a constitution of which the conveniency is inestimable. This their semi-voluntary character, is ex- actly such as suits with the wants and functions of the ani- mal, III. We may also, upon the subject of muscles, observe, that many of our most important actions are achieved by the combined help of different muscles. Frequently, a diagonal motion is produced, by the contraction of tendons, pulling in the direction of the sides of the parallelogram. This is the case, as hath been already noticed, with some of the oblique nutations of the head. Sometimes the num- ber of co-operating muscles is very great. Dr. Nieuentyt, in the Leipzic Transactions, reckons up a hundred muscles that are employed every time we breathe ; yet we take in, or let out, our breath, without reflecting what a work is thereby performed ; what an apparatus is laid in of instru- 84 OF THE MUSCLES. ments for the service, and how many such contribute their assistance to the effect. Breathing with ease is a blessing of every moment ; yet, of all others, it is that which we possess with the least consciousness. A man in an asthma is the only man who knows how to estimate it. IV. Mr. Home has observed,* that the most important and the most delicate actions are performed in the body by the smallest muscles; and he mentions, as his examples, the muscles which have been discovered in the iris of the eye and the drum of the ear. The tenuity of these mus- cles is astonishing. They are microscopic hairs ; must be magnified to be visible ; yet are they real effective mus- cles ; and not only such, but the grandest and most pre- cious of our faculties, sight and hearing, depend upon their health and action. V. The muscles act in the limbs with what is called a mechanical disadvantage. The muscle at the shoulder, by which the arm is raised, is fixed nearly in the same manner, as the load is fixed upon a steelyard, within a few decimals, we will say, of an inch, from the centre upon which the steelyard turns. In this situation, we find that a very heavy draught is no more than sufficient to countervail the force of a small lead plummet, placed upon the long arm of the steelyard, at the distance of perhaps iifteen or twenty inches from the centre, and on the other side of it. And this is the disadvantage, which is meant. And an absolute dis- advantage, no doubt, it would be, if the object were to spare the force of muscular contraction. But observe how conducive is this constitution to animal conveniency. Me- chanism has always in view one or other of these two pur- poses ; either to move a great weight slowly, and through a small space ; or to move a light weight rapidly, through a considerable sweep. For the former of these purposes, a different species of lever, and a different collocation of the muscles, might be better than the present ; but for the second, the present structure is the true one.. Now, so it happens, that the second, and not the first, is that which the occasions of animal life principally call for. In what concerns the human body, it is of much more consequence to any man to be able to carry his hand to his head with due expedition, than it would be to have the power of rais- ing from the ground a heavier load (of two or three more hundred weight, we will suppose,) than he can lift at pre- *Phil. Trans, part 1. 1800. p. 8. OF THE MUSCLES' < 85 sent. This last is a faculty, which, upon some extraordi- nary occasions, he may desire to possess ; but the other is what he wants and uses every hour and minute. -In like manner, a husbandman or a gardener will do more execu- tion, by being able to carry his scythe, his rake or his flail, with a sufficient despatch through a sufficient space, than if, with greater strength, his motions were proportionably more confined and slow. It is the same with a mechanic in the use of his tools. It is the same also with other animals in the use of their limbs. In general, the vivacity of their motions would be ill exchanged for greater force under a clumsier structure. We have offered our observations upon the structure of muscles in general ; we have also noticed certain species of muscles ; but there are also single muscles, which bear marks of mechanical contrivance, appropriate as well as particular. Out of many instances of this kind we select the following : — I. Of muscular actions, even of those which are well understood, some of the most curious are incapable of pop- ular explanation ; at least without the aid of plates and figures.* This is in a great measure the case, with a very familiar, but, at the same time, a very complicated motion, that of the lower jaw; and with the muscular structure by which it is produced. One of the muscles concerned, may, however, be described in such a manner, as to be, X thinks sufficiently comprehended for our present purpose. The problem is to pull the lower jaw down. The obvious method should seem to be, to place a straight muscle, viz. to fix a string from the chin to the breast, the contraction of which would open the mouth, and produce the motion rec^uired at once. But it is evident that the form and liberty of the neck forbid a muscle being laid in such a position ; and that, consistently with the preservation of this form, the motion which we want, must be effectuated, by some muscu- lar mechanism disposed further back in the jaw. The me- chanism adopted is as follows: (PI. XV. fig. 1, 2.) A certain muscle called the digastric rises on the side of the face, considerably above the insertion of the lower jaw ; and comes down, being converted in its progress into a a round tendon. Now it is evident, that the tendon, whilst it pursues a direction descending towards the jaw, must> by its contraction, pull the jaw up, instead of down. What * The want of the aid of plates and figui'es, which the author here expresses, is now suppUed in this Boston edition, bb OF THE MUSCLES. then was to be done ? This, we find, is done. The de- scending tendon, when it is got low enough, is passed through a loop, or ring, or pulley, in the os-hyoides, and then made to ascend ; and, having thus changed its line of direction, is inserted into the inner part of the chin ; by which device, viz. the turn at the loop, the action of the muscle (which in all muscles is contraction) that before would have pulled the jaw up, now as necessarily draws it down. " The mouth," saith Heister, " is opened by means of this trochlea in a most wonderful and elegant manner." IL What contrivance can be more mechanical than the following, viz. a slit in one tendon to let another ten- don pass through it ? This structure is found in the ten- dons which move the toes and fingers. The long tendon, as it is called, in the foot, v/hich bends the first joint of the toe, passes iliroiigh the short tendon which bends the sec- ond joint ; which course allows to the sinew more liberty and a more commodious action than it would otherwise have been capable of exerting.* (PI. XVI. fig. 1, 2.) There is nothing, I believe, in a silk or cotton-mill : in the belts, or straps, or ropes, by which motion is communicated from one part of the machine to another, that is more artificial, oi' more evidently so, than ihis perforation. III. The next circumstance which I shall mention, un- der this head of muscular arrangement, is so decisive a mark of intention, that it always appeared to me, to super- sede, in some measure, the necessity of seeking for any other observation upon the subject ; and that circumstance is, the tendons, which pass from the leg to the foot being bound bown by a ligament at the ankle. (Pi. XVI. fig. 3.) The foot is placed at a considerable angle with the leg. It is manifest, therefore, that flexible strings, passing along the interior of the angle, if left to themselves, would, when stretched, start from it. The obvious preventive is to tie them down, And this is done in fact. Across the instep, or rather just above it, the anatomist finds a strong liga- ment ; under which the tendons pass to the foot. The ef- fect of the ligament as a bandage, can be made evident to the senses ; for if it be cut, the tendons start up. The simplicity, yet the clearness of this contrivance, its exact resemblance to established resources of art, place it amongst the most indubitable manifestations, of design with which we are acquainted. * Ches, Anat, p. 94, 119, OF TrfE MUSCLES. 8T There is also a further use to be made of the present example, and that is, as it precisely contradicts the opin- ion, that the parts of animals may have been all formed by what is called appetency, i. e. endeavour, perpetuated, and imperceptibly working its effect, through an incalcu- lable series of generations. We have here no endeavour, but the reverse of it ; a constant renitency and reluctance The endeavour is all the other way. The pressure of the ligament constrains the tendons ; the tendons re-act upon the pressure of the ligament. It is impossible that the lig- ament should ever have been generated by the exercise of the tendon, or in the course of that exercise, forasmuch as the force of the tendon perpendicularly resists the fibre which confines it, and is constantly endeavouring, not to form, but to rupture and displace, the threads of which the ligament is composed. Keill has reckoned up, in the human body, four hundred and forty-six muscles, [See note, p. 77,] dissectible and de- scriable ; and hathassigned an use to every one of the num- ber. This cannot be all imagination. Bishop Wilkins hath observed from Galen that there are, at least, ten several qualifications to be attended to in each particular muscle, viz. its proper figure, its just magni- tude, its fulcrum, its point of action supposing the figure to be fixed, its collocation with respect to its two ends, the upper and the lower, the place, the position of the whole muscle, the introduction into it of nerves, arteries, veins. How are things, including so many adjustments, to be made, or when made, how are they to be put together, without intelligence? I have sometimes wondered, why we are not struck with mechanism in animal bodies, as readily and as strong- ly as we are struck with it, at first sight, in a watch or a mill. One reason of the difference may be that animal bodies are, in a great measure, made up of soft, flabby, substances, such as muscles and membranes; whereas we have been accustomed to trace mechanism in sharp lines, in the configuration of hard materials, in the moulding, chiseling, and filing into shapes, such articles as metals or wood. There is something, therefore, of habit in the case; but it is sufficiently evident, that there can be no proper reason for any distinction of the sort. Mechanism may be displayed in the one kind of substance, as well as in the other. 88 OF THE MUSCLES. Although the few instances we have selected, even as they stand in our description, are nothing short, perhaps, of logical proofs of design, yet it must not be forgotten, that, in every part of anatomy, description is a poor sub- stitute for inspection. It was well said by an able anato- mist,* and said in reference to the very part of the sub- ject which we have been treating of, *' Imperfecta hsec musculorum descriptio, non minus arida est legentibus, quam inspectantibus fuerit jucunda eorundem prseparatio. Elegantissima enim mecanices artificia, creberrime in illis obvia, verbis nonnisi obscure exprimuntur ; carnium autem ductu, tendinum colore, insertionum proportione, et trochlearium distributione, occulis exposita, omnem su- perant admirationem." The following remarks upon the structured the tendons, from the An- imal Mechanics already quoted, will form an instructive addition to the foregoing Chapter, to the subject of which they bear a near relation. Ed. Of the Cordage of the Tendons. Where nature has provided a perfect system of columns and levers, and pullies, w'e may antici})ate that the cords by which the force of the muscles is concentrated on the movea- ble bones, must be constructed with as curious a provision for their offices. In this surmise we shall not be disappoint- ed. To understand what is necessary to the strength of a rope or a cable, we must learn what has been the object of the im- provements and patents in this manufacture. The first pro- cess in rope-making, is hatchelling the hemp : that is, combing out the short fibres, and placing the long ones parallel to one another. The second is, spinning the hemp into yarns. And here the principle must be attended to, which goes through the whole process in forming a cable ; vrliich is that the fibres of the hemp shall bear an equal strain : and the difficulty may be easily conceived, since the twisting must derange the par- allel position of the fibres. Each fibre, as it is twisted, ties the other fibres together, so as to form a continued line, and it bears, at the same time, a certain portion of the strain, and so each fibre alternately. The third step of the process is making the yarns. Warping the yarns, is stretching them to a certain length ; and for the same reason, that so much at- tention has been paid to the arrangement of the fibres for the yarns, the same care is taken in the management of the yarns for the strands. The fourth step of the process is to * Sterno in Bias. Anat. Animal, p. 2. c. 4, OF THE MUSCLES. 89 form the strands into ropes. The difficulty of the art has been to make them bear aiike, especially in great cables, and this has been the object of patent machinery. Tlie hardening^ by twisting, is also an essential part of the process of rope- making : for without this, it would be little better than ex- tended parallel fibres of hemp. In this twisting, first of the yarns, and then of the strands, those which are on the outer surface must be more stretched than those near the centre ; consequently, when there is a strain upon the rope, the outer fibres will break first, and the others in succession. It is to avoid this, that each yarn and each strand, as it is twisted or hardened, shall be itself revolving, so that when drawn into the cable, the whole component parts may, as nearly as possi- ble, resist the strain in an equal degree ; but the process is not perfect, and this we must conclude from observing how different the construction of a tendon is from that of a rope. A tendon consists of a strong cord, apparently fibrous ; but which, by the art of the anatomist, may be separated into lesser cords, and these, by maceration, can be shown to con- sist of cellular membrane, the common tissue that gives firm- ness to all the textures of the animal body. The peculiarity ihere results merely from its remarkable condensation. But the •cords of which the larger tendon consists, do not he parallel to each other, nor are they simply twisted like the strands of a rope ; they are, on the contrary, plaited or interwoven to- gether. If the strong tendon of the heel, or Achilles tendon, be taken as an example, on first inspection, it appears to consist of parallel fibres, but by maceration, these fibres are found to be a web of twisted cellular texture. If you take your handkerchief, and, slightly twisting it, draw it out like a rope, it will seem to consist of parallel cords; such is, in fact, so far the structure of a tendon. But, as we have stated, there is something more admirable than this, for the tendon consists of subdivisions, which are like the strands of a rope ; but instead of being twisted simply as by the process of hard- ening, they are plaited or interwoven in a way that could not be imitated in cordage by the turning of a wheel. Here then is the difiference — by the twisting of a rope, the strands cannot resist the strain equally, whilst we see that this is pro- vided for in the tendon by the regular interweaving of the yarn, if we may so express it, so that every fibre deviates from the parallel line in the same degree, and, consequently, receives the same strain when the tendon is pulled. If we seek for examples illustrative of this structure of the tendons, we must turn to the subject of ship-rigging, and see there how the seaman contrives, by undoing the strands and yarns of a rope, and twisting them anew, to make his splicing strong- er than the original cordage. A sailor opens the ends of two 90 OF THE MUSCLES. ropes, and places the strand of one opposite and between th6 strand of" another, and so interlaces them. And this explains wlty a hawser-rope, a sort of small cable, is spun of three strands ; for as they are necessary for many operations in the ringing of a ship, they must be formed in a way that admits of being cut and spliced, for the separation of three strands, at least, is necessary for knotting, splicing, whipping, mail- ing, &c., which are a few of the many cm-ious contrivances for joining the ends of ropes, and for strengthening them by filling up the interstices to preserve them from being cut or frayed. As these methods of splicing and plaiting in the subdivisions of the rope make an intertexture stronger than the original rope, it is an additional demonstration, if any were wanted, to show the perfection of the cordage of an animal machine, since the tendons are so interwoven; and until the yarns of one strand be separated and interwoven with the yarns of another strand, and this done with regular ex- change, the most approved patent ropes must be inferior to the corresponding part of the animal machinery. A piece of cord of a new patent has been shown to us, which is said to be many times stronger than any other cord of the same diameter. It is so far upon the principle here stated, that the strands are plaited instead of being twisted ; but the tendon has still its superiority, for the lesser yarns of each strand in it are interwoven with those of other strands. It however, gratifies us to see, that the principle we draw from the animal body is here confirmed. It may be asked, do not the tendons of the human body sometimes break ? They do ; but in circumstances which only add to the interest of the subject. By the exercise of the tendons, (and their exercise is the act of being pulled upon by the muscles, or having a strain made on them, they become tirmer and strong- er ; but in the failure of muscular activity, they become less capable of resisting the tug made upon tiiem, and if, after a long confinement, a man has some powerful excitement to muscular exertion, then the tendon breaks. An old gen- tleman, whose habits have been long staid and sedentary, and who is very guarded in his walk, is upon an annual festi- val tempted to join the young people in a dance ; then he breaks his tendo Achillis. Or a sick person, long confined to bed, is, on rising, subject to a rupture or hernia, because the tendinous expansions guarding against protrusion of the internal parts, have become weak from disuse. Such circumstances remind us that we are speaking of a living body, and that, in estimating the properties of the ma- chinery, we ought not to forget the influence of life, and that the natural exercise of the parts, whether they be active or passive, is the stimulus to tlie circulation through them, and to their growth and perfection. OF THE VESSELS, (fec. 91 CHAP. X. OF THE VESSELS OF ANIMAL BODIES. The circulation of the hlood, through the bodies of men and quadrupeds, and the apparatus by which it is carried on. compose a system, and testify a contrivance, perhaps the best understood of any part of the animal frame. The lymphatic vessels, or the nervous system, may be more sub- tile and intricate ; nay, it is possible that in their structure they may be even more artificial than the sanguiferous ; but we do not know so much about them. The utility of the circulation of the blood, I assume as an acknowledged point. One grand purpose is plainly answered by it ; the distributing to every part, every ex- tremity, every nook and corner of the body, the nourish- ment which is received into it by one aperture. What en- ters at the mouth finds its way to the fingers' end. A more difficult mechanical problem could hardly I think be pro- posed, than to discover a method of constantly repairing the waste, and of supplying an accession of substance to every part of a complicated machine at the same time. This system presents itself under two views : first, the disposition of the blood-vessels, i. e. the laying of the pipes ; and, secondly, the construction of the engine at the centre, viz. the heart, for driving the blood through them. I. The disposition of the blood-vessels, as far as regards the supply of the body, is like that of the water pipes in a city, viz. large and main trunks branching off by smaller pipes (and these again by still narrower tubes,) in every direction, and towards every part, in which the fluid, which they convey, can be wanted. So far the water pipes, which serve a town, may represent the vessels, which carry the blood from the heart. But there is another thing necessary to the blood, which is not wanted for the water; and that is, the carrying of it back again to its source. For this ofiice a reversed system of vessels is prepared, which uniting at their extremities with the extremities of the first system, collects the divided and subdivided streamlets, first by capillary ramifications into larger branch- es, secondly, by these [branches into trunks ; and thus re- turns the blood (almost exactly inverting the order in which it went out) to the fountain from whence its motion pro- ceeded. All which is evident mechanism. 92 OF THE VESSELS The body, therefore, ccnitains two systems of blood-ves- sels, arteries and veins. Between the constitution of the systems there are also two differences, suited to the func- tions which the systems have to execute. The blood, in going out, passing always from wider into narrower tubes; and, in coming back, from narrower into wider ; it is evi- dent, that the impulse and pressure upon the sides of the blood-vessels, will be much greater in one case than the other. Accordingly, the arteries which carry out the blood, are formed with much tougher and stronger coats, than the veins which bring it back. That is one difference ; the other is still more artificial, or, if I may so speak, indicates, still more clearly, the care and anxiety of the artificer. Forasmuch as in the arteries, by reason of the greater force with which the blood is urged along them, a wound or rup- ture would be more dangerous, than in the veins ; these vessels are defended from injury, not only by their texture^ but by their situation ; and by every advantage of situation which can be given to them. They are buried in sinuses, or they creep along grooves, made for them, in the bones ; for instance, the under edge of the ribs is sloped and fur- rowed solely for the passage of these vessels. Sometimes they proceed in channels, protected by stout parapets on each side ; which last description is remarkable in the bones of the fingers, these being hollowed out, on the un- der side, like a scoop, and v/ith such a concavity that the finger may be cut across to the bone without hurting the artery which runs along it. At other times, the arteries pass in canals wrought in the substance, and in the very middle of the substance, of the bone ; this takes place in the lower jaw, and is found where there would, otherwise, be danger of compression by sudden curvature. All this care is wonderful, yet not more than what the importance of the case required. To those, who venture their lives in a ship, it has been often said, that there is only an inch board between them and death ; but in the body itself, es- pecially in the arterial system, there is, in many parts, only a membrane, a skin, a thread. For which reason this sys- tem lies deep under the integuments ; whereas the veins, in which the mischief that ensues from injuring the coats is much less, lie in general above the arteries, come nearer to the surface, are more exposed. It may be further observed concerning the two systems taken together, that, though the arterial, with its trunks and branches and small twigs, may be imagined to issue or OP ANIMAL BODIES. 93 proceed, in other words to grow from the heart, like a plant from its root, or the fibres of a leaf from its foot-stalk, (which, however, were it so, would be only to resolve one mechanism into another,) yet the venal, the returning system, can never be formed in this manner. The arteries might go on shoot- ing out from their extremities, i. e. lengthening and sub- dividing indefinitely ; but an inverted system, continually uniting its streams, instead of dividing, and thus carrying back what the other system carried out, could not be refer- red to the same process. II. The next thing to be considered is the engine which works this machinery, viz. the heart. (PI. XVII. fig. 1.) For our purpose it is unnecessary to ascertain the principle upon which the heart acts. Whether it be irritation excited by the contact of tlie blood, by the influx of the nervous fluid, or whatever else be the cause of its motion, it is some- thing, which is capable of producing, in a living muscular fibre, reciprocal contraction and relaxation. This is the power we have to work with ; and the inquiry is, how this power is applied in the instance before us. There is pro- vided in the central part of the body, a hollow muscle, in- vested with spiral fibres, running in both directions, the layers intersecting one another ; in some animals, however, appearing to be semi-circular rather than spiral. By the contraction of these fibres, the sides of the muscular cavities are necessarily squeezed together, so as to force out from them any fluid which they may at that time contain ; by the relaxation of the same fibres, the cavities are in their turn dilated ; and, of course, prepared to admit every fluid which may be poured into them. Into these cavities are inserted the great trunks, both of the arteries which carry out the blood, and of the veins which bring it back. This is a general account of the apparatus ; and the simplest idea of its action is, that, by each contraction, a portion of blood is forced as by a syringe into the arteries ; and, at each dilation, an equal portion is received from the veins. This produces, at each pulse, a motion and change in the mass of blood, to the amount of what the cavity contains, which, in a full grown human heart, I understand, is about an ounce, or two table-spoons full. How quickly these changes succeed one another, and by this succession, how sufficient they are to support a stream or circulation throughout the system, may be understood by the following computation, abridged from Keill's Anatomy, p. 117. ed. 3. *' Each ven- I 2 •)4 OF THE VESSELS tricle will at least contain one ounce of blood. The heart contracts four thousand times in one hour ; from which it follows, that there passes through the heart, every hour, four thousand ounces, or three hundred and fifty pounds of blood. Now the whole mass of blood is said to be about twenty-five pounds, so that a quantity of blood equal to the whole mass of blood passes through the heart fourteen times in one hour ; wdiich is about once every four minutes." Consider what an affair this is, when we come to very large animals. The aorta of a whale is larger in the bore than the main pipe of the water works at London Bridge ; and the water roaring in its passage through that pipe, is in- ferior, in impetus and velocity, to the blood gushing from the whale's heart. Hear Dr. Hunter's account of the dis- section of a whale. " The aorta measured a foot in diame- ter. Ten or fifteen gallons of blood is thrown out of the heart at a stroke, w4th an immense velocity, through a tube of a foot diameter. The whole idea fills the mind v/ith wonder.'"* : The account which we have here stated, of the injec- tion of blood into the arteries by the contraction, and of the corresponding reception of it from the veins by the di- lation of the cavities of the heart, and of the circulation being thereby maintained through the blood-vessels of the body, is true, but imperfect. The heart performs this of- fice, but it is in conjunction with another of equal curiosi- ty and importance. It was necessary that the blood should be successively brought into contact, or contiguity, or prox- imity with the air. I do not know that the chemical rea- son, upon which this necessity is founded, has been yet sufficiently explored. It seems to be made to appear, that the atmosphere which we breathe is a mixture of two kinds of air ; one pure and vital, the other, for the purposes of life, effete, foul, and noxious : that wlien we have drawn in our breath, the blood in the lungs imbibes from the air, thus brought in contiguity with it, a portion of its pure in- gredient ; and, at the same time, gives out the effete or corrupt air which it contained, and which is carried away, along with the halitus, every time we respire. At least, by comparing the air which is breathed from the lungs, with the air before it enters the lungs, it is found to have lost some of its pure part, and to have brought away with it an addition of its impure part. Whether these experiments ' Dr, Hunter's account of the dissection of a whale. Phil. Trans. OF ANIMAL BODIES. 95 satisfy the question, as to the need which the blood stands in, of being visited by continual accesses of air, is not for us to inquire into ; nor material to our argument : it is suf- ficient to know, that, in the constitution of most animals such a necessity exists, and that the air, by some means or other, must be introduced into a near communication with the blood. The lungs of animals are constructed for this purpose. They consist of blood-vessels and air-vessels ly- ing close to each other ; and wherever there is a branch of the trachea or windpipe, there is a branch accompanying it of the vein and artery, and the air-vessel is always in the middle between the blood-vessels.* The internal surface of these vessels, upon which the application of the air to the blood depends, would, if collected and expanded, be, in a man, equal to a superfices of fifteen feet square. Now in order to give the blood in its course, the benefit of this organization, (and this is the part of the subject with which we are chiefly concerned,) the following operation takes place. As soon as the blood is received by the heart from the veins of the body, and before that it is sent out again into its arteries, it is carried, by the force of the contraction of the heart, and by means of a separate and supplementary artery, to the lungs, and made to enter the vessels of the lungs ; from which, after it has under- gone the action, whatever it be, of that viscus, it is brought back by a large vein once more to the heart, m order, when thus concocted and prepared, to be from thence distributed anew into the system. This assigns to the heart a double office. The pulmonary circulation is a system within a system ; and one action of the heart is the origin of both. For this complicated function, four cavities become ne- cessary ; and four are accordingly provided : two, call- ed ventricles, which send out the blood, viz. one into the lungs, in the first instance ; the other into the mass, after it has returned from the lungs : two others also, called auricles, which receive the blood from the veins; viz. one, as it comes immediately from the body ; the other, as the same blood comes a second time after its circulation through the lungs. So that there are two receiving cavi- ties, and two forcing cavities. The structure of the heart has reference to the lungs, for without the lungs one of each would have been sufficient. The translation of the ^Keill's Anat. p. 121. 96 OP THE VESSELS blood in the heart itself is after this manner. The receiv- ing cavities respectively communicate with the forcing cav- ities, and, by their contraction, unload the received blood into them. The forcing cavities, when it is their turn to contract, compel the same blood into the mouths of the ar- teries. The account here given will not convey to a reader ig- rant of anatomy, any thing like an accurate notion of the form, action, or use of the parts, (nor can any short and popular account do this,) but it is abundantly suffi- cient to testify contrivance ; and, although imperfect, being true as far as it goes, may be relied upon for the only purpose for which we offer it, the purpose of this con- clusion. " The wisdom of the Creator," saith Hamburgher, '' is in nothing seen more gloriously than in the heart." And how well doth it execute its office ! An anatomist, who understood the structure of the heart, might say before- hand that it would play : but he would expect, I think, from the complexity of its mechanism, and the delicacy of many of its parts, that it should always be liable to de- rangement, or that it would soon work itself out. Yet shall this wonderful machine go, night and day, for eighty years together, at the rate of a hundred thousand strokes every twenty-four hours, having, at every stroke, a great resistance to overcome ; and shall continue this action for this length of time, without disorder, and without weari- ness. But further ; from the account, which has been given of the mechanism of the heart, it is evident that it must re- quire the interposition of valves ; that the success indeed of its action must depend upon these, for when any one of its cavities contracts, the necessary tendency of the force will be to drive the enclosed blood, not only into the mouth of the artery where it ought to go, but also back again in- to the mouth of the vein from which it flowed. In like manner, when by the relaxation of the fibres the same cav- ity is dilated, the blood would not only run into it from the vein, w^hich was the course intended, but back from the ar- tery, through which it ought to be moving forward. The way of preventing a reflux of the fluid, in both these cases, is to fix valves ; which, like flood-gates, may open a way to the stream in one direction, and shut up the passage against it in another. (PI. XVII. fig. 2, 3, 4.) The heart, constitut- ed as it is, can no more work v/ithout valves than a pump OF ANIMAL BODIES. 97 can. When the piston descends in a pump, if it were not for the stoppage by the valve beneath, the motion would only thrust down the water, which it had before drawn up. A similar consequence would frustrate the action of the heart. Valves, therefore, properly disposed, i. e. properly with respect to the course of the blood which it is neces- sary to promote, are essential to the contrivance. And valv&s so disposed a?'e, accordingly, protnded. A valve \s placed in the communication between each auricle and its ventricle, lest when the venticle contracts, part of the blood should get back again into the auricle, instead of the whole entering, as it ought to do, the mouth of the artery. A valve is also fixed at the mouth of each of the great arteries which take the blood from the heart ; leaving the passage free, so long as the blood holds its proper course forward ; closing it, whenevei the blood, in consequence of the relaxation of the ventricle, would attempt to flow back. There is some variety in the construction of these valves, though all the valves of the body act nearly upon the same principle, and are destined to the same use. In general they consist of a thin membrane, lying close to the side of the vessel, and consequently allowing an open passage whilst the stream runs one way, but thrust out from the side by the fluid get- ting behind it, and opposing the passage of the blood,, when it would flow the other way. Where more than one membrane is employed, the different membranes only com- pose one valve. Their joint action fulfils the office of a valve : for instance ; over the entrance of the right auricle of the heart into the right ventricle, three of these skins or membranes are fixed, of a triangular figure ; the bases of the triangles fastened to the flesh ; the sides and sum- mits loose ; but, though loose, connected by threads of a determinate length with certain small fleshy prominences adjoining. The effect of this construction is, that, when the ventricle contracts, the blood endeavouring to escape in all directions, and amongst other directions pressing up- wards, gets between these membranes and the sides of the passage ; and thereby forces them up into such a position, as that, together, they constitute, when raised, a hollow cone (the strings before spoken of, hindering them from proceeding or separating further ;) which cone, entirely occupying the passage, prevents the return of the blood in- to the auricle. A shorter "account of the matter may be this. So long as the blood proceeds in its proper course, the membranes which compose the valve are pressed close 98 OF THE VESSELS to the side of the vessel, and occasion no impedient to the circulation ; when the blood would regurgitate, they are raised from the side of the vessel, and meeting in the middle of its cavity, shut up the channel. Can any one doubt of contrivance here ; or is it possible to shut our eyes against the proof of it ? This valve, also, is not more curious in its structure, than it is important in its office. Upon the play of the valve, even upon the proportioned length of the strings or fibres which check the ascent of the membranes, depends, as it should seem, nothing less than the life itself of the animal. We may here likewise repeat, what we before observed concerning some of the ligaments of the body, that they could not be formed by any action of the parts themselves. There are cases, in which, although good uses appear to arise from the shape or configuration of a part, yet that shape and configuration itself may seem to be produced by the action of the part, or by the action or pressure of adjoin- ing parts. Thus the bend, and the internal smooth con- cavity of the ribs, may be attributed to the equal pressure of the soft bowels ; the particular shape of some bones and joints, to the traction of the annexed muscles, or to the position of contiguous muscles. But valves could not be so formed. Action and pressure are all against them. The blood, in its proper course, has no tendency to produce such things ; and, in its improper or reflected current, has a tendency to prevent their production. Whilst we see therefore the use and necessity of this machinery, we can look to no other account of its origin or formation than the intending mind of a Creator. Nor can we without admi- ration reflect, that such thin membranes, such weak and tender instruments, as these valves are, should be able to hold out for seventy or eighty years. Here also we cannot consider but with gratitude, how happy it is that our vital motions are involuntary. We should have enough to do, if we had to keep our hearts beating, and our stomachs at work. Did these things de- pend, we will not say upon our eflfort, but upon our bidding, our care, or our attention, they would leave us leisure for nothing else. We must have been continually upon the watch, and continually in fear ; nor would this constitution have allowed of sleep. It might perhaps be expected, that an organ so precious, of such central and primary importance, as the heart is, ghQuld be defended by a case. The fact is, that a mem- OF ANIMAL BODIES. 99 branous purse or bag, made of strong tough materials, is provided for it ; holding the heart within its cavity ; sitting loosely and easily about it ; guarding its substance, without confining its motion ; and containing likewise a spoonful or two of water, just sufficient to keep the surface of the heart in a state of suppleness and moisture. How should such a loose covering be generated by the action of the heart ? Does not the enclosing of it in a sack, answering no other purpose but that of enclosure, show the care that has been taken of its preservation ? One use of the circulation of the blood (probably amongst other uses) is to distribute nourishment to the different parts of the body. How minute and multiplied the ramifi- cations of the blood-vessels, for that purpose, are ; and how thickly spread, over at least the superfices of the body, is proved by the single observation, that we cannot prick the point of a pin into the flesh, without drawing blood, i. e. without finding a blood-vessel. Nor, internally, is their diffusion less universal. Blood-vessels run along the sur- face of membranes, pervade the substance of muscles, pen- etrate the bones. Even into every tooth, we trace, through a small hole in the root, an artery to feed the bone, as well as a vein to bring back the spare blood from it ; both which, with the addition of an accompanying nerve, form a thread only a little thicker than a horse-hair. Wherefore, when the nourishment taken in at the mouth, has once reached, and mixed itself with the blood, every part of the body is in the way of being supplied with it. And this introduces another grand topic, namely, the man- ner in which the aliment gets into the blood; which is a subject distinct from the preceding, and brings us to the consideration of another entire system of vessels. I. For this necessary part of the animal economy an apparatus is provided, in a great measure, capable of being, what anatomist call, demonstrated, that is, shown in the dead body ; and a line or course of conveyance, which we can pursue by our examinations. First, The food descends by wide passages into the in- testines, undergoing two great preparations on its way, one, in the mouth by mastication and moisture, (can it be doubted with what design the teeth were placed in the road to the stomach, or that there was choice in fixing them in this situation?) The other by digestion in the stomach itself. Of this last surprising dissolution I say nothing ; because it is chemistry, and I am endeavouring to display 1 55852 100 OF THE VESSELS mechanism. The figure and position of the stomach, (I speak all along with a reference to the human organ) are calculated for detaining the food long enough for the action of its digestive juice. (PI. XVIII. fig. 1.) It has the shape of the pouch of a bag-pipe ; lies across the body ; and the pylorus, or passage by which the food leaves it, is somewhat higher in the body, than the cardia or orifice by which it enters ; so that it is by the contraction of the muscular coat of the stomach, that the contents, after having under- gone the application of the gastric menstruum, are gradually pressed out. In dogs and cats, this action of the coats of the stomach has been displayed to the eye. It is a slow and gentle undulation, propagated from one orifice of the stomach to the other. For the same reason that I omitted, for the present, offering any observation upon the digestive fluid, I shall say nothing concerning the bile or the pan- creatic juice, further than to observe upon the mechanism, viz. that from the glands in which those secretions are elaborated, pipes are laid into the first of these intestines, through which pipes the product of each gland flows into that bowel, and is there mixed with the aliment, as soon almost as it passes the stomach ; adding also as a remark, how grievously this same bile offends the stomach itself, yet cherishes the vessel that lies next to it. Secondly, We have now the aliment in the intestines, converted into pulp, and, though lately consisting of per- haps ten different viands, reduced to nearly an uniform sub- stance, and to a state fitted for yielding its essence, which is called chyle, but which is milk, or more nearly resem- bling milk than any other liquor with which it can be com^ pared. For the straining off of this fluid from the digested aliment in the course of its long progress through the body, myriads of capillary tubes, i. e. pipes as small as hairs, open their orifices into the cavity of every part of the intestines. (PI. XIX.) These tubes, which are so fine and slender as not to be visible unless when distended with chyle, soon unite into larger branches. The pipes, formed by this union, terminate in glands, iiom^ which other pipes of a still larger diameter arising, carry the chyle, from all parts into a common reservoir or receptacle. This receptacle is a bag, large enough to hold about two table spoons full ; and from this vessel a duct or main pipe proceeds, climbing up the back part of the chest, and then ereeping along the gullet till it reach the neck. Here it meets the river. Here it discharges itself into a large vein, which soon conveys OF ANIMAL BODIES. 101 the chyle, now flowing along with the old blood, to the heart. This whole route can be exhibited to the eye. Nothing is left to be supplied by imagination or conjec- ture. Now, beside the subserviency of this whole struc- ture to a manifest and necessary purpose, we may remark, two or three separate particulars in it, which show, not on- ly the contrivance, but the perfection of it. We may remark, first, the length of the intestines, which, in the human subject, is six times that of the body. Simply for a pas- sage, these voluminous bowels, this prolixity of gut,"^ seems in no wise necessary ; but, in order to allow time and space for the successive extraction of the chyle from the digested aliment, namely, that the chyle, which escapes the lacteals of one part of the guts, may be taken up by those of some other part, the length of the canal is of evident use and conduciveness. Secondly , We must also remark their peristal- tic motion ; which is made up of contractions, following one another like waves upon the surface of a fluid, and not unlike what we observe in the body of an earthworm crawl- ing along the ground ; and which is effected by the joint action of longitudinal and of spiral, or rather perhaps of a great number of separate semi-circular fibres. This cu- rious action pushes forward the grosser part of the aliment, at the same time that the more subtile parts, which we call chyle, are, by a series of gentle compression, squeezed in- to the narrow orifices of the lacteal veins. Thirdly, It was necessary that these tubes, which we denominate lac- teals, or their mouths* at least, should be made as narrow as possible, in order to deny admission into the blood to any particle, which is of size enough to make a lodgement afterwards in the small arteries, and thereby to obstruct the circulation : and it was also necessary that this extreme tenuity should be compensated by multitude ; for a large quantity of chyle (in ordinary constitutions, not less, it has been computed, than two or three quarts in a day) is, by some means or other, to be passed through them. Accord- ingly, we find the number of the lacteals exceeding all powers of computation ; and their pipes so fine and slen- der, as not to be visible, unless filled, to the naked eye ; and their orifices, which open into the intestines, so small, as not to be discernible even by the best microscope. Fourthly, The main pipe which carries the chyle from the reservoir to the blood, viz. the thoracic duct, being fixed in an almost upright position, and wanting that advantage of K 103 OF THE VESSELS propulsion which the arteries possess, is furnished with a succession of valves to check the ascending fluid, when once it has passed them, from falling back. These valves look upwards, so as to leave the ascent free, but to prevent the return of the chyle, if, for want of sufficient force to push it on, its weight should at any time cause it to de- scend. Fifthly, The chyle enters the blood in an odd place, but perhaps the most commodious place possible, viz. at a large vein in the neck, so situated with respect to the cir- culation, as speedily to bring the mixture to the heart. And this seems to be a circumstance of great moment; for had the chyle entered the blood at an artery, or at a dis- tant vein, the fluid, composed of the old and the new ma- terials, must have performed a considerable part of the cir- culation, before it received that churning in the lungs, which is, probably, necessary for the intimate and perfect union of the old blood with the recent chyle. Who could have dreamt of a communication between the cavity of the in- testines and the left great vein of the neck 1 Who could have suspected that this communication should be the me- dium through which all nourishment is derived to the body ; or this the place, where, by a side inlet, the important junc- tion is formed between the blood and the material which feeds it? II. We postponed the consideration o^ digestion, lest it should interrupt us in tracing the course of the food to the blood ; but, in treating of the alimentary system, so prin- cipal a part of the process cannot be omitted. Of the gastric juice, the immediate agent by which that change which food undergoes in our stomachs is effected, we shall take our account, from the numerous, careful, and varied experiments of the Abbe Spallanzani. 1. It is not a simple diluent, but a real solvent. A quarter of an ounce of beef had scarcely touched the sto- mach of a crow, when the solution began. 2. It has not the nature of saliva ; it has not the nature of bile ; but is distinct from both. By experiments out of the body it appears, that neither of these secretions act up- on alimentary substances, in the same manner as the gas- tric juice acts. 3. Digestion is not putrefaction ; for the digesting fluid resists putrefaction most pertinaciously ; nay, not only checks its further progress, but restores putrid substances. 4. It is not a fermentative process : for the solution begins at the surface, and proceeds towards the centre, OF ANIMAL BODIES. lOr contrary to the order in which fermentation acts an4 spreads. 5. It is not the digestion of heat ; for the cold maw of a cod or sturgeon will dissolve the shells of crabs and lob- sters, harder than the sides of the stomach which contains them. In a word, animal digestion carries about it the marks of being a power and a process, completely sui generis ; dis- tinct from every other ; at least from every chemical pro- cess with which we are acquainted. And the most wonder- ful thing about it is, its appropriation, its subserviency to the particular economy of each animal. The gastric juice of an owl, falcon, or kite, will not touch grain : no, not even to finish the macerated and half digested pulse, which is left in the crops of the sparrows that the bird devours. In poultry, the trituration of the gizzard, and the gastric juice, conspire in the work of digestion. The gastric juice will not dissolve the grain whilst it is whole. Grains of barley inclosed in tubes or spherules are not affected by it But if the same grain be by any means broken or ground, the gastric juice immediately lays hold of it. Here then is wanted, and here we find, a combination of mechanism and chemistry. For the preparatory grinding, the gizzard lends its mill. And, as all mill work should be strong, its structure is so, beyond that of any other muscle belonging to the animal. The internal coat also, or lining of the gizzard, is, for the same purpose, hard and cartilaginous. But, for- asmuch as this is not the sort of animal substance suited for the reception of glands, or for secretion, the gastric juice, in this family, is not supplied, as in membranous stomachs, by the stomach itself, but by the gullet, in which the feeding glands are placed, and from which it trickles down into the stomach. In sheep, the gastric fluid has no effect in digesting plants unless they have been previously masticated. It only produces a slight maceration ; nearly such as common wa- ter would produce, in a degree of heat somewhat exceed- ing the medium temperature of the atmosphere. But, pro- vided that the plant has been reduced to pieces by chewing, the gastric juice then proceeds with it, first by softening its substance ; next by destroying its natural consistency ; and lastly, by dissolving it so completely, as not even to spare the toughest and most stringy parts, such as the nerves of the leaves. 104 OF THE VESSELb- f So far our accurate and indefatigable Abbe. Dr. Ste- vens, of Edinburgh, in 1777, found by experiments tried with perforated balls, that the gastric juice of the sheep and the ox speedily dissolved vegetables, but made no impres- sion upon beef, mutton, and other animal bodies. Dr. Hun- ter discovered a property of this fluid, of a most curious kind ; viz. that, in the stomachs of animals which feed up- on flesh, irresistibly as this fluid acts upon animal substan- ces, it is only upon the dead substance, that it operates at all. The living fibre suffers no injury from lying in con- tact with it. Worms and insects are found alive in the stomachs of such animals. The coats of the human stomach in a healthy state, are insensible to its presence ; yet, in cases of sudden death, (wherein the gastric juice, not having been weakened by disease, retains its activity,) it has been known to eat a hole through the bowel which contains it.* How nice is this discrimination of action, yet how necessary ! But to return to our hydraulics. III. The gall bladder is a very remarkable contrivance. It is the reservoir of a canal. (PI. XVIII. fig. 1, 2.) It does not form the channel itself, i. e. the direct communi- cation between the liver and the intestines, which is by an- other passage, viz. the ductus hepaticus, continued under the nan^e of the ductus communis ; but it lies adjacent to this channel, joining it by a duct of its own, the ductus cysticus ; by which structure it is enabled, as occasions may require, to add its contents to, and increase, the flow of bile into the duodenum. And the position of the gall bladder is such as to apply this structure to the best advan- tage. In its natural situation it touches the exterior sur- face of the stomach, and consequently is compressed by the distension of that vessel : the effect of which compression is, to force out from the bag, and send into the duodenum, an extraordinary quantity of bile, to meet the extraordinary demand which the repletion of the stomach by food is about to occasion.! Cheselden describes"! the gall bladder as seated against the duodenum, and thereby liable to have its fluid pressed out, by the passage of the aliment through that cav- ity ; which likewise will have the effect of causing it to' be received into the intestine, at a right time, and in a due proportion. ^ Phil. Trans, vol. Ixii. p, 447. t Keill's Anat. p. 64. I Anat. p. 164. OF ANIMAL BODIES. 105 There may be other purposes answered by this contri- vance ; and it is probable, that there are. The contents of the gall bladder are not exactly of the same kind as what passes from the liver through the direct passage.* It is possible that the gall may be changed, and, for some purpo- ses, meliorated by keeping. The entrance of the gall duct into the duodenum furnish- es another observation. Whenever either smaller tubes are inserted into larger tubes, or tubes into vessels and cavi- ties, such receiving tubes, vessels, or cavities, being subject to muscular constriction, we always find a con- trivance to prevent regurgitation. In some cases, valves are used ; in other cases, amongst which is that now before us, a different expedient is resorted to : which may be thus described. The gall duct enters the duodenum obliquely : after it has pierced the first coat, it runs near two fingers breadth between the coats, before it opens into the cavity of the intestine. t The same contrivance is used in another part, where there is exactly the same occasion for it, viz. in the insertion of the ureters into the bladder. These enter the bladder near its neck, running obliquely for the space of an inch between its coats.| It is, in both cases, sufficiently evident, that this structure has a necessary mechanical tendency to resist regurgitation ; for whatever force acts in such a direction as to urge the fluid back into the orifices of the tubes, must, at the same time, stretch the coats of the vessels, and thereby compress that part of the tube, which is included between them. IV. Amongst the vessels of the human body, the^pipe which conveys the saliva from the place where it is made, to the place where it is wanted, deserves to be reckoned amongst the most intelligible pieces of mechanism with which we are acquainted. (PI. XX. fig. 1, 2.) The saliva, we all know, is used in the mouth; but much of it is manufactured on the outside of the cheek, by the parotid gland, which lies between the ear and the angle of the low- er jaw. In order to carry the secreted juice to its destina- tion, there is laid from the gland on the outside, a pipe, about the thickness of a wheat straw, and about three fin- gers breadth in length ; which, after riding over the masse- ter iiiuscle, bores for itself a hole through the very middle * Keill's from Malpighius, p. 62. IKeill's Anat. p. 62 t Ches, Anat. p. 260. K 2 10^ OF THE VESSELS of the cheek ; enters by that hole, which is a complete per- foration of the buccinator muscle, into the moutli ; and tliere discharges its fluid very copiously. V. Another exquisite structure, differing indeed from the four preceding instances, in that it does not relate to the conveyance of fluids, but still belonging, like these, to the class of pipes or conduits of the body, is seen in the larynx. (PI. XXI. fig. 1, 2.) We all know, that there go down the throat two pipes, one leading to the stomach, the other to the lungs ; the one being the passage for the food, the other for the breath and voice : we know also that both these passages open into the bottom of the mouth ; the gullet, necessarily, for the conveyance of the food ; and the wind- pipe, for the speech and the modulation of sound, not much less so : therefore, the difficulty was, the passages being so contiguous, to prevent the food, especially the liquids, which we swallow into the stomach, from entering the wind-pipe, i. e. the road to the lungs ; the consequence of which er- ror, when it does happen, is perceived by the convulsive throes that are instantly produced. This business, which is very nice, is managed in this manner. The gullet (the passage for food) opens into the mouth like the cone or upper part of a funnel, the capacity of which forms indeed the bottom of the mouth. Into the side of this funnel, at the part which lies the lowest, enters the wind-pipe, by a chink or slit, with a lid or flap, like a little tongue, accu- rately fitted to the orifice. The solids or liquids which we swallow, pass over this lid or flap, as they descend by the funnel into the gullet. Both the weight of the food, and the action of the muscles concerned in swallowing, con- tribute to keep the lid close down upon the aperture, whilst any thing is passing ; whereas, by means of its natural car- tilaginous spring, it raises itself a little, as soon as the food is passed, thereby allowing a free inlet and outlet for the respiration of air by the lungs. And we may here remark the almost complete success of the expedient, viz. how sel- dom it fails of its purpose, compared with the number of in- stances in which it fulfils it. Reflect, how frequently we swallow, how constantly we breathe. In a city feast, for example, what deglutition, what anhelation ! yet does this little cartilage, the epiglottis, so effectually interpose its of- fice, so securely guard the entrance of the wind-pipe, that, whilst morsel after morsel, draught after draught, are cours- ing one another over it, an accident of a crumb or a drop slipping into this passage, (which nevertheless must be OP ANIMAL BODIES. 107 opened for the breath every second of time,) excites, in the whole company, not only alarm by its danger, but surprise by its novelty. Not two guests are choked in a century.* There is no room for pretending, that the action of the parts may have gradually formed the epiglottis : I do not mean in the same individual, but in a succession of genera- tions. Not only the action of the parts, has no sach ten- dency, but the animal could not live, nor consequently the parts act, either without it, or with it, in a half formed state. The species was not to wait for the gradual formation or expansion of a part, which was, from the first, necessary to the life of the individual. Not only is the larynx curious, but the whole wind-pipe possesses a structure, adapted to its peculiar office. It is made up, (as any one may perceive by putting his fingers to his throat) — of stout cartilaginous ringlets, placed at small and equal distances from one another. Now this is not the case with any other of the numerous conduits of the body. The use of these cartilages is to keep the pas- sage for the air constantly open ; which they do mechanic- ally. A pipe with soft membranous coats, liable to col- lapse and close when empty, would not have answered here ; although this be the general vascular structure, and a structure which serves very well for those tubes, which are kept in a state of perpetual distension by the fluid they in- close, or which afford a passage to solid and protruding substances. Nevertheless, (which is another particularity well worthy of notice,) these rings are not complete, that is, are not car- tilaginous and stiff all round ; but their hinder part, which is contiguous to the gullet, is membranous and soft, easily yielding to the distensions of that organ occasioned by the descent of solid food. The same rings are also bevelled olT * The same general structure of these parts is found in all other aiumals of the same class with mankind, but there is a singular varia- tion from it in the elephant, by which, if possible, the influence of a de- riving intelligence is more wonderfully exemplified than in the ordi- nary structure. It is well known that this animal drinks by sucking up the liquid into its trunk, and then after thursting the end of it into its mouth, blowing the liquid into its throat. In this case, the act of blowing through the trunk and swallowing, must be both going on at the same instant, and not in successive instants as in man. The liquid must be passing down the throat, while the epiglottis is open and the air issuing. In order to provide against interference, a channel is pro- vided on each side of the epiglottis, along which the drink passes quietly on, without running into the wind pipe. Ed. 108 OF THE VESSELS at the upper and lower edges, the better to close upon one another, when the trachea is compressed or shortened. The constitution of the trachea may suggest likewise an- other reflection. The membrane which lines its inside, is, perhaps, the most sensible, irritable, membrane of the body. It rejects the touch of a crumb of bread, or a drop of water, with a spasm which convulses the whole frame ; yet, left to itself, and its proper office, the intromission of air alone, nothing can be so quiet. It does not even make itself felt ; a man does not know that he has a trachea. This capaci- ty of perceiving with such acuteness ; this impatience of offence, yet perfect rest and ease when let alone ; are pro- perties, one would have thought, not likely to reside in the same subject. It is to the junction, however, of these al- most inconsistent qualities, in this as well as in some other delicate parts of the body, that we owe our safety and our comfort ; our safety to their sensibility, our comfort to their repose. The larynx, or rather the whole wind-pipe taken together, (for the larynx is only the upper part of the wind-pipe,) be- sides its other uses, is also a musical instrument, that is to say, it is mechanism expressly adapted to the modulation of sound ; for it has been found upon trial, that, by relaxing or tightening the tendinous bands at the extremity of the wind-pipe, and blowing in at the other end, all the cries and notes might be produced of which the living animal was capable. It can be sounded, just as a pipe or flute is sounded. Birds, says Bonnet, have, at the lower end of the wind-pipe, a conformation like the reed of a hautboy, for the modulation of their notes. A tuneful bird is a ven- triloquist. The seat of the song is in the breast. (PI. XXI. fig. 3.) The use of the lungs in the system has been said to be obscure ; one use however is plain, though, in some sense, external to the system, and that is, the formation, in con- junction with the larynx, of voice and speech. They are, to animal utterance, what the bellows are to the organ. For the sake of method, we have considered animal bo- dies under three divisions, their bones, their muscles, and their vessels ; and we have stated our observations upon these parts separately. But this is to diminish the strength of the argument. The wisdom of the Creator is seen, not OF ANIMAL BODIES, 109 in their separate but their collective action ; in their mutual subserviency and dependence : in their contributing togeth- er to one effect, and one use. It has been said, that a man cannot lift his hand to his head without finding enough to convince him of the existence of a God. And it is well said ; for he has only to reflect, familiar as this action is, and simple as it seems to be, how many things are requisite for the performing of it : how many things which we un- derstand, to say nothing of many more, probably, which we do not ; viz. first, a long, hard, strong cylinder, in order to give to the arm its firmness and tension \ but which, being rigid, and in its substance, inflexible, can only turn upon joints ; secondly, therefore, joints for this purpose, one at the shoulder to raise the arm, another at the elbow to bend it ; these joints continually fed with a soft mucilage to make the parts slip easily upon one another, and held together by strong brakes to keep them in their position : then, thirdly, strings and wires, i. e. muscles and tendons, artificially inserted for the purpose of drawing the bones in the directions in which the joints allow them to move. Hitherto we seem to understand the mechanism pretty well ; and understanding this, we possess enough for our conclu- sion ; nevertheless, we have hitherto only a machine stand- ing still, a dead organization, an apparatus. To put the system in a state of activity (to set it at work) a further provision is necessary, viz. a communication with the brain by means of nerves. We know the existence of this com- munication, because we can see the communicating threads, and can trace them to the brain ; its necessity we also know, because, if the thread be cut, if the communication be intercepted, the muscle becomes paralytic ; but beyond this we know little ; the organization being too minute and subtile for our inspection. To what has been enumerated, as officiating in the single act of a man's raising his hand to his head, must be added, likewise, all that is necessary, and all that contributes, to the growth, nourishment, and sustentation of the limb, the re- pair of its waste, the preservation of its health ; such as the circulation of the blood through every part of it ; its lym- phatics, exhalants, absorbents ; its excretions and integu- ments. All these share in the result ; join in the effect ; and how all these, or any of them come together without a designing, disposing intelligence, it is impossible to con- eeive. 110 OF THE ANIMAL STRUCTURE CHAP. XI. OF THE ANIMAL STRUCTURE REGARDED AS A MAgg. Contemplating an animal body in its collective ca- pacity, we cannot forget to notice, what a number of in- struments are brought together, and often within how small a compass. In a Canary bird, for instance, and in the ounce of matter which composes its body, (but which seems to be all employed,) we have instruments for eating, for digesting, for nourishment, for breathing, for generation, for running, for flying, for seeing, for hearing, for smelling ; €ach appropriate,each entirely different from all the rest. The human, or indeed the animal frame, considered as a mass or assemblage, exhibits in its composition three properties, which have long struck my mind, as indubita- ble evidences, not only of design, but of a great deal of at- tention and accuracy in prosecuting the design. I. The first is, the exact correspondency of the two sides of the same animal ; the right hand answering to the left, leg to leg, eye or eye, one side of the countenance to the other ; and with a precision, to imitate which in any tolerable degree, forms one of the difficulties of statuary, and requires, on the part of the artist^ a constant attention to this property of his work, distinct from every other. It is the most difficult thing that can be to get a wig made even ; yet how seldom is the face awry ? And "what care is taken that it should not be so, the anatomy of its bones demonstrates. The upper part of the face is com- posed of thirteen bones, six on each side, answering each to each, and the thirteenth, without a fellow, in the mid- dle ; the lower part of the face is in like manner composed of six bones, three on each side, respectively corresponding, and the lower jaw in the centre. In building an arch, could more be done in order to make the curve true'^. i. e. the parts equi-distant from the middle, alike in figure and po- sition. The exact resemblance of the eyes, considering how compound this organ is in its structure, how various and how delicate are the shades of colour with which its iris is tinged, how differently, as to effect upon appearance, the eye may be mounted in its socket, and how differently in different heads eyes actually are set, is a property of ani- mal bodies much to be admired. Of ten thousand eyes, I do not know that it would be possible to match one, except REGARDED AS A MASS. 11 1 with its own fellow ; or to distribute them into suitable pairs by any other selection than that which obtains. This regularity of the animal structure is rendered more remarkable by the three following considerations. First, the limbs, separately taken, have not this correlation of parts ; but the contrary of it. A knife drawn down the chine cuts the human body into two parts, externally equal and alike ; you cannot draw a straight line which Avill di- vide a hand, a foot, the leg, the thigh, the cheek, the eye, the ear, into two parts equal and alike. Those parts which are placed upon the middle or partition line of the body, or which traverse that line, as the nose, the tongue, the lips, may be so divided, or, more properly speaking, are double organs ; but other parts cannot. This shows that the cor- respondency which we have been describing, does not arise by any necessity in the nature of the subject ; for, if necessary, it would be universal, whereas it is observed only in the system or assemblage ; it is not true of the separate parts ; that is to say, it is found where it conduces to beau- ty or utility ; it is not found, where it would subsist at the expense of both. The two wings of a bird always corres- pond ; the two sides of a feather frequently do not. In cen- tipedes, millepedes, and the whole tribe of insects, no two legs on the same side are alike ; yet there is the most exact parity between the legs opposite to one another. 2. The next circumstance to be remarked, is, that, whilst the cavities of the body are so configurated, as externally, to exhibit the most exact correspondency of the opposite sides, the contents of these cavities have no such corres- pondency. A line drawn down the middle of the breast divides the thorax into two sides exactly similar ; yet these two sides enclose very different contents. The heart lies on the left side ; a lobe of the lungs on the right ; balancing each other, neither in size nor shape. The same thing holds of the abdomen. The liver lies on the right side, without any similar viscus opposed to it on the left. The spleen indeed is situated over against the liver ; but agree- ing with the liver, neither in bulk nor form. There is no equipollency between these. The stomach is a vessel, both irregular in its shape, and oblique in its position. The fold- ings and doublings of the intestines do not present a parity of sides. Yet that symmetry which depends upon the cor- relation of the sides, is externally preserved throughout the whole trunk ; and is the more remarkable in the lower parts of it, as the integumonts are soft ; and the shape, consequent- 112 OF THE ANIMAL STRUCTURE ly, is not, as the thorax is by its ribs, reduced by natural stays. It is evident, therefore, that the external proportion does not arise from any equality in the shape or pressure of the internal contents. What is it indeed but a correc- tion of inequalities 1 an adjustment, by mutual compensa- tion of anomalous forms into a regular congeries ? the ef- fect, in a word, of artful, and, if we might be permitted so to speak, of studied collocation ? 3. Similar also to this, is the third observation ; that, an, internal inequality in the feeding vessels is so managed, as to produce no inequality in parts which were intended to correspond. The right arm answers accurately to the left, both in size and shape ; but the arterial branches, which supply the two arms, do not go off from their trunk, in a pair, in the same manner, at the same place, or at the same angle. Under which want of similitude, it is very difficult to conceive how the same quantity of blood should be pushed through each artery ; yet the result is right : the two limbs, which are nourished by them, perceive no difference of supply, no effects of excess or deficien- cy. Concerning the difference of manner, in which the sub- clavian and carotid arteries, upon the different sides of the body, separate themselves from the aorta, Chesselden seems to have thought, that the advantage which the left gain by going off at a much acuter angle than the right, is made up to the right by their going off together in one branch.* It is very possible that this may be the compen- sating contrivance : and, if it be so, how curious, how hy- drostatical ! II. Another perfection of the animal mass is the pack- age. I know nothing which is so surprising. Examine the contents of the trunk of any large animal. Take no- tice how soft, how tender, how intricate they are ; how constantly in action, how necessary to life. Reflect upon the danger of any injury to their substance, any derange- ment of their position, any obstruction to their office. Ob- serve the heart pumping at the centre, at the rate of eighty strokes in a minute : one set of pipes carrying the stream away from it, another set, bringing, in its course, the fluid back to it again : the lungs performing their elaborate of- fice, viz. distending and contracting their many thousand vesicles, by a reciprocation which cannot cease for a min- * Ches. Anat. p. 184. ed. 7. REGARDED AS A MASS. 113 ute : the stomach exercising its powerful chemistry : the bowels silently propelling the changed aliment ; collecting from it, as it proceeds, and transmitting to the blood an incessant supply of prepared and assimilated nourishment ; that blood pursuing its course; the liver, the kidneys, the pancreas, the parotid, with many other known and dis- tinguishable glands, drawing off from it, all the while, their proper secretions. These several operations, togeth- er with others more subtile but less capable of being inves- tigated, are going on within us, at one and the same time. Think of this ; and then observe how the body itself, the case which holds this machinery, is rolled, and jolted, and tossed about, the mechanism remaining unhurt, and with very little molestation even of its nicest motions. Observe a rope dancer, a tumbler, or a monkey ; the sudden inversions and contortions which the internal parts sustain by the postures into which their bodies are thrown ; or rather observe the shocks, which these parts, even in ordinary subjects, some- times receive from falls and bruises, or by abrupt jerks and twists, without sensible, or with soon recovered damage. Observe this, and then reflect how firmly every part must be secured, how carefully surrounded, how well tied down and packed together. This property of animal bodies has never, I think, been considered under a distinct head, or so fully as it deserves. I may be allowed, therefore, in order to verify my observa- tion concerning it, to set forth a short anatomical detail, though it oblige me to use more technical language, than I should wish to introduce into a work of this kind. 1. The heart (such care is taken of the centre of life) is placed between two soft lobes of the lungs : is tied to the mediastinum and to the pericardium, which pericardium is not only itself an exceedingly strong mem.brane, but adheres firmly to the duplicature of the mediastinum, and, by its point, to the middle tendon of the diaphragm. The heart is also sustaiiied in its place by the great blood-vessels which issue from it.* 2. The lungs are tied to the sternum by the mediasti- num, before ; to the vertebrse by the pleura, behind. It seems indeed to be the very use of the mediastinum (which is a membrane that goes straight through the middle of the thorax, from the breast to the back) to keep the contents * Keill's Anat. p. 107. ed. 3. L 114 OF THE ANIMAL STRUCTURE of the tliorax in their places ; in particular to hinder one lobe of the lungs from incommoding another, or the parts of the lungs from pressing upon each other when we lie on one side.* 3. The liver is fastened in the bod}^ by two ligaments ; the first, which is large and strong, comes from the cover- ing of the diaphragm, and penetrates the substance of the liver; the second is the umbilical vein, which, after birth, degenerates into a ligament. The first, which is the prin- cipal, fixes the liver in its situation, whilst the body holds an erect posture ; the second prevents it from pressing up- on the diaphragm when we lie down ; and both togethei' sling or suspend the liver when we lie upon our backs, so that it may not compress or obstruct the ascending vena cava,t to which belongs the important office of returning the blood from the body to the heart. 4. The bladder is tied to the navel by the urachus trans- formed into a ligament ; thus what was a passage for the urine to the foetus, becomes after birth, a support or stay to the bladder. The peritonaeum also keeps the viscera from confounding themselves with, or pressing irregularly upon the bladder ; for the kidneys and bladder are contain- ed in a distinct duplicature of that membrane, being there- by partitioned off from the other contents of the abdomen. 5. The kidneys are lodged in a bed of fat. 6. The imncrcas or sweetbread is strongly tied to the peritonaeum, which is the great WTapping sheet, that en- closes all the bowels contained in the lower belly. J 7. The spleen also is confined to its place by an adhe- sion to the peritonaeum and diaphragm, and by a connexion v/ith the omentum. § It is possible, in my opinion, that the spleen may be merely a stuffings a soft cushion, to fill up a vacancy or hollow, which, unless occupied, would leave the package loose and unsteady ; for supposing that it answers no other purpose than this, it must be vascular, and admit of a circulation through it, in order to be kept alive, or be a part of a living body. 8. The omentum, epiploon, or caul, is an apron, tuck- ed up, or doubling upon itself, at its lowest part. The up- per edge is tied to the bottom of the stomach, to the spleen, as hath already been observed, and to part of the duode- num. The reflected edge also, after forming a doubling, * Keill's Anat. p. 119. ed. 3. t Ches. Anat. p. 162. t-Keill's Anat. p. 57. § Ches. Anat. p. 167. REGARDED AS A MASS. 115 comes up behind the front flap, and is tied to the colon and adjoining viscera.* 9. The septa of the brain, probably, prevent one part of that organ from pressing with too great a weight upon another part. The processes of the dura mater divide the cavity of the scull, like so many inner partition walls; and thereby confine each hemisphere and lobe of the brain to the chamber which is assigned to it, without its being liable to rest apon, or intermix with, the neighbouring parts. The great art and caution of packing is to prevent one thing hurting another. This, in the head, the chest, and the abdomen, of an animal body, is, amongst other methods, provided for, by membranous partitions and wrappings, which keep the parts separate. The above may serve as a short account of the manner in which the principal viscera are sustained in their places. But, of the provisions for this purpose, by far, in my opin- ion, the most curious, and where also such a provision was most wanted, is in the guts. It Ls pretty evident, that a long narrow tube (in man about five times the length of the body) laid from side to side in folds upon one another, winding in oblique and circuitous directions, composed al- so of a soft and yielding substance, must, without some ex- traordinary precaution for its safety, be continually displac- ed by the various, sudden, and abrupt motions of the body which contains it. I should expect, that, if not bruised or wounded by every fall, or leap, or twist, it would be entan- gled, or be involved with itself: or, at the least, slipped and shaken out of the order in which it is disposed, and which order is necessary to be preserved for the carrying on of the important functions, which it has to execute in the ani- mal economy. Let us see therefore how a danger so seri- ous, and yet so natural to the length, narrowness, and tubu- lar form of the part, is provided against. The expedient is admirable, and it is this. The intestinal canal, through- out its whole process, is knit to the edge of a broad fat membrane, called the mesentery. It forms the margin of this mesentery, being stitched and fastened to it like the edging of a ruffle ; being four times as long as the mesen- tery itself, it is, what a sempstress would call, ''gathered on" to it. This is the nature of the connexion of the gut with the mesentery : and being thus joined to, or rather made a part of the mesentery, it is folded and wrapped up " Ches. Anat. p. 149. 116 OF THE ANIxMAL STRUCTURE together with it. Now the mesentery, having a considera- ble dimension in breadth, being in its substance withal, both thick and suety, is capable of a close and safe folding, in comparison of what the intestinal tube would admit of, if it had remained loose. The mesentery likewise not only keeps the intestinal canal in its proper place and position under all the turns and windings of its course, but sustains the numberless small vessels, the arteries, the veins, the lympheducts, and, above all, the lacteals, which lead from or to almost every point of its coats and cavity. This membrane, which appears to be the great support and se- curity of the alimentary apparatus, is itself strongly tied to the first three vertebrae of the loins.* III. A third general property of animal forms is beauty, I do not mean relative beauty, or that of one individual above another of the same species, or of one species com- pared with another species ; but I mean generally, the pro- vision which is made in the body of almost every animal,, to adapt its appearance to the perception of the animals with which it converses. In our own species, for example^ only consider what the parts and materials are, of which the fairest body is composed ; and no further observation will be necessary to show, how well these things are wrap- ped up so as to form a mass, which shall be capable of symmetry in its proportion, and of beauty in its aspect ; how the bones are covered, the bowels concealed, the rough- nesses of the muscles smoothed and softened ; and how over the whole is drawn an integument w^hich converts the disgusting materials of a dissecting-room into an object of attraction to the sight, or one, upon which it rests, at least, with ease and satisfaction. Much of this effect is to be at- tributed to the intervention of the cellular or adipose mem- brane, which lies immediately under the skin ; is a kind of lining to it; is moist, soft, slippery, and compressible; every where filling up the interstices of the muscles, and forming thereby their roundness and flowing line, as well as the evenness and polish of the whole surface. All which seems to be a strong indication of design, and of a design studiously directed to this purpose. And it be- ing once allowed, that such a purpose existed with respect to any of the productions of nature, we may refer, with a considerable degree of probability, other particulars to the same intention ; such as the tints of flowers, the plumage * Keill's Anat. p. 45. REGARDED AS A MASS. 117 of birds, the furs of beasts, the bright scales of fishes, the painted wings of butterflies and beetles, the rich colours and spotted lustre of many tribes of insects. There are parts also of animals ornamental, and the properties by which they are so, not subservient, that we know of, to any other purpose. The irides of most ani- mals are very beautiful, without conducing at all, by their beauty, to the perfection of vision ; and nature could in no part have employed her pencil to so much advantage, be- cause no part presents itself so conspicuously to the ob- server, or communicates so great an effect to the whole as- pect. In plants, especially in the flowers of plants, the princi- ple of beauty holds a still more considerable place in their composition ; is still more confessed than in animals. Why, for one instance out of a thousand, does the corolla of the tulip when advanced to its size and maturity, change its colour 1 The purposes, so far as we can see, of vegeta- ble nutrition, might have been carried on as well by con- tinuing green. Or, if this could not be, consistently with the progress of vegetable life, why break into such a varie- ty of colours ? This is no proper effect of age, or of declen- sion in the ascent of the sap ; for that, like the autumnal tints, would have produced one colour in one leaf, with marks of fading a.nd withering. It seems a lame account to call it, as it has been called, a disease of the plant. Is it not more probable, that this property, which is indepen- dent, as it should seem, of the wants and utilities of the plant, was calculated for beauty, intended for display 1 A ground, I know, of objection, has been taken against this whole topic of argument, namely, that there is no such thing as beauty at all : in other words, that whatever is useful and familiar comes of course to be thought beauti- ful ; and that things appear to be so, only by their alliance with these qualities. Our idea of beauty is capable of be- ing so modified by habit, by fashion, by the experience of advantage or pleasure, and by associations arising out of ^ that experience, that a question has been made whether it be not altogether generated by these causes, or would have any proper existence without them. It seems, however a carrying of the conclusion too far, to deny the existence of the principle, viz. a native capacity of perceiving beauty, on account of the influence, or the varieties proceeding from that influence, to which it is subject ; seeing that prin- L 2 118 OF THE ANIMAL STRUCTURE ciples the most acknowledged, are liable to be affected in the same manner. I should rather argue thus ; ihe ques- tion respects objects of sight. Now every other sense hath its distinction of agreeable and disagreeable. Some tastes offend the palate, others gratify it. In brutes and insects, this distinction is stronger, and more regular, than in man. Every horse, ox, sheep, swine, when at liberty to choose, and when in a natural state, that is, when not vitiated by habits forced upon it, eats and rejects the same plants. Many insects which feed upon particular plants, will rather die than change their appropriate leaf All this looks like a determination in the sense itself to particular tastes. In like manner, smells affect the nose with sensations pleasur- able or disgusting. Some sounds, or compositions of sound, delight the ear, others torture it. Habit can do much in all these cases, (and it is well for us that it can ; for it is this power which reconciles us to many necessities,) but has the distinction, in the mean time, of agreeable and disa- greeable, no foundation in the sense itself] What is true of the other senses, is most probably true of the eye, (the anal- ogy is irresistible) viz. that there belongs to it an original constitution, fitted to receive pleasure from some impres- sions, and pain from others. I do not however know that the argument which al- leges beauty as a final cause, rests upon this concession. We possess a sense of beauty, however we come by it. It in fact exists. Things are not indifferent to this sense ; all objects do not suit it ; many, which we see, are agree- able to it, many others disagreeable. It is certainly not the effect of habit upon the particular object, because the most agreeable objects are often the most rare ; many, which are very common, continue to be offensive. If they be made supportable by habit, it is all which habit can do ; they never iDecome agreeable. If this sense, therefore, be acquired, it is a result ; the produce of numerous and com- plicated actions of external objects upon the senses, and of the mind upon its sensations. With this result there must be a certain congruity to enable any particular ob- ject to please; and that congruity, we contend, is con- sulted in the aspect which is given to animal and vegetable bodies. IV. The skin and covering of animals is that upon which their appearance chiefly depends, and it is that part which, perhaps, in all animals is most decorated ; and most free from impurities. But were beauty, or agreeableness REGARDED AS A MASS. 119 of aspect, entirely out of the question, there is another purpose answered by this integument, and by the colloca- tion of the parts of the body beneath it, which is of still greater importance ; and that purpose is concealment. Were it possible to view through the skin the mechanism of our bodies, the sight would frighten us out of our wits. " Durst we make a single movement," asks a lively French writer, " or stir a step from the place we were in, if we saw our blood circulating, the tendons pulling, the lungs blow- ing, the humours filtrating, and all the incomprehensible assemblage of fibres, tubes, pumps, valves, currents, piv- ots, which sustain an existence, at once so frail and so pre- sumptuous ?" V. Of animal bodies, considered as masses, there is another property, more curious than it is generally thought to be ; which is the faculty of ^^a/icZZ/zo-; and it is more remarkable in two-legged animals than in quadrupeds, and most of all, as being the tallest, and resting upon the small- est base, in man.* There is more, I think, in the matter, than we are aware of. The statue of a man, placed loose upon its pedestal, would not be secure of standing half an hour. You are obliged to fix its feet to the block by bolts and solder, or the first shake, the first gust of wind, is sure to throw it down. Yet this statue shall express all the mechanical proportions of a living model. It is not there- fore the mere figure, or merely placing the centre of grav- ity Vv^ithin the base, that is sufficient. Either the law of gravitation is suspended in favour of living substances, or something more is done for them, in order to enable them to uphold their posture. There is no reason whatever to doubt, but that their parts descend by gravitation in the same manner as those of dead matter. The gift there- fore appears to me to consist, in a faculty of perpetually shifting the centre of gravity, by a set of obscure indeed, but of quick, balancing actions, so as to keep the line of direction, which is a line drawn from that centre to the * Anatomy explains the mode in which the weight of the body is transmitted to the feet ; the muscles which prevent the head from fall- ing forward in standing, have their fixed point in the neck ; those which perform the same office with regard to the vertebral column, have theirs in the pelvis ; those which preserve the pelvis in equi- librium are attached to the thighs, or to the bones of the legs; those which prevent the thighs from falling backward are inserted into the tibia; and lastly, those that preserve the tibia in their verti* cal position have their fixed point in the feet ; these preserve us firm ia a standing position. Fawton, 120 Of THE ANIMAL STRUCTURE ground, within its prescribed limits. Of these actions it may be observed, first, that they in part constitute what we call strength. The dead body drops down. The mere adjustment, therefore, of weight and pressure, which may be the same the moment after death as the moment before, does not support the column. In cases also of extreme weakness the patient cannot stand upright. Secondly ; that these actions are only in a small degree voluntary. A man is seldom conscious of his voluntary powers in keep- ing himself upon his legs. A child learning to walk is the greatest posture-master in the world ; but art, if it may be so called, sinks into habit ; and he is soon able to poise himself in a great variety of attitudes without being sen- sible either of caution or effort. But still there must be an aptitude of parts upon which habit can thus attach ; a previous capacity of motion which the animal is thus taught to exercise, and the facility with which this exercise is acquired, forms one object of our admiration. What parts are principally employed, or in what manner each contributes its office is, as hath already been confessed, difficult to explain. Perhaps the obscure motion of the bones of the feet may have their share in this effect. They are put in action by every slip or vacillation of the body, and seem to assist in restoring its balance. Certain it is, that this circumstance in the structure of the foot, viz. its being composed of many small bones, applied to, and articulating with one another, by diversely shaped sur- faces, instead of being made of one piece, like the last of a shoe, is very remarkable.* I suppose also that it would be difficult to stand firm upon stilts or wooden legs, though their base exactly imitated the figure and dimensions of the sole of the foot. The alternation of the joints, * There is no part of the human frame which is more wonderfully con- structed than the foot. It has the requisite strcnoth to support the weight of the body, and often an additional burden; llexibility, that it may be adapted to the inequaUties of the surface on wliichwe tread ; and elas- ticity, to assist in walking, running, and springing from the ground. This advantage we possess from the number of joints, the arch of the foot being composed of twenty-six bones. These bones have a con- siderable play on each other ; and as each articulating surface is cover- ed with cartilage, the essential property of which is elasticity, the jarring is thus prevented which would result from a contact of the bones. "The first question which naturally arises, is. Why there should be so many bones ? The answer is — In order that there may be so many joints; for the structure of a joint not only permits motion, but bestows elasticity." _ Paxton. REGARDED AS A MASS. 121 the knee joint bending backward, the hip joint forward ; the flexibility, in every direction, of the spine, especially in the loins and neck, appear to be of great moment in preserving the equilibrium of the body. With respect to this last circumstance it is observable, that the vertebrae are so confined by ligaments as to allow no more slipping upon their bases, than what is just sufficient to break the shock which any violent motion may occasion to the body. A certain degree also of tension of the sinews appears to be essential to an erect posture ; for it is by the loss of this, that the dead or paralytic body drops down. The whole is a won- derful result of combined powers, and of very complicated operations. We have said that this property is the most worthy of observation in the human body : but a bird, resting upon its perch, or hopping upon a spray, affords no mean speci- men of the same faculty. A chicken runs off as soon as it is hatched from the egg ; yet a chicken, considered geo- metrically, and with relation to its centre of gravity, its line of direction, and its equilibrium, is a very irregular solid. Is this gift, therefore, or instruction ? May it not be said to be with great attention, that nature hath balanc- ed the body upon its pivots 1 I observe also in the same bird a piece of useful me- chanism of this kind. In the trussingof a fowl, upon bend* ing the legs and thighs up towards the body, the cook find's that the claws close of their own accord. Now let it be remembered, that this is the position of the limbs, in which the bird rests upon it perch. And in this position it sleeps in safety ; for the claws do their office in keeping hold of the support, not by any exertion of voluntary power, which sleep might suspend, but by the traction of the tendons, in consequence of the attitude which the legs and thighs take by the bird sitting down, and to which the mere weight of the body gives the force that is necessary. VI. Regarding the human body as a mass ; regarding the general conformations which obtain in it ; regarding, also, particular parts in respect to those conformations ; we shall be led to observe what I call '' interrupted analogies." The following are examples of what I mean by these terms : and I do not know how such critical deviations can, by any possible hypothesis, be accounted for, without design. 1. All the bones of the body are covered with a pGri- osteum, except the teeth ; where it ceases, and an enamel of ivory, which saw^ ^nd files will hardly touch; comes inta 122 OF THE ANIMAL STRUCTURE, &C. its place. No one can doubt of the use and propriety of this difference ; of the " analogy" being thus " interrupted ;" of the rule, which belongs to the conformation of the bones, stopping where it does stop ; for, had so exquisitely sensi- ble a membrane as the periosteum, invested the teeth, as it invests every other bone of the body, their action, necessa- ry exposure, and irritation, would have subjected the ani- mal to continual pain. General as it is, it was not the sort of integument which suited the teeth. What they stood in need of, was a strong, hard, insensible, defensive coat ; and exactly such a covering is given to them, in the ivory en- amel which adheres to their surface. 2. The scarf-skin, which clothes all the rest of the body, gives way, at the extremities of the toes and fingers, to nails. A man has only to look at his hand, to observe with what nicety and precision, that covering, which extends over every other part, is here superseded by a different sub- stance, and a different texture. Now, if either the rule had been necessary, or the deviation from it accidental, this effect would not be seen. When I speak of the rule being necessary, I mean the formation of the skin upon the surface being produced by a set of causes constituted with- out design, and acting, as all ignorant causes must act, by a general operation. Were this the case, no account could be given of the operation being suspended at the finger's ends, or on the back part of the fingers, and not on the •fore part. On the other hand ; if the deviation were acci- dental, an error, an anomalism ; were it any thing else than settled by intention ; we should meet with nails upon other parts of the body. They would be scattered over the sur- face, like warts or pimples. 3. All the great cavities of the body are enclosed by membranes except the skull. Why should not the brain be content with the same covering as that which serves for the other principal organs of the body? The heart, the lungs, the liver, the stomach, the bowels, have all soft integuments, and nothing else. The muscular coats are all soft and membranous. I can see a reason for this distinction in the final cause, but in no other. The importance of the brain to life, (which experience proves to be immediate,) and the extreme tenderness of its substance, make a solid case more necessary for it, than for any other part ; and such a case the hardness of the skull supplies. When the small- est portion of this natural casquet is lost, how carefully, yet how imperfectly is it replaced by a plate of metal ? If an COMPARATIVE ANATOMY. 123 anatomist should say, that this bony protection is not con- fined to the brain, but is extended along the course of the spine, I answer, that he adds strength to the argument. If he remark, that the chest also is fortified by bones, I reply, that I should have alleged this instance myself, if the ribs had not appeared subservient to the purpose of motion, as as well as of defence. What distinguishes the skull from every other cavity is, that the bony covering completely surrounds its contents, and is calculated, not for motion, but solely for defence. Those hollows likewise, and ine- qualities, which we observe in the inside of the skull, and which exactly fit the folds of the brain, answer the impor- tant design of keeping the substance of the brain steady, and of guarding it against concussions. CHAP. XII. COMPARATIVE ANATOMY. Whenever we find a general plan pursued, yet with such variations in it, as are, in each case required by the particular exigency of the subject to which it is applied, we possess, in such plan and such adaptation, the strongest evi- dence, that can be aflforded, of intelligence and design ; an evidence, which most completely excludes every other hypothesis. If the general plan proceeded from any fixed necessity in the nature of things, how could it accommodate itself to the various wants and uses which it had to serve under ditferent circumstances, and on different occasions ? Arkwright's mill was invented for the spinning of cotton. We see it employed for the spinning of wool, flax, and hemp, with such modifications of the original principle, such variety in the same plan, as the texture of those dif- ferent materials rendered necessary. Of the machine's being put together with design, if it were possible to doubt, whilst we saw it only under one mode, and in one form ; when we came to observe it in its different applications, with such changes of structure, such additions, and supple- ments, as the special and particular use in each case de- manded, we could not refuse any longer our assent to the proposition, "that intelligence, properly and strictly so called, (including under that name, foresight, consideration, reference to utility) had been employed, as well in the 124 COMPARATIVE ANATOMY. primitive plan, as in the several changes and accommoda- tions which it is made to undergo." Very much of this reasoning is applicable to what has been called Comparative Anatomy, In their general econ- omy, in the outlines of the plan, in the construction as well as offices of their principal parts, there exists, between all large terrestrial animals, a close resemblance. In all life is sustained, and the body nourished, by nearly the same ap- paratus. The heart, the lungs, the stomach, the liver, the kidneys, are much alike in all. The same fluid (for no distinction of blood has been observed) circulates through their vessels, and nearly in the same order. The same cause, therefore, whatever that cause was, has been con- cerned in the origin ; has governed the production of these different animal forms. When we pass on to smaller animals, or to the inhabi- tants of a different element, the resemblance becomes more distant and more obscure, but still the plan accompanies us. And, what we can never enough commend, and which it is our business at present to exemplify, the plan is attend- ed through all its varieties and deflections by subservien- cies to special occasions and utilities. I, The covering of different animals (though whether I am correct in classing this under their anatomy I don't know) is the first thing which presents itself to our observa- tion ; and is, in truth, both for its variety, and its suitable- ness to their several natures, as much to be admired as any part of their structure. We have bristles, hair, wool, furs, feathers, quills, prickles, scales ; yet in this diversity both of material and form, we cannot change one animal's coat for another, without evidently changing it for the worse ; taking care however to remark, that these coverings are in many cases armour as well as clothing ; intended for pro- tection as well as warmth. The human animal is the only one which is naked, and the only one that can clothe itself. This is one of the proper- ties which renders him an animal of all climates, and of all seasons. He can adapt the warmth or lightness of his covering to the temperature of his habitation. Had he been born with a fleece upon his back, although he might have been comforted by its warmth in high latitudes, it would have oppressed him by its weight and heat as the species spread towards the equator. COMPARATIVE ANATOMY. 125 What art, however, does for men, nature has, in many instances, done for those animals which are incapable of art. Their clothing, of its own accord, changes with their necessities. This is particularly the case with that large tribe of quadrupeds which are covered with furs. Every dealer in hare-skins, and rabbit-skins, knows how much the fur is thickened by the approach of winter. It seems to be a part of the same constitution and the same design, that wool, in hot countries, degenerates, as it is called, but in truth (most happily for the animal's ease) passes into hair ; whilst, on the contrary, that hair, in the dogs of the polar regions, is turned into wool, or some- thing very like it. To which may be referred, what natural- ists have remarked, that bears, wolves, foxes, hares, which do not take the water, have the fur much thicker on the back than the belly : whereas in the beaver it is the thick- est upon the. belly; as are the feathers in waterfowl. We know the final cause of all this ; and we know no other. The covering of birds cannot escape the most vulgar ob- servation. Its lightness, its smoothness, its warmth : the disposition of the feathers all inclined backward, the down about their stem, the overlapping of their tips, their differ- ent configuration in different parts, not to mention the va- riety of their colours, constitute a vestment for the body, so beautiful, and so appropriate to the life which the animal is to lead, as that, I think, we should have had no concep- tion of any thing equally perfect, if we had never seen it or can now imagine any thing more so. Let us suppose (v/hat is possible only in supposition) a person who had never seen a bird, to be presented with a plucked pheasant, and bid to set his wits to work, how to contrive for it a covering which shall unite the qualities of warmth, levity, and least resistance to the air, and the highest degree of each ; giving it also as much of beauty and ornament as he could afford. He is the person to behold the work of the Deity, in this part of his creation, with the sentiments which are due to it. The commendation, which the general aspect of the feathered world seldom fails of exciting, will be increased by further examination. It is one of those cases in which the philosopher has more to admire, than the common ob- server. Every feather is a mechanical wonder. If we look at the quill, we find properties not easily brought M 126 COMPARATIVE ANATOMY. togetlier, strength and lightness. I know few things more remarkable, than the strength and lightness of the very pen, with which I am writing. If we cast our eye to the upper part of the stem, we see a material, made for the purpose, used in no other class of animals, and in no other part of birds ; tough, light, pliant, elastic. The pith, also, which feeds the feathers, is amongst animal substances, sui generis ; neither bone, flesh, membrane, nor tendon. But the artificial part of a feather is a heard, or, as it is sometimes, I believe, called, the vane. By the Ijeards are meant, what are fastened on each side of the stem, and what constitute the breadth of the feather; what we usual- ly strip off, from one side or both, when we make a pen. The separate pieces, or laminae, of which the beard is composed, are called threads, sometimes filaments, or rays. Now the first thing which an attentive observer will remark is, how much stronger the beard of the feather shows it- self to be, when pressed in a direction perpendicular to its plane, than when rubbed, either up or down, in the line of the stem ; and he will soon discover the structure which occasions this difference, viz. that the laminae whereof these beards are composed, are flat^ and placed with their flat sides towards each other ; by which means, whilst they easily bend for the approaching of each other, as any one may perceive by drawing his finger ever so lightly upwards, they are much harder to bend out of their plane, which is the direction in which they have to encounter the impulse and pressure of the air ; and in which their strength is wanted, and put to the trial. This is one particularity in the structure of a feather : a second is still more extraordinary. Whoever examines a feather, cannot help taking notice, that the threads or la- minae of which we have been speaking, in their natural state unite; that their union is something more than the mere apposition of loose surfaces ; that they are not part- ed asunder without some degree of force ; that nevertheless there is no glutinous cohesion between them : that, there- fore, by some mechanical .means or other, they catch or clasp among themselves, thereby giving to the beard or vane its closeness and compactness of texture. Nor is this all : when two lamina?, which have been separated by acci- dent or force, are brought together again, they immediately redasp : the connexion, whatever it was, is perfectly re- covered, and the beard of the feather becomes as smooth COMPARATIVE ANATOMY. 127 and firm as if nothing had happened to it. Draw your fin- ger down the feather, which is against the grain, and you break, probably, the junction of some of the contiguous threads ; draw your finger up the feather, and you restore all things to their former state. This is no common con- trivance ; and now for the mechanism by which it is ef- fected. The threads or laminae above mentioned are inter- laced with one another ; and the interlacing is perform- ed by means of a vast number of fibres or teeth, which the laminse shoot forth on each side, and which hook and grapple together. A friend of mine counted fifty of these fibres in one twentieth of an inch. These fibres are crook- ed ; but curved after a different manner ; for those, which proceed from the thread on the side towards the extremity of the feather, are longer, more flexible, and bent down- ward : whereas those which proceed from the side towards the beginning or quill end of the feather are shorter, firm- er, and turn upwards. The process then which takes place is as follows. When two laminse are pressed togeth- er, so that these long fibres are forced far enough over the short ones, their crooked parts fall into the cavity made by the crookeYhat we have to state has been the result of the studies of many naturalists; but although they have laboured, as it were, in their own department of comparative anatomy, they have failed to seize upon it with the privilege of genius, and to handle it in the masterly manner of Cuvier. " Suppose a man ignorant of anatomy to pick up a bone in an unex- plored country, he learns nothing, except that some animal has lived and died there ; but the anatomist can, by that single bone, estimate, not merely the size of the animal, as well as if he saw the print of its fjot, but the form and joints of the skeleton, the structure of its jaws, and teeth, the nature of its food, and its internal economy. This, to one ignorant of the subject, must appear wonderful, but it is after this m.anner that the anatomist proceeds ; let us suppose that he has taken up that portion of bone in the limb of the quadruped which corresponds to the human wrist ; and that he finds that the form of the bone does not admit of free motion in various directions, like the paw of the carnivorous creature. It is obvious, by the structure of the part, that the limb must have been merely for supporting the animal, and for progression, and not for seizing prey. This leads him to the fact that there were no bones resembling those of the hand and fingers, or those of the claws of the tiger ; for the motions which that conformation of bones permits in the paw, would be useless, without the rotation of the wrist — he concludes that these bones were formed in one mass, like the cannon bone, pastern-bone, and coffin-bones of the horse's foot. " The motion limited to flection and extension of the foot of a hoofed animal implies the absence of a collar bone and a restrained motion in the shoulder joint ; and thus the naturalist, from the specimen in his hand, has got ?i perfect notion of all the bones of the anterior extrem- ity ! The motions of the extremities imply a condition of ihe spine which unites them. Each bone of the spine will have thai form which permits the bounding of the stag, or the galloping of the horse, but it •will not have that form of joining which admits the turning or writh- ing of the spine, as in the leopard or the tiger. " And now he comes to the head : — the teeth of a carnivorous animal, he says, would be useless to rend prey, unless there were claws to hold it, and a mobility of the extremities like the hand, to grasp it. He considers, therefore, that the teeth must have been for bruising herbs, and the back teeth for grinding. The socketing of these teeth in the jaw gives a peculiar form to these bones, and the muscles which move them are also peculiar ; in short, he forms a conception of the shape of the skull. From this point he may set out anew, for RELATIONS. 1^ a falcon, or a kite, acts upon the animal fibre alone ; it will not act upon seeds or grasses at all. On the other hand, the conformation of the mouth of the sheep, or of the ox, is suited for browsing upon herbage. Nothing about these animals is fitted for the pursuit of living prey. Accord- ingly it has been found by experiments, tried not many years ago with perforated balls, that the gastric juice of ruminating animals, such as the sheep and the ox, speedily dissolves vegetables, but makes no impression upon animal bodies. This accordancy is still more particular. The gastric juice even of granivorous birds, will not act upon the grain, whilst whole and entire. In performing the ex- periment of digestion with the gastric juice in vessels, the grain must be crushed and bruised, before it be submitted to the menstruum ; that is to say, must undergo by art, with- out the body, the preparatory action which the gizzard ex- erts upon it within the body, or no digestion will take place. So strict is the relation between the offices assigned to the digestive organ ; between the mechanical operation, and the chemical process. II. The relation of the kidneys to the bladder, and of the ureters to both, i. e. of the secreting organ to the ves- sel receiving the secreted liquor, and the pipe laid from one by the form of the teeth, he ascertains the nature of the stomach, the length of the intestines, and all the peculiarities which mark a vegeta- ble feeder. " Thus the whole parts of the animal system are so connected with one another, that from one single bone or fragment of bone, be it of the jaw, or of the spine, or of the extremity, a really accurate concep- tion of the shape, motions, and habits of the animal, may be formed. " It will readily be understood that the same process of reasoning will ascertain, from a small portion cf a skeleton, the existence of a car- nivorous animal, or of a fowl, or of a bat, or of a lizard, or of a fish ; and what a conviction is here brought home to us, of the extent of that plan which adapts the members of everj^ creature to its proper office, and yet exhibits a system extending through the whole range of animated beings, whose motions are conducted by the operation of muscles and bones ! " After all, this is but a part of the wonders disclosed through the knowledge of a thing so despised as a fragment of bone. It carries us into another science ; since the knowledge of the skeleton not only teaches us the classification of creatures, now alive, but affords proofs of the former existence of animated beings which are not now to be found on the surface of the earth. We are thus led to an unexpected conclusion from such premises; not merely the existence of an indi- vidual animal, or race of animals ; but even the changes which the globe itself has undergone in times before all existing records, and be- fore the creation of human beings to inhabit the earth, are opened to our contemplation. 156 RELATIONS. to the other for the purpose of conveying it from one to the other, is as manifest as it is amongst the dilYerent ves- sels employed in a distillery, or in the communications be- tween them. The animal structure, in this case, being simple, and the parts easily separated, it forms an instance of correlation which may be presented by dissection to every eye, or which, indeed, without dissection, is capable of be- ing apprehended by every understanding. This correla tion of instruments to one another fixes intention some- where. Especially when every other solution is negatived by the conformation. If the bladder had been merely an expan- sion of the ureter, produced by retention of the fluid, there ought to have been a bladder for each ureter. One receptable, fed by two pipes, issuing from different sides of the body, yet from both conveying the same fluid, is not to be accounted for by any such supposition as this. III. Relation of parts to one another accompanies us throughout the whole animal economy. Can any relation be more simple, yet more convincing, than this, that the eyes are so placed as to look in the direction in which the legs move and the hands work ? It might have happened very differently, if it had been left to chance. There were, at least, three quarters of the compass out of four to have erred in. Any considerable alteration in the position of the eye, or the figure of the joints, would have disturbed the line, and destroyed the alliance between the sense and the limbs. IV But relation perhaps is never so striking, as when it subsists, not between different parts of the same thing, but between different things. The relation between a lock and a key is more obvious, than it is between differ- ent parts of the lock. A bow was designed for an arrow, and an arrow for a bow ; and the design is more evident their being separate implements. Nor does the works of the Deity want this clearest spe- cies of relation. The sexes are manifestly made for each other. They form the grand relation of animated nature ; universal, organic, mechanical ; subsisting, like tlie clear- est relations of art, in different individuals : unequivocal, in- explicable, without design : — So much so, that, were every other proof of contrivance in nature dubious or obscure, this alone would be sufficient. The example is complete. Nothing is wanting to the argument, I see no way what- ever of getting over it. RELATIONS. 157 V. The teats of animals, which give suck, bear a re- lation to the mouth of the suckling progeny ; particularly to the lips and tongue. Here also, as before, is a corres- pondency of parts ; which parts subsist in different indi- viduals. These are general relations, or the relations of parts which are found, either in all animals, or in large classes and descriptions of animals. Particular relations, or the relations which subsist between the particular configura- tion of one or more parts of certain species of animals, and the particular configuration of one or more other parts of the same animal, (which is the sort of relation, that is, perhaps, most striking,) are such as the following: I. In ihesivan; the web-foot, the spoon-bill, the long neck, the thick down, the graminivorous stomach, bear all a relation to one another, inasmuch as they all concur in one design, that of supplying the occasions of an aquatic fowl, floating upon the surface of shallow pools of water, and seeking its food at the bottom. Begin with any one of these particularities of structure, and observe how the rest follow it. The web-foot qualifies the bird for swimming ; the spoon bill enables it to graze. But how is an animal, floating upon the surface of pools of water, to graze at the bottom, except by the mediation of a long neck ? A long neck accordingly is given to it. Again, a warm blooded ani- mal, which was to pass its life upon water, required a de- fence against the coldness of that element. Such a defence is furnished to the swan, in the muffin which its body is wrapped. But all this outward apparatus would have been in vain, if the intestinal system had not been suited to the digestion of vegetable substances. I say suited to the di- gestion of vegetable substances; for it is well known, that there are two intestinal systems found in birds, one with a membranous stomach and a gastric juice, capable of dissolv- ing animal substances alone ; the other with a crop and gizzard, calculated for the moistening, brusing, and after« terwards digesting, of vegetable aliment. Or set off with any other distinctive part in the body of the swan; for instance, with the long neck. The long neckjwithoutthe web-foot, would have been an encumbrance to the bird ; yet there is no necessary connexion between a long neck and a web-foot. In fact they do not usually go together. How happens it, therefore, that they meet only when a particular design demands the aid of both I 158 RELATIONS. II. This mutual relation, arising from a subserviency to a common purpose, is very observable also in the parts of a mole. The strong short legs of that animal, the pal- mated feet, armed with sharp nails, the pig-like nose, the teeth, the velvet coat, the small external ear, the sagacious smell, the sunk protected eye, all conduce to the utilities, or to the safety, of its underground life. It is a special purpose, specially consulted throughout. The form of the feet fixes the character of the animal. They are so many shovels; they determine its action to that of rooting in the ground ; and every thing about its body agrees with this destination. The cylindrical figure of the mole, as well as the compactness of its form, arising from the terseness of its limbs, proportionally lessens its labour ; because, accord- ing to its bulk, it thereby requires the least possible quanti- ty of earth to be removed for its progress. It has nearly the same structure of the face and jaws as a swine, and the same office for them. The nose is sharp, slender, tendinous, strong ; w^ith a pair of nerves going down to the end of it. The plush covering, which, by the smooth- ness, closeness, and polish of the short piles that compose it, rejects the adhesion of almost every species of earth, de- fends the animal from cold and wet, and from the impedi- ment, which it would experience by the mould sticking to its body. From soils of all kinds, the little pioneer comes forth bright and clean. Inhabiting dirt, it is, of all animals, the neatest. But what I have always most admired in the mole, is its 'Cyes. This animal occasionally visiting the surface, and •wanting, for its safety and direction, to be informed when -it does so, or when it approaches it, a perception of light Avas necessary. I do not know that the clearness of sight depends at all upon the size of the organ. What is gained by the largeness or prominence of the globe of the eye is width in the field of vision. Such a capacity would be of no use to an animal which was to seek its food in the dark. The mole did not want to look about it ; nor would a large advanced eye have been easily defended from the annoy- ance, to which the life of the animal must constantly ex- pose it. How indeed v/as the mole, working its way un- der ground, to guard its eyes at all ? In order to meet this difficulty, the eyes are made scarcely larger than the head of a corking-pin ; and these minute globules are sunk so deep in the skull, and lie so sheltered within the velvet of its covering, as that any contraction of what may be COMPENSATION. 159 called the eyebrows, not only closes up the apertures which lead to the eyes, but presents a cushion, as it were, to- any sharp or protruding substance, which might push against them. This aperture even in its ordinary .state is like a pin hole in a piece of velvet, scarcely pervious to- loose particles of earth. Observe then, in this structure, that which we call re- lation. There is no natural connexion between a small sunk eye and a shovel palmated foot. Palmated feet might have been joined with goggle eyes ; or small eyes might have been joined with feet of any other form. What was it therefore which brought them together in the mode? That which brought together the barrel, the chain, and the fusee, in a watch ; design : and design, in both cases, in- ferred, from the relation which the parts bear to one an- other in the prosecution of a common purpose. As hath already been observed, there are different ways of stating the relation, according as we set out from a different part. In the instance before us, we may either consider the shape of the feet, as qualifying the animal for that mode of life and inhabitation, to which the structure of its eyes confines it; or we may consider the structure of the eye, as the only one which would have suited with the action to which the feet are adapted. The relation is manifest, whichever of the parts related we place first in the order cf our consideration. In a word ; the feet of the mole are inade for digging ; the neck, nose, eyes, ears and skin, are peculiarly adapted to an underground life ; and this is y-hat I call relation. (PI. XXX. fig. 1.) CHAR XVI. COMPENSATION. Compensation is a species of relation. It is relation^, v/hen the defects of one part, or of one organ, are supplied by the structure of another part, or of another organ. Thus, 1. The short, unbending neck of the elephant ^ is com- pensated by the length and flexibility of his proboscis. He could not have reached the ground without it ; or, if it be supposed that he might have fed upon the fruit, leaves, or branches of trees, how was he to drink 1 Should it be 160 COMPENSATION. asked, why is the elephant's neck so short ? it may be an- swered that the weight of a head so heavy, could not have been supported at the end of a longer lever. To a form therefore in some respects necessary, but in some respects also inadequate to the occasion of the animal, a supple- ment is added, which exactly makes up the deficiency un- der which he laboured. If it be suggested, that this proboscis may have been produced in a long course of generations, by the constant endeavour of the elephant to thrust out his nose, (which is the general hypothesis by which it has lately been attempt- ed to account for the forms of animated nature,) I would ask, how was the animal to subsist in the mean time, dur- ing the process ; until this elongation of snout were com- pleted 1 What was to become of the individual, whilst the species was perfecting ? Our business at present is, simply to point out the rela- tion, which this organ bears to the peculiar figure of the animal to which it belongs. And, herein, all things corres- pond. The necessity of the elephant's proboscis arises from the shortness of his neck ; the shortness of the neck is rendered necessary by the weight of the head. Were we to enter into an examination of the structure and anat- omy of the proboscis itself, we should see in it one of the most curious of all examples of animal mechanism. (PI. XXX, fig. 2, 3, 4, 5.) The disposition of the ringlets and fibres, for the purpose, first of forming a long cartilag- inous pipe ; secondly, of contracting and lengthening that pipe ; thirdly, of turning it in every direction at the will of the animal ; with the superaddition at the end, of a fleshy production, of about the length and thickness of a finger, and performing the office of a finger, so as to pick up a straw from the ground ; these properties of the same organ taken together, exhibit a specimen, not only of de- sign, (which is attested by the advantage,) but of consum- mate art, and as I may say, of elaborate preparation, in accomplishing that design. II. The hook in the wing of a hat, is strictly a me- chanical, and, also, a compensating contrivance. (PI. XXX. fig. 6.) At the angle of its wing there is a bent claw, exactly in the form of a hook, by which the bat at- taches itself to the sides of rocks, caves, and buildings, lying hold of crevices, joinings, chinks, and roughnesses. It hooks itself by this claw ; remains suspended by this hold ; takes its flight from this position ; which operations COMPENSATION. 161 compensate for the decrepitude of its legs and feet. With- out her hook, the bat would be the most helpless of all animals. She can neither run upon her feet, nor raise herself from the ground. These inabilities are made up to her by the contrivance in her wing ; and in placing a claw on that part, the Creator has deviated from the analogy observed in winged animals. A singular defect required a singular substitute. III. The crane kind are to live and seek their food amongst the waters ; yet, having no web-feet, are incapa- ble of swimming. To make up for this deficiency, they are furnished with long legs for wading, or long bills for grouping ; or usually with both. This is compensation. But I think the true reflection upon the present instance is, how every part of nature is tenanted by appropriate in- habitants. Not only is the surface of deep waters peopled by numerous tribes of birds that swim, but marshes and shallow pools are furnished with hardly less numerous tribes of birds that wade. IV. The common parrot has, in the structure of its beak, both an inconveniency, and a compensation for it. When I speak of an inconveniency, I have a view to a di- lemma which frequently occurs in the works of nature, viz. that the peculiarity of structure by which an organ is made to answer one purpose, necessarily unfits it for some other purpose. This is the case before us. The upper bill of a parrot is so much hooked, and so much overlaps the lower, that, if, as in other birds, the lower chap alone had motion, the bird could scarcely gape wide enough to receive its food ; yet this hook and overlapping of the bill could not be spared, for it forms the very instrument by which the bird climbs ; to say nothing of the use which it makes of it in breaking nuts, and the hard substances upon which it feeds. How, therefore, has nature provided for the open- ing of this occluded mouth ? By making the upper chap moveable, (PI. XXX. fig. 7.) as well as the lower. In most birds, the upper chap is connected, and makes but one piece with the skull ; but in the parrot, the upper chap is joined to the bone of the head by a strong membrane, placed on each side of it, which lifts and depresses it at pleasure. * * Goldsmith's Nat. Hist. vol. v. p. 274. P i62 COMPENSATION. V. The spifler^s irch is a compensating contrivance The spider lives upon flies, without wings to pursue them ; a case, one would have thought, of great difficulty : yet provided for; and provided for by a resource, which no stratagem, no effort of the animal, could have produced, had not both its external an internal structure been speci- fically adapted to the operation. VI. In many species of insects the eye is fixed ; and consequently without the power of turning the pupil to the object. This great defect is however perfectly compensate cd; and by a mechanism which we should not suspect. The eye is a multiplying glass ; with a lens looking in every direction, and catching every object. By which means, although the orb of the eye be stationary, the field of vision is as ample as that of other animals ; and is commanded on every side. (PI. XXX. fig. 8.) When this lattice work was first observed, the multiplicity and minuteness of the surfaces must have added to the surprise of the discovery. Adams tells us, that fourteen hundred of these reticulations have been counted in the two eyes of a drone bee. In other cases, the compensation is effected by the num- ])er and position of the eyes themselves. (Pi. XXX. fig. 9.) The spider has eight eyes, mounted upon different parts of the head, two in front, two in the top of the head, two on each side. These eyes are without motion ; but, by their situation, suited to comprehend every view, which the wants or safety of the animal render it necessary for it to take. VII. The memoirs for the Natural History of Animals, published by the French Academy, A. D. 1687, furnish us with some curious particulars in the eye of a chamelion. Instead of two eyelids, it is covered by an eyelid with a hole in it. This singular structure appears to be ?i cofnpen- satorij, and to answer to some other singularities in the shape of the animal. The neck of the chamelion is inflex- ible. To make up for this, the eye is so prominent, as that more than half of the ball stands out of the head. By means of which extraordinary projection, the pupil of the eye can be carried by the muscles in every direction, and is capable of being pointed towards every object. But, then, so unusual an exposure of the globe of the eye, re- quires, for its lubricity and defence, a more than ordinary protection of eyelid, as well as a more than ordinary supply of moisture ; yet the motion of an eyelid, formed accord- ing to the common construction, would be impeded, as it COMPENSATION. 163 should seem, by the convexity of the organ. The aperture in the lid meets this difficulty. It enables the animal to keep the principal part of the surface of the eye under cov- er, and to preserve it in a due state of humidity, without shutting out the light; or without performing every moment a nictitation, which, it is probable, would be more labori- ous to this animal than to others. VIII. In another animal, and in another part of the animal economy, the same Memoirs describe a most re- markable substitution. The reader will remember what we have already observed concerning the intestinal canal ; that its length, so many times exceeding that of the body, promotes the extraction of the chyle from the aliment, by giving room for the lacteal vessels to act upon it through a greater space. Tliis long intestine, wherever it occurs, is, in other animals, disposed in the abdomen from side to side in returning folds. But, in the animal now under our notice, the matter is managed otherwise. The same intention is mechanically effectuated ; but by a mechanism of a different kind. The animal of which I speak, is an amphibious quadruped, which our authors call the alope- cias, or sea fox. The intestine is straight from one end to the other : but in this straight, and consequently short intestine, is a winding, cork-screw, spiral passage, through which, the food, not without several circumvolutions, and in fact by a long rout, is conducted to its exit. Here the shortness of the gut is compensated by the obliquity of the perforation. IX. But the works of the Deity are known by expedi- ents. Where we should look for absolute destitution, where we can reckon up nothing but wants, some contri- vance always comes in to supply the privation. A sncdl^ without wings, feet, or thread, climbs up the stalks of plants, by the sole aid of a viscid humour discharged from her skin. She adheres to the stems, leaves, and fruits of plants, by means of a sticking plaster. A muscle^ which might seem, by its helplessness, to lie at the mercy of every wave that went over it, has the singular power of spinning strong, tendinous threads, by which she moors her shell to rocks and timbers. A cockle, on the contrary, by means of its stiff tongue, works for itself a shelter in the sand. The provisions of nature extend to casesf the most desperate. A lobster has a difficulty, in its constitution so great, that one could hardly conjecture beforehand how sature would dispose of it. In most animals, the skia 164 COMPENS ATION. grows with tlieir growth. If. instead of a soft skin, there be a shell, still it admits of a gradual enlargement. If the shell, as in the tortoise, consist of several pieces^ the ac- cession of substance is made at the sutures. Bivalve shells grow bigger by receiving an accretion at their edge ; it is the same with spiral shells at their mouth. The simplici- ty of their form admits of this. But the lobster's shell be- ing applied to the limbs of the body, as well as to the body itself, allows not of either of the modes of growth which are observed to take place in other shells. Its hardness resists expansion ; and its complexity renders it incapable of increasing its size by addition of substance to its edge. How then was the growth of the lobster to be provided for ? Was room to be made for it in the old shell, or was it to be successively fitted with new ones ? If a change of shell became necessary, how was the lobster to extricate himself from his present confinement ? How was he to uncase his buckler, or draw his legs out of his boots? The process, which fishermen have observed to take place, is as follows. At certain seasons, the shell of a lobster grows soft, the animal swells its body, the seams open, and the claws burst at the joints. When the shell has thus become loose upon the body, the animal makes a second eflfort, and by a tremulous spasmodic motion, casts it off. In this state the liberated but defenceless fish, retires into holes in the rock. The released body now suddenly pushes it growth. In about eight-and-forty hours, a fresh concretion of hu- mour upon the surface, i. e. a new shell is formed, adapted in every part to the increased dimensions of the animal. This wonderful mutation is repeated every year. If there be imputed defects without compensation, I should suspect that they were defects only in appearance. Thus, the body of the sloth has often been reproached for the slowness of its motions, which has been attributed to an imperfection in the formation of its limbs. But it ought to be observed, that it is this slowness, which alone suspends the voracity of the animal. He fasts during his migration from one tree to another ; and this fast may be necessary for the relief of his over-charged vessels, as well as to allow time for the concoction of the mass of course and hard food which he has taken into his stomach. The tardiness of his pace seems to have reference to the capac- ity of his organs, and to his propensities with respect to COMPENSATION. 165 feed, i. e. is calculated to counteract the effects of reple- tion.* Or there may be cases, in which a defect is artificial, and compensated by the very cause which produces it. Thus the sheej), in the domesticated state in which we see it, is destitute of the ordinary means of defence or escape ; is incapable either of resistance or flight. But this is not so with the wild animal. The natural sheep is swift and ac- tive : and, if it lose these qualities when it comes under the subjection of man, the loss is compensated by his pro- tection. Perhaps there is no species of quadruped what- ever, which suffers so little as this does, from the depreda- tion of animals of prey. For the sake of making our meaning better understood, we have considered this business of compensation under certain particularities of constitution, in which it appears to be most conspicuous. This view of the subject neces- sarily limits the instances to single species of animals. But there are compensations, perhaps, not less certain, which extend over large classes, and to large portions of living nature. I. In quadrupeds, the deficiency of teeth is usually com- pensated by the faculty of rumination. The sheep, deer, and ox tribe, are without fore-teeth in the upper jaw. These ruminate. The horse and ass are furnished with teeth in the upper jaw, and do not ruminate. In the former class the grass and hay descend into the stomach, nearly in the state in which they are cropped from the pasture, or gath- ered from the bundle. In the stomach they are softened by the gastric juice, which in these animals is unusually copious. Thus softened, and rendered tender, they are returned a second time to the action of the mouth, where * Blumenbach states in his Manual of Natural History, that he had conversed with many Hollanders who had lived in Guiana, and from them collected, that this apparently miserable animal, is rather an en- viable one. First, he nourishes himself entirely from leaves, and, there- fore, when he has once climbed a tree, he can live on the same dish a quarter of a year. Secondly, he does not diink at all. Thirdly, on a tree he is exposed to but few enemies, and when the sloth marks that a tiger-cat is climbing up a branch, it goes softly to the end of the branch, and rocks it till the tiger-cat falls off, so that seldom is there an instance that a tiger-cat surprises one ; even upon the ground, so powerful are the claws of the sloth, and so fearful its cries, that its enemies generally get the worst. So idle is Buflfbn's declamation against the goodness and wisdom of Providence drawn from this beast. Paxton, P 3 166 COMPEN^SAl-lOl^f* the grinding teeth complete at their leisure the trituration \vhich is necessary, but which was before left imperfect. I say the trituration which is necessary ; for it appears from experiments that the gastric fluid of sheep, for example^ has no effect in digesting plants, unless they have been previously masticated ; that it only produces a slight ma- ceration, nearly as common water would do in a like degree of heat ; but that, when once vegetables are reduced to pieces by mastication, the fluid then exerts upon them its specific operation. Its first effect is to soften them, and to destroy their natural consistency ; it then goes on to dis- solve them ; not sparing even the toughest parts, such as the nerves of the leaves.* I think it very probable that the gratification also of the animal is renewed and prolonged by this faculty. Sheep, deerj and oxen, appear to be in a state of enjoyment whilst they are chewing the cud. It is then, perhaps, that they best relish their food* II. In birds, the compensation is still more striking. They have no teeth at all. What have they then to make up for this severe want? I speak of granivorous and herbivorous birds ; such as common fowls, turkeys^ ducks, geese, pigeons, &/C. for it is concerning these alone that the question need be asked. All these are furnished with a peculiar and most powerful muscle, called the gizzard; the inner coat of which is fitted up with rough plates, which, by a strong friction against one another, break and grind the hard aliment as eflfectually, and by the same mechani- cal action, as a coffee-mill would do. It has been proved by the most correct experiments, that the gastric juice of these birds will not operate upon the entitle grain ; not even when softened by water or macerated in the crop. Therefore without a grinding machine within its body, without the trituration of the gizzard, a chicken would have starved upon a heap of corn. Yet why should a bill and a gizzard go together ? Why should a gizzard never be found where there are teeth 1 Nor does the gizzard belong to birds as such. A giz- zard is not found in birds of prey. Their food requires not to be ground down in a mill. The compensatory con- trivance goes no further than the necessity. In both class- es of birds, however, the digestive organ within the body, bears a strict and mechanic^ relation to the external in- ^ Spal. Dis. HI. sec. 140. COMPENSATION. 167 struments for procuring food. The soft membranous sto- mach, accompanies the hooked, notched beak ; the short, muscular legs ; the strong, sharp, crooked talons : The car- tilaginous stomach, attends that conformation of bill and toes, which restrains the bird to the picking of seeds or the cropping of plants. III. But to proceed with our compensations. A very numerous and comprehensive tribe of terrestrial animals are entirely without feet; yet locomotive; and, in a very considerable degree, swift in their motion. How is the i€ant of ftet compensated? It is done by the disposition of the muscles and fibres of the trunk. In consequence of the just collocation, and by means of the joint action of longitudinal and annular fibres, that is to say, of strings and rings, the body and train of reptiles* are capable of be- ing reciprocally shortened and lengthened, drawn up and stretched out. The result of this action is a progressive, and, in some cases, a rapid movement of the whole body, in any direction to which the will of the animal determines it. The meanest creature is a collection of wonders. The play of the rings in an earth-worm, as it crawls; the undu- iatory motion propagated along the body ; the beards or prickles, with which the annuli are armed, and which the animal can either shut up close to its body, or let out to lay hold of the roughnesses of the surface upon which it creeps ; and, the power arising from all these, of changing its place and position, afford, when compared with the provisions for motion in other animals, proofs of new and appropriate mechanism. Suppose that we had never seen an animal move upon the ground without feet, and that the problem was, muscular action, i. e. reciprocal contraction and relaxation being given, to describe how such an animal might be constructed, capable of voluntarily changing place. Something, perhaps, like the organization of rep- tiles, might have been hit upon by the ingenuity of an ar- * Contraction and expansion is the mode of progression in worms, but not in reptiles ; in the class of serpents locomotion consists simply of repeated horizontal undulations, viz. flexion and extension. Thus the head being the fixed point, the body and tail assume several curves ; the tail then becomes the fixed point, the curvatures are straightened, and thus the animal advances with a serpentine motion. By these successive curvatures and right lines alternating, it moves forward at each step nearly the length of the whole body ; the ribs, which Sir E. Home considers to act as feet, having nothing to do with locomotion unless as affording a fulcrum for the muscles. Paxton. WS THE RELATION OF ANIMATED BODIES list ; or might have been exhibited in an automaton, by the combination of springs, spiral wires, and ringlets: but to the solution of the problem would not be denied, surely, the praise of invention and of successful thought ; least of all could it ever be questioned, whether intelligence had been employed about it, or not. CHAP. XVII. THE RELATION OF ANIMATED BODIES TO INANIMATE NATURE. We have already considered relation, and under differ- ent views ; but it was the relation of parts to parts, of the parts of an animal to other parts of the same animal, or of another individual of the same species. But the bodies of animals, hold, in their constitution and properties, a close and important relation to natures alto- gether external to their own ; to inanimate substances, and to the specific qualities of these, e. g. they hold a strict re- lation to the elements by which they are surrounded. I. Can it be doubted, whether the loings of birds bear a relation to air, and the Jins of Jish to water? They are instruments of motion, severally suited to the properties of the medium in which the motion is to be performed : which properties are different. Was not this difference contemplated, when the instruments were differently con- stituted ? II. The structure of the animal ear depends for its use not simply upon being surrounded by a fluid, but upon the specific nature of that fluid. Every fluid would not serve ; its particles must repel one another; it must form an elastic medium ; for it is by the successive pulses of such a medi- um, that the undulations excited by the sounding body are carried to the organ ; that a communication is formed be- tween the object and the sense ; which must be done be- fore the internal machinery of the ear, subtile as it is, can act at all. III. The organs of voice, and respiration, are, no less than the ear, indebted for the success of their opera- tion, to the peculiar qualities of the fluid in w'hich the animal is immersed. They, therefore, as well as the ear, TO INANIMATE NATURE. 169 are constituted upon the supposition of such fluid, i. e. of a fluid with such particular properties, being always pres- ent. Change the properties of the fluid, and the organ cannot act ; change the organ, and the properties of the fluid would be lost. The structure, therefore, of our or- gans, and the properties of our atmosphere, are made for one another. Nor does it alter the relation, whether you allege the organ to be made for the element, (which seems the most natural way of considering it,) or the element as prepared for the organ. IV. But there is another fluid with which we have to do; with properties of its own ; with laws of acting, and of be- ing acted upon, totally different from those of air and water: and that is light. To this new, this singular element ; to qualities perfectly peculiar, perfectly distinct and remote from the qualities of any other substance with which we are acquainted, an organ is adapted, an instrument is cor- rectly adjusted, not less peculiar amongst the parts of the body, not less singular in its form, and, in the substance of which it is composed, not less remote from the materials, the model, and the analogy of any other part of the animal frame, than the element to which it relates, is specific amidst the substances with which we converse. If this does not prove appropriation, I desire to know what would prove it. Yet the element of light and the organ of vision, how* ever related in their office and use, have no connexion whatever in their original. The action of rays of light upon the surfaces of animals has no tendency to breed eyes in their heads. The sun might shine for ever upon living bodies without the smallest approach towards producing the sense of sight. On the other hand also, the animal eye does not generate or emit light. V. Throughout the universe there is a wonderful pro- portioning of one thing to another. The size of animals, of the human animal especially, when considered with re- spect to other animals, or to the plants which grow around him, is such, as a regard to his conveniency would have pointed out. A giant or a pigmy could not have milked goats, reaped corn, or mowed grass ; we may add, could not have rode a horse, trained a vine, shorn a sheep, with the same bodily ease as we do, if at all. A pifijmy would have been lost among rushes, or carried oflT by birds of prey. It may be mentioned, likewise, that the model and the materials of the human body being what they are, a much 170 THE RELATION OF ANIMATED BODIES greater bulk would have broken down by its own weight. The persons of men, who much exceed the ordinary stat- ure, betray this tendency. VI. Again, (and which includes a vast variety of partic- ulars, and those of the greatest importance,) how close is the suitableness of the earth and sea to their several inhab- itants; and of these inhabitants to the places of their ap- pointed residence ? Take the earth as it is ; and consider the corresponden- cy of the powers of its inhabitants \v'ith the properties and condition of the soil which they tread. Take the inhab- itants as they are ; and consider the substances which the earth yields for their use. They can scratch its surface, and its surface supplies all which they want. This is the length of their faculties ; and such is the constitution of the globe, and their own. that this is sufficient for all their occasi )ns. When we pass from the earth to the sea^ from land to water, we pass through a great change ; but an adequate change accompanies us of animal forms and functions of animal capacities and wants, so that correspondency remains. The earth in its nature is very different from the sea, and the sea from the earth ; but one accords with its inhab- itants, as exactly as the other. VII. The last relation of this kind which I shall men- tion is that of sleep to night. And it appears to me to be a relation which was expressly intended. Two points are manifest; first, that the animal frame requires sleep ; sec- ondly, that night brings with it a silence, and a cessation of activity, which allows of sleep being taken without in- terruption, and without loss. Animal existence is made up of action and slumber ; nature has provided a season for each. An animal, which stood not in need of rest, would always live in daylight. An animal, which, though made for action, and delighting in action, must have its strength repaired by sleep, meets by its constitution the returns of day and night> In the human species, for instance, where the bustle, the labour, the motion of life, upheld by the constant presence of light, sleep could not be enjoyed with~ ^out being disturbed by noise, and without expense of that ^time, which the eagerness of private interest would not con- tentedly resign. It is happy therefore for this part of the ^^ireation, I mean that it is conformable to the frame anci ^wants of their constitution, that nature, by the very dispo- sition of her elements, has commanded, asitwere^ and im^ TO INANIMATE NATURE. 171 posed upon them, at moderate intervals, a general intermis- sion of their toils, their occupations, and pursuits. But it is not for man, either solely or principally, that night is made. Inferior, but less perverted natures, taste its solace, and expect its return, with greater exactness and advantage than he does. I have often observed, and never observed but to admire, the satisfaction, no less than the regularity, with which the greatest part of the irration- al world yield to this soft necessity, this grateful vicissi- tude ; how comfortably the birds of the air, for example, address themselves to the repose of the evening ; with what alertness they resume the activity of the day. Nor does it disturb our argument to confess, that certain species of animals are in motion during the night, and at rest in the day. With respect even to them it is still true, that there is a change of condition in the animal, and an external change corresponding with it. There is still the relation, though inverted. The fact is, that the repose of other animals sets these at liberty, and invites them to their food or their sport. If the relation of sleep to night, and in some instances, its converse, be real, we cannot reflect without amazement upon the extent to which it carries us. Day and night are things close to us ; the change applies immediately to our sensations ; of all the phenomena of nature, it is the most familiar to our experience ; but in its cause, it belongs to the great motions which are passing in the heavens. Whilst the earth glides round her axle, she ministers to the alter- nate necessities of the animals dwelling upon her surface, at the same time that she obeys the influence of those at- tractions, which regulate the order of many thousand worlds. The relation therefore of sleep to night, is the relation of the inhai>itants of the earth to the rotation of their globe; probably it is more ; it is a relation to the system, of which that globe is a part; and, still further, to the congregation of systems, of which theirs is only one. If this account be true, it connects the meanest individual with the universe itself; a chicken roosting upon its perch, with the spheres revolving in the firmament. VIII. But if any one object to our representation, that the succession of day and night, or the rotation of the earth upon which it depends, is not resolvable into central at- traction, we will refer him to that which certainly is — to the change of the seasons. Now the constitution of ani- mals susceptible of torpor, bears a relation to winter, simi- 172 INSTINCTS. lar to that which sleep bears to night. Against not only the cold, but the want of food, which the approach of winter induces, the Preserver of the world has provided, in many animals by migration, in many others by torpor. As one example out of a thousand, the bat, if it did not sleep through the winter, must have starved, as the moths and flying insects, upon which it feeds, disappear. But the transition from summer to winter, carries us into the very midst of physical astronomy, that is to say, into the midst of those laws which govern the solar system at least, and probably all the heavenly bodies. CHAP. XVIII. INSTINCTS. The order may not be very obvious, by which I place instincts, next to relations. But I consider them as a species of relation. They contribute, along with the ani- mal organization, to a joint eflfect, in which view they are related to that organization. In many cases they refer from one animal to another animal ; and when this is the case, become strictly relations in a second point of view. An instinct is a propensity prior to experience, and in- dependent of instruction. We contend, that it is by in- stinct that the sexes of animals seek each other ; that animals cherish their offspring ; that the young quadruped is directed to the teat of its dam ; that birds build their nests and brood with so much patience upon their eggs ; that insects which do not sit upon their eggs, deposit them in those particular situations, in which the young, when hatched, find their appropriate food ; that it is instinct, which carries the salmon, and some other fish, out of the sea into rivers, for the purpose of shedding their spawn in fresh water. We may select out of this catalogue the incubation of eggs. I entertain no doubt, but that a couple of sparrows hatched in an oven, and kept separate from the rest of their species, would proceed as other sparrows do, in every office which related to the production and preservation of their brood. Assuming this fact, the thing is inexplicable upon any other hypothesis, than that of an instinct, impress- INSTINCTS. 173 ed upon the constitution of the animal. For, first, what should induce the female bird to prepare a nest before she lays her eggs'? It is in vain to suppose her to be possess- ed of the faculty of reasoning; for no reasoning will reach the case. The fulness or distention which she might feel in a particular part of her body, from the growth and so- lidity of the egg within her, could not possibly inform her, that she was about to produce something, which, when pro- duced, was to be preserved and taken care of Prior to experience, there was nothing to lead to this inference, or to this suspicion. The analogy was all against it ; for in every other instance, what issued from the body was cast out and rejected. But, secondly, let us suppose the egg to be produced into day ; how should birds know that their eggs contain their young ; there is nothing either in the aspect, or in the internal composition of an egg, which could lead even the most daring imagination to a conjecture, that it was here- after to turn out, from under its shell, a living, perfect bird. The form of the egg bears not the rudiments of a resemblance to that of the bird. Inspecting its contents, we find still less reason, if possible, to look for the result which actually takes place. If we should go so far, as, from the appearance of order and distinction in the dis- position of the liquid substances which we noticed in the egor, to o;uess that it might be designed for the abode and nutriment of an animal, (which would be a very bold hy- pothesis,) we should expect a tadpole dabbling in the slime, much rather than a dry, winged, feathered creature ; a compound of parts and properties impossible to be used in a state of confinement in the egg, and bearing no conceiv- able relation, either in quality or material, to any thing ob- served in it. From the white of an egg, would any one look for the feathers of a goldfinch 1 or expect from a sim- ple uniform mucilage, the most complicated of all ma- chines, the most diversified of all collections of substances ? nor would the process of mcubation, for some time at least, lead us to suspect the event. Who that saw red streaks, shooting in the fine membrane which divides the white from the yolk, would suppose that these were about to be- come bones and limbs? Who, that espied two discoloured points first making their appearance in the cicatrix, would have had the courage to predict, that these points were to grow into the heart and head of a bird 1 It is difficult to a 174 INSTINCTS. strip the mind of its experience. It is difficult to resusci- tate surprise, when familiarity has once laid the sentiment asleep. But could we forget all that we know, and which our sparrows never knew, about oviparous generation : could we divest ourselves of every information, but what we derive from reasoning upon the appearances or quality discovered in the objects presented to us, I am convinced that Harlequin coming out of an egg upon the stage, is not more astonishing to a child, than the hatching of a chick- en both would be, and ought to be, to a philosopher. But admit the sparrow by some means to know, that within that egg was concealed the principle of a future bird, from wliat chemist was she to learn that ioarmth was necessary to bring it to maturity, or that the degree of warmth, imparted by the temperature of her own body, was the degree required ? To suppose, therefore, that the female bird acts in this process from a sagacity and reason of her own, is to sup- pose her to arrive at conclusions, which there are no prem- ises to justify. If our sparrow, sitting upon her eggs, expect young sparrows to come out of them, she forms, I will venture to say, a wild and extravagant expectation, in opposition to present appearances, and to probability. She must have penetrated into the order of nature, further than any faculties of ours will carry us ; and it hath been well ob- served, thai this deep sagacity, if it be sagacity, subsists in conjunction with great stupidity, even in relation to the same subject. " A chemical operation," says Addison, " could not be followed with greater art or diligence, than is seen in hatching a chicken ; yet is the process carried on without the least glimmering of thought or common sense. The hen will mistake a piece of chalk for an egg; is insensible of increase or diminution of their number ; does not distin- guish between lier own, and those of another species; is frightened when her supposititious breed of ducklings take the water." But it will be said, that what reason could not do for the bird, observation, or instruction, or tradition might. Now if it be true, that a couple of sparrows brought up from the first in a state of separation from all other birds, would build their nest, and brood upon their eggs, then there is an end of this solution. What can be the tradi- tionary knowledge of a chicken hatched in an oven ? Of young birds taken in their nests, a few species breed, when kept in cages ; and they which do so, build their INSTINCTS. 175 nests nearly in the same manner as in the wild state, and sit upon their eggs. This is sufficient to prove an instinct, without having recourse to experiments upon birds, hatched by artificial heat, and deprived, from their birth, of all communication with their species ; for we can hardly bring ourselves to believe, that the parent bird informed her un- fledged pupil of the history of her gestation, her timely preparation of a nest, her exclusion of the eggs,- her long incubation, and of the joyful eruption at last of her expect- ed offspring , all which the bird in the cage must have iearnt in her infancy, if we resolve her conduct into institu- tion. Unless we will rather suppose that she remembers her own escape from the egg ; had attentively observed the conformation of the nest in which she was nurtured; and had treasured up her remarks for future imitation. Which is not only extremely improbable, (for who that sees a brood of callow birds in their nest, can believe that they are taking a plan of their habitation ?) but leaves unac- counted for, one principal part of the difficulty, " the pre- paration of the nest before the laying of the egg.^^ This she could not gain from observation in her infancy. It is remarkable also, that the hen sits upon eggs which she has laid without any communication with the male ; and which are therefore necessarily unfruitful. That se- cret she is not let into. Yet, if incubation had been a sub- ject of instruction or of tradition, it should seem that this distinction would have formed part of the lesson ; whereas the instinct of nature is calculated for a state of nature; the exception, here alluded to, taking place, chiefly, if not solely, amongst domesticated fowls, in which nature is forced out of her course. There is another case of oviparous economy, which is still less likely to be the eflect of education, than it is even in birds, namely, that of moths and butterjlies, which de- posit their eggs in the precise substance, that of a cabbage for example, from which, not the butterfly herself, but the caterpillar which is to issue from her egg, draws its ap- propriate food. The butterfly cannot taste the cabbage. Cabbage is no food for her ; yet in the cabbage, not by chance, but studiously and electively, she lays her eggs. There are, amongst many other kinds, the willow cater- pillar, and the cabbage caterpillar; but we never find upon a willow, the caterpillar which eats the cabbage ; nor the re- verse. This choice, as appears to me, cannot in the butter- 176 INSTINCTS. fly proceed from instruction. She had no teacher in her caterpillar state. She never knew her parent. I do not see, therefore, how knowledge, acquired by experience, if it ever were such, could be transmitted from one genera- tion to another. There is no opportunity either for instruc- tion or imitation. The parent race is gone before the new brood is hatched. And, if it be original reasoning in the butterfly, it is profound reasoning indeed. She must re- member her caterpillar state, its tastes and habits ; of which memory she shows no signs whatever. She must conclude from analogy, for here her recollection cannot serve her, that the little round body, which drops from her abdomen, will at a future period produce a living creature, not like herself, but like the caterpillar, which she remembers herself once to have been. Under the influence of these reflections she goes about to make provision for an order of things, which, she concludes, will, some time or other, take place. And it is to be observed, that not a few out of many, but that all butterflies argue thus, all draw this conclusion, all act upon it.* But suppose the address, and the selection, and the plan, which we perceive in the preparations which many irra- tional animals make for their young, to be traced to some probable origin ; still there is left to be accounted for, that which is the source and foundation of these phenomena, that which sets the whole at work, the a-ro^'/vi, the pa- rental aff'ection, which I contend to be inexplicable upon any other hypothesis than that of instinct. For we shall, hardly, I imagine, in brutes, refer their conduct towards their off'spring to a sense of duty, or of decency, a care of reputation, a compliance with publick manners, with publick laws, or with rules of life built upon a long experience of their utility. And all attempts to ac- * The dragon-fly is an inhabitant of the air, and could not exist in water ; yet in this element, which is alone adapted for her young, she drops her eggs. Not less surprising is the parental instinct of the gad-fly, (Gastero- philus equi,) whose larvae are destined to be nourished in the stomach and intestines of the horse ! How shall the parent convey tliem there ? By a mode truly extraordinary — Flying round the animal, she curiously poises her body while she deposites her eggs on the hairs of his skin. Whenever, therefore, the horse chances to lick the part of his body to which they are attached, they adhere to the tongue, and from thence pass into the stomach and intestines. And what increases our surprise is, that the fly places her eggs almost ex- clusively on the knee and the shoulder, on those parts the horse is 8ure to hck. Faxton, INSTINCTS. 177* count for the parental affection from association, I think, fail. With what is it associated 1 Most immediately with the throes of parturition, that is, with pain, and terror, and disease. The more remote, but not less strong association, that which depends upon analogy, is all against it. Every thing else, which proceeds from the body, is cast away and rejected. In birds, is it the egg which the hen loves ? or is it the expectation which she cherishes of a future progeny, that keeps her upon her nest? What cause has she to expect delight from her progeny ? Can any rational answer be given to the question, why, prior to experience, the brood- ing hen should look for pleasure from her chickens 1 It does not, I think, appear, that the cuckoo ever knows her young ; yet, in her way, she is as careful in making provi- sion for them, as any other bird. She does not leave her egg in every hole. The salmon suffers no surmountable obstacle to oppose her progress up the stream of fresh rivers. And what does she do there 1 She sheds a spawn, which she immediately quits, in order to return to the sea ; and this issue of her body she never afterwards recognises in any shape what- ever. Where shall we find a motive for her efforts, and her perseverance? Shall we seek it in argumentation, or in instinct ? The violet crab of Jamaica performs a fa- tiguing march of some months' continuance, from the mountains to the sea side. When she reaches the coast, she casts her spawn into the open sea; and sets out upon her return home. Moths and butterflies, as hath already been observed, seek out for their eggs, those precise situations and sub- stances, in which the offspring caterpillar will find its ap- propriate food. That dear caterpillar, the parent butterfly, must never see. There are no experiments to prove that she would retain any knowledge of it, if she did. How shall we account for her conduct? I do not mean for her art and judgment in selecting and securing a maintenance for her young, but for the impulse upon which she acts. What should induce her to exert any art, or judgment, or choice, about the matter ? The undisclosed grub, the ani- mal, which she is destined not to know, can hardly be the object of a particular affection, if we deny the influence of instinct. There is nothing, therefore, left to her, but that of which her nature seems incapable, an abstract anx- a 2 78 INSTINCTS. lety for the general preservation of the species ; a kind of patriotism ; a solicitude, lest the butterfly race should cease from the creation. Lastly, the principle of association will not explain the discontinuance of the affection when the young animal is grown up. Association, operating in its usual way, would rather produce a contrary effect. The object would become more necessary by habits of society ; whereas birds and beasts, after a certain time, banish their off- spring ; disown their acquaintance ; seem to have even no knowledge of the objects which so lately engrossed the attention of their minds, and occupied the industry and labour of their bodies. This change, in different animals, takes place at different distances of time from their birth ; but the time always corresponds with the ability of the young animal to maintain itself ; never anticipates it. In the sparrow tribe, when it is perceived that the young brood can fly and shift for themselves, then the parents forsake them forever ; and though they continue to live together, pay them no more attention than they do to other birds in the same flock, * I believe the same thing is true of all gregarious quadrupeds. In this part of the case the variety of resources, expedi- ents, and materials, which animals of the same species are said to have recourse to, under different circumstances and when differently supplied, makes nothing against the doc- trine of instincts. The thing which we want to account for is the propensity. The propensity being there, it is probable enough that it may put the animal upon different actions according to different exigencies. And this adapt- ation of resources may look like the effect of art and con- sideration, rather than of instinct; but still the propensity is instinctive. For instance, suppose what is related of the wood-pecker to be true, that, in Europe, she deposits '^her eggs in cavities, which she scoops out in the trunks of soft or decayed trees, and in which cavities the eggs lie con- cealed from the eye, and in some sort safe from the hand of man ; but that, in the forests of Guinea and the Brazils, which man seldom frequents, the same bird hangs her nest to the twigs of tall trees ; thereby placing them out of the reach of monkeys and snakes, i. e. that in each situa- tion she prepares against the danger which she has most occasion to apprehend ; suppose, I say, this to be true, and * Goldsmith's Nat. Hist. vol. iv. p. 244. Instincts. 179 to be alleged, on the part of the bird that builds these nests', as evidence of a reasoning and distinguishing precaution, still the question returns, whence the propensity to build at all ? Nor does parental affection accompany generation by any universal law of animal organization, if such a thing were intelligible. Some animals cherish their progeny with the most ardent fondness, and the most assiduous attention ; others entirely neglect them ; and this distinction always meets the constitution of the young animal, with respect to its wants and capacities. In many, the parental care extends to the young animal ; in others, as in all oviparous fish, it is confined to the egg, and even, as to that, to the disposal of it in its proper element. Also, as there is gen- eration without parental affection, so is there parental in- stinct, or what exactly resembles it, without generation. In the bee tribe, the grub is nurtured neither by the father nor the mother, but by the neutral bee. Probably the case is the same with ants. I am not ignorant of the theory, which resolves instinct into sensation ; which asserts, that what appears to have a view and relation to the future, is^the result only of the present disposition of the animal's body, and of pleasure or pain experienced at the time. Thus the incubation of eggs is accounted for by the pleasure which the bird is supposed to receive from the pressure of the smooth con- vex surface of the shells against the abdomen, or by the relief, which the mild temperature of the egg may afford to the heat of the lower part of the body, which is observ- ed at this time to be increased beyond its usual state. This present gratification is the only motive with the hen for sitting upon her nest ; the hatching of the chickens is with respect to her, an accidental consequence. The affection of viviparous animals for their young, is in like manner solved by the relief, and perhaps the pleasure, which they receive from giving suck. The young animal's seeking, in so many instances, the teat of its dam, is explained from the sense of smell, which is attracted by the odour of the milk. The salmon's urging its way up the stream of fresh water rivers, is attributed to some gratification or refresh- ment, which, in this particular state of the fish's body, she receives from the change of element. Now of this theory it may be said. First, that, of the cases which require solution, there are few, to which it can be applied with tolerable probability : 180 INSTINCTS. — that there are none, to which it can be applied without strong objections, furnished by the circumstances of the case. The attention of the cow to its calf, and of the ewe to its lamb, appear to be prior to their sucking. The at- traction of the calf or lamb to the teat of the dam is not explained by simply referring it to the sense of smell. What made the scent of milk so agreeable to the lamb that it should follow it up with its nose, or seek with its mouth the place from which it proceeded I No observation, no experience, no argument, could teach the new dropped animal, that the substance, from which the scent issued, was the material of its food. It had never tasted milk be- fore its birth. None of the animals, which are not de- signed for that nourishment, ever offer to suck, or to seek out any such food. What is the conclusion, but that the sugescent parts of animals are fitted for their use, and the knowledge of that use put into them? We assert, secondly, that, even as to the cases in which the hypothesis has the fairest claim to consideration, it does not at all lessen the force of the argument for inten- tion and design. The doctrine of instinct, is that of ap- petencies, superadded to the constitution of an animal, for the affectuating of a purpose beneficial to the species. The above-stated solution would derive these appetencies from organization ; but then this organization is not less speci- fically, not less precisely, and, therefore, not less evidently adapted to the same ends, than the appetencies themselves W'Ould be upon the old hypothesis. In this way of consid- ering the subject, sensation supplies the place of foresight ; but this is the effect of contrivance on the part of the Creator. Let it be allowed, for example, that the hen is induced to brood upon her eggs by the enjoyment or re- lief, which, in the heated state of her abdomen, she ex- periences from the pressure of round smooth surfaces, or from the application of a temperate warmth. How comes this extraordinary heat or itching, or call it what you will, which you suppose to be the cause of the bird's inclina- tion, to be felt, just at the time when the inclination itself is wanted ; vvhen it tallies so exactly, with the internal constitution of the egg, and with the help which that con- stitution requires in order to bring it to maturity? In my opinion, this solution, if it be accepted as to the fact, ought to increase, rather than otherwise, our admiration of the contrivance. A gardener lighting up his stoves, just when he wants to force his fruit, and when his trees require the INSTINCTS. 181 heat, gives not a more certain evidence of design. So, again ; when a male and female sparrow come together, they do not meet to confer upon the expediency of perpetuating their species. As an abstract proposition, they care not the value of a barley corn whether the species be perpetu- ated, or not. They follow their sensations ; and all those consequences ensue, which the wisest counsels could have dictated, which the most solicitous care of futurity, w^hich the most anxious concern for the sparrow world, could have produced. But how do these consequences ensue? The sensations, and the constitution upon which they de- pend, are as manifestly directed to the purpose which we see fulfilled by them ; and the train of intermediate effects, as manifestly laid and planned with a view to that purpose, that is to say, design is as completely evinced by the phe- nomena, as it would be, even if we suppose the operations to begin, or to be carried on, from what some will allow to be alone properly called instincts, that is, from desires di- rected to a future end, and having no accomplishment or gratification distinct from the attainment of that end. In a word ; I should say to the patrons of this opinion. Be it so ; be it, that those actions of animals which we re- fer to instinct, are not gone about with any view to their consequences, but that they are attended in the animal with a present gratification, and are pursued for the sake of that gratification alone ; what does all this prove, but that the p'ospection, which must be somewhere, is not in the animal, but in the Creator? In treating of the parental affection in brutes, our busi- ness lies rather with the origin of the principle, than with the effects and expressions of it. Writers recount these with pleasure and admiration. The conduct of many kinds of animals towards their young, has escaped no observer, no historian of nature. " How will they caress them,'* says Derham, "with their affectionate notes, lull and quiet them with their tender parental voice ; put food into their mouths ; cherish, and keep them warm ; teach them to pick and eat, and gather food for themselves; and in a word, perform the part of so many nurses, deputed by the sovereign Lord and Preserver of the world, to help such young and shiftless creatures?" Neither ought it, under this head, to be forgotten, how much the instinct costs the animal which feels it ; how much a bird, for example, gives up, by sitting upon her nest ; how repugnant it is to her organization, her habits, and her pleasures. An animal. 182 OF INSECTS. formed for liberty, sul)mits to confinement, in tlie very sea- son when every thing invites her abroad : what is more, an animal delighting in motion, made for motion, ail whose motions are so easy and so free, hardly a moment, at other times, at rest, is, for inany hours of many days together, fixed to her nest, as close as if her limbs were tied down by pins and wires. For my j)art, 1 never see a bird in that situation, but I recognize an invisible haiid, detaining the contented prisoner from her fields and groves, for a i)urpose, as the event j)roves, the most worthy of the sacrifice, the most imi)ortant, the most beneficial. But the loss of liberty is not the whole of wliat the pro- creant bird suffers. Harvey tells us, that he has often found the female wasted to skin and bone by sitting upon her eggs. One observation more, and I will dismiss the subject. The pairing of birds, and the nun-pairing of beasts, forms a distinctioii between the two classes, which shows that the conjugal instinct is modified with a reference to utility, founded on the condition of the ofispring. In quadrupeds, the young animal draws its nutriment from the body of the dam. The male parent neither does, nor can, contribute any part to its susteatation. Tn tlie feathered race, the young bird is supplied by an importation of food, to procure and bring home, which, in a sufficient quantity for the de- mand of a numerous brood, requires the industry of both parents. In this difference we see a reason for the vagrant instinct of the quadruped, and for the faithful love of tho feathered mate. CHAP. XIX. OP INSECTS. We are not writing a system of natural history ; there- fore, we have not attended to the classes, into wliich the subjects of that science are distributed. What we had to observe concerning different species of animals, fell easily, for the most part, within the divisions, which the course of our argument led us to adopt. There remain, however, some remarks upon the insect tribe, which could not prop- erly be introduced under any of these heads ; and which, therefore, we have collected into a chapter by themselves. The structure, and the use of the parts of insects, are less understood than that of (juadrupeds and birds, not only OF INSECTS. 183 by reason of their minuteness, or the minuteness of their parts, (for tliat minuteness we can, in some measure, fol- low with glasses) but also, by reason of the remoteness of their manners and modes of life frotn those of larger ani- mals. For instauce ; insects, under all their varieties of form, are endowed with cuiteniKE, which is the name given to those long feelers that rise from each side of the head ; but to u))at common use or want of the insect kind, a pro- vision, so universal is subservient, has not yet been ascer- tained ; and it has not been ascertained, because it admits not of a clear, or very probable comj)arison, with any or- gans which we possess ourselves, or with the organs of an- imals which resemble ourselves in their functions and fac- ulties, or with which we are better acquainted than we are with insects. We want a ground of analogy. This diffi- culty stands in our way as to some particulars in the in- sect constitution which we might wish to be acquainted with. Nevertheless, there are many contrivances in the bodies of insects, neither dubious in their use, nor obscure in their structure, and most properly mechanical. These form parts of our argument. I. The chjtra, or scaly wings of the genus of scarabeeus or beetle, furnish an instance of this kind. The true wincr of the animal is a light transparent membrane, finer than the finest gauze, and not unlike it. It is also when ex- panded, in proportion to the size of the animal, very large. In order to protect this delicate structure, and perhaps, also to preserve it in a due state of suppleness and humidi- ty, a strong, hard case is given to it, in the shape of the horny wing which we call the elytron. When the animal is at rest, the gauze wings lie folded up under this impene- trable shield. When the beetle })repares for flyinf;^ he raises the integument, and spreads out his thin membrane to the air. And it cannot be observed without admiration, what a tissue of cordage, i. e. of muscular tendons, must run, in various and complicated, but determinate directions, along this fine surface, in order to enable the animal, either to gather it up into a certain precise form, whenever it desires to place its wings under the shelter which na- ture hath given to them ; or to expand again their folds, when wanted for action. (P). XXXII. fig. 1.) In some insects, the elytra cover the whole body ; in others, half; in others, only a small part of it; but in all, they completely hide and cover the true wings. (PI. XXXII. fig. 2.) 184 OF INSECTS. Also, many or most of the beetle species lodge in holes in the earth, environed by hard, rough substances, and have fre- quently to squeeze their way through narrow passages ; in which situation, wings so tender, and so large, could scarcely have escaped injury, without both a firm covering to defend them, and the capacity of collecting themselves up under its protection. II. Another contrivance, equally mechanical, and equal- ly clear, is the awl or borer, fixed at the tails of various species of flies ; and with which they pierce, in some cases, plants ; in others, wood : in others, the skin and flesh of animals ; in others, the coat of the chrysalis of in- sects of a different species from their own; and in others, even lime, mortar and stone. I need not add, that hav- ing pierced the substance, they deposit their eggs in the hole. The descriptions, which naturalists give of this or- gan, are such as the following : — It is a sharp-pointed instrument, which, in its inactive state, lies concealed in the extremity of the abdomen, and which the animal draws out at pleasure, for the purpose of making a puncture in the leaves, stem or bark of the particular plant, which is suited to the nourishment of its young. In a sheath, which divides and opens whenever the organ is used, there is enclosed, a compact, solid, dentated stem, along which runs a gutter or groove, by which groove, after the pene- tration is effected, the egg, assisted in some cases by a peristaltic motion, passes to its destined lodgment. In the oestrum or gad-fly, the wimble draws out like the pieces of a spy-glass ; the last piece is armed with three hooks, and is able to bore through the hide of an ox. Can any thing more be necessary to display the mechanism, than to re- late the fact? (PI. XXXII. fig. 3, 4.) III. The stings of insects, though for a different pur- pose, are, in their structure, not unlike the piercer. The sharpness to which the point in all of them is wrought ; the temper and firmness of the substance of which it is composed ; the strength of the muscles by which it is darted out, compared with the small ness and weakness of the insect, and with the soft and friable texture of the rest of the body; are properties of the sting to be noticed, and not a little to be admired. The sting of a bee will pierce through a goatskin glove. It penetrates the human skin more readily than the finest point of a needle. The action of the sting aflfords an example of the union of chemistry and mechanism, such as, if it be not a proof of contrivance, OF INSECTS. 185 nothing is. First, as to the chemistry ; how highly con- centrated must be the venom, which, in so small a quantity, can produce such powerful effects 1 And in the bee we may observe, that this venom is made from honey, the only food of the insect, but the last material from which I should have expected, that an exalted poison could, by any pro- cess or digestion whatsoever, have been prepared. In the next place, with respect to the mechanism, the sting is not a simple, but a compound instrument. The visible sting, though drawn to a point exquisitely sharp, is in strictness only a sheath ; for, near to the extremity, may be perceived by the microscope two minute orifices, from which orifices, in the act of stinging, and, as it should seem after the point of the main sting has buried itself in the flesh, are launch- ed out two subtile rays, which may be called the true or proper stings, as being those, through which the poison is infused into the puncture already made by the exterior sting. I have said that chemistry and mechanism are here united ; by which observation I meant, that all this machinery would have been useless, telum imbelle, if a supply of poison, intense in quality, in proportion to the smallness of the drop, had not been furnished to it by the chemical elaboration which was carried on in the insect's body ; and that, on the other hand, the poison, the result of this pro- cess, could not have attained its effect, or reached its enemy, if, when it was collected at the extremity of the abdomen, it had not found there a machinery, fitted to con- duct it to the external situations in which it was to operate, viz. an awl to bore a hole, and a syringe to inject the fluid. Yet these attributes, though combined in their action, are independent in their origin. The venom does not breed the sting ; nor does the sting concoct the venom. (PI. XXXIl. fig. 5.) IV. The proboscis, with which many insects are en- dowed, comes next in order to be considered. (PI. XXXII. fig. 6, 7, 8.) It is a tube attached to the head of the animal. In the bee, it is composed of two pieces, connected by a joint ; for, if it were constantly extended, it would be too much exposed to accidental injuries ; therefore, in its in- dolent state, it is doubled up by means of the joint, and in that position lies secure under a scaly pent-house. In many species of the butterfly, the proboscis, when not in use, is coiled up like a watch spring. In the same bee, the proboscis serves the office of the mouth, the insect R 136 OF INSECTS. having no other; and how much better adapted it is, than a mouth would be, for the collecting of the proper nourish- ment of the animal, is sufficiently evident. The food of the bee is the nectar of flowers ; a drop of syrup, lodged deep in the bottom of the corolls, in the recesses of the petals, or down the neck of a monopetalous glove. Into these cells the bee thrusts its long narrow pump, through the cavity of which it sucks up this precious fluid^ inaccessible to every other approach. The ringlets of which the probos- bis of the bee is composed, the muscles by which it is ex- tended and contracted, form so many microscopical won- ders. The agility also, with which it is moved, can hardly fail to excite admiration. But it is enough for our pur- pose to observe in general^ the suitableness of the structure to the use, of the means to the end, and especially the wis- dom, by which nature has departed from its most general analogy (for animals being furnished with mouths are such) when the purpose could be better answered by the devia- tion. In some insects, the proboscis, or tongue, or trunk, is ^hut up in a sharp-pointed sheath, which sheath, being of a much firmer texture than the proboscis itself^ asj well as sharpened at the point, pierces the substance which con- tains the food, and then opens within the icound, to allow the enclosed tube, through which the juice is extracted, to perform its office. Can any mechanism be plainer than this is; or surpass this? V. The ?«etemo?'p7i05/5 of insects from grubs" into moths and flies, is an astonishing process. A hairy caterpillar is transformed into a butterfly. Observe the change. We * have four beautiful wings, where there were none before ^ a tubular proboscis, in the place of a mouth with jaws and teeth ; six long legs, instead of fourteen feet. In another case, we see a white, smooth, soft worm, turned into a black, hard, crustaceous beetle, vvith gauze wings. These, as I said, are astonishing processes, and must require, as it should seem, a proportionably artificial apparatus. The hypothesis which appears to me most probable is, that, in the grub, there exist at the same time three animals, one within another, all nourished by the same digestion, and by a communicating circulation ; but in different stages of maturity. The latest discoveries, made by naturalists, seem to favour this supposition. The insect already equip- ped with wings, is descried under the membranes, both of the worm and the nymph. In some species, the proboscis^ OF INSECTS. 187 the antennae, the limbs and wings of the fly, have been observed to be folded up within the body of the caterpillar ; and with such nicety, as to occupy a small space only under the two first wings. This being so, the outermost animal^ which, beside its own proper character, serves as an integu- ment to the other two, being the furthest advanced, dies, as we suppose, and drops off first. The second, the pupa or chrysalis, then offers itself to observation. This also, in its turn, dies ; its dead and brittle husk falls to pieces, and makes way for the appearance of the fly or moth. Now, if this be the case, or indeed whatever explication be adopted, we have a prospective contrivance of the most curious kind ; we have organizations three deep^ yet a vas- cular system, which supplies nutrition, growth, and life, to all of them together. VI. Almost all insects are oviparous. Nature keeps her butterflies, moths and caterpillars, locked up during the winter in their egg state ; and we have to admire the various devices, to which, if we may so speak, the same nature hath resorted, for the security of the egg. Many insects enclose their eggs in a silken web ; others cover them with a coat of hair, torn from their own bodies ; some glue them together ; and others, like the moth of the silk-worm, glue them to the leaves upon which they are deposited, that they may not be shaken off by the wind, or washed away by rain ; some again make incisions into leaves, and hide an egg in each incision ; whilst some en- velope their eggs with a soft substance, which forms the first aliment of the young animal : and some again make a hole in the earth, and, having stored it with a quantity of proper food, depasite their eggs in it. In all which we are to observe, that the expedient depends, not so much upon the address of the animal, as upon the physical re- sources of his constitution. The art also with which the young insect is coiled up in the egg, presents, where it can be examined, a subject of great curiosity. The insect, furnished with all the members which it ought to have, is rolled up into a form which seems to contract it into the least possible space ; by vv^hich con- traction, notwithstanding the smallness of the egg, it has room enough in its apartment, and to spare. This folding of the limbs appears to me to indicate a special direction ; for, if it were merely the effect of compression, the col- location of the parts would be more various than it is. Xu the same species^ I believe^ it is always the same. 188 OF INSECTS. These observations belong to the whole insect tribe, or to a great part of them. Other observations are limited to fewer species ; but not, perhaps, less important or satis- factory. I. The organization in the abdomen of the silk-icorm or spider, whereby these insects form their thread, is as incontestably mechanical, as a wire-drawer's mill. In the body of the silk-worm, are two bags, remarkable for their form, position, and use. (PL XXXIII. fig 1.) They wind round the intestine, when drawn out they are ten inches in length, though the animal itself be only two. Within these bags is collected a glue ; and communicating with the bags, are two paps or outlets, perforated, like a grater, by a number of small holes. The glue or gum, being pass- ed through these minute apertures, forms hairs of almost imperceptible fineness ; and these hairs, when joined, com- pose the silk which we wind off from the cone, in which the silk-worm has wrapped itself up; in the spider the web is formed of this thread. In both cases, the extremity of the thread, by means of its adhesive quality, is first at- tached by the animal to some external hold ; and the end being now fastened to a point, the insect, by turning round its body, or by receding from that point, draws out the thread through the holes above described, by an operation, as hath been observed, exactly similar to the drawing of wire. The thread, like the wire, is form.ed by the hole through which it passes. In one respect there is a dif- ference. The wire is the metal unaltered, except in figure. In the animal process, the nature of the substance is some- what changed, as well as the form ; for, as it exists within the insect, it is a soft, clammy gum or glue. The thread acquires, it is probable, its firmness and tenacity from the action of the air upon its surface, in the moment of expo- sure ; and a thread so fine is almost all surface. This property, however, of the paste, is part of the contrivance. (PI. XXXIII. fig. 2.) The mechanism itself consists of the bags, or reser- voirs, into which the glue is collected, and of the external holes communicating with these bags : and the action of the machine is seen, in the forming of a thread, as wire is formed, by forcing the material already prepared, through holes of proper dimensions. The secretion is an act too subtile for our discernment, except as we perceive it by the produce. But one thing answers to another : the secretory glands to the quality and consistence required m «3P INSECTS. 189 tlie secreted substance ; the bag to its reception. The outlets and orifices are constructed, not merely for reliev- ino- the reservoirs of their burthen, but for manufacturino- the contents into a form and texture, of great external use, or rather indeed of future necessity, to the life and func- tions of the insect. II. Bees, under one character or other, have furnished every naturalist with a set of observations. I shall, in this place, confine myself to one ; and that is the relation which obtains between the wax and the honey. No .per- son, who has inspected a bee-hive, can forbear remarking, how commodiously the honey is bestowed in the comb : and amongst other advantages, how eflfectually the fermenta- tion of the honey is prevented by distributing it into small cells. The fact is, that when the honey is separated from the comb, and put into jars, it runs into fermentation, with a much less degree of heat than what takes place in a hive. This may be reckoned a nicety ; but independently of any nicety in the matter, I would ask, what could the bee do with the honey, if it had not the wax? how, at least, could it store it up for winter ? The wax, therefore, zxi" swers a purpose with respect to the honey ; and the honey constitutes that purpose with respect to the wax. This is the relation between them. But the two substances, though, together, of the greatest use^ and, without each other, of little, come from a different origin. The bee finds the honey, but makes the wax. The honey is lodged in the nectaria of flowers, and probably undergoes little alteration ; is merely collected ; whereas the wax is a ductile tenacious paste, made out of a dry powder, not simply by kneading it with a liquid, but by a digestive process in the body of the bee. What account can be rendered of facts so circum- stanced, but that the animal, being intended to feed upon honey, was, by a peculiar external configuration, enabled to procure it 1 that, moreover, Avanting the honey when it could not be procured at all, it was further endued with the no less necessary faculty of constructing repositories for its preservation ? which faculty, it is evident, must de- pend, primarily, upon the capacity of providing suitable materials. Two distinct functions go to make up the ability. First, the power in the bee, with respect to wax, of loading the farina of flowers upon its thighs; microsco- pic observers speak of the spoon-shaped appendages, with which the thighs of bees are beset for this very purpose ; R 2 190 OF INSECTS. but inasmuch as the art and will of the bee may be sup- posed to be concerned in this operation, there is, secondly, that which doth not rest in art or will, a digestive faculty which converts the loose powder into a stiff substance. This is a just account of the honey and the honey comb'; and this account, through every part, carries a creative intelli- gence along with it. The sting also of the bee has this relation to the honey, that it is necessary for the protection of a treasure which invites so many robbers. III. Our business is with mechanism. In the panorpa tribe of insects, there is a forceps in the tail of the male insect, with which he catches and holds the female. (PI. XXXIII. fig. 3.) Are a pair of pincers more mechanical, than this provision, in their structure ? or is any structure more clear and certain in its design 1 IV. St. Pierre tells us,* that in a fly with six feet^ (I do not remember that he describes the species) the pair next the head, and the pair next the tail, have brushes at their extremities, with which the fly dresses, as there may be occasion, the anterior or the posterior part of its body: but that the middle pair have no such brushes, the situation of these legs not admitting of the brushes, if they were there, being converted to the same use. This is a very ex- act mechanical distinction. V. If the reader, looking to our distributions of science ; wish to contemplate the chemistry, as well as the mechan- ism of nature, the insect creation will afford him an ex- ample. I refer to the light in the tail of n glow-worm. Two points seem to be agreed upon by naturalists concerning it ; first, that it is phosphoric ; secondly, that its use is to at- tract the male insect. The only thing to be inquired af- ter, is the singularity, if any such there be, in the natur- al history of this animal, which should render a pro- vision of this kind more necessary for it, than for other insects. That singularity seems to be the difference, which subsists between the male and the female ; which difference is greater than what we find in any other species of animal whatever. The glow-worm is a female caterpillar ; the male of which is dijiy; lively, comparatively small, dissimi- lar to the female in appearance, probably also as distinguish- ed from her in habits, pursuits, and manners, as he is un- like in form and external constitution. (PI. XXXIII. fig. * Vol. i. p. 342. OF INSECTS. 191 4, 5.) Here then is the adversity of the case. The cater- pillar cannot meet her companion in the air. The winged rover disdains the ground. They might never therefore be brought together, did not this radiant torch direct the volatile mate to his sedentary female. In this example we also see the resources of art antici- pated. One grand operation of chemistry is the making of phosphorus ; and it was thought an ingenious device, to make phosphoric matches supply the place of lighted tapers. Now this very thing is done in the body of the glow-worm. The phosphorus is not only made, but kin- dled ; and caused to emit a steady and genial beam, for the purpose which is here stated, and which I believe to be the true one. VI. Nor is the last the only instance that entomology affords, in which our discoveries, or rather our projects, turn out to be imitations of nature. Some years ago, a plan was suggested, of producing propulsion by reaction in this way. By the force of a steam engine^ a stream of water was to be shot out of the stern of a boat ,- the im- pulse of which stream upon the water in the river, was to push the boat itself forward ; it is, in truth, the principle by which sky-rockets ascend in the air. Of the use or the practicability of the plan t am not speaking ; nor is it my concern to praise its ingenuity, but it is certainly a contrivance. Now, if naturalists are to be believed, it is exactly the device, which nature has made use of, for the motion of some species of aquatic insects. The larva of the dragon-jly, according to Adams, swims by ejecting water from its tail ; is driven forwards by the reaction of water in the pool upon the current issuing in a direction backward from its body. (PI. XXXIII. fig. 6.) VII. Again ; Europe has lately been surprised by the elevation of bodies in the air by means of a balloon. The discovery consisted in finding out a manageable substance, which was, bulk for bulk, lighter than air ; and the appli- cation of the discovery was, to make a body composed of this substance, bear up, along with its own weight, some heavier body which was attached to it. This expedient, so new to us, proves to be no other than what the author of nature has employed in the gossamer spider. We fre- quently see this spider's thread floating in the air, and extended from hedge to hedge, across a road or brook of four or five yards width. The animal which forms the thread, has no wings wherewith to fly from one extremity 192 OF INSECTS. to the other of this line ; nor muscles to enable it to spring or dart to so great a distance. Yet its Creator hath laid for it a path in the atmosphere ; and after this manner. Though the animal itself be heavier than the air, the thread which it spins from its bowels is specifically lighter. This is its balloon. The spider left to itself would drop to the ground ; but being tied to its thread, both are supported. We have here a very peculiar provision ; and to a contempla- tive eye it is a gratifying spectacle, to see this insect wafted on her thread, sustained by a levity not her own, and trav- ersing regions, which, if we examined only the body of the animal, might seem to have been forbidden to its na- ture. I must now crave the reader's permission to introduce into this place, for want of a better, an observation or two upon the tribe of animals, whether belonging to land or water, which are covered by shells. I. The 5//6'Z/5 of s??«?75 are a wonderful, a mechanical, and, if one might so speak concerning the works of nature, an original contrivance. Other animals have their proper retreats, their hybernacula also or winter quarters, but the snail carries these about with him. He travels with his tent; and this tent, though as was necessary, both light and thin, is completely impervious either to moisture or air. The young snail comes out of its egg with the shell upon its back ; and the gradual enlargement which the shell receives, is derived from the slime excreted by the animal's skin. Now the aptness of this excretion to the purpose, its property of hardening into a shell, and the action, w^iatever it be, of the animal, whereby it avails itself of its gift, and of the constitution of its glands, (to say nothing of the work being commenced before the animal is born,) are things, which can, with no probability, be referred to any other cause than to express design ; and that not on the part of the animal alone, in which design, though it might build the house, could not have supplied the material. The will of the animal could not determine the quality of the ex- cretion. Add to which, that the shell of a snail, with its pillar and convolution, is a very artificial fabric ; whilst a snail, as it should seem, is the most numb and unprovided of all artificers. In the midst of variety, there is likewise a regularity, which would hardly be expected. In the same species of snail the number of turns is, usually, if not always, the same. The sealing up of the mouth of OF INSECTS. 193 the shell by the snail, is also well calculated for its warmth and security ; but the cerate is not of the same substance with the shell. II. Much of what has been observed of snails belongs to shell-Jish and their shells, particularly to those of the univalve kind ; with the addition of two remarks. One of which is upon the great strength and hardness of most of these shells. I do not know, whether, the weight being given, art can produce so strong a case as are some of these shells. Which defensive strength suits well with the life of an animal, that has often to sustain the dangers of a stormy element and a rocky bottom, as well as the attacks of voracious fish. The other remark is, upon the property in the animal excretion, not only of congealing, but of con- gealing, or, as a builder would call it, setting in water, and into a cretaceous substance, firm and hard. This property is much more extraordinary, and, chemically speaking, more specific, than that of hardening in the air ; which may be reckoned a kind of exsiccation, like the drying of clay into bricks. III. In the bivalve order of shell-fish, cockles, muscles,, oysters, &c. what contrivance can be so simple or so clear, as the insertion, at the back, of a tough, tendinous sub- stance, that becomes, at once, the ligament which binds the two shells together, and the Jdnge upon which they open and shut. IV. The shell of a lobster's tail, in its articulations and overlappings, represents the jointed part of a coat of mail ; or rather, which I believe to be the truth, a coat of mail is an imitation of a lobster's shell. The same end is to be answered by both ; the same properties, therefore, are re- quired in both, namely, hardness and flexibility, a covering which may guard the part without obstructing its motion. For this double purpose, the art of man, expressly exercised upon the subject, has not been able to devise any thing better than what nature presents to his observation. Is not this therefore mechanism, which the mechanic, having a similar purpose in view, adopts? Is the structure of a coat of mail to be referred to art? Is the same structure of the lobster, conducing to the same use, to be referred to any thing less than art ? Some, who may acknowledge the imitation, and assent to the inference which we draw from it, in the instance be- fore us, may be disposed, possibly, to ask, why such imita? 194 OF INSECTS. tions are not more frequent than they are, if it be true, as we allege, that the same principle of intelligence, design, and mechanical contrivance, was exerted in the formation of natural bodies, as we employ in the making of the vari- ous instruments by which our purposes are served. The answers to this question are, first, that it seldom happens, that precisely the same purpose, and no other, is pursued in any work which we compare of nature and of art ; sec- ondly, that it still seldomer happens, that we can imitate nature, if we would. Our materials and our workmanship are equally deficient. Springs are wires, and cork and leather, produce a poor substitute for an arm or a hand. In the example which we have selected, I mean of a lobster's shell compared with a coat of mail, these difficulties stand less in the way, than in almost any other that can be as- signed ; and the consequence is, as we have seen, that art gladly borrows from nature her contrivance, and imitates it closely. But to return to insects. I think it is in this class of animals, above all others, especially when we take in the multitude of species which the microscope discovers, that we are struck with what Cicero has called " the insatiable variety of nature." There are said to be six thousand species of flies ; seven hundred and sixty butterflies ; each different from all the rest, (St. Pierre.) The same writer tells us from his own observation, that thirty -seven species of winged insects, with distinctions well expressed, visited a single strav/berry plant in the course of three weeks.* Rat/ observed, within the compass of a mile or two of his own house, two hundred kinds of butterflies, nocturnal, and diurnal. He likewise asserts, but, I think, without any grounds of exact computation, that the number of species of insects, reckoning all sorts of them, may not be short of ten thousand.! And in this vast variety of animal forms, (for the observation is not confined to insects, though more applicable perhaps to them than to any other class,) we are sometimes led to take notice of the different methods, or rather of the studiously diversified methods, by which * Vol. i. p. 3. t Wisd. of God, p. 23. The number of species of insects known to entomologists, and preserved in cabinets, is at present not less than forty tliousand. This number, however, must probably form a small proportion of the whole number which exist upon the earth. tSee Kirly and Spence's Entomology. £d. OF INSECTS. 195 one and the same purpose is attained. In the article of breathing, for example, which was to be provided for in. some way or other, besides the ordinary varieties of lungs gills, and breathing-holes, (for insects in general respire, not by the mouth, \FI XXXIII. fig. 7.) but through holes in the sides,) the nymphsB of gnats have an apparatus to raise their backs to the top of the water, and so take breath. (PL XXXIII, fig. 8.) The hydrocanthari do the like by thrusting their tails out of the water.* The maggot of the eruca labra, (PI. XXXIII. fig. 9.) has a long tail, one part sheathed within another, (but which it can draw out at pleasure,) with a starry tuft at the end, by which tuft, when expanded upon the surface, the insect both supports itself ifi the water, and draws in the air which is necessary. In tlie article of natural clothing, we have the skins of ani- mals invested with scales, hair, feathers, mucus, froth ; or itself turned in a shell or crust; in the no less necessary article of offence and defence, we have teeth, talons, beaks,, horns, stings, prickles, with (the most singular expedient for the same purpose) the power of giving the electric shock, f and as is credibly related of some animals, of driving away their pursuers by an intolerable fo&tor, or of blackening the water| through which they are pursued. The consideration of these appearances might induce us to believe that varieti/ itself, distinct from every other reason, was a motive in the mind of the Creator, or with the agents of his will. * Derham, p. 7. t The raja torpedo, gymnotus electricuSf and some other fish, have a curious apparatus of nerves, which, iq its effects, may be compared to an electrical battery. In the first named ^is^, the electrical organs are situated between the head and the pectoral fins. When the inte- guments are raised, the organ appears, consisting of some hundred pentagonal and hexagonal cells, filled with a glairy fluid. Minute blood-vessels are dispersed over it, and its nerves are of extraordinary size. When the hand is applied to the electrical organs, a benumbing effect is instantly felt in the fingers and the arm. When caught in a net, it has been known to give a violent shock to the hands of the fish- erman who ventures to seize it. Pkil. Trans. 1816. p. 120. and 1817, p. 32. Paxton. t The several species of sepia or cuttle fish, have this faculty. They possess a bag situated on, or near the liver, called the ink-hag, from its containing a black fluid, the contents of which is discharged by a muscular sheath compressing the body of the animal. By this singular evacuation, the creature renders the surrounding element so black and bitter, when in danger of being attacked, that an enemy will not pursue it. lb. 196 OF PLANTS. To this great variety in organized life the Deity hag given, or perhaps there arises out of it, a corresponding variety of animal appetites. For the final cause of this we have not far to seek. Did all animals covet the same element, retreat, or food, it is evident how much fewer could be supplied and accommodated, that what at present live conveniently together, and find a plentiful subsistence. What one nature rejects, another delights in. Food, which is nauseous to one tribe of animals, becomes by that very property which makes it nauseous, an alluring dainty to another tribe. Carrion is a treat to dogs, ravens, vultures, fish. The exhalations of corrupted substances attract flies by crowds. Maggots revel in putrefaction. CHAP. XX. OF PLANTS. I THINK a designed and studied mechanism to be in gen- eral, more evident in animals, that in plants ; and it is un- necessary to dwell upon a weaker argument, where a stronger is at hand. There are, however, a few observations upon the vegetable kingdom, which lie so directly in our way, that it would be improper to pass them by without notice. The one great intention of nature in the structure of plants, seems to be the perfecting of the seed; and, what is part of the same intention, the preserving of it until it be perfected. This intention shows itself, in the first place^ by the care which appears to be taken to protect and ripen, by every advantage which can be given to them of situa- tion in the plant, those parts which most immediately con- tribute to fructification, viz. the antherae, the stamina, and the stigmata. These parts are usually lodged in the cen- tre, the recesses, or the labyrinths of the flower ; during their tender and immature state, are shut up in the stalk, or sheltered in the bud ; as soon as they have acquired firmness of texture sufficient to bear exposure, and are ready to perform the important office which is assigned to them, they are disclosed to the light and air, by the burst- ing of the stem or the expansion of the petals : after which they have, in many cases, by the very form of the flower during its blow, the light and warmth reflected upon them OF PLANTS. ^ 197 from the concave side of the cup. What is called also the sleep* of plants, is the leaves of petals disposing themselves in such a manner as to shelter the young stems, buds, or fruit. They turn up, or they fall down, according as this purpose renders either change or position requisite. In the growth of corn, whenever the plant begins to shoot, the two upper leaves of the stalk join together, embrace the ear, and protect it till the pulp has acquired a certain de- gree of consistency. In some water plants, the flowering and fecundation are carried on within the stem, which af- terwards opens to let loose the impregnated seed.t The pea or papilionaceous tribe enclose the parts of fructifica- tion within a beautiful folding of the internal blossom, sometimes called, from its shape, the boat or keel ; itself also protected under a penthouse formed by the external petals. This structure is very artificial ; and, what adds to the value of it, though it may diminish the curiosity, very general. It has also this further advantage, (and it is an *The periodical change in the direction of leaves, which has been called the " Sleep of Plants," is undeniably connected with the stimu- lating operation of light. It is established, that during the clear light of the sun, the leaves become erect, and move their upper sur- face to the light, whilst, on the contrary, during the absence of light they either hang dovvnvt'ards, and turn to the horizon, or they take an upright position, so that the under surface of the leaves is turned more outward. On account of this particular position of what has been called " Sleeping Plants," we cannot properly ascribe this direc- tion to sleep, because the leaves do sometimes even raise themselves during this state with greater energy, and press upon the stem or leaf- stalk, ibr the purpose of turning their lower surface outwards. This change is much rather, therefore, the consequence of the contest be- tween the activity of the plant, and the great activity of nature. This change is the more evident, and the sleep of leaves the more striking, the finer and more compounded the organization of the leaves are. We hence most frequently observe it in the pinnated leaves of leguminous plants, although also in some others, as in atriplex. That an internal and self-dependent activity is to be taken into ac- count in this sleep of plants, is plain from the fact that this sleep does not equally follow fromashort withdrawing of the light, but only from its complete and long-continued removal ; as also from this other cir- cumstance, that leaves fall asleep or awake at fixed hours, whether the sky be serene or troubled, exactly as happens with regard to ani- mals. Other stimuli, too, and especially heat, have a great influence upon this phenomenon, because, in the cold, leaves awaken later and fall more easily asleep, notwithstanding the influence of light. Vide Elements of the Philosophy of Plants, by Decandalle. Paxton. + Phil. Trans, part ii. 1796, p. 502. 198 OF PLANTS. advantage strictly mechanical,) that all the blossoms turn their backs to the wind, whenever the gale blows strong enough to endanger the delicate parts upon which the seed depends. I have observed this a hundred times in a field of peas in blossom. It is an aptitude which results from the figure of the flower, and, as we have said, is strictly mechanical; as much so, as the turning of a weather-board or tin cap upon the top of a chimney. Of the poppy, and of many similar species of flowers, the head, while it is growing, hangs down, a rigid curvature in the upper part of the stem giving to it that position ; and in that position it is impenetrable by rain or moisture. When the head has acquired its size, and is ready to open, the stalk erects itself, for the purpose, as it should seem, of presenting the flower, and, with the flower, the instruments of fructifica- tion, to the genial influence of the sun's rays. This al- ways struck me as a curious property ; and specifically, as well as originally, provided for in the constitution of the plant ; for if the stem be only bent by the weight of the head, how comes it to straighten itself when the head is the heaviest ? These instances, show the at- tention of nature to this principal object, the safety and maturation of the parts upon which the seed depends. In trees, especially in those which are natives of colder climates, this point is taken up earlier. Many of these trees (observe in particular the ash and the horse-chestnut) pro- duce the embryos of the leaves and flowers in one year, and bring them to perfection the following. There is a winter therefore to be gotten over. Now what we are tore- mark is, hbw nature has prepared for the trials and sever- ities of that season. These tender embryos are, in the first place, wrapped up with a compactness, which no art can imitate : in which state, they compose what we call the bud. This is not all. The bud itself is enclosed in scales ; which scales are formed from the remains of past leaves, and the rudiments of future ones. Neither is this the whole. In the coldest climates a third preservative is add- ed, by the bud having a cortiof gumor resin, which, being congealed, resists the strongest frosts. On the approach of warm weather this gum is softened, and ceases to be a hinderance to the expansion of the leaves and flowers. All this care is part of that system of provisions which has for its object and consummation, the production and perfect- ing of the seeds. OF PLANTS. 199 The SEEDS themselves are packed up in a capsule, a vessel composed of coats, (PL XXXIV. fig. 1.) which, compared with the rest of the flower, are strong and tough. From this vessel projects a tube, through which tube the ferina, or some subtile fecundating effluvium that issues from it, is admitted to the seed. And here also occurs a mechanical variety, accommodated to the different circum- stances under which the same purpose is to be accomplish- ed. In flowers which are erect, the pistil is shorter than the stamina; (PI. XXXIV. fig. 2,) and the pollen, shed from the antheree into the cup of the flower, is caught in its descent by the head of the pistil, called the stigma. But how is this managed when the flowers hang down, (as does the crown imperial, for instance) and in which posi- tion, the farina, in its fall, would be carried from the stig- ma, and not towards it ? The relative length of the parts is now inverted. The pistil in these flowers is usually longer, instead of shorter, than the stamina, (PI. XXXIV. fig. 3.) that its protruding summit may receive the pollen as it drops to the ground. In some cases, (as in the nigcl- la,) (PI. XXXIV. fig. 4.) where the shafts of the pistils, or styles are disproportionably long, they bend down their extremities upon the antherse, that the necessary approxi- mation may be efiected.* * Amongst the various means which nature has provided for the , purpose of assisting the impregnation of plants, that afforded by the agency of insects is not one of the least. In the spring and summer months numerous species of these lively little beings may be seen in almost every expanded flower ; and whether they are in search of honey which is contained in the nectaries of many flowers, or what- ever may be the object of their attraction, by being continually on the move, they, no doubt, further the dispersion of the pollen, and thus, in a great measure, contribute to the fertility of the plants they visit. In many plants, as those which belong to the Linnoean class dicBcia, where the stamens and pistils are in separate flowers, and those flowers situated on two separate plants of the same species, the operation of insects, or the efficacy of winds is indispensably necessary to the per- fecting the fruit, by transporting the pollen of the one to the stigma of the other. Some plants, indeed, that have perfect, or united flowers, have the anthers so situated that it is almost impossible the pollen can, of itself, reach the stigma ; in this case insects generally become the auxiliaries to the fertilization of the seed. An instance of this may be seen in the aristolochia dematitis. " According to Professor Willdenow, the flow- er of this plant is so formed, that the anthers of themselves cannot im- pregnate the stigma; but this important affair is devolved upon a particular species of tipula. (T. pcnnicornis.) The throat of the flower is lined with dense hair, pointing downward so as to form a 200 OF PLANTS. But (to pursue this great work in its progress,) the im- pregnation, to which all this machinery relates, being com- pleted, the other parts of the flower fade and drop off, whilst the gravid seed-vessel, on the contrary, proceeds to increase its bulk, always to a great, and in some species, (in the goard, for example, and melon,) to a surprising compara- tive size ; assuming in different plants an incalculable va- riety of forms, but all evidently conducing to the security of the seed. By virtue of this process, so necessary, but so diversified, we have the seed, at length, in stone-fruits and nuts, incased in a strong shell, the shell itself enclosed in a pulp or husk, by which the seed within is, or hath been, fed; or, more generally (as in grapes, oranges, and the numerous kinds of berries) plunged over head in a glutinous syrup, contained within a skin or bladder; at other times (as in apples and pears) embedded in the heart of a firm, fleshy substance ; or, (as in strawberries) prick- ed into the surface of a soft pulp. These and many other varieties exist in what we call fruits.* In pulse, and grain, and grasses ; in trees, and shrubs, and flowers; the variety of the seed-vessels is in- kind of funnel, or entrance like that of some kinds of mouse-traps, through which the insects may easily enter but not return: several creep in, and, uneasy at their confinement, are constantly moving to and fro, and so deposit the pollen upon the stigma ; but when the work intrusted to them is completed, and impregnation has taken place, the hair which prevented their escape shrinks, and adheres closely to the sides of the llower, and these little go-betweens of Flora at length leave their prison. A writer,, however, in the Annual Medical Re- view (ii. 400.) doubts the accuracy of this f\ict, on the ground that he could never find T. pennicornis, though .^. clematitis has produced fruit two years at Bronipton." Introduction to Entomology, by Kirhy anil Spence, vol. i. p. 293. That the tipula penniconiis does enter the flowers of arisfolochia clematitis, as recorded by Professor Willdenow, I can confidently af- firm, from having observed them in great plenty in the inflated base of the corolla every year, for these last fifteen years, in the Oxford Botanic Garden, where the plant generally forms fruit. The first time I found this insect in the flowers of the above species of arisfolochia^ was on the 12th of July, 1812, at Godstow, near Oxford, where the plant was then growing in a wild state near the ruins of the nunnery. For the above observations, the Editor is indebted to an excellent botanist, Mr. W. Baxter. Paxton. * From the conformation of fruits alone, one might be led, even without experience, to suppose, that part of this pravision was des- tined for the utilities of animals. As limited to the plant, the provision itself seems to go beyond its object. The flesh of an ap])le, the pulp of an orange, the meat of a plumb, " the fatness of the olive," appear to be more than sufficient iox the uourishing of the seed or kerneL OF PLANTS. 201 computable. We have the seeds (as in the pea tribe) re- gularly disposed in parchment pods, which though soft and membranous, completely exclude the wet even in the heaviest rains ; the pod also, not seldom (as in the bean) lined v/ith a fine down ; at other times (as in the senna) distended like a blown bladder ; or we have the seed en- veloped in wool (as in the cotton plant,) lodged (as in pines) between the hard and compact scales of a cone ; or bar- ricadoed (as in the artichoke and thistle) with spikes and prickles ; in mushrooms, placed under a penthouse ; in ferns, within slits in the back part of the leaf; or (which is the most general organization of all^ we find them cov- ered by strong, close tunicles, and attached to the stem ac- cording to an order appropriated to each plant, as is seen in the several kinds of grain, and of grasses. In which enumeration what we have first to notice is^ unity of purpose under variety of expedients. Nothing can be more single than the design ; more diversified than the means. Pellicles, shells, pulps, pods, husks, skins, scales armed with thorns, are all employed in prosecuting the same intention. Secondly ; we may observe, that in all these cases, the purpose is fulfilled within a just and lim- ited degree. We can perceive, that if the seeds of plants •were more strongly guarded than they are, their greater The event shows that this redundancy, if it be one, ministers to the support and gratification of animal natures ; and when we observe a provision to be more than sufficient for one purpose, yet wanted for another purpose, it is not unfair to conclude that both purposes were contemplated together. It favours this view of the subject to remark, that fruits are not (which they might have been) ready altogether, but that they ripen in succession throughout a great part of the year ; some in summer ; some in autumn ; that some require the slow maturation of the winter, and supply the spring ; also, that the coldest fruits grow in the hottest places. Cucumbers, pin«-apples, melons, are the natur- al produce of warm climates, and contribute greatly, by their cool- ness, to the refreshment of the inhabitants of those countries. "The eatable part of the cherry or peach, first serves the purposes of perfecting the seed or kernel, by means of vessels passing through the stone, and which are very visible in a peach-stone. After the kernel is perfected, the stone becomes hard, and the vessels cease their functions. But the substance surrounding the stone is not then thrown away as useless. That which was before only an instrument for per- fecting the kernel, now receives and retains to itself the whole of the sun's influence, and thereby becomes a grateful food to man. Also, what an evident mark of design is the stone protecting the kernel I— The intervention of the stone prevents the second use from interfering srith the first." Paxton, B 2 202 OF PLANTS. security would interfere with other uses. Many species of animals would suffer, and many perish, if they could not obtain access to them. The plant would overrun the soil ; or the seed be wasted for the want of room to sow it- self. It is, sometimes, as necessary to destroy particular species of plants, as it is, at other times, to encourage their growth. Here, as in many cases, a balance is to be main- tained between opposite uses. The provisions for the pre- servation of seeds appear to be directed, chiefly against the inconstancy of the elements, or the sweeping destruction of inclement seasons. The depredations of animals, and the injuries of accidental violence, are allowed for in the abundance of the increase. The result is, that, out of the many thousand different plants which cover the earth, not a single species, perhaps, has been lost since the crea- tion. When nature has perfected her seeds, her next care is to disperse them. The seed cannot answer its purpose, while it remains confined in the capsule. After the seeds therefore are ripened, the pericarpium opens to let them out ; and the opening is not like an accidental bursting, but, for the most part, is according to a certain rule in each plant. What I have always thought very extraordina- ry, nuts and shells, which we can hardly crack with our teeth, divide and make way for the little tender sprout which proceeds from the kernel. Handling the nut, I could hardly conceive how the plantule was ever to get out of it. There are cases, it is said, in which the seed- vessel by an elastic jerk, at the moment of its explosion, casts the seed to a distance. We all however know, that many seeds (those of the most composite flowers, as of the thistle, dandelion, &c.) are endowed with what are not improperly called wings ; that is, downy appendages, by which they are enabled to float in the air, and are carried of- tentimes by the wind to great distances from the plant which produces them. It is the swelling also of this downy tuft within the seed-vessel, that seems to overcome the re- sistance of its coats, and to open a passage for the seed to escape. But the constitution of seeds is still more admirable than cither their preservation or their dispersion. In the body of the seed of every species of plant, or nearly of every one, provision is made for two grand purposes ; first, for the safety of the germ ; secondly, for the temporary support of the future plant. The sprout, as folded up in the seed, is OF PLANTS. 20^ delicate and brittle, beyond any other substance. It can- not be touched without being broken. Yet, in beans, peas, grass-seeds, grain, fruits, it is so fenced on all sides, so shut up and protected, that, whilst the seed itself is rudely handled, tossed into sacks, shovelled into heaps, the min- iature plant, the sacred particle, remains unhurt. It is wonderful also, how long many kinds of seeds, by the help of their integuments, and perhaps of their oils, stand out against decay. A grain of mustard seed has been known to lie in the earth for a hundred years ; and, as soon as it had acquired a favourable situation, to shoot as vigorously as if just gathered from the plant. Then, as to the second point, the temporary support of the future plant, the matter stands thus. In grain, and pulse, and kernels, and pippins, the germ composes a very small part of the seed. The rest consists of a nutritious substance, from which the sprout draws its aliment for some considerable time after it is put forth : viz. until the fibres, shot out from the other end of the seed, are able to imbibe juices from the earth, in a sufficient quantity for its demand. It is owing to this constitution, that we see seeds sprout, and the sprouts, make a considerable progress without any earth at all. It is an economy also, in which we remark a close analogy between the seeds of plants, and the eggs of animals. The same point is provided for, in the same manner, in both. In the egg, the residence of the living principle, the cica- trix, forms a very minute part of the contents. The white, and the white only, is expended in the formation of the chicken. The yolk, very little altered or diminished, is wrapped up in the abdomen of the young bird, when it quits the shell ; and serves for its nourishment, till it has learnt to pick its own food. This perfectly resembles the first nutrition of a plant. In the plant, as well as in the animal, the structure has every character of contrivance belonging to it ; in both it breaks the transition from pre- pared to unprepared aliment ; in both it is prospective and compensatory. In animals which suck, this intermediate nourishment is supplied by a different source. In all subjects the most common observations are the best, when it is iheir truth and strength which have made them common. There are, of this sort, two concerning plants, which it falls within our plan to notice. The Jirst relates to, what has already been touched upon, their ger- mination. When a grain of corn is cast into the ground, this is the change which takes place. From one end of 204 Cyp PLANTS. the grain issues a green sprout ; from the other a number of white fibrous threads. (PI. XXXIV. fig. 5.) How can this -be explained ? Why not sprouts from both ends ? Why not fibrous threads from both ends 1 To what is the difference to be referred, but to design ; to the different uses which the parts are thereafter to serve ; uses which discover them- selves in the sequel of the process ? The sprout, or plum- ule, struggles into the air , and becomes the plant, of which, from the first, it contained the rudiments; the fibres shoot into the earth ; and, thereby, both fix the plant to the ground, and collect nourishment from the soil for its sup- port.* Now, what is not a little remarkable, the parts is- suing from the seed take their respective directions, into whatever position the seed itself happens to be cast. If the seed be thrown into the wrongest possible position, that is, if the ends point in the ground, the reverse of what they ought to do, every thing, nevertheless, goes on right. The sprout, after being pushed down a little way, makes a bend and turns upwards ; the fibres, on the contrary, after shooting at first upwards, turn down. Of this extraor- dinary vegetable fact an account has lately been attempted to be given. " The plumule, it is said, is stimulated by the air into action, and elongates itself when it is thus most excited , the radicle is stimulated by moisture, and elongates itself when it is thus most excited. Whence one of these grows upwards in quest of its adapted object, * " The seed, the last production of vigorous vegetation, is wonder- fully diversified in form. Being of the highest importance to the re- sources of nature, it is defended above all other parts of the plant, by soft, pulpy substances, as in the esculent fruits; by thick membranes, as in the leguminous vegetables ; and by hard shells, or a thick epi- dermis, as in the palms and grasses. " In every seed there is to be distinguished, first, the organ of nourishment ; secondly, the nascent plant, or the plume \ thirdly, the nascent root, or the radicle. " In the common garden bean, the organ of nourishment is divided into two lobes, called cotyledons ; the plume is the small white point between the upper part of the lobes; and the radicle is the small curv- ed cone at their base. " In wheat, and in many of the grasses, the organ of nourishment is a single part, and these plants are called monocotyledonous. In other vcases it consists of more than two parts when the plants are called polycotyledonous. In the greater number of instances, it is, how- ever, simply divided into two, and is dicotyledonous. ■" The matter of the seed, when examined in its common state, ap- pears dead and inert ; it exhibits neither the forms nor the functions of iife. But let it be acted upon by moisture, heat and air, and its organiz- OF PLANTS. 205 and the other downward."* Were this account better verified by experimentt than it is, it only shifts the con- trivance. It does not disprove the contrivance ; it only re- moves it a little further back. Who, to use our author's own language, " adapted the objects 1" Who gave such a quality to these connate parts, as to be susceptible of dif- ferent " stimulation ;" as to be ** excited," each only by its own element, and precisely by that, which the success of the vegetation requires ? I say, ** which the success of the vegetation requires," for the toil of the husbandman would have been in vain ; his laborious and expensive preparation of the ground in vain ; if the event must, after all, depend upon the position in which the scattered seed was sown. Not one seed out of a hundred would fall in a right di- rection. Our second observation is upon a general property of climbing plants, which is strictly mechanical. In these plants, from each knot or joint, or as botanists call it, ax- illa of the plant, issue, close to each other, two shoots ; one, bearing the flower and fruit, the other, drawn out into a wire, a long, tapering, spiral tendril, that twists itself round any thing that lies within its reach. Considering, ed powers are soon distinctly developed. The cotyledons expand, the membranes burst, the radicle acquires new matter, descends into the soil, and the plume rises towards the free air. By degrees, the organs of nourishment of dicotyledonous plants become vascular, and are con- verted into seed leaves, and the perfect plant appears above the soil. Nature has provided the elements of germination on every part of the surface ; water and pure air and heat are universally active, and the means for the preservation and multiplication of life, are at once simple and grand." Sir H. Davy's Elements of Agricultural Chemistry^ ii. ed. p. 70. Paxton. * Darwin's Phytologia, p. 144. t " Gravitation has a very important influence on the growth of plants ; and it is rendered probable, by the experiments of Mr. Knight, that they owe the peculiar direction of their roots and branches al- most entirely to its force. " That gentleman fixed some seeds of the garden bean on the cir- cumference of a wheel, which in one instance was placed vertically, and in the other horizontally, and made to revolve by means of another wheel worked by water, in such a manner, that the number of the re- volutions could be regulated ; the beans were supplied with moisture, and were placed under circumstances favourable to germination. The great velocity of motion given to the wheel was such, that it perform- ed 250 revolutions in a minute. It was found that in all cases the beans grew, and that the direction of the roots and stems was influenced by the motion of the wheel. When the centrifugal force was made superior to the force of gravitation, which was supposed to be done when the vertical wheel performed 150 revolutions in a minute, all the 5206 OF PLANTS. that, in this class, two purposes are to be provided for (and together,) fructification and support, the fruitage of the plant, and the sustentation of its stalk, what means could be used more effectual, or, as I have said, more mechanical, than what this structure presents to our eyes? Why or how, without a view to this double purpose, do two shoots, of such different and appropriate forms, sprint from the same joint, from contiguous points of the same stalk ? It never happens thus in robust plants, or in trees. " We see not," says Ray, ** so much as one tree, or shrub, or herb, that hath a firm and strong stem, and that is able to mount up and stand alone without assistance, furnished with these tendrils.^* Make only so simple a comparison as that between a pea and a bean. Why does the pea put forth tendrils, the bean not ; but because the stalk of the pea cannot support itself, the stalk of the bean can; we may add also, as a circumstance not to be overlooked, that, in the pea tribe, these clasps do not make their appearance, till they are wanted ; till the plant has grown to a height to stand in need of support. This word " support," suggests to us a reflection upon the property of grasses, of corn, Eind canes. The hollow radicles, in whatever way they were protruded from the position of the seeds, turned their points outwards from the circumference of the wheel, and in their subsequent growth receded nearly at right angles from its axis ; the germens (plumules) on the contrary, took the op- posite direction, and in a few days their points all met in the centre of the wheel. " When the centrifugal force was made merely to modify the force of gravitation in the horizontal wheel, where the greatest velocity of revolution was given, the radicles pointed downwards about ten de- gi-ees below, and the germens (plumules) as many degrees above the horizontal line of the wheel's motion ; and the deviation from the per- pendicular was less in proportion as the motion was less rapid. " These facts afford a rational solution of this curious problem, re- specting which, different plilosophers have given such different opin- ions; some referring it to the nature of the sap, as De la Hire, others, as Darwin, to the living powers of the plant, and the stimulus of air upon the leaves, and of moisture upon the roots. The effect is now shown to be connected with mechanical causes ; and there seems no other power in nature to which it can with propriety be referred but gravity, which acts universally, and which must tend to dispose the parts to take a uniform direction. " The direction of the radicles and germens (plumules) is such, that both are supplied with food, and acted upon by those external agents which are necessary for their development and growth. The roots come in contact with the fluids in the ground ; the leaves are exposed to light and air; and the same grand law which preserves the planets Jn their orbits is thus essential to the functions of vegetable life." JDavy's El dgr. Chem. ii. Ed. p, 32. Faxton, OF PLANTS. 207 stems of these classes of plants, are set, at certain intervals, with joints. These joints are not found in the trunks of trees, or in the solid stalks of plants. There may be other uses of these joints; but the fact is, and it appears to be, at least, one purpose designed by them, that they corrobo- rate the stem ; which, by its length and hollowness, ^vould, otherwise, be too liable to break or bend. Grasses are Nature's care. With these she clothes the earth ; with these she sustains its inhabitants. Cattle feed upon their leaves ; birds upon their smaller seeds ; men upon the larger ; for, few readers need be told that the plants, which produce our bread-corn belong to this class. In those tribes, which are more generally considered as grasses, their extraordinary means and powers of preserva- tion and increase, their hardiness, their almost uncon- querable disposition to spread, their faculties of revivis- cence, coincide with the intention of nature concerning them. They thrive under a treatment by which other plants are destroyed. The more their leaves are consum- ed, the more their roots increase. The more they are trampled upon, the thicker they grow. Many of the seem- ingly dry and dead leaves of grasses revive, and renew their verdure, in the spring. In lofty mountains, where the summer heats are not sufficient to ripen the seeds, grasses abound, which are viviparous, and consequently able to propagate themselves without seed. It is an obser- vation, likewise, which has often been made, that herbi- vorous animals attach themselves to the leaves of grasses ; and, if at liberty in their pastures to range and choose, leave untouched the stravrs which support the flowers.* The general properties of vegetable nature, or properties comrflon to large portions of that kingdom, are almost all which the compass of our argument allows to bring for- ward. It is impossible to follow plants into their several species. We may be allowed, however, to single out three or four of these species as worthy of a particular notice, either by some singular mechanism, or by some peculiar provision, or by both. In Dr. Darwin's Botanic Garden, (line 395, note,) is the following account of the vaUisiicria, as it has been observ- ed in the river Rhone. (PI. XXXV. fig. 1, 2, 3.) ''They have roots at the bottom of the Rhone. The flowers of the female plant float on the surface of the water, and are * With. Bot. Arr. vol. i. p. 2S. ed. 2d. 208 OF PLANTS. furnished with an elastic, spiral stalk, which extends or contracts as the water rises or falls ; this rise or fall, from the torrents which flow into the river, often amounting to many feet in a few hours. The flowers of the male plant are produced under water; and, as soon as the fecundat- ing ferina is mature, they separate themselves from the plant ; rise to the surface ; and are wafted by the air, or borne by the currents, to the female flowers." Our atten- tion in this narrative will be directed to two particulars; first, to the mechanism, the "elastic, spiral stalk," which lengthens or contracts itself according as the water rises or falls ; secondly, to the provision which is made for bring- ing the male flower, which is produced under w'ater, to the female flower, which floats upon the surface. II. My second example I take from Withering. (Ar- rang. vol. ii. p. 209. ed. 3.) " The cuscuta europcE is a para- sitical plant. (Plate XXXVI.) The seed opens, and puts forth a little spiral body which does not seek the earth to take root , but climbs in a spiral direction, from right to left, up other plants, from which, by means of vessels, it draws its nourishment." The "little spiral body" proceeding from the seed is to be compared with the fibres which seeds send out in ordinary cases; and the comparison ought to regard both the form of the threads and the direction. They are straight; this is spiral. They shoot downwards; this points upwards. In the rule, and in the exception, we equally perceive design. III. A better known parasitical plant is the evergreen shrub, called the misseltoe. What we have to remark in it, is a singular instance of compensation. No art has yet made these plants take root in the earth. Here therefore might seem to be a mortal defect in their constitution. Let us examine how this defect is made up to them. The seeds are endued with an adhesive quality so tenacious, that, if they be rubbed upon the smooth bark of almost any tree, they will stick to it. And then what follows ? Roots springing from these seeds, insinuate their fibres in- to the woody substance of the tree ; and the event is, that a misseltoe plant is produced next winter;* of no other plant do the roots refuse to shoot in the ground ; of no other plant do the seeds possess this adhesive, generative quali- ty, when applied to the bark of trees. * Withering, Bot. Arr. vol. i. p. 203, ed. 2d. OF PLANTS. 209 IV. Another instance of the compensatory system is in the autumnal crocus or meadow saffron, (colchicum autum- nale.) (PI. XXXVII.) I liave pitied this poor plant a thousand times. Its blossom rises out of the ground in the most forlorn condition possible, without a sheath, a fence, a calyx, or even a leaf to protect it ; and that not in the spring, not to be visited by summer suns, but under all the disadvantages of the declining year. When we come how- ever to look more closely into the structure of this plant, we find, that instead of its being neglected, nature has gone out of her course to provide for its security, and to make up to it for all its defects. The seed-vessel, which in other plants is situated within the cup of the flower, or just beneath it, in this plant lies buried ten or twelve inches under ground within the bulbous root. The tube of the flower, which is seldom more than a few tenths of an inch long, in this plant extends down to the root. The stiles always reach the seed-vessel ; but it is in this, by an elon- gation unknown to any other plant. All these singularities contribute to one end. " As this plant blossoms late in the year, and, probably, would not have time to ripen its seeds before the access of winter, which would destroy them, Providence has contrived its structure such, that this im- portant office may be performed at a depth in the earth out of the reach of the usual effects of frost.* That is to say, in the autumn nothing is done above ground but the busi- ness of impregnation ; which is an affair between the an- therae and the stigmata. The maturation of the impregnated seed, which in other plants proceeds within a capsule, ex- posed together with the rest of the flower to the open air, is here carried on, and during the whole winter, within the heart, as we may say, of the earth ; that is, " out of the reach of the usual effects of frost." But then a new difficulty presents itself. Seeds, though perfected, are known not to vegetate at this depth in the earth. Our seeds, therefore, though so safely lodged, would, after all, be lost to the purpose for which all seeds are intended. Lest this should be the case, " a second admirable provis- ion is made to raise them above the surface when they are perfected, and to sow them at a proper distance :" viz. the germ grows up in the spring, upon a fruit stalk, accom- panied with leaves. The seeds now, in common with * Withering, ubi supra, p. 360. T 210 THE ELEMENTS. those of Other plants, have the benefit of the summer, and are sown upon the surface. The order of vegetation externally is this : The plant produces its flowers in Sep- tember ; its leaves and fruits in the spring following. V. I give the account of the dioncea muscipula, (Plate XXXVIIl.) an extraordinary American plant, as some late authors have related it ; but, whether we be yet enough ac- quainted with the plant to bring every part of this account to the test of repeated and familiar observation, I am unable to say. Its leaves are jointed, and furnished with two rows of strong prickles ; their surfaces covered with a number of minute glands, which secrete a sweet liquor, that allures the approach of flies. When these parts are touched by the legs of flies, the two lobes of the leaf instantly spring up, the rows of prickles lock themselves fast together, and squeeze the unwary animal to death."* Here, under a new model, we recognise the ancient plan of nature ; viz. the relation of parts and provisions to one another, to a common oflice, and to the utility of the organized body to ■which they belong. The attracting syrub, the rows of strong prickles, their position so as to interlock, the joints of the leaves ; and, what is more than the rest, that sin- gular irritability of their surfaces, by which they close at a touch ; all bear a contributory part in producing an ef- fect, connected either with the defence, or with the nu- trition, of the plant. CHAP. XXI. THE ELEMENTS. When we come to the elem.ents, we take leave of our mechanics ; because we come to those things, of the or- ganization of which, if they be organized, we are confess- edly ignorant. This ignorance is implied by their name. To say the truth, our investigations are stopped long be- fore we arrive at this point. But then it is for our com- fort to find, that a knowledge of the constitution of the el- ements is not necessary for us. For instance, as Addison has well observed, " we know water sufliciently when we know how to boil, how to freeze, how to evaporate, how to make it fresh, how to make it run or spout out, in what * Smellie's Phil, of Nat. His. vol. i. p. 5. THE ELEMENTS. 211 quantity and direction we please, without knowing what water is." The observation of this excellent writer has more propriety in it now, than it had at the time it was made: for the constitution, and the constituent parts of water, appear in some measure to have been lately discov- ered; yet it does not, I think, appear, that we can make any better or greater use of water since the discovery, than we did before it. We can never think of the elements without reflecting upon the number of distinct uses which are consolidated in the same substance. The air supplies the lungs, sup- ports fire, conveys sound, reflects light, diffuses smells, gives rain, wafts ships, bears up birds. 'E| v^xro? rcc Trccvrx; toater, beside maintaining its own inhabitants, is the uni- versal nourisher of plants, and through them of terrestrial animals, is the basis of their juices and fluids: dilutes their food, quenches tlieir thirst, floats their burdens. jpfVe warms, dissolves, enlightens; is the great promoter of vegetation and life, if not necessary to the support of both. We might enlarge, to almost any length we pleased, up- on each of these uses; but it appears to, me almost suffi- cient to state them. The few remarks which I judge it necessary to add, are as follow. I. Air is essentially diff*erent from earth. There ap- pears to be no necessity for an atmosphere's investing our globe: yet it does invest it; and we see how many, how various, and how important are the purposes which it answers to every order of animated, not to say of organized, beings, which are placed upon the terres- trial surface, I think that every one of these uses will be understood upon the first mention of them, except it be that of reflecting light, which may be explained thus. If I had the power of seeing only by means of rays com- ing directly from the sun, whenever I turned my back up- on the luminary, I should find myself in darkness. If I had the power of seeing by reflected light, yet by means only of light reflected from solid masses, these masses would shine, indeed, and glisten, but it would be in the dark. The hemisphere, the sky, the world, could only be illnmi' 7iated, as it is illuminated, by the light of the sun being from all sides, and in every direction, reflected to the eye, by particles, as numerous, as thickly scattered, and as widely diffused, as are those of the air, 212 THE ELEMENTS. Another general quality of the atmosphere is, the power of evaporating fluids. The adjustment of this quality to our use is seen in its action upon the sea. In the sea, water and salt are mixed together most intimately ; yet the atmosphere raises the water, and leaves the salt. Pure and fresh as drops of rain descend, they are collected from brine. If evaporation be solution, (which seems to be probable,) then the air dissolves the water and not the salt. Upon whatever it be founded, the distinction is critical ; so much so, that, when v\e attempt to imitate the process by art, we must regulate our distillation with great care and nicety, or, together with the water, we get the bitterness, or, at least, the distastefulness of the marine substance: and, after all, it is owing to this original elective power in the air, that we can effect the separation which we wi&h, by any art or means whatever. By evaporation water is carried up into the air ; by the converse of evaporation it falls down upon the earth. And how does it fall ? Not by the clouds being all at once con- verted into water, and descending like a sheet; not in rushing down in columns from a spout; but in moderate drops, as from a colander. Our watering-pots are made to imitate showers of rain. Yet, d priori, I should have thought either of the two former methods more likely to have taken place than the last. By respiration, flame, putrefaction, air is rendered un- fit for the support of animal life. By the constant oper^ ation of these corrupting principles, the whole atmosphere, if there were no restoring causes, would come at length to be deprived of its necessary degree of purity. Some of these causes seem to have been discovered, and their efii- cacy ascertained by experiment. And so far as the dis- covery has proceeded, it opens to us a beautiful and a wonderful economy. Vegetation proves to be one of them, A sprig of mint, corked up with a small portion of foul air placed in the light, renders it again capable of supporting life or flame. Here, therefore, is a constant circulation of benefits maintained between the two great provinces of organized nature. The plant purifies, what the animal has poisoned : in return, the contaminated air is more than ordinarily nutritious to the plant. Agitation with water turns out to be another of these restoratives. The foulest air, shaken in a bottle with water for a sufficient length of time, recovers a great degree of its purity. Here then again, allowing for the scale upon which nature works, we THE ELEMENTS. 'SIS see the salutary effects of storms and tempests. The yesty waves, which confound the heaven and the sea, are doing the very thing which is done in the bottle. Nothing can be of greater importance to the living creation, than the salubrity of their atmosphere. It ought to reconcile us therefore to these agitations of the elements, of which we sometimes deplore the consequences, to know, that they tend powerfully to restore to the air that purity, which so many causes are constantly impairing. II. In WATER, what ought not a little to be admired, are those negative qualities which constitute its purity. Had it been vinous, or oleaginous, or acid ; had the sea been filled, or the rivers flowed with wine or milk ; fish, constituted as they are, must have died; plants, constitut- ed as they are, would have withered ; the lives of animals, which feed upon plants, must have perished. Its very in- sipiditi/, which is one of those negative qualities, renders it the best of all menstrua. Having no taste of its own, it becomes the sincere vehicle of every other. Had there been a taste in water, be it what it might, it would have infected every thing we ate or drank, with an importunate repetition of the same flavour. Another thing in this element, not less to be admired, is the constant round which it travels ; and by which, without suffering either adulteration or waste, it is contin- ually offering itself to the wants of the habitable globe. From the sea are exhaled those vapours which form the clouds. These clouds descend in showers, which, pene- trating into the crevices of the hills, supply springs. Which springs flow in little streams into the vallies ; and, there uniting, become rivers. Which rivers, in return, feed the ocean. So there is an incessant circulation of the same fluid ; and not one drop probably more or less now than there was at the creation. A particle of water takes its departure from the surface of the sea, in order to fulfil cer- tain important offices to the earth ; and, having executed the service which was assigned to it, returns to the bosom which it left. Some have thought that we have too much water upon the globe ; the sea occupying above three quarters of its whole surface. But the expanse of ocean, immense as it is, may be no more than sufficient to fertilize the earth. Or, independently of this reason, I know not why the sea may not have as good a right to its place as the land. It T 2 214 THE ELEMENTS. may proportionably support as many inhabitants ; minister to as large an aggregate of enjoyment. The land only af- fords a habitable surface ; the sea is habitable to a great depth. III. Of FIRE, we have said that it dissolves. The only idea probably which this term raised in the reader's mind was, that of fire melting metals, resins, and some other substances, fluxing ores, running glass, and assisting us in many of our operations, chemical or culinary. Now these are only uses of an occasional kind, and give us a very imperfect notion of what fire does for us. The grand im- portance of this dissolving power, the great office indeed of fire in the economy of nature, is keeping things in a state of solution, that is to say, in a state of fluidity. Were it not for the presence of heat, or of a certain degree of it, all fluids would be frozen. The ocean itself would be a quar- ry of ice ; universal nature stiff" and dead. We see, therefore, that the elements bear not only a strict relation to the constitution of organized bodies, but a relation to each other. Water could not perform its of- fice to the earth without air ; nor exist as water, without fire. IV. Of LIGHT, (whether we regard it as of the same substance with fire, or as a different substance,) it is alto- gether superfluous to expatiate upon the use. No man dis- putes it. The observations, therefore, which I shall offer, respect that little which we seem to know of its constitution. Light travels from the sun, at the rate of twelve millions of miles in a minute. Urged by such a velocity, with wh3.t force must its particles drive against, I will not say the eye, the tenderest of animal substances, but every sub- stance, animate or inanimate, which stands in its way ? It might seem to be a force sufficient to shatter to atoms the hardest bodies. How then is this effect, the consequence of such prodi- gious velocity guarded against ? By a proportionable mi- niitencss of the particles of which light is composed. It is impossible for the human mind to imagine to itself any thing so small as a particle of light. But this extreme ex- ility, though difficult to conceive, is easy to prove. A drop of tallow, expended in the wick of a farthing candle, shall shed forth rays sufficient to fill a hemisphere of a mile di- ameter ; and to fill it so full of these rays, that an aperture not larger than the pupil of an eye, wherever it be placed within the hemisphere, shall be sure to receive some of them. What floods of light are continually poured from ASTRONOMY. 215 the sun, we cannot estimate ; but the immensity of the sphere which is filled with its particles, even if it reached no further than the orbit of the earth, we can in some sort compute : and we have reason to believe, that, throughout this whole region, the particles of light lie, in latitude at least, near to one another. The spissitude of the sun's rays at the earth is such, that the number which falls upon a burning glass of an inch diameter, is sufficient, when concentrated, to set wood on fire. The tenuity and the velocity of particles of light, as as- certained by separate observations, may be said to be pro- portioned to each other: both surpassing our utmost stretch of comprehension, — but proportioned. And it is this pro- portion alone, which converts a tremendous element into a welcome visitor. It has been observed to me by a learned friend, as hav- ing often struck his mind, that, if light had been made by a common artist, it would have been of one uniform colour: whereas, by its present composition, we have that variety of colours, which is of such infinite use to us for the dis- tinguishing of objects ; which adds so much to the beauty of the earth, and augments the stock of our innocent pleasures. With which may be joined another reflection, viz. that, considering light as compounded of rays of seven differ- ent colours, (of which there can be no doubt, because it can be resolved into these rays by simply passing it through a prism) the constituent parts must be well mixed and blended together, to produce a fluid, so clear and colour- less, as a beam of light is, when received from the sun. CHAP. XXII. ASTRONOMY.* My opinion of Astronomy has always been, that it is not the best medium through which to prove the agency of an intelligent Creator ; but that, this being proved, it shows beyond all other sciences, the magnificence of his opera- tions. The mind, which is once convinced, it raises to '^ For the articles in this chapter marked with an asterisk, I am in- tlebted to some obligins: communications, received (through the hands of the Lord Bishop of Elphin) from the Rev. J. Brinkley, M. A. An- drew's Professor of Astronomy in the University of Dubhn. 216 ASTRONOMY. sublimer views of the Deity, than any other subject af- fords ; but It is not so well adapted, as some other subjects are, to the purpose of argument. We are destitute of the means of examining the constitution of the heavenly bodies. The very simplicity of their appearance is against them. We see nothing, but bright points, luminous circles, or the phases of spheres reflecting the light which falls upon them. Now we deduce designs from relation, aptitude, and cor- respondence of parts. Some degree therefore of complex- ity is necessary to render a subject fit for this species of argument. But the heavenly bodies do not, except perhaps in the instance of Saturn's ring, present themselves to our observation as compounded of parts at all. This, which may be a perfection in them, is a disadvantage t^ us, as inquirers after their nature. They do not come within our mechanics. And what we say of their forms is true of their motions. Their motions are carried on without any sensible interme- diate apparatus; whereby we are cut off from one principal ground of argumentation, analogy. We have nothing wherewith to compare them ; no invention, no discovery, no operation or resource of art, which, in this respect, re- sembles them. Even those things which are made to im- itate and represent them, such as orreries, planetaria, celes- tial globes, &c. bear no affinity to them, in the cause and principle by which their motions are actuated. I can as- sign for this difference a reason of utility, viz. a reason why though the action o'i terrestrial hod'iQs upon each other be, in almost all cases, through the intervention of solid or fluid substances, yet central attraction does not operate in this manner. It was necessary that the intervals between the planetary orbs should be devoid of any inert matter, either fluid or solid, because such an intervening substance would, by its resistance, destroy those very motions, which attrac- tion is employed to preserve. This may be a final cause of the difference; but still the difference destroys the an- alogy.* * The moon has no perceptible atmosphere ; and as no effects have been observed like those which would be produced by vapours or ex- halations from its surface, it is possible that there are no fluids upon it. There is no reason, however, from these circumstances for deny- ing the existence of sensitive beings upon it, although they must be very differently constituted from ourselves, to whom air and water are essentially necessary. Faxton. ASTRONOMY. 217 Our ignorance, moreover, of the sensitive natures, by which other planets are inhabited, necessarily keeps from us the knowledge of numberless utilities, relations, and subserviencies, which we perceive upon our own globe. After all ; the real subject of admiration is, that we un- derstand so much of astronomy as we do. That an animal confined to the surface of one of the planets, bearing a less proportion to it, than the smallest microscopic insect* does to the plant it lives upon ; that this little, busy, in- quisitive creature, by the use of senses which were given to it for its domestic necessities, and by means of the as- sistance of those senses which it has had the art to procure, should have been enabled to observe the whole system of worlds to which its own belongs ; the changes of place of the immense globe, which compose it ; and with such accuracy, as to mark out, before -hand, the situation in the heavens in which they will be found in any future point of time ; and that these bodies, after sailing through regions of void and trackless space, should arrive at the place where they were expected, not within a minute, but within a few seconds of a minute, of the time prefixed and predicted ; all this is wonderful, whether we refer our admiration to the constancy of the heavenly motions themselves, or to thQ perspicacity and precision with which they have been non ticed by mankind. Nor is this the whole, nor indeed the chief part, of what astronomy teaches. By bringing reason to bear upon observation, (the acutest reasoning upon the exactest observation,) the astronomer has been able, out of the confusion, (for such it is) under which the motions of the heavenly bodies present themselves to the eye of a mere gazer upon the skies, to elicit their order and their real paths. Our knowledge therefore of astronomy is admirable, though imperfect ; and, amidst the confessed desiderata and desideranda, which impede our investigation of the wisdom of the Deity, in these the grandest of his works, there are to be found, in the phenomena, ascertained cir^ * Hooke describes a minute animalcule, which he discovered with a microscope, upon the vine. From his data an estimate may be made of its bulk ; but it is not so easy to fix upon any determinate quantity for the size of tlie plant. However, to put the case strongly, let the bulk of it be taken as equal to that of a cylinder one inch in diameter, and a mile in length. Such a cylinder would contain above 345 cubic feet, and yet it would be many million times less, when compared with the animalcule, than the earth is whgn compared with the bulk of a man, Faxton, 218 ASTRONOMY. cumstances and laws, sufficient to indicate an intellectual agency in three of its principal operations, viz. in choosing, in determining, in regulating; in choosing, out of a bound- less variety of suppositions which were equally possible, that which is beneficial ; in determining, what, left to it- self, had a thousand chances against conveniency, for one in its favour ; in re^^^/«f^«^ subjects, as to quantity and de- gree, which, by their nature, were unlimited with respect to either. It will be our business to offer, under each of these heads, a few instances, such as best admit of a popu- lar explication. I. Amongst proofs of choice, one is, fixing the source of light and heat in the centre of the system. The sun is ignited and luminous; the planets which move round him, cold and dark. There seems to be no antecedent necessity for this order. The sun might have been an opaque mass; some one, or two, or more, or any, or all, of the planets, globes of fire. There is nothing in the nature of the heav- enly bodies, which requires that those which are stationary should be on fire, that those which move should be cold ; forj in fact, comets are bodies on fire,* yet revolve round a centre ; nor does this order obtain between the primary planets and their secondaries, which are all opaque. When we consider, therefore, that the sun is one ; that the planets going round it are, at least, seven ;t that it is indifferent to their nature which are luminous and which are opaque : and also, in what order with respect to each other, these two kinds of bodies are disposed j we may judge of the im- * It may be reasonably doubted whether comets are ever absolute- ly "on fire;" and yet some of them, from their near approach to the sun, must certainly be "capable of intense heat." If we conceive the earth's distance from the sun to be divided into 1000 parts, the comet of 16S0 was, at one time, not more distant than six of those parts from the sun. From hence Sir I. Newton calculated that it was exposed to a heat which was 2000 times greater than that of a red-hot iron. Paxton. t The seven planets here alluded to, are Mercury, Venus, the Earth, Mars, Jupiter, Saturn, and the Georgium Sidus ; we now Jinow that there are four more, Ceres, Pallas, Juno and Vesta ; the first of these was discovered in 1801, the second was observed in March, 1802, the third, was not discovered till 1804, nor the last till 1807. Now Dr. Paley's dedication is. dated July, 1802; it is very possible, therefore, that this 22d chapter was written before he had heard of Pallas, and even while it was yet doubtful whether Ceres was a comet or a planet. This will explain the reason for his hav- ing qualified the expression, and having said, " at least seven." ASTROTSF()MY. 219 probability of the present arrangement taking place by chance. If, by way of accounting for the state in which we find the solar system, it be alleged, (and this is one amongst the guesses of those who reject an intelligent Creator) that the planets themselves are only cooled or cooling masses, and were once, like the sun, many thousand times hotter thaii red hot iron ; then it follows, that the sun also himself must be in his progress towards growing cold ; which puts an end to the possibility of his having existed, as he is,- from eternity. This consequence arises out of the hypoth- esis with still more certainty, if we make a part of it, what the philosophers, who maintain it, have usually taught, thai the planets were originally masses of matter struck off, in a state of fusion, from the body of the sun, by the percus- sion of a comet, or by a shock from some other cause with which we are not acquainted ; for, if these masses, partak- ing of the nature and substance of the sun's body, have in process of time lost their heat, that body itself, in time likewise, no matter in how much longer time, must lose its heat also ; and therefore be incapable of an eternal dura- tion in the state in which we see it, either for the time to come, or the time past. The preference of the present to any other mode of dis- tributing luminous and opaque bodies I take to be evident. It requires more astronomy than I am able to lay before the reader, to show, in its particulars, what would be the effect to the system, of a dark body at the centre, and of one of the planets being luminous: but I think it manifest, without either plates or calculation, first, that, supposing the necessary proportion of magnitude between the central and the revolving bodies to be preserved, the ignited planet would not be sufficient to illuminate and warm the rest of the system ; secondly, that its light and heat would be im- parted to 'the other planets, much more irregularly than light and heat are now received from the sun. (*) II. Another thing, in which a choice appears to be exercised, and in which, amongst the possibilities out of which the choice was to be made, the number of those which were wrong, bore an infinite proportion to the num- ber of those which were right, is in what geometricians call the axis of rotation. This matter I will endeavour to explain. The earth, it is well known, is not an exact globe, but an oblate spheroid, something like an orange. JN^ow the axes of rotation, or the diameters upon which such 220 ASTRONOMYr a body may be made to turn round, are as many as can be drawn through its centre to opposite points upon its whole surface ; but of these axes none are permanent^ except either its shortest diameter, i. e. that which passes through the heart of the orange from the place where the stalk is inserted into it, and which is but one ; or its longest diame- ters, at right angles with the former, which must all ter- minate in the single circumference which goes round the thickest part of the orange. This shortest diameter is that upon which in fact the earth turns ; and it is, as the reader sees, what it ought to be, a permanent axis ; where- as, had blind chance, had a casual impulse, had a stroke or push at random, set the earth a-spinning, the odds were in- finite, but that they had sent it round upon a wrong axis^ And what would have been the consequence? The difference between a permanent axis and another axis is this. When a spheroid in a state of rotatory motion gets upon a perma- nent axis, it keeps there ; it remains steady and fakhful to its position ; its poles preserve their direction with respect to the plane and to the centre of its orbit ; but, whilst it turns upon an axis which is not permanent, (and the num- ber of those, we have seen, infinitely exceeds the number of the other,) it is always liable to shift and vacillate from one axis to another, with a corresponding change in the inclination of its poles. Therefore, if a planet once set off revolving upon any other than its shortest, or one of its long- est axes, the poles on its surface would keep perpetually changing, and it never would attain a permanent axis of rotation. The effect of this unfixedness and instability would be, that the equatorial parts of the earth might be- come the polar, or the polar the equatorial ; to the utter de- struction of plants and animals, which are not capable of interchanging their situations, but are respectively adapted to their own. As to ourselves, instead of rejoicing in our temperate zone, and annually preparing for the moderate vicissitude, or rather the agreeable succession of seasons, j^hich we experience and expect, we might come to be locked up in the ice and darkness of the arctic circle, with bodies neither inured to its rigours, nor provided with shel- ter or defence against them. Nor would it be much bet- ter, if the trepidation of our pole, taking an opposite course, should place us under the heats of a vertical sun. But, if it would fare so ill with the human inhabitant, who can live under greater varieties of latitude than any other ani- mal, still more noxious would this translation of climate ASTRONOMY. 22 have proved to life in the rest of the creation ; and, most perhaps of all, in plants. The habitable earth, and its beautiful variety, might have been destroyed, by a simple mischance in the axis of rotation.* (*) III. All this, however, proceeds upon a supposition of the earth having been formed at first an oblate spheriod. There is another supposition ; and, perhaps, our limited information will not enable us to decide between them. The second supposition is, that the earth, being a mixed mass, somewhat fluid, took, as it might do, its present form, by the joint action of the mutual gravitation of its parts and its rotatory motion. This, as we have said, is a point in the history of the earth, which our observations are not sufficient to determine. For a very small depth below the surface (but extremely small, less, perhaps, than an eight thousandth part,t compared with the depth of the centre) we find vestiges of ancient fluidity. But this fluidity must hav€ gone down many hundred times further than we can penetrate, to enable the earth to take its present oblate form ; and, whether any traces of this kind exist to that depth, we are ignorant. Calculations were made a few years ago of the mean density of the earth, by comparing the force of its attraction with the force of attraction of a rock of granite, the bulk of which could be ascertained ; and the upshot of the calculation was, that the earth upon an average, through its whole sphere, has twice the density *^The earth being an oblate spheroid, we may suppose it to be cut by a plane passing through A B, Fig 3, Plate XXXIX, which may rep- rent its axis, and the common section of this plane with the spheroid will be an ellipse like A D B E ; of this ellipse A B will be an axis ; and, from the property of the curve, it will also be the shortest line which can be drawn through the centre C. If now the diameter D E be drawn at right angles to A B, it will be the longest line which can be drawn in the ellipse, and it will represent a diameter of the equator. As the plane passing through A B is not confined to one situation more than another, D E may represent any "one of the longest axes of the spheroid," and will, as well as A B, always be a " permanent axis of rotation." But if any other diameter, as G H, is taken, the earth could not continue to revolve permanently about it. Paxton. t The "deep St. John," one of the deepest mines in the Hartz, was found by M. Deluc to sink 1359 feet. This was in 1778; and it may, since that time, have been carried lower, but probably not to the depth of the mine of Valenciana in New Spain, the bottom of which, according to Humboldt, is 1681 feet below the surface. Now the di- ameter of the earth being about 7912 miles, "the eight-thousandth part of the depth of the centre " must be 2611 feet, or nearly half a mile. Ibid, u 222 ASTRONOiMY. of granite, or about five times that of water. Therefore it cannot be a hollow shell, as some have formerly supposed ; nor can its internal parts be occupied by central fire, or by water. The solid parts must greatly exceed the fluid parts ; and the probability is, that it is a solid mass throughout, composed of substances, more ponderous the deeper we go. Nevertheless, we may consider the present face of the earth to have originated from the revolution of a sphere, covered with a surface of a compound mixture ; the fluid and solid parts separating, as the surface became quiescent. Here then comes in the moderating hand of the Creator. If the water had exceeded its present proportion, even but by a trifling quantity compared with the whole globe, all the land would have been covered ; had there been much less than there is, there would not have been enough to fertilize the continent.* Had the exsiccation been progressive, such as we may suppose to have been produced by an envaporat- ing heat, how came it to stop at the point at which we see it? Why did it not stop sooner; why at all? The man- date of the Deity will account for this : nothing else will. VI. Of centripetal forces. By virtue of the simplest law that can be imagined, viz. that a body continues in the state in which it is, whether of motion or rest : and, if in motion, goes on in the line in which it was proceeding, and with the same velocity, unless there be some cause for change ; by virtue, I say, of this law, it comes to pass (what may appear to be a strange consequence) that cases arise, in which attraction, incessantly drawing a body to- wards a centre, never brings, nor ever will bring, the l3ody to that centre, but keep it in eternal circulation round it. If it were possible to fire off" a cannon ball with a velocity of five miles in a second, and the resistance of the air could be taken away, the cannon ball would for ever wheel round the earth, instead of falling down upon it.t This is the * Nearly three quarters of tlic earth's suiface are covered by the sea. Now evaporation is proportionate to the surface of the fluid, and consequently a less expanse of waters would not have afforded a suffi- cient f-upply of rain, which does not now fall upon the whole, in greater quantities than are required " to fertilize the earth." Paxton, t If a body be projected horizontally from a station A, Fig. 6, Piute XXXIX, which is at a certain height, its weight or the force of gravity will draw it towards the earth. It may be supposed to come down, for example, at B. But from the tendency which the body has to continue in the state of motion which is communicated to it, it will be carried further before it falls, if it is projected with a greater force. Hence, if this force be increased, it may be made to reach C ; by a greater in- crease, it may be carried to D; or even round to A, from whence it originally set out. Ibid. ASTRONOMY. 223 principle which sustains the heavenly motions. The Deity having appointed this law to matter, than which, as we have said before, no law could be more simple, has turned it to a wonderful account in constructing planetary systems. The actuating cause in these systems, is an attraction which varies reciprocally as the square of the distance ; that is, at double the distance, has a quarter of the force : at half the distance, four times the strength ; and so on. Now, concerning this law of variation, we have three things to observe; first, that attraction, for any thing we know about it, was just as capable of one law of variation as of another ; secondly ; that, out of an infinite number of possible laws, those which were admissible for the purpose of supporting the heavenly motions, lay within certain narrow limits ; thirdly; that of the admissible laws, or those which come within the limits prescribed, the law that actually prevails is the most beneficial. So far as these propositions can be made out, we may be said, I think, to prove choice and regulation ; choice, out of boundless variety ; and regula- tion, of that which, by its own nature, was, in respect of the property regulated, indifferent and indefinite. I. First, then, attraction, for any thing we know about it, was originally indifferent to all laws of variation depend- ing upon change of distance, i. e. just as susceptible of one law as of another. It might have been the same at all distances. It might have increased as the distance in- creased. Or it might have diminished with the increase of the distance, yet in ten thousand different proportions from the present : It might have followed no stated law at all. If attraction be, what Cotes, with many other Newtonians have thought it to be, a primordial property of matter, not dependent upon, or traceable to, any other material cause, then, by the very nature and definition of a primordial prop- erty, it stood indifferent to all laws. If it be the agency of something immaterial, then also, for any thing we know of it, it was indifferent to all laws. If the revolution of bodies round a centre depend upon vortices, neither are these limited to one law more than another. There is, I know, an account given of attraction, which should seem, in its very cause, to assign to it the law, which we find it to observe, and which, therefore, makes that law, a law not of choice, but of necessity ; and it is the account which ascribes attraction to an emanation from the attracting body. It is probable, that the influence of such an emanation will be proportioned to the spissitude of the '^24 ASTRONOMY. rays of which it is composed ; which spissitude, supposing the rays to issue in right lines on all sides from a point, will be reciprocally as the square of the distance.* The mathe- matics of this solution we do not call in question ; the question with us is, whether there be any sufficient reason to believe, that attraction is produced by an emanation. For my part, I am totally at a loss to comprehend, how particles streaming from a centre, should draw a body to- wards it. The impulse, if impulse it be, is all the other way. Nor shall we find less difficulty in conceiving, a conflux of particles, incessantly flowing to a centre, and carrying down all bodies along with it, that centre also it- self being in a state of rapid motion through absolute space ; for, by what source is the stream fed, or what be- comes of the accumulation ? Add to which, that it seems to imply a contrariety of properties, to suppose an ethereal fluid to act, but not to resist ; powerful enough to carry down bodies with great force towards a centre, yet, in- consistently with the nature of inert matter, powerless and perfectly yielding with respect to the motions which result from the projectile impulse. By calculations drawn from ancient notices of eclipses of the moon, we can prove, that if such a fluid exist at all, its resistance has had no sensi- ble effect upon the moon's motion for two thousand five hundred years. The truth is, except this one circumstance of the variation of the attracting force at different distances agreeing with the variation of the spissitude, there is no reason vvhatever to support the hypothesis of an emanation ; and, as it seems to me, almost insuperable reasons against it. * Let the liajht of a candle fall upon a square object like A B C D, Fig. 4, Plate XXXIX, and if a screen be placed parallel to the object, and at double the distance, the shadow E F G H, received upon it, will be four times the size of the object itself. For the rays passing in straight lines by the angles A, B, C, D, the sides E F, F G, G H, H E, must be each double of A B, B C, CD, DA: therefore, the shadow may be divided into four squares, each equal in size to the object. At three times the distance from the candle, the sides of the shadow- would each be three times as large as the sides of the object, and its area would, therefore, contain nine times the space. For the same reason if the distance be increased four, five, or six times, the area of the shadow will contain sixteen, twenty-five, or thirty-six squares, each equal to the object. Now the quantity of light which falls upon the object would, if it had not been intercepted, have spread over that part of the screen which is occupied by the shadow ; and as the sur- face is increased, over which a certain quantity of rays is spread, in the same ratio their spissitude or density will be diminished ; consequently this spissitude will be reciprocally as the squares of the distances. Paxton. ASTRONOMY. 225 (*) II. Our second proposition is, that, whilst the pos- sible laws of variation were infinite, the admissible laws, or the laws compatible with the preservation of the system, lay within narrow limits. If the attracting force had va- ried according to any direct law of the distance, let it have been what it would, great destruction and confusion would have taken place. The direct simple proportion of the distance would, it is true, have produced an ellipse ; but the perturbing forces would have acted with so much ad- vantage, as to be continually changing the dimensions of the ellipse, in a manner inconsistent with our terrestrial creation. For instance ; if the planet Saturn, so large and so remote, had attracted the earth, both in proportion to the quantity of matter contained in it, which it does ; and also in any proportion to its distance, i. e. if it iiad pulled the harder for being the further off, (instead of the reverse of it,) it vvould have dragged the globe which we inhabit out of its course, and have perplexed its motions, to a de- gree incompatible with oor security, our enjoyments, and probably our existence. Of the inverse laws, if the cen- tripetal force had changed as the cube of the distance, or in any higher proportion, that is, (for I speak to the un- learned,) if, at double the distance, the attractive force had been diminished to an eighth part, or to less than that, the consequence would have been, that the planets, if they once began to approach the sun, would have fallen into his body; if they once, though by ever so little, increased their distance from the centre, would for ever have receded from it. The laws therefore of attraction, by which a system of revolving bodies could be upheld in their motions, lie within narrow limits, compared with the possible laws. I much underrate the restriction, when I say, that in a scale of a mile they are confined to an inch. ' All direct ratios of the distance are excluded, on account of danger from perturbing forces ; all reciprocal ratios, except what lie beneath the cube of the distance, by the demonstrable consequence, that every, the least change of distance, would, under the operation of such laws, have been fatal to the repose and order of the system. We do not know, that is, v.'e seldom reflect, how interested we are in this matter. Small irregularities may be endured ; but, changes within these limits being allowed for, the permanency of our ellipse is a question of life and death to our whole sensitive world. U 2 226 ASTRONOMY. (*) III. That the subsisting law of attraction falls within the limits which utility requires, when these limits bear so small a proportion to the range of possibilities, upon which chance might equally have cast it, is not, with any appearance of reason, to be accounted for, by any other cause than a regulation proceeding from a designing mind. But our next proposition carries the matter somewhat fur- ther. We say, in the third place, that, out of the different laws which lie within the limits of admissible laws, the best is made choice of; that there are advantages in this particular law which cannot be demonstrated to belong to any other law ; and concerning some of which, it can be demonstrated that they do not belong to any other. (*) 1. Whilst this law prevails between each particle of matter, the united attraction of a sphere, composed of that matter, observes the same law. This property of the law is necessary, to render it applicable to a system com- posed of spheres, but it is a property which belongs to no other lav/ of attraction that is admissible. The law of va- riation of the united attraction is in no other case the same as the law of attraction of each particle, one case excepted, and that is of the attraction varying directly as the distance ; the inconveniency of which law in other respects we have already noticed.* We may follow this regulation somewhat farther, and still more strikingly perceive that it proceeded from a designing mind. A law both admissible and convenient was requisite. In what way is the law of the attracting globes obtained? Astronomical observations and terrestrial experiments show that the attraction of the globes of the system is made up of the attraction of their parts ; the attraction of each globe being compounded of the attraction of its parts. Kovv, the admissible and convenient law which exists, could not: be ob- tained in a system of bodies gravitating by the united grav- itation of their parts, unless each particle of matter were attracted by a force varying by one particular law, viz. va- rying inversely as the square of the distance ; for, if the ac- tion of the particles be according to any other law what- ever, the admissible and convenient law which is adopted *Let A, Fig. 5, Plate XXXIX, represent a sphere composed of par- ticles, which mutually attract each other with a force, which varies reciprocally as the squares of the distances ; their uuited attraction, on a similar particle P without the sphere, will be according to the same law ; that is, the particle will be attracted towards the sphere with a force which will also vary reciprocally as the square of C P, its dis- tance from the centre of the sphere. Paxton. ASTRONOMY. 227 could not be obtained. Here then are clearly shown regu- lation and design. A law both admissible and convenient was to be obtained : the mode chosen for obtaining that law was by making each particle of matter act. After this choice was made, then farther attention was to be given to each particle of matter, and one, and one only particular law of action to be assigned to it. No other law would have an- swered the purpose intended. (*) 2. All systems must be liable io perturbations. And therefore to guard against these perturbations, or rather to guard against their running to destructive lengths, is per- haps the strongest evidence of care and foresight that can be given. Now we are able to demonstrate of our law of attraction, what can be demonstrated of no other, and what qualiiies the dangers which arise from cross but unavoidable influences, that the action of the parts of our system upon one another will not cause })ermanently increasing irregular- ities, but merely periodical or vibratory ones ; that is, they will come to a limit, and then go back again. This we can demonstrate only of a system, in which the following prop- erties concur, viz. that the force shall be inversely as the square of the distance ; the masses of the revolving bodies small, compared with that of the body at the centre ; the or- bits not much inclined to one another ; and their eccentricity little. In such a system the grand points are secure. The mean distances and periodic times, upon which depend our temperature, and the regularity of our year, are constant. The eccentricities, it is true, will still vary, but so slowly, and to so small an extent, as to produce no inconveniency from fluctuation of temperature and season. The same as to the obliquity of the planes of the orbits. For instance, the inclination of the ecliptic to the equator will never change above two degrees, (out of ninety,) and that will require many thousand years in performing. It has been rightly also remarked, that, if the great planets, Jupiter and Saturn, had moved in lower spheres, their influences would have had much more effect as to disturbing the planetary motions than they now have. While they revolve at so great distances from the rest, they act almost equally on the sun and on the inferior planets, which has nearly the same consequence as not acting at all upon either. If it be said that the planets might have been sent round the sun in exact circles, in which case, no change of dis- tance from the centre taking place, the law of variation of 228 ASTRONOMY. the attracting power would have never come in question ; one law would have served as well as another ; an answer to the scheme may be drawn from the consideration of these same perturbing forces. The system retaining in other respects its present constitution, though the planets had been at first sent round in exact circular orbits, they could not have kept them ; and if the law of attraction had not been what it is, (or, at least, if the prevailing law had trans- gressed the limits above assigned,) every evagation would have been fatal ; the planet once drawn, as drawn it neces- sarily must have been out of its course, would have wan- dered in endless error. (*) V. What we have seen in the law of the centripetal force, viz. a choice guided by views of utility, and a choice of one law out of thousands which might equally have tak- en place, we see no less in the figures of the planetary or- bits. It was not enough to fix the law of the centripetal force, though by the wisest choice ; for, even under that law, it was still competent to the planets to have moved in paths possessing so great a degree of eccentricity, as, in the course of every revolution, to be brought very near to the sun, and carried away to immense distances from him. The comets actually move in orbits of this sort : and, had the planets done so, instead of going round in orbits near- ly circular, the change from one extremity of temperature to another must, in ours at least, have destroyed every ani- mal and plant upon its surface. Now, the distance from the centre at which a planet sets off, and the absolute force of attraction at that distance being fixed, the figure of its orbit, its being a circle, or nearer to, or further off from a circle, viz. a rounder or a longer oval, depends up- on two things, the velocity with which, and the direction in which the planet is projected. And these, in order to produce a right result, must be both brought witiiin certain narrow limits. One, and only one velocity, united with one, and only one direction, will produce a perfect circle. And the velocity must be near to this velocity, and the di- rection also near to this direction to produce orbits, such as the planetary orbits are, nearly circular ; that is, ellipses with small eccentricities. The velocity and the direction must both be right. If the velocity be wrong, no direction will cure the error; if the direction be in any considerable degree oblique, no velocity will produce the orbit required. Take, for example, the attraction of gravity at the surface of the earth. The force of that attraction being what it is, out ASTRONOMY. 229 of all the degrees of velocity, swift and slow, with which a ball might be shot off, none would answer the purpose of which we are speaking but what was nearly that of five miles in a second.* If it were less than that, the body would not get round at all, but would come to the ground: if it were in any considerable degree more than that, the body would take one of those eccentric courses, those long ellipses, of which we have noticed the inconveniency.t If * The moon describes in one second of time, nearly two thirds of a a mile in its orbit round the earth ; and if its distance were diminished it might still continue to revolve nearly in a circle round the same centre, if its velocity were increased so as to compensate for the great- er attraction, which would now draw it constantly out of the rectilinear direction, in v^iiich it would otherwise move. This distance may be supposed to be diminished till the moon is brought near to the earth's surface, and it would, under these circumstances, still continue to com- plete its revolution, if its velocity were increased to about five miles in a second. Now for the description of such a revolution, there is no difference between the moon and any other material substance at the same distance ; for they would both be drawn down through the same space in the same time by the force of attraction towards the earth's centre ; and therefore a cannon ball projected parallel to the horizon with this velocity, would (if there were no resistance from the air or other acci- dental circumstance) complete its circular revolution, and come back to the place from which it had set out, in a few minutes less than an hour and a half, which is equivalent to the velocity of about five miles in a second. Paxton. t The ball is supposed to be fired from a place not far from the earth's surface ; it can, therefore, be easily conceived that if its direc- tion is much depressed below the horizon, it must be soon brought down to the ground ; but it is not equally obvious that an elevation of any magnitude would likewise prevent its completing its revolution round the earth. Abstracting from the air's resistance, and of course omitting the supposition of a projectile force sufficient to carry the ball off into infinite space, it will move in the curve of an ellipse, of which one of the foci is situated in the centre of the earth. Now a body moving uninterruptedly in an ellipse must return in time to the same point from^which it set out. The body, therefore, which, when project- ed from A , Fig. 6, PI. XXXIX, comes down to the earth at C, would have continued its course along the dotted line, and returned to A, if the mass of matter in the earth had been collected together at its centre, so as not to interfere with the motion of the projectile. Let us now conceive the body to be projected back from C, with the velocity which it had ac- quired in its fall, and with the direction in which it reached the earth, it would then pass through A, and come down on the other side of A I, in just the same curve, in which it had fallen from A to C. The same would apply to bodies projected upwards from B or D ; and if the velocities of projection were less or greater than what would have been acquired in falling from A, the bodies would still turn, but at some less or more distant; point. The longest diameter, however, of the ellipsis in v/hich they move must always pass through the earth's centre ; and if the bodies rise on one side of this diameter, they must 230 ASTRONOMY. the velocity reached at the rate of seven miles in a second, or went beyond that, the ball would fly off" from the earth, and never be heard of more. In like manner with respect to the direction; out of the innumerable angles in which the ball might be sent off, I mean angles formed with a line drawn to the centre, none would serve but what was nearly a right one ; out of the various directions in which the cannon might be pointed, upwards and downwards, every one would fail, but what was exactly or nearly hori- zontal. The same thing holds true of the planets; of our own among the rest. We are entitled, therefore, to ask and to urge the question, Why did the projectile velocity, and the projectile direction of the earth happen to be near- ly those wliich would retain it in a circular form ? Why not one of the infinite number of velocities, one of the in- finite number of directions, which would have made it ap- proach much nearer to, or recede much farther from, the sun? The planets going round, all in the same direction, and all nearly in the same plane, afforded to Buffon a ground for asserting, that they had all been shivered from the sun by the same stroke of a comet, and by that stroke project- ed into their present orbits. Now, beside that this is to attribute to chance the fortunate concurrence of velocity and direction which we have been here noticing, the hy- pothesis, as I apprehend, is inconsistent with the physical laws by which the heavenly motions are governed. If the planets were struck off from the surface of the sun, they would return to the surface of the sun again. Nor will this difficulty be got rid of, by supposing that the same vio- lent blow which shattered the sun's surface, and separated large fragments from it, pushed the sun himself out of his place ; for the consequence of this would be, that the sun ■and system of shattered fragments would have a progres- sive motion, which, indeed, may possibly be the case with our system ; but then each fragment would, in ev- ery revolution, return to the surface of the sun again. The hypothesis is also contradicted by the vast difference which fall down on the other. Now it will be seen that the curves at B, C, and D, make the angles ABI, ACI, ADI less, as the body is supposed to go farther and farther before it falls, and that the curves in which the body can complete a revolution near the surface, will, in all its parts, be nearly parallel to it. Hence, the cannon ball fired upwards will come back again to the ground; and not be able completely to go round the earth upon any other supposition, excepting that of its being fired ia nearly an horizontal direction. Paxton. ASTRONOMY. 231 subsists between the diameters of the planetary orbits. The distance of Saturn from the sun (to say nothing of the Georgium Sidus) is nearly twenty-five times that of Mercury ; a disparity which it seems impossible to recon- cile with Buffon's scheme. Bodies starting from the same place, with whatever difference of direction or velocity they set off, could not have been found at these different distances from the centre, still retaining their nearly circu- lar orbits. They must have been carried to their proper distances before they were projected.* To conclude : In astronomy, the great thing is to raise the imagination to the subject, and that oftentimes in opposi- tion to the impression made upon the senses. An allusion, for example, must be got over, arising from the distance at which we view the heavenly bodies, viz. the apparent slmD- ness of their motions. The moon shall take some hours in getting half a yard from a star which it touched. A mo- tion so deliberate, we may think easily guided. But what is the fact? The moon, in fact, is, all this while, driving through the heavens, at the rate of considerably more than two thousand miles in an hour ; which is more than double of that, with which a ball is shot off from the mouth of a cannon. Yet is this prodigious rapidity as much under government, as if the planet proceeded ever so slowly, or were conducted in its course inch by inch. It is also diffi- cult to bring the imagination to conceive (what yet, to judge tolerably of the matter, it is necessary to conceive) how loose, if we may so express it, the heavenly bodies are. Enormous globes, held by nothing, confined by nothing, are turned into free and boundless space, each to seek its course by the virtue of an invisible principle ; but a princi- ple, one, common, and the same, in all ; and ascertainable. To preserve such bodies from being lost, from running together in heaps, from hindering and distracting one * " If we suppose the matter of the system to be accumulated in the centre by its gravity, 7io mechanical principles, with the assistance of this power of gravity could separate the vast mass into such parts as the sun and planets ; and after carrying them to their, different distances, project them in their several directions, preserving still the equal- ity of action and reaction, or the state of the centre of gravity of the system. Su-ch an exquisite structure of things could only arise from the contrivance and powerful influences of an intelligent, free, and most potent agent. The same powers, therefore, which at present govern the material universe, and conduct its various motions, are very different from those, which were necessary to have produced it from nothing, or to have disposed it in the admirable form in which it now proceeds." Maclaurin's Account of JVewton's Phil. p. 407, ed.3. 232 ASTRONOMY. another's motions, in a degree inconsistent with any con- tinuing order ; i. e. to cause them to form planetary systems, systems that, when formed, can be upheld, and, most es- pecially, systems accommodated to the organized and sen- sitive natures which the planets sustain, as we know to be the case, where alone we can know what the case is, upon our earth ; all this requires an intelligent interposition, be- cause it can be demonstrated concerning it, that it requires an adjustment of force, distance, direction, and velocity, out of the reach of chance to have produced ; an adjust- ment, in its view to utility similar to that which we see in ten thousand subjects of nature which are nearer to us, but in power, and in the extent of space through which that pov/er is exerted, stupendous. But many of the heavenly bodies, as the sun and fixed stars, are stationary. Their rest must be the effect of an absence, or of an equilibrium of attractions. It proves also that a projectile impulse was originally given to some of the heavenly bodies, and not to others. But further ; if attrac- tion act at all distances, there can be only one quiescent centre of gravity in the universe ; and all bodies whatever must be approaching this centre, or revolving round it. According to the first of these suppositions if the duration of the world had been long enough to allow of it, all its parts, all the great bodies of which it is composed, must have been gathered together in a heap round this point. No changes, however, which have been observed, afford us the smallest reason for believing that either the one sup- position or the other is true ; and then it will follow, that attraction itself is controlled or suspended by a superior agent ; that there is a power above the highest of the pow- ers of material nature ; a will which restrains and circum- scribes the operations of the most extensive.* * It must here, hov.ever, be stated, that many astronomers deny that any of the heavenly bodies are absolutely stationary. Some of the brightest of the fixed stars have certainly small motions; and of the rest, the distance is too great, and the intervals of our observation too short to enable us to pronounce with certainty that tliey may not have the same. The motions in the fixed stars which have been observed, are considered either as proper to each of tliem., or as compounded of the motion of our system, and of motions proper to each star. By a comparison of these motions, a motion in our system is supposed to be discovered. By continuing this analogy to other, and to all systems, it is possible to suppose that attraction is unlimited, and that the whole ma- terial universe is revolving round some fixed point within its con- taining sphere or space, paley. The milky way is known to derive its appearance from a congerief? of very small stars, but there are luminous spots in the heaven, which OF THE PERSONALITY OF THE DEITY. 333 CHAP. XXIII. OF THE PERSONALITY OF THE DEITY. Contrivance, if established, appears to me to prove ev- ery thing which we wish to prove. Amongst other things, it proves the personality of the Deity, as distinguished from what is sometimes called nature, sometimes called a principle : which terms, in the mouths of those who use them philosophically, seem to be intended to admit and to express an efficacy, but to exclude and to deny a personal agent. Now that which can contrive, which can design, must be a person. These capacities constitute personality, for they imply consciousness and thought. They require that which can perceive an end or purpose ; as well as the power of providing means, and of directing them to their end.* They require a centre in which perceptions unite, and from which volitions flow — which is mind The acts of a mind prove the existence of a mind : and in whatever a mind resides is a person. The seat of intellect is a per- son. We have no authority to limit the properties of mind to any particular corporeal form, or to any particular cir- cumscription of space. These properties subsist, in created nature, under a great variety of sensible forms. Also, ev- ery animated being has its scusorium, that is, a certain por- tion of space, within which perception and volition are ex- erted. This sphere may be enlarged to an indefinite ex- tent; may comprehend the universe; and being so imagin- ed, may serve to furnish us with as good a notion, as we are capable of forming, of the immensity/ of the divine na- ture, i. e. of a Being, infinite as well in essence as in pow- er ; yet nevertheless a person, cannot be separated into distinct stars by the most powerful telescopes ; these have been observed in some instances to alter their form, which Sir W. Herschell attributed to the mutual attraction of the luminous particles which composed them. Some of the fixed stars appear double, and even multiple, vAien highly magnified. The same great astronomer, whom we have just mentioned, v;as induced to believe that there were separate systems ; and his son, assisted by Mr. South, has established that some of them have undoubtedly a revolution round a common centre of gravity anal- ogous to the motions of the sun and planets. Paxton. "Priestley's Letters to a Philosophical Unbeliever, p. iciSj ed. 2?» w '234 OF THE PEESONALITY OF THE DEITT. " No man hath seen God at any time." And this, I be- lieve, makes the great difficuhy. Now it is a difficulty which chiefly arises from our not duly estimating the state of our faculties. The Deity, it is true, is the object of none of our senses ; but reflect what limited capacities an- imal senses are. Many animals seem to have but one sense, or perhaps two at the most, touch and taste. Ought such an animal to conclude against the existence of odours, sounds, and colours'? To another species is given the sense of smelling. This is an advance in the knowledge of the powers and properties of nature : but if this favour- ed animal should infer from its superiority over the class last described, that it perceived every thing which was per- ceptible in nature, it is known to us, though perhaps not. suspected by the animal itself, that it proceeded upon a false and presumptuous estimate of its faculties. To an- other is added the sense of hearing ; which lets in a class of sensations entirely unconceived by the animal before spoken of; not only distinct, but remote from any which it had ever experienced, and greatly superior to them. Yet this last animal has no more ground for believing that its senses comprehend all things, and ail properties of things which exist, than might have been claimed by the tribes of animals beneath it ; for we know, that it is still possible to possess another sense, that of sight, which shall disclose to the percipient a new world. This fifth sense makes the animal what the human animal is; but to infer that possi- bility stops here, that either this fifth sense is the last sense, or that the five comprehended all existence, is just as unwarrantable a conclusion, as that which might have been made by any of the different species w^hich possessed fewer or even by that, if such there be, which possessed only one. The conclusion of the one-sense animal, and the conclusion of the five-sense animal, stand upon the same authority. There may be more and other senses than those which we have. There may be senses suited to the perception of the powers, properties and substance of spirits. These may belong to higher orders of rational agents ; for there is not the smallest reason for supposing that we are the highest, or that the scale of creation stops with us. The great energies of nature are known to us only by their effects. The substances which produce them, are as much concealed from our senses as the divine essence it- self Gravitation, though constantly present, though con- OF THE PERSONALITY OP THE DEITY. 235 stantly exerting its influence, though every where around 'tis, near us, and within us, though diffused throughout all space, and penetrating the texture of all bodies with which we are acquainted, depends, if upon a fluid, upon a fluid which, though both powerful and universal in its operation, is no object of sense to us ; if upon any other kind of substance or action, upon a substance and action from which ice receive no distinguishable impressions. Is it then to be v/ondered at, that it should, in some measure, be the same with the divine nature ? Of this, however, we are certam,that, whatever the Deity be, neither the universe, nor any part of it which we see^ can be he. The universe itself is merely a collective name ; its parts are all which are real, or which are things. Now inert matier is out of the question ; and organized substances include marks of contrivance. But whatever includes marks of contrivance, whatever in its constitution testifies design, necessarily carries us to something beyond itself, to some other being, to a designer prior to, and out of itself No animal, for instance, can have contrived its own limbs and senses ; can have been the author to itself of the design with which they were constructed. That supposition involves all the absurdity of self-creation, i. e. of acting without existing. Nothing can be God, which is ordered by a wisdom and a will which itself is void of: which is indebted for any of its properties to contrivance ah extra. The not having that in his nature which requires the exertion of another prior being, (which property is sometimes called self-sufficiency, and sometimes self-com- prehension,) appertains to the Deity, as his essential dis- tinction, and removes his nature from that of all things which we see. Which consideration contains the answer to a question that has sometimes been asked, namely : Why, since something or other must have existed from eternity, may not the present universe be that something? The contrivance perceived in it proves that to be impossible. Nothing contrived can, in a strict and proper sense, be eternal, forasmuch as the contriver must have existed before the contrivance. Wherever we see marks of contrivance, we are led for its cause to an intelligent author. And this transition of the understanding is founded upon uniform experience. We see intelligence constantly contriving, that is, we see mtelligence constantly producing effects, marked and dis- tinguished by certain properties; not certain particular ^36 OP THE PERSONALITY OF THE DEITV. properties, but by a kind and class "of properties, such n^ relation to an end, relation of parts to one another, and to a common purpose. We see, vviierever we are witnesses to the actual formation of things, nothing except intelli- gence producing effects so marked and distinguished. Fur- nished with this experience, we view the productions of nature. We observe them also marked and distinguished in the same manner. We wish to account for their origin. Our experience suggests a cause perfectly adequate to this account. No experience, no single instance or example, can be offered in favour of any other. In this cause, there- fore, we ought to rest , in this cause the common sense of mankind has, in fact, rested, because it agrees with that which in all cases is the foundation of knowledge, the un- deviating course of their experience. The reasoning is the same as that by which we conclude any ancient appearances to have been the effects of volcanoes or inun- dations ; namely, because they resemble the effects which fire and water produce before our eyes ; and because we have never known these effects to result from any other op- eration. And this resemblance may subsist in so many circumstances, as not to leave us under the smallest doubt in forming our opinion. Men are not deceived by this rea- soning ; for w^henever it happens, as it sometimes does hap- pen, tiiat the truth comes to be known by direct informa- tion, it turns out to be what was expected. In like man- ner, and upon the same foundation, (which in truth is that of experience,) we conclude that the works of nature pro- ceed from intelligence and design, because, in the proper- ties of relation to a purpose, subserviency to a use, they resemble wiiat intelligence and design are constantly pro- ducing, and what nothing except intelligence and design ever produce at all. Of every argument which would raise a question as to the safety of this reasoning, it may be observed, that, if such argument be listened to, it leads to the inference, not only that the present order of nature is insufficient to prove the existence of an intelligent Creator, but that no imaginable order would be sufficient to prove it , that no contrivance, were it ever so mechanical, ever so precise, ever so clear, ever so perfectly like those which we ourselves employ, would support this conclusion. A doctrine to which, I conceive, no sound mind can assent. The force, however, of the reasoning is sometimes sunk by our taking up with mere names. We have already no^. OP THE PERSONALITY OP THE BEIT'/. 237 liced * and we must here notice again, the misapplication of the term ** law," and the mistalve concerning the idea which that term expresses in physics, whenever such idea is made to take the place of power, and still more of an in- telligent power, and, as such, to be assigned for the cause of any thing, or of any property of any thing that exists. This is what we are secretly apt to do when we speak of or- ganized bodies (plants for instance, or animals,) owing their production, their form, their growth, their qualities, their beauty, their use, to any law or laws of nature ; and when we are contented to sit down with that answer to our inquiries concerning them. I say once more, that it is a perversion of language to assign any law as the efficient, operative cause of any thing. A law pre-supposes an agent, for it is only ^he mode according to which an agent proceeds : it implies a power, for it is the order according to which that power acts. Without this agent, without this power, which are both distinct from itself, the " law" does nothing — is nothing. What has been said concerning *' law," holds true of jnechanism. Mechanism is not itself power. Mechanism without power, can do nothing. Let a watch be contrived and constructed ever so ingeniously ; be its parts ever so many, ever so complicated, ever so finely wrought, or arti- ficially put together, it cannot ^o without a weight or spring ; i. e. without a force independent of, and ulterior to its me- chanism. The spring acting at the centre will produce different motions and different results, according to the variety of the intermediate mechanism. One and the self- same spring, acting in one and the same manner, viz. by simply expanding itself, may be the cause of a hundred dif- ferent, and all useful movements, if a hundred different and well devised sets of wheels be placed between it and the final effect, e. g. may point out the hour of the day, the day of the month, the age of the moon, the position of the planets, the cycle of the years, and many other serviceable notices ; and these movements may fulfil their purposes with more or less perfection, according as the mechanism is better or worse contrived, or better or worse executed, or in a better or worse state of repair ; but, in all cases, it is necessary that the spring act at the centre. The course of our reasoning upon such a subject would be this. By inspecting the watch, even when standing still, we get a ^ Chap. I. sec. vii. W 3 •J3S OF THE PERSONALITY OF THE DEITY. proof of contrivance, and of a contriving mind, having been employed about it. In the form and obvious relation of its parts we see enough to convince us of this. If we pull the works in pieces, for the purpose of a closer examination^ we are still more fully convinced. But, when we see the watch going, we see proof of another point, viz. that there is a power somewhere, and somehow or other applied to it , a power in action ; that there is more in the subject than the mere wheels of the machine ; that there is a secret spring or a gravitating plummet; in a word, that there is force and energy, as v/ell as mechanism. So, then, the watch in motion establishes to the observer two conclusions : one — that thought, contrivance, and de- sign, have been employed in forming, proportioning, and arranging of its parts ; and that, whoever, or wherever he be, or were, such a contriver there is, or was : the other — that force or power, distinct from mechanism, is, at this present time, acting upon it. If I saw a hand-mill, even at rest, I should see contrivance ; but, if I saw it grinding, I should be assured that a hand was at the windlass, though in another room. It is the same in nature. In the works of nature we trace mechanism; and this alone proves con- trivance ; but living, active, moving, productive nature, proves also the exertion of a power at the centre ; for, wherever the pov/er resides^ may be denominated the centre. The intervention and disposition of what arc called " second causes" fall under the same observation. This disposition is or is not mechanism, according as we can or cannot trace it by our senses, and means of examination. That is all the difference there is; and it is a difference v.hich respects our faculties, not the things themselves. Now where the order of second causes is mechanical, what is here said of mechanistn strictly applies to it. But it would be always mechanism, (natural chemistry, for in- stance, would be mechanism,) if our senses were acute enough to descry it. Neither mechanism, therefore, in the woiks of nature, nor the intervention of what are call- ed second causes, (for I think that they are the same thing, j excuses tlie necessity of an agent distinct from both. If, in tracing these causes, it be said, that we find cer- tain general properties of matter, which have nothing in them that bespeaks intelligence, I answer, that, still, the managing of these properties, the pointing and directing them to the uses which we see made of them, demands in- OF THE PEBSONALl'fiT ©F TUB DEITY. 2'31> \elligence in the highest degree. For example, suppose animal secretions to be elective attractions, and that such and such attractions universally belong to such and such substances; in all which there is no intellect concerned; still the choice and collocation of these substances, the fix- ing upon right substances and disposing them in right places, must be an act of intelligence. What mischief would fol- low, were there a single transposition of the secretory or- gans ; a single mistake in arranging the glands which com- pose them ? There 'may be many second causes, and many courses of second causes, one behind another, between what we observe of nature, and the Deity; but there must be in- telliffence somewhere; there must be more in nature than what we see ; and, amongst the things unseen, there must be an intelligent, designing, author. The philosopher be- holds with astonishment tlie production of things around him. Unconscious particles of matter take their stations, and severally range themselves in an order., so as to become collectively plants or animals, i. e. organized bodies *vith parts bearing strict and evident rehition to one another and to the utility of the whole , and it should seem that these particles could not move in any other way than as they do, for they testify not the smallest sign of choice, or liberty, or discretion. There may be particular intelli- gent beings, guiding these molions in each case; or thev jnay be the result of trains of mechanical dispositions, fix- ed before hand by an intelligent appointment, and kept in- action by a power at the centre. But in either case, there must be intelii<^:^ence. The minds of most men arc fond of uhat they call a lirinciijlc^ and of the appearance of simplicity, in account- ing for phenomena. Yet this principle, this simpiicity_, resides meiely in the name; which name after all, comprises, perhaps, under it a diversified, multifarious, or progressive operation, distinguisiiable into parts. The power, in organized bodies, of producing bodies like tbem- ielves, is one of these principles. Give a philosopher this, and he can get on. But he does not reflect, u'hat this mode of production, this principle (if such he choose to call it,) requires ; how much it presupposes ; what an ap- paratus of instruments, some of which are strictly mechan- ical, is necessary to its success ; what a train it includes of operations and changes, one succeeding another, one related to another, one ministering to another ; all advanc,- 240 OF THE PERSONALITY OF THE DEITY. ing, by intermediate, and, frequently, by sensible steps, to their ultimate result. Yet, because the whole of this com- plicated action is wrapped up in a single term , generation^ we are to set it down as an elementary principle ; and to suppose, that, when we have resolved the things which we see into this principle, we have sufficiently accounted for their origin, without the necessity of a designing, intelli- gent Creator. The truth is, generation is not a principle, but di process. We might as well call the casting of metals a principle ; we might, so far as appears to me, as well call spinning and weaving principles ; and then, referring the texture of cloths, the fabric of muslins and calicoes, the patterns of diapers and damasks, to these as principles, pretend to dispense with intention, thought, and contrivance, on the part of the artist ; or to dispense, indeed, with the necessity of any artist at all either in the manufacturing of the article, or in the fabrication of the machinery by which the manufactory was carried on. And, after all, how, or in what sense, is it true, that animals produce their like 1 A butterfly, with a proboscis instead of a mouth, with four wings and six legs, produces a hairy caterpillar, with jaws and teeth, and fourteen feet. A frog produces a tadpole. A black beetle, with gauze wings and a crusty covering, produces a white, smooth, soft worm ; an ephemeron fly, a cod-bait maggot. These, by a progress through different stages of life, and action, and enjoyment, (and, in each state, provided with imple- ments and organs appropriated to the temporary nature which they bear,) arrive at last at the form and fashion of the parent animal. But all this is process, not principle ; and proves, moreover, that the property of animated bodies of producing their like, belongs to them, not as a primordial property, not by any blind necessity in the nature of things, but as the effect of economy, wisdom, and design ; because the property itself assumes diversities, and submits to devia- tions, dictated by intelligible utilities, and serving distinct purposes of animal happiness. The opinion which would consider " generation" as a principle in nature ; and which would assign this principle as a cause, or endeavour to satisfy our minds with such a cause of the existence of organized bodies, is confuted, in my judgment, not only by every mark of contrivance dis- coverable in those bodies for which it gives us no contriver, offers no account whatever ; but also by the further consid- eration, that things generated possess a clear relation to OF THE PERSONALITY OP THE DEITV. 241 things not generated. If it were merely one part of a gen- erated body bearing a relation to another part of the same body, as the mouth of an animal to the throat, the throat to the stomach, the stomach to the intestines, those to the recruiting of the blood, and, by means of the blood, to the nourishment of the whole frame or if it were only one generated body, bearing a relation to another generated body, as the sexes of the same species to each other, animals of prey to their prey, herbivorous and gra- iiivorous animals to the plants or seeds upon which they feed, it might be contended, that the whole of this corres- pondency was attributable to generation, the common origin from which these substances proceeded. But what shall we say to agreements which exist between thmgs generated and things not generated? Can it be doubted, was it ever doubted, but that the lungs of animals bear a relation to the air, as a permanently elastic fluid ? They act in it and by it ; they cannot act without it. Now, if generation produced the animal, it did not produce the air ; yet their properties correspond. The ei/e is made for light, and light for the eye. The eye would be of no use without lights and light perhaps of little without eyes ; yet one is produc- ed by generation ; the other not. The ear depends upon undulations of air. Here are two sets of motions ; first, of the pulses of the air ; secondly, of the drum, bones, and nerves of the ear ; sets of motions bearing an evident re- ference to each other ; yet the one, and the apparatus for the one, produced by the int- rvention of generation ; the other altogether independent of it. If it be said, that the air, the light, the elements, the world itself, is generated, I answer that I do not comprehend the proposition. If the term mean any thmg, similar ta what it means, when applied to plants or animals, the pro- position is certainly without proof; and, I think, draws as near to absurdity, as any proposition can do, which does iiot include a contradiction in its terms. I am at a loss to conceive, how the formation of the world can be compared to the generation of an animal. If the term generation sig- nify something quite different from what it signifies upoii ordinary occasions, it may, by the same latitude, signify any thing. In which case a word or phrase taken from the language of Otaheite, would convey as much theory con- cerning the origin of the universe, as it does to talk of its being generated. We know a cause (intelligence) adequate to the appear- ances, which we wish to account for; we have this cause '242 OF THE PERSONALITY OF THE DEITY. continually producing similar appearances ; yet, rejecting" this cause, the sufficiency of which we know, and the ac- tion of which is constantly before our eyes, we are invited to resort to suppositions, destitute of a single fact for their support, and confirmed by no analogy with which we are acquainted. Were it necessary to inquire into the motives of men's opinions, I mean their motives separate from their arguments, I should almost suspect, that, because the proof of a Deity drav/n from the constitution of nature is not only popular but vulgar, (which may arise from the cogency of the proof, and be indeed its highest recommendation,) and because it is a species almost of puerility to take up with it ; for these reasons, minds, which are habitually in search of invention and originality, feel a resistless inclina- tion to strike off into other solutions and other expositions. The truth is, that many minds are not so indisposed to any thing which can be offered to them, as they are to the flatness of being content with common reasons ; and what is most to be lamented, minds conscious of superiority are the most liable to this repugnancy. The " suppositions" here alluded to, all agree in one character. They all endeavour to dispense wi+h the ne- cessity in nature of a particular, personal intelligence ; that is to say, with the exertion of an intending, contriving mindj in the structure and formation of the organized con- stitutions which the world contains. They would resolve all productions into unconscious energies, of a like kind, in. that respect, with attraction, m-agnetism, electricity, &c. without any thing further. In this the old system of atheism and the new agree. And I much doubt, whether the new schemes have advanc- 43d any thing upon the old, or done more than changed the terms of the nomenclature. For instance, I could never .see the difference between the antiquated system of atoms, and Buffon's organic molecules. This philosopher having made a planet by knockmg off from the sun a piece of melt- ed glass, in consequence of the stroke of a comet ; and hav- ing set it in motion, by the same stroke, both round its own axis and the sun, finds his next difficulty to be, how to bring plants and animals upon it. In order to solve this difficulty, we are to suppose the universe replenished with particles, endowed with life, but without organization or senses of their own ; and endowed also with a tendency to marshal themselves into organized forms. The concourse c>f these particles, by virtue of this tendency^ but without OF THE PERSONALITY OP THE DEITY. 24S intelligence, will, or direction, (for I do not find that any of these qualities are ascribed to them,) has produced the living forms which we now see. Very few of the conjectures, which philosophers hazard upon these subjects, have more of pretension in them, than the challenging you to show the direct impossibility of the hypothesis. In the present example, there seemed to be a positive objection to the whole scheme upon the very face of it; vv^hich was, that if the case were as here repre- sented, new combinations ought to be perpetually taking place ; new plants and animals, or organized bodies which were neither, ought to be starting up before our eyes every day. For this, however, our philosopher has an answer. Whilst so many forms of plants and animals are already in existence, and, consequently, so many " internal moulds," as he calls them, are prepared and at hand, the organic particles run into these molds, and are employed in supply- ing an accession of substance to them, as well for their growth, as for their propagation. By which means things keep their ancient course. But, says the same philosopher, should any general loss or destruction of the present con- stitution of organized bodies take place, the particles, for want of '' moulds" into which they might enter, would run into different combinations, and replenish the waste with new species of organized substances. Is there any history to countenance this notion ? Is it known, that any destruction has been so repaired? any desert thus repeopled ? So far as I remember, the only natural appearance men- tioned by our author, by way of fact whereon to build his hypothesis, the only support on which it rests, is the forma- tion of icoinns in the intestines of animals, which is here ascribed to the coalition of superabundant organic particles, floating about in the first passages ; and which have com- bined themselves into these simple animal forms, for want of internal moulds, or of vacancies in those moulds, into which they might be received. The thing referred to is rather a species of facts, than a single fact ; as some other cases may, with equal reason, be included under it. But to make it a fact at all, or in any sort applicable to the question, we must begin with asserting an equivocal g^uex- ation contrary to analogy, and without necessity : contrary to an analogy, which accompanies us to the very limits of our knowledge or inquiries, for wherever, either in plants or aTiimals, we are able to examine the subject, we find pro- 244 OP THE PERSONALITY OF THE DEITY. creation from a parent form ; without necessity ; for I ap.- pre hen d that it is seldom difficult to suggest methods by which the eggs or spawn, or yet invisible rudiments of these vermin, may have obtained a passage into the cavi- ties in which they are found.* Add to this, that their con- iitancij to their species^ which, I believe, is as regular in these as in the other vermes, decides the question against our philosopher, if, in truth, any question remained upon the subject. Lastly ; these wonder-working instruments, these " in- ternal moulds," what are they after all ? what, when exam- ined, but a name without signification; unintelligible, it not self-contradictory ; at the best, differing in nothing from the " essential forms" of the Greek philosophy ? One short sentence of BufTon's work exhibits his scheme as follows. '* When this nutritious and prolific matter, which is diffus- ed throughout all nature, passes through the internal mould of an animal or vegetable, and finds a proper matrix or re- ceptacle, it gives rise to an animal or vegetable of the same species." Does any reader annex a meaning to the expres- sion, "internal mould," in this sentence? Ought it then to be said, that, though we have little notion of an internal mould, we have not much more of a designing mind ? The very contrary of this assertion is the truth. When we speak of an artificer or an architect, we talk of what is comprehen- sible to our understanding, and familiar to our experience. W^e use no other terras than what refer us for their mean- ing to our consciousness and observation, what express the constant objects of both : whereas names, like that we have mentioned, refer us to nothing, excite no idea, convey a sound to the ear, but I think do no more. Another system, w^hich has lately been brought forward, and with much ingenuity, is that of appetencies. The principle, and the short account of the theory, is this. Pieces of soft, ductile matter, being endued with propensi- ties or appetencies for particular actions, would, by contin- ual endeavours, carried on through a long series of genera- tions, work themselves gradually into suitable forms ; and at length acquire, though perhaps by obscure and almost imperceptible improvements, an organization fitted to the action which their respective propensities led them to exert. * I trust I may be excused for not citing as another fact which is to confirm the hypothesis, a grave assertion of this writer, that the branch- es ©f trees upon which the stag feeds, break out a^in in its hor»s. Such facts merit no discussion. OF THE PERSONALITY OF THE DEITY. 245 A piece of animated matter, for example, that was endued with a propensity to jiy, though ever so shapeless, though no other we will suppose than a round ball, to begin with, would, in a course of ages, if not in a million of years, perhaps in a hundred millions of years, (for our theorists having eternity to dispose of, are never sparing in time,) ac- quire wings. The same tendency to locomotion in an aquatic animal, or rather in an animated lump which might happen to be surrounded by water, would end in the pro- duction o^ Jins ; in a living substance confined to the solid earth, would put out legs and/ce^ ; or, if it took a different turn, would break the body into ringlets, and conclude by crmoling upon the ground. Although I have introduced the mention of this theory into this place, I am unwilling to give to it the name of an utlmstic scheme, for two reasons ; first, because, so far as I am able to understand it, the original propensities and the numberless varieties of them (so different, in this re- spect, from the laws of mechanical nature, which are few and simple) are, in the plan itself, attributed to the ordina- tion and appointment of an intelligent and designing Creator : secondly, because, likewise, that large postulatum, which is all along assumed and presupposed, the faculty in living bodies of producing other bodies organized like themselves, seems to be referred to the same cause ; at least is- not at- ten»pted to be accounted for by any other. In one impor- tant respect, however, the theory before us coincides with atheistic systems, viz. in that, in the formation of plants and animals, in the structure and use of their parts, it does away final causes. Instead of the parts of a plant or ani- mal, or the particular structure of the parts, having been intended for the action or use to which we see them appli- ed, according to this theory they have themselves grown out of that action, sprung from that use. The theory, therefore, dispenses with that v/hich we insist upon, the ne- cessity in each particular case, of an intelligent, designing mind, for the contriving and determining of the forms which organized bodies bear. Give our philosopher these appetencies ; give him a portion of living irritable matter (a nerve, or the clipping of a nerve,) to work upon ; give also to his incipient or progressive forms, the power in ev- ery stage of their alteration, of propagating their like ; and, if he is to be believed, he could replenish the world with all the vegetable and animal productions which we at pres* ent see in it. X 246 OF THE PERSONALITY OF THE DEITY. The scheme under consideration is open to the same ob- jection with other conjectures of a similar tendency, viz. a total defect of evidence. No changes, like those which the theory requires, have ever been observed. All the changes in Ovid's Metamorphoses might have been effected by these appetencies, if the theory were true ; yet not an example, nor the pretence of an example is offered, of a single change being known to have taken place. Nor is the or- der of generation obedient to the principle upon which this theory is built. The mammae* of the male have not van- ished by inusitation ; ncc surtorvm, per midta scecula, Jv- dcBoriim propagiiu deest prapidinm. It is easy to say, and it has been said, that the alterative process is too slow to be perceived ; that it has been carried on through tracts of im- measurable time ; and that the present order of things is the result of a gradation of which no human records can trace the steps. It is easy to say this ; and yet it is still true that the hypothesis remains destitute of evidence. The analogies which have been alleged are of the fol- lowing kind. The buneh of a camel, is said (o be no oth- er than the effect of carrying burthens ; a service in which the species has been employed from the most ancient times of the world. The first race, by the daily loading of the back, would probably find a small grumous tumour to be formed in the flesh of that part. The next progeny would bring this tumour into the world with them. I'he life, to which they were destined, would increase it. The cause, which first generated the tubercle, being continued, it would go on, through every succession, to augment its size, till it attained the form and the bulk under which it now appears. This may serve for one instance ; another, and that also of the passive sort, is taken from certain species of birds. Birds of the crcme kind, as the crane itself, the heron, bit- tern, stork, have, in general, their thighs bare of feathers. This privation is accounted for from the habit of wading in water, and from the effect of that element to check the growth of feathers upon these parts ; in consequence of which, the health and vegetation of the feathers declined through each generation of the animal ; the tender down, exposed to cold and wetness, became weak, and tUin, and * I confess myf=elf totally at a loss to guess at the reason, either final or efficient, for this part of the animal frame, unless there be some foundation for an opinion, of which I draw the hint from a paper of Mr. Everard Home's, (Phil. Transac. 1799, p. 2.) viz. that the mammas of the foetus may be formed before the sex is determined. OF THE PERSONALITY 013 THE DEITY. 247 rare, till the deterioration ended in the result which we see, of ahsolute nakedness. I will meniion a third instance, because it is drawn from an active habit, as the two last were from passive habits ; and that is the poach of the pe- lican. The description, which naturalists give of this organ is as follows : " From the lower edges of the under chap, hangs a bag, reaching from the whole length of the bill to the neck, which is said to be capable of containing fifteen quarts of water. This bag the bird has a power of wrinkling up into the hollow of the under chap. When the bag is empty it is not seen ; but when the bird has fished with success, it is incredible to what an extent it is often dilated. The first thing the pelican does in fishing, is to fill the bag ; and then it returns to digest its burthen at leisure. The bird preys upon the large fishes, and hi'les them by dozens in its pouch. When the bill is opened to its widest extent, a person may run his head into the bird's mouth ; and conceal it in his monstrous pouch, thus adapted for very singular purposes."* Now this extraordinary con- formation, is nothing more, say our philosophers, than the result of habit ; not of the habit or effort of a single pelican, or of a single race of pelicans, but of a habit perpetuated through a long series of generations. The pelican soon found the conveniency of reserving in its mouth, when its appetite was glutted, the remainder of its prey, which is fish. The fulness produced by this attempt, of course stretched the skin which lies between the under chaps, as being the most yielding part of the mouth. Every disten- sion increased the cavity. The original bird, and many generations which succeeded him, might find difficulty enough in making the pouch answer this purpose : but future pelicans, entering upon life with a pouch derived from their progenitors, of considerable capacity, would more read- ily accelerate its advance to perfection, by frequently press- ing down the sac with the weight of fish which it might now be made to contain. These, or of this kind, are the analogies relied upon. Now in the first place, the instances themselves are unau- thenticated by testimony ; and in theory, to say the least of them, open to great objections. Who ever read of camels without bunches, or with bunches less than those with which they are at present usually formed ? A bunch, not unlike the camel's, is found between the shoulders of the buffalo ; of the origin of which it is impossible to give the account ^ Goldsmith, vpl. vi. p. 52, 248 OF THE PERSONALITY OF THE DEITY. whicli is here given. In the second example : Why should the application of water, which appears to promote and thicken the growth of feathers upon the bodies and breasts of geese and swans and other water fowls, have divested of this covering the thighs of cranes ? The third instance, which appears to me as plausible as any that can be produc- ed, has this against it, that it is a singularity restricted to the species ; whereas, if it had its commencement in the cause and manner which have been assigned, the like eon- formation might be expected to take place in other birds, which feed upon fish How comes it to pass, that the pel- ican alone was the inventress, and her descendants the only inheritors, of this curious resource ? But it is the less necessary to controvert the instances themselves, as it is a straining of analogy beyond all limits of reason and credibility, to assert that birds, and beasts, and fish, with all their variety and complexity of organiza- tion, have been brought into their forms, and distinguished into their several kinds and natures, by the same process (even if that process could be demonstrated, or had it ever been actually noticed) as m.ight seem to serve for the grad- ual generation of a camel's bunch, or a pelican's pouch. The solution, when applied to the works of nature gen- erally, is contradicted by many of the phenomena, and to- tally inadequate to others. The ligaments or strictures, by which the tendons are tied down at the angles of the joints, could, by no possibility, be formed by the motion or exer- cise of the tendons themselves ; by any appetency exciting^ these parts into action ; or by any tendency arising there-^ from. The tendency is all the other way : the conatus in constant opposition to them. Length of time does not help the case at all, but the reverse. The valves also in the blood-vessels, could never be formed in the manner, which our theorist proposes. The blood, in its right and natural course, has no tendency to form them. When obstructed or refluent, it has the contrary. These parts could not grow out of their use, though they had eternity to grow in. The senses of animals appear to me altogether incapable of receiving the explanation of their origin which this theo- ry affords. Including under the word '• sense" the organ and the perception, we have no account of either. How will our philosopher get at vision, or make an eye ? How should the blind animal effect sight, of which blind animals, we know, have neither conception nor desire 1 Affecting it, by what operation of its will, by what endeavour to see^ OP THE NATURAL ATTRIBUTES, &/C, ^49 could it so determine the fluids of its body, as to inchoate the formation of an eye? or, suppose the eye formed, would the perception follow? The same of the other senses. And this objection holds its force, ascribe what you will to the hand of time, to the power of habit, to changes, too slow- to be observed by man, or brought within any comparison which he is able to make of past things with the present : concede what you please to these arbitrary and unattested suppositions, how will they help you ? Here is n.) incep- tion. No laws, no course, no powers jf naiure which pre- vail at present, nor any analogous to these, could give com- mencement to a new sense. And it is in vain to inquire, how that might proceed, which could never begin. I think the senses, to be the most inconsistent with the hypothesis before us, of any part of the animal frame. But other parts are sufficiently so. The solution does not ap- ply to the parts of animals, which have little in them of mo- tion. It we could suppose jomts and muscles to be gradu- ally formed by action and exercise, what action or exercise could form a skull, and fill it with brains ? No effort of the animal could detf rmine the clothing of its skin What co- natus could give prickles to the porcupine or hedgehog, or to the sheep its fleece ? In the last place ; what do these appetencies mean when applied to plants ? I am not able to give a signification to the term, which can be transferred from animals to plants ; or which is common to both. Yet a no less successful or- ganization is found in plants, than what obtains in animals. A solution is wanted for one as well as the other. Upon the whole ; after all the schemes and struggles of a reluctant philosophy, the necessary resort is to a Deity. The marks of design are too strong to be got over. Design must have had a designer. That designer must have been a person. That person is God. CHAPTER XXIV. OP THE NATURAL ATTRIBUTES OF THE DEITY. It is an immense conclusion, that there is a God ; a perceiving, intelligent, designing Being ; at the head of cre- ation, and from whose will it proceeded. The attributes of such a Being, suppose his reality to be proved, must be ad- X2 •260 OP THE NATURAL ATTRIBUTES equate to the magnitude, extent, and multiplicity of his op- erations : which are not only vast beyond comparison with those performed by any other power, but, so far as respects our conceptions of them, infinite, because they are unlimit- ed on all sides. Yet the contemplation of a nature so exalted, however surely we arrive at the proof of its existence, overwhelms our faculties. The mind feels its powers sink under the subject. One consequence of which is. that from painful abstraction the thoughts seek relief in sensible images. Whence may be deduced the ancient and almost uni- versal propensity to idolatrous substitutions. They are the resources of a labouring imagination. False religions usu- ally fall in with the natural propensity : true religions, or such as have derived themselves from the true, resist it. It is one of the advantages of the revelations which we acknowledge, that, whilst they reject idolatry with its many pernicious accompaniments, they introduce the Deity to hu- man apprehension, under an idea more personal, more de- terminate, more within its compass, than the theology of nature can do. And this they do by representing him ex- clusively under the relation in which he stands to ourselves ; and, for the most part, under some precise character, re« suiting from that relation, or from the history of his provi- dences : Which method suits the span of our intellects much better, than the universality wliich enters into the idea of God, as deduced from the views of nature. When there- fore, these representations are well founded in point of au- thority, (for all depends upon that,) they afford a conde- scension to the state of our faculties, of which, they who have reflected most upon the subject, will be the first to acknowledge the want and the value. Nevertheless, if we be careful to imitate the documents of our religion, by confining our explanations to what concerns ourselves, and do not affect more precision in our ideas than the subject allows of, the several terms, which are employ- ed to denote the attributes of the Deity, may be made, even in natural religion, to bear a sense, consistent with truth and reason, and not surpassing our comprehension. These terms are, omnipotence, omniscience, omnipres- ence, eternity, self-existence, necessary existence, spiritu- ality. " Omnipotence," " omniscience ;" infinite power, infinite knowledge, are superlatives ; expressing our conception of these attributes in the strongest and most elevated terms OF THE DEITY, 251 which language supplies. We ascribe power to the Deity under the name of " omnipotence," the strict and correct conclusion being, that a power, which could create such a world as this is, must be, beyond all comparison, greater than any which we experience in ourselves, than any which we observe in other visible agents ; greater, also, than any which we can want, for our individual protection and pres- ervation, in the Being upon whom we depend. It is a pow- er likewise, to which we are not authorized by our obser- vation or knowledge, to assign any limits of space or dura- tion. Very much of the same sort of remark is applicable to the term " omniscience," infinite knowledge, or infinite wisdom. In strictness of language, there is a difference between knowledge and wisdom ; wisdom always suppos- ing action, and action directed by it. With respect to the first, viz. knowledge, the Creator must kiiGw^ intimately^ the constitution and properties of the things which he cre- ated : which seems also to imply a foreknowledge of their action upon one another, and of their changes ; at least, so iar as the same result from trains of physical and necessary causes. His omniscience also, as far as respects things pres- ent, is deducible from his nature, as an intelligent being, joined with the extent, or rather the universality, of his op- erations. Where he acts, he is ; and, where he is, he per- ceives. The wisdom of the Deity, as testified in the works of creation, surpasses all idea we have of wisdom, drawn from the highest intellectual operations of the highest class of intelligent Beings with whom we are acquainted ; and, which is of the chief importance to us, whatever be its com- pass or extent, which it is evidently impossible that we should be able to determine, it must be adequate to the con- duct of that order of things under which we live. And this is enough. It is of very inferior consequence, by what terms we express our notion, or rather our admiration of this attribute. The terms, which the piety and the usage of language have rendered habitual to us, may be as proper as any other. We can trace this attribute much beyond what is necessary' for any conclusion to which we have occasion to apply it. The degree of knowledge and power, requisite for the formation of created nature, cannot, with respect to us, be distinguished from infinite. The divine " omnipresence" stands, in natural theology, upon this foundation. In every part and place of the uni- verse, with which we are acquainted, v/e perceive the exer- !i52 OP THE NATURAL ATTRIBUTES, &C. tion of a power, which we believe, mediately or immediate' Jy> to proceed from the Deity. For instance ; in what part or point of space, that has ever been explored, do we not discover attraction ? In what regions, do we not find light ? In what accessible portion of our globe, do we not meet with gravity, magnetism, electricity ; together with the properties also and powers of organized substances, of veg- etable or of animated nature? Nay, further, we may ask, what kingdom is there of nature, what corner of space, in which there is any thing that can be examined by us, where we do not fall upon contrivance and design ? The only re- flection perhaps which arises in our minds from this view of the world around us is, that the laws of nature every where prevail ; that they are uniform and universal. But what do we mean by the laws of nature, or by any law ? Effects are produced by power, not by laws. A law cannot execute it- self. A law refers us to an agent. Now an agency so general, as that we cannot discover its absence, or assign the place in which some effect of its continued energy is not found, may, in popular language at least, and, perhaps, without much deviation from philosophical strictness, be called universal ; and, with not quite the same, but with no inconsiderable propriety, the person or Being, in whom that power resides, or from whom it is derived, may be taken to be omnipreseJit. He who upholds all things by his power, may be said to be every where present. This is called a virtual presence. There is also what metaphysicians denominate an essential ubiquity : and which idea the language of scripture seems to favour : but the former, I think, goes as far as natural theology carries us. " Eternity," is a negative idea, clothed with a positive name. It supposes, in that to which it is applied, a present existence ; and is tne negation of a beginning, or an end of that existence. As applied to the Deity, it has not been controverted by those uho acknowledge a Deity at all. Most assuredly, there never was a time in which nothing existed, because that condition must have continued. The universal blank must have remained ; nothing could rise up out of it ; nothing could ever have existed since ; noth- ing could exist now. In strictness, however, we have no concern with duration prior to that of the visible world. Up- on this article, therefore, of theology, it is sufficient to know, that the contriver necessarily existed before the contri- , vance. OP THB UNITr OP THE DEITY. 253 " Self-existence," is another negative idea, viz. the ne- gation of a preceding cause, as of a progenitor, a maker, an autlior, a creator. '* Necessary existence," means demonstrable existence. " Spirituality" expresses an idea, made up of a negative part, and of a positive part. The negative part, consists in the exclusion of some of the known properties of matter, especially of solidity, of the vis inertics, and of gravitation. The positive part, comprises perception, thought, will, pow- er, action, by which last term is meant the origination of mo- tion ; the quality, perhaps, in which resides the essential superiority of spirit over matter " which cannot move, un- less it be moved ; and cannot but move, when impelled by another."* I apprehend that there can be no difficulty in applying to the Deity both parts of this idea. CHAPTER XXV. THE UNITY OF THE DEITY. Of the " unity of the Deity" the proof is, the uniformitij of plan observable in the universe. The universe itself is a system ; each part either depending upon other parts, or being connected with other parts by some common law of motion, or by the presence of some common substance. One principle of gravitation causes a stone to drop towards the earth, and the moon to wheel round it. One law of at- traction carries all the different planets about the sun. This philosophers demonstrate. There are also other points of agreement amongst them, which may be considered as marks of the identity of their origin, and of their intelli- gent author. In all are found the conveniency and stabili- ty derived from gravitation. They all experience vicissi- tudes of days and nights, and changes of season. They all, at least Jupiter, Mars, and Venus, have the same advanta- ges from their atmosphere as we have. In all the planets^ the axes of rotation are permanent. Nothing is more prob- able, than that the same attracting influence, acting accord- ing to the same rule, reaches to the fixed stars : but if this be only probable, another thing is certain, viz. that the same element of light does. The light from a fixed star affects our eyes in the same manner, is refracted and reflect- •I" Bishop Wilkin's Principles of Nat. Rel. p. 106. 254 OF THE UNITY OP THE DEITY. ed according to the same laws, as the light of a candle. The velocity of the light of the fixed stars, is also the same as the velocity of the light of the sun, reflected from the sa- tellites of Jupiter. The heat of the sun, in kind, differs nothing from the heat of a coal fire. In our own globe the case is clearer. New countries are continually discovered, but the old laws of nature are always found in them: new plants, perhaps,, or animals, but al- ways in company with plants and animals, which we al- ready know : and always possessmg many of the same gen- eral properties. We never get among sucii original, or to- tally different, modes of existence, as to indicate, that we are come into the province of a different Creator, or under the direction of a different will. In truth, the same order of things attends us, wherever we go. The elements act upon one another, electricity operates, the tides rise and fall, the magnetic needle elects its position, in one region of the earth and sea, as well as in another. One atmos- phere invests all parts of the globe, and connects all ; one sun illuminates ; one moon exerts its specific attraction upon all parts. If there be a variety in natural effects, as e. g. in the tides of different seas, that very variety is the result of the same cause, acting under different circumstances. In many cases this is proved ; in all is probable. The inspection and comparison of Uvins[ forms add to this argument examples without number. Of all large ter- restrial animals the structure is very much alike. Their senses nearly the same. Their natural functions and pas- sions nearly the same. Their viscera nearly the same, both in substance, shape, and office. Digestion, nutrition, cir- culation, secretion, go on, in a similar manner, in all. The great circulating fluid is the same : for, I think, no differ- ence has been discovered in the proportion of hlood, from whatever animal it be drawn. The experiment of transfu- sion proves, that the blood of one animal will serve for an- other. The skeletons also of the larger terrestrial animals, show particular varieties, but still under a great general affinity. The resemblance is somewhat less, yet sufficiently evident between quadrupeds and birds. They are all alike in five respects, for one in which they differ. Jnjisk, which belong to another department, as it were, of nature, the points of comparison become fewer. But we never lose sight of our analogy, e. g. we still meet with a stomach, a liver, a spine ; with bile and blood ; with teeth ; with eyes — which eyes are only slightly varied from 04ir own, and which variation, in truth demonstratesj net OF THE UNITY OF THE DEITy* 255 an interruption, but a continuauce, of the same exquisite plan ; for it is the adaptation of the organ to the element, viz. to the different refraction of light passing into the eye out of a denser medium. The provinces, also, themselves, of water and earth, are connected by a species of animals which inhabit both ; and also by a large tribe of aquatic animals, which closely resemble the terrestrial in their inter- nal structure: I mean the cetaceous tribe, which have hot blood, respiring lungs, bowels, and other essential parts, like those of land animals. This similitude, surely bespeaks the same creation and the same Creator. Insects and shell fsh appear to me to differ from other classes of animals the most widely of any Yet even here, beside many points of particular resemblance, there exists a general relation of a peculiar kind. It is the relation of inversion : the law of contrariety : namely, that, whereas, in other animals, the bones, to which the muscles are attach- ed, lie within the body, in insects and shell-fish they lie on the outside of it. The shell of a lobster performs to the an- imal the office of a hojie, by furnishing to the tendons that fixed basis or immoveable fulcrum, without which mechan- ically they could not act. The crust of an insect is its shell, and answers the like purpose. The shell also of an oyster stands in the place of a bone ; the bases of the muscles be- ing fixed to it, in the same manner, as, in other animals, they are fixed to the bones. All which (under wonderful varieties, indeed, and adaptation of form) confesses an im- itation, a remembrance, a carrying on of the same plan. The observations here made are equally applicable to plants ; but I think unnecessary to be pursued. It is a very striking circumstance, and alone sufficient to prove all which we contend for, that, in this part likewise of organized nature, we perceive a continuation of the sex- ual system. Certain, however it is, that the whole argument for the divine unity, goes no farther than to an unity of counsel. It may likewise be acknowledged, that no arguments which vv'e are in possession of, exclude the ministry of sub- ordinate agents. If such there be, they act under a presid- ing, a controlling will ; because they act according to cer- tain general restrictions, by certain common rules, and, as it should seem, upon a general plan : but still such agents, and different ranks, and classes^ and degrees of them, may be employed. 356 THE GOODNESS OF THE DEITY. CHAPTER XXVI. OF THE GOODNESS OF THE DEITY. The proof of the divine goodness rests upon two propo- sitions, each, as we contend, capable of being made out by observations drawn from the appearances of nature. The first is, ** that, in a vast plurality of instances in which contrivance is perceived, the design of the contri- vance is henejidal. The second, " that the Deity has superadded pleasure to animal sensations, beyond what was necessary for any other purpose, or when the purpose, so far as was necessa- ry, might have been effected by the operation of pain." First, ** in a vast plurality of instances, in which contri- vance is perceived, the design of the contrivance is benefi- daV No productions of nature display contrivance so manifest- ly as the parts of animals : and the parts of animals have all of them, I believe, a real, and, with very few exceptions^ all of them a known and intelligible subserviency to the use of the animal. Now, when the multitude of animals is considered, the numoer of parts in each, their figure and fitness, the facultie- depending upon them, the variety oi species, the complexity of structure, the success, in so ma- ny cases, and felicity of the result, we can never reflect, without the profoundest adoration, upon the character of that Being from wiiom all these things have proceeded : we cannot help acknowledging, what an exertion of benevo- lence creation was ; of a benevolence, how minute in its care, how vast in its comprehension. When v/e appeal to the parts and faculties of animals, and to the limbs and senses of animals in particular, we state, I conceive, the proper medium of proof for the con- clusion which we wish to establish. I will not say, that the insensible parts of nature are made solely for the sensi- tive parts ; but this I say, that, when we consider the be- nevolence of the Deity, we can only consider it in relation to sensitive Being. Without this reference, or referred to any thing else, the attribute has no object : the term has no meaning. Dead matter is nothing. The parts, there- fore, especially the limbs and senses of animals, although they constitute, in mass and quantity, a small portion of the jnaterial creation, yet, since they alone are instruments of THE GOODNESS OF THE DEITY. '2ol perception, they compose what may be called the whole ot visible nature, estimated with a view to the disposition oi its author. Consequently, it is in these that we are to seek his character. It is by these that we are to prove, that the world was made with a benevolent design. Nor is the design abortive. It is a happy world after all. The air, the earth, the water, teem with delighted exis- tence. In a spring noon, or a summer evening, on which- ever side I turn my eyes, myriads of happy beings crowd upon my view. " The insect youth are on the wing.'' Swarms of new-born flies are trying their pinions in the air. Their sportive motions, their wanton mazes, their gratuitous activity, their continual change of place without use or purpose, testify their joy, and the exultation whicli they feel in their lately discovered faculties. A bee amongst the flowers in spring, is one of the most cheerful objects that can be looked U[)on. Its life appears to be all enjoyment ; so busy, and so pleased : yet it is only a specimen of insect life, with which, by reason of the animal being half domesti- cated, we happen to be better acquainted than we are with that of others. The wJioIc winged insect tribe, it is proba- ble, are equally intent upon their proper employments, and under every variety of constitution, gratified, and perhaps equally gratified, by the offices which the Author of their nature has assigned to them. But the atmosphere is not the only scene of enjoyment for the insect race. Plants are covered with aphides, greedily sucking their juices, and constantly, as it should seem, in the act of sucking. It cannot be doubted but that this is a state of gratification. What else should fix them so close to the operation, and so long ? Other species are running about with an alacrity in their motions which carries with it every mark of pleasure. Large patches of ground are sometimes half covered with these brisk and sprightly natures. If we look to what the umters produce, shoals of the fry of fish fre- quent the margins of rivers, of lakes, and of the sea itself. These are so happy, that they know not what to do with themselves. Their attitudes, their vivacity, their leaps out of the water, their frolicks in it, (which I have noticed a thousand times with equal attention and amusement,) all condu -^ to show their excess of spirits, and are simply the effects v\ that excess. Walking by the seaside, in a calm evening, upon a sandy shore, and with an ebbing tide, I have frequently remarked the appearance of a dark cloud, Y 258 THE GOODNESS OF THE DEITV. or, rather very thick mist, hanging over the edge of tijt? water, to the height, perhaps, of half a yard, and of the breadth of two or three yards, stretching along the coast as far as the eye could reach, and always retiring with the wa- ter. When this cloud came to be examined, it proved to be nothing else than so much space, filled with young shrimps, in the act of bounding into the air from the shal- low margin of the water, or from the wet sand. If any mo- tion of a mute animal could express delight, it was this ; if the} had meant to make signs of their happiness, they could not have done it more intelligibly. Suppose then, what I have no doubt of, each individual of this number to be in a state of positive enjoyment, what a sum, collectively, of gratification and pleasuie have we here before our view ! The yoimg of all animals appear to me to receive pleas- ure simply from the exercise of their limbs and bodily fac- ulties, without reference to any end to be attained, or any use to be answered by the exertion. A child, without knowing any thing of the use of language, is in a high de- gree delighted with being able to speak. Its incessant rep- etition of the few articulate sounds, or perhaps, of the sin- gle word, which it has learned to pronounce, proves ihis point clearly. Nor is it less pleased with its first success- ful endeavours to walk, or rather to run, (which precedes walking,) although entirely ignorant of the importance of the attainment to its future life, and even without apply- ing it to any present purpose. A child is delighted with speaking without having any thing to say ; and with walk- ing, without knowing where to go. And, prior to both these, 1 am disposed to believe, that the waking hours of infancy are agreeably taken up with the exercise of vision, or perhaps more properly speaking, with learning to see. But it is not for youth alone, that the great Parent of creation hath provided. Happiness is found with the purring cat, no less than with the playful kitten : in the arm chair of dozing age, as well as in either the sprightliness of the dance, or the animation of the chace. To novelty, to acuteness of sensation, to hope, to ardour of pursuit, suc- ceeds, what is, in no inconsiderable degree, an equivalent for them all, " perception of ease." Herein is the exact difference between the young and the old. The young are not happy, but when enjoying pleasure ; the old are happy when free from pain. And this constitution suits with the degrees of anim.ai power which they respectively possess. The vigour of youth was to be stimulated to action by the THE GOODNESS OF THE DEITY. 259 impatience of rest; whilst, to the imbecility of age, quiet- ness and repose become positive gratifications. In one im- portant respect the advantage is with the old. A state of i^ase is, generally speaking, more attainable than a state of pleasure A constitution, therefore, which can enjoy ease, is preferable to that which can taste only pleasure. The same perception of ease oftentimes renders old age a con- ditiV)n of great comfort ; especially when riding at its an- chor, after a busy or tempestuous life. It is well describ- ed by Rousseau, to be the interval of repose and enjoy- ment, between the hurry and the end of life. Hovv far the same cause extends to other animal natures cannot be judg- ed of with certainty. The appearance of satisfaction, with which most animals as their activity subsides, seek and en- joy rest, affords reason to believe, that this source of grati- fication is appointed to advanced life, under all, or most, of its various forms. In the species with which we are best acquainted, namely, our own, I am far, even as an observer of human life, from thinking, that youth is its happiest sea- son, much less the only happy one : as a Christian, I am willing to believe that there is a great deal of truth in the following representation given by a very pious writer, as well as excellent man.* " To the intelligent and virtuous, old age presents a scene of tranquil enjoyments, of obedient appetites, of well regulated affections, of maturity in knowl- edge, and of calm preparation for immortality. In this se- rene and dignified state, placed, as it were, on the confines of two worlds, the mind of a good man reviews what is past with the complacency of an approving conscience, and looks forward, with humble confidence in the mercy of God, and with devout aspirations, towards his eternal and ever increasing favour." What is seen in different staores of the same life, is still more exemplified in the lives of different animals. Animal enjoyments are infinitely diversijiert. The modes of life, to which the organization of different animals respectively de- termines them, are not only of various, but of opposite kinds. Yet each is happy in its own. For instance ; animals of prey, live much alone ; animals of a milder constitution, in society. Yet the herring, which lives in shoals, and the sheep, which lives in flocks, are not more happy in a crowd, or more contented amongst their companions, than is the pike, or the lion, with the deep solitudes of the pool, or the forest. ' Father's Instructions, by Dr. Percival of Manchester, p. 317. 2C0 THE GOODNESS OP THE DEITY, But it will be said, that the instances which we have here brought forward, whether of vivacity or repose, or of appa- rent enjoyment derived from either, are picked and favour- able instances. We answer, First, that they are instances, nevertheless, which comprise large provinces of sensitive existence ; that every case which we have described, is the case of millions At this moment, in every given moment ot time, how many myriads of animals are eating their food, gratifying their appetites, ruminating in their holes, accom- plishing their wish, s, pursuing their pleasures, taking their pastimes ! In each individual how many things must go right for it to be at ease ; yet how large a proportion out of every species, is so in every assignable instant ! Second- ly, we contend, in the terms of our original proposition, that throughout the whole of life, as it is diffused in nature, and as far as we are acquiiinted with it, looking to the average of sensations, the plurality and the preponderancy is in fa- vour of happiness by a vast excess. In our own species, in which perhaps the assertion may be more questionable than in any other, the prepollency of good over evil, of health, for example, and ease, over pain and distress, is evinced by the very notice which calamities excite. What inquiries does the sickness of our friends produce 1 What conversa- tion their misfortunes'? This shows that the common course of things is in favour of happiness ; that happiness is the rule, misery the exception. Were the order revers- ed, our attention would be called to examples of health and competency, instead of disease and want. One great cause of our insensibility to the goodness of the Creator is the very eite?isivejiess of his bounty. We prize but little, what we share only in common with the rest, or with the generality, of our species. When we hear of blessings, we think forthwith of successes, of prosperous fortunes, of honours, riches, preferments, i e. of those ad- vantages and superiorities over others, which we happen either to possess, or to be in pursuit of, or to covet. The common benefits of our nature entirely escape us. Yet these are the great things. These constitute, what most properly ought to be accounted blessings of Providence ; what alone, if we might so speak, are worthy of its care. Nightly rest, and daily bread, the ordinary use of our limbs^ ■md senses, and understandings, are crifts which admit of no comparison with any other. Yet, because almost every man we meet v;ith possesses these, we leave them out of • *nr enumeration. They raise no sentiment : they move no THE GOODNESS OP THE DEITV. 261 gratitude. Now, herein, is our judgment perverted by our selfishness. A blessing ought, in truth, to be the moj-e sat- isfactory, the bounty at least of the donor is rendered more conspicuous, by its very diifusion, its coiiiaionness, its cheap- ness ; by its falling to the lot, and forming the happiness, of the great bulk and body of our species, as well as of our- selves. Nay, even when we do not possess it, it ought to be matter of thankfulness that others do. But we have a different way of thinking. We court distinction. That is not the worst ; we can see nothing but what has dis- tinction to recommend it. This necessarily contracts our views of the Creator's beneficence within a narrow com- pass ; and most unjustly. It is in those things which are so common as to be no distinction, that the amplitude of the divine benignity is perceived. But pain, no doubt, and privations, exist, in numerous instances, and to a degree, which, collectively, would be very great, if they were compared with any other thing than with the mass of animal fruition. For the application, therefore, of our proposition to that mixed state of things which these exceptions induce, two rules are necessary, and both, I think, just and fiiir rules. One is, that we regard those effects alone which are accompanied with proofs of intention : The other, that, when we cannot resolve all ap- pearances into benevolence of design, we mike the few give place to the many ; the little to the great ; that we take our judgment from a large and decided preponderancy, if there be one. I crave leave to transcribe into this place, what I have said upon this subject in my moral philosophy " When God created the human species, either he wished their hap- piness, or he wished their misery, or he was indifferent and unconcerned about either. " If he had wished our misery, he might have made sure of his purpose, by forming our senses to be so many sores and pains to us, as they are now instruments of gratifica- tion and enjoyment ; or by placing us amidst objects, so ill suited to our perceptions, as to have continually offended us, instead of ministering to our refreshment and delight. He might have made, for example, every thing we tasted bitter ; every thing we saw loathsome ; every thing we touched a sting ; every smell a stench ; and every sound a discord. " If he had been indifferent about our happiness or mis- Y2 •J6.;J TJIE GOODNESS OP THE DEITY, cry, we must impute to our good fortune (as all design by this supposition is excluded) both the capacity of our senses to receive pleasure, and the supply of external objects fitted to produce it. " But either of these, and still more both of them, be- ing too much to be attributed to accident, nothing remains but the first supposition, that God, when he created the hu- man species, wished their happiness ; and made for them die provision which he has made, with that view and for that purpose. " The same argument may be proposed in different terms ; (bus : Contrivance proves design , and the predominant tendency of the contrivance indicates the disposition of the designer. The world abounds with contrivances ; and all the contrivances which we are acquainted with, are direct- ed to beneficial purposes. Evil, no doubt, exists ; but is never, that we can perceive, the object of contrivance. Teeth are contrived to eat, not to ache ; their aching now and then is incidental to the contrivance, perhaps insepara- ble from it : or even, if you will, let it be called a defect in the contrivance ; but it is not the object of it. This is a distinction which well deserves to be attended to. In de- scribing implements of husbandry, you would hardly say of the sickle, that it is made to cut the reaper's hand, though, from the construction of the instrument, and the manner of using it, this mischief often follows. But if you had oc- casion to describe instruments of torture or execution, this oiigme, you would say, is to extend the sinews ; this to dis- locate the joints ; this to break the bones ; this to scorch the soles of the feet. Here pain and misery are the very objects of the contrivance. Now, nothing of this sort is to be found in the works of nature. We never discover a train of contrivance to bring about an evil purpose. No anatomist ever discovered a system of organization, calcu- lated to produce pain and disease ; or, in explaining the parts of the human body, ever said, this is to irritate ; this to inilame ; this duct is to convey the gravel to the kidneys ; this gland to secrete the humour which forms the gout : if by chance he come at a part of which he knows not the use, the most he can say is, that it is useless , no one ever suspects that it is put there to incommode, to an- noy, or to torment." The two cases which appear to me to have the most of difficulty in them, as forming the most of the appearance of Qsception to the represeatation here given, are those o^ven- THE CfOODNESS OF THE BEITY. ^63 Qfuous animals, and of animals preying upon one anotheF„ These properties of animals, wherever they are found, must, I think, be referred to design ; because there is, in all eases of the first, and most cases of the second, an express and distinct organization provided for the producmg of them. Under the first head, the fangs of vipers, the stings of wasps and scorpions, are as clearly intended for their purpose, as any animal structure is for any purpose the most incontest- ably beneficial. And the same thing must, under the se- cond head, be acknowledged of the talons and beaks of birds, of the tusks, teeth, and claws of beasts of prey, of the shark's mouth, of the spider's web, and of numberless wea- pons of offence belonging to different tribes of voracious in- sects. We cannot, therefore, avoid the difficulty by say- ing, that the effect was not intended. The only question open to us is, whether it be ultimately evil. From the con- fessed and felt imperfection of our knowledge, we ought to presume, that there may be consequences of this economy which are hidden from us : from the benevolence v/hich pervades the general designs of nature, we ought also to presume, that these consequences, if they could enter into our calculation, would turn the balance on the favourable side. Both these I contend to be reasonable presumptions. Not reasonable presumptions, if these two cases were the only cases which nature presented to our observation ; bufc reasonable presumptions under the reflection, that the cases in question are combined with a multitude of intentions, all proceeding from the same author, and all, except these, directed to ends of undisputed utility. Of the vindications, however, of this economy, which we are able to assign, such as most extenuate the difficulty are the following : With respect to venomous bites and stings, it may be ob- served, 1. That, the animal itself being regarded, the faculty complained of is good: being conducive, in all cases, to the defence of the animal ; in some cases, to the subduing of its prey ; and, in some probably, to the killing of it, when caught, by a mortal wound inflicted in the passage to the stomach, which may be no less merciful to the victim, than salutary to the devourer. In the viper, for instance, the poisonous fang may do that, which in other animals of prey, is done by the crush of the teeth. Frogs and mice might he swallowed alive without it. 2. But it will be said, that this provision, when it comes to the case of bites, deadly even to human bodies and to ^ti4 THE GOODNESS OF THE DEITV. those of large quadrupeds, is greatly overdone; that it migh' have fuliilled its use, and yet have been much less delete- rious than it is. Now I believe the case of bites, which produce death in large animals, (of stings I think there are none,) to be very few. The experiments of the Abbe Fon- tana, which were numerous, go strongly to the proof of this point. He found that it required the action of five exaspe- rated vipers to kill a dog of a moderate size ; but that, to the killing of a mouse or a frog, a single bite was sufficient : which agrees with the use which we assign to the faculty. The Abbe seemed to be of opinion, that the bite even of the rattlesnake would not usually be mortal ; allowing, how- ever, that in certain particularly unfortunate cases, as when the puncture had touched some very tender part, pricked a principal nerve for instance, or, as it is said, some more considerable lymphatic vessel, death might speedily ensue. 3. It has been, I think, very justly remarked concerning serpents, that, whilst only a few species possess the veno- mous property, that property guards the whole tribe. The most innocuous snake is avoided with as much care as a viper. Now the terror, with which large animals regard this class of reptiles, is its protection ; and this terror is founded in the formidable revenge, wiiich a few of the num- ber, compared with the wiiole, are capable of taking. The species of serpents, described by Linnseus, amount to two hundred and eighteen, of which thirty-two only are poison- ous. 4. It seems to me, that animal constitutions are provid- ed, not only for each element, but for each state of the ele- ments, i e. for every climate, and for every temperature ; and that part of the mischief complained of arises from an- imals (the human animal most especially) occupying situ- ations upon the earth vv'hich do not belong to them, nor were ever intended for their habitation. The folly and wickedness of mankind, and necessities proceeding from these causes, have driven multitudes of the species to seek a refuge amongst burninir sands, whilst countries blessed with hospitable skies, and with the most fertile soils, re- main almost without a human tenant. We invade the ter- ritories of wild beasts and venomous reptiles, and then com- plain that we are infested by their bites and stings. Some accounts of Africa place this observation in a strong point of view. " The deserts," says Adanson, " are entirely bar- ren, except where they are found to produce serpents ; and in such quantities, that some extensive plains are almost THE GOODNESS OF THE DEITX", 265 entirely covered with them." These are the natures appro- priated to the situation. Let them enjoy their existence ; let them have their country. Surface enough will be left to man, though his numbers were increased an hundred fold, and left to him, where he might live exempt from these annoyances. The second case, viz. that of animals devouring one an- other, furnishes a consideration of much larger extent. To judge, whether, as a general provision, this can be deem- ed an tvil, even so far as we understand its consequences, which, probaoly, is a partial understanding, the follovving reflections are fit to be attended to. 1, Immortality upon this earth is out of the question. Without death there could be no generation, no sexes, no parental relation, i. e. as things are constituted, no animal happiness. The particular duration of life, assigned to dif- ferent animals, can form no part of the objection ; because, whatever that duration is, whilst it remains finite and limited, it may always be asked, why it is no longer. The natural age of different animals varies from a single day to a century of years. No account can be given of this ; nor could any be given, whatever other proportion of life had obtained amongst them. The term then of life in different animals being the same as it is, the question is, what mode of taking it away is best even for the animal itself. Now, according to the established order of nature, (which we must suppose to prevail, or we cannot reason at all upon the subject,) the three methods by which life is usually put an end to, are acute diseases, decay, and violence. The simple and natural life of brutes, is not often visited by acute distempers ; nor could it be deemed an improvement of their lot, if they were. Let it be considered, therefore, in w^hat a condition of suffering and misery a brute animal is placed, which is left to perish by decay. In human sick- ness or mfirmity, there is the assistance of man's rational fellow creatures, if not to alleviate his pains, at least to min- ister to his necessities, and to supply the place of his own activity. A brute, in his wild and natural state, does eve- ry thing for himself. When his strength therefore, or his speed, or his limbs, or his senses fail him, he is delivered over, either to absolute famine, or to the protracted wretch- edness of a life slowly wasted by scarcity of food. Is it then to see the world filled with droopingj superannuated, 266 THE GOODNESS OF THE DEITY. half Starved, helpless and unhelped animals, that you would alter the present system of pursuit and prey ? 2. Which system is also to them the spring of motion and activity on both sides. The pursuit of its prey, forms the employment, and appears to constitute the pleasure, of a considerable part of the animal creation. The using of the means of defence, or flight, or precaution, forms also the business of another part And even of this latter tribe, we have no reason to suppose, that their happiness is much molested by their fears. Their danger exists continually ; and in some cases they seem to be so far sensible of it, as to provide, in the best manner they can, against it ; but it is only when the attack is actually made upon them, that they appear to suffer from it. To contemplate the insecu- rity of their condition with anxiety and dread, requires a degree of reflection, which (happily for themselves) they do not possess A hare notwithstanding the number of its dangers and its enemies, is as playful an animal as any other 3. But to do justice to the question, the system of animal destruction ought always to be considered in strict connex- ion with another property of animal nature, viz. supe)'fecun- dity. They are countervailing qualities One subsists by the correction of the other. In treating, therefore, of the subject under this view, (which is, I believe, the true one,) our business will be, first to point out the advantages which are gained by the powers in nature of a superabundant mul- tiplication ; and then, to show, that these advantages are so many reasons for appointing that system of animal hos- tilities, which we are endeavouring to account for. In almost all cases nature produces her supplies with profusion. A single cod fish spawns, in one season, a greater number of eggs than all the inhabitants of England ;imount to. A thousand other instances of prolific genera- tion might be stated, v^hich, though not equal to this, would carry on the increase of the species with a rapidity which outruns calculation, and to an immeasurable extent. The advantages of such a constitution are two : first, that it tends to keep the world always full ; whilst, secondly, it allows the proportion between the several species of animals to be differently modified, as different purposes require, or as dif- ferent situations may afford for them room and food. Where this vast fecundity meets with a vacancy fitted to receive the species, there it operates with its whole effect ; there it pours in its numbers, and replenishes the waste. THE GOODNESS OP THE DEITY. 267 We complain of what we call the exorbitant multiplication of some troublesome insects, not reflecting that large por- tions of nature might be left void without it If the ac- counts of travellers may be depended upon, immense tracts of forest in North America would be nearly lost to sensitive existence if it were not for gnats. " In the thinly inhabit- ed regions of America, in which the waters stagnate, and the chmate is warm, the whole air is filled with crowds of these insects." Thus it is, that where we look for solitude and deathlike silence, we meet with animation, activity, enjoyment ; with a busy, a happy, and a peopled world. Again ; hosts of 7n{ce are reckoned amongst the plagues of the northeast part of Europe ; whereas vast plains in Sibe- ria, as we learn from good authority, would be lifeless with- DUt them. The Caspian deserts are converted by their presence into crowded warrens. Between the Volga and he Yaik, and in the country of Hyrcania, the ground, says Pallas, is in many places covered with little hills, raised by the earth cast out in forming the burrows. Do we so envy these blissful abodes, as to pronounce the fecundity by which they are supplied with inhabitants, to be an evil ; a subject of complaint, and not of praise ? Further ; by virtue of this same superfecundity, Vt^hat we term destruc- tion, becomes almost instantly the parent of life What we call blights, are oftentimes legions of aniiuated beings, claiming their portion in the bounty of nature. What cor- rupts the produce of the earth to us, prepares it for them. And it is by means of their rapid multiplication, that they take possession of their pasture : a slow propagation would not meet the opportunity But in conjunction with the occasional use of this fruit- fulness, we observe, also, that it allows the proportion be- tween the several species of animals to be differently modi- fied, as different purposes of utility may require. When the forests of America come to be cleared, and the swamps drained, our gnats will give place to other inhabitants. If the population of Europe should spread to the north and the east, the mice will retire before the husbandman and the shepherd, and yield their station to herds and flocks. In what concerns the human species, it may be a part of the scheme of Providence that the earth should be inhabited by a shifting, or perhaps a circulating population. In this economy it is possible that there may be the following ad- vantages : When old countries are become exceedingly corrupt, simpler modes of life, purer morals, and better in- ?i68 THE GOODNESS OP THE DEH'Y. stitutions, may rise up in new ones, whilst fresh soils reward the cultivator with more plentiful returns. Thus the differ- ent portions of the globe come into use in succession as the residence of man ; and, in his absence, entertain other guests, which by their sudden multiplication fill the chasm. In domesticated animals we find the effect of their fecundity to be, that we can always command numbers : we can always have as many of any particular species as we please, or as we can support. Nor do we complain of its excess ; it being much more easy to regulate abundance, than to supply scarcity. But then this superfecundity , though of great occasional use and importance, exceeds the ordinary capacity of nature to receive and support its progeny. AH superabundance supposes destruction, or must destroy itself Perhaps there is no species of terrestrial animals whatever, which would not overrun the earth, if it were permitted to multiply in perfect safety ; or offish, which would not fill the ocean : at least, if any single species were left to their natural increase without disturbance or restraint, the food of other species would be exhausted by their maintenance. It is necessary, therefore, that the effects of such prolific faculties be cur- tailed. In conjunction with other checks and limits, ail sub- servient to the same purpose, are the thinnings which take place among anim-als, by their action upon one another. In some instances we ourselves experience, very directly, the use of these hostilities. One species of insects rids us of another species ; or reduces their ranks. A third species perhaps keeps the second within bounds : and birds or liz- ards are a fence against the inordinate increase by which even these last might infest us. In other, more numerous, and possibly more important instances, this disposition of things, although less necessary or useful to us, and of course less observed by us, may be necessary and useful to certain other species ; or even for the preventing of the loss of cer- tain species from the universe : a misfortune which seems to be studiously guarded against. Though there may be the appearance of failure in some of the details of nature's works, in her great purposes there never are. Her species never fail. The provision which was originally made for continuing the replenishment of the world, has proved itself to be effectual through a 1 )ng succession of ages. What further shows, that the system of destruction amongst animals holds an express relation to the system of fecundity ; that they are parts indeed of one compensatoi'y THE GOODNESS OF THE DEITY. 269 scheme ; is, that, in each species, the fecundity bears a proportion to the smallness of the animal, to the weakness, to the shortness of its natural term of life, and to the dangers and enemies by which it is sui rounded. An ele- phant produces but one calf: a butterfly lays six hundred eggs. Birds of prey seldoin produce more than two eggs: the sparrow tribe, and the duck tribe, frequently sit upon a dozen In the rivers, we meet with a thousand minnows for one pike ; in the sea, a mdlion of herrings ibr a single shark. Compensation obtains throughout. Defenceless- ness and devastation are repaired by fecundity. We have dwelt the longer upon these considerations, be- cause the subject to which they apply, namely, tiiat of ani- mals devouring one another, forms the chief, if not the only instance, in the works of the Deity, of an ecpnomy, stamp- ed by marks of design, in which the character of utility can be called in question. The case oi venomous animals is of much mferioi consequence to the case of prey, aiid, in some degree, is also included unier it. To both cases it is prob- able that many more reasons belong, than those of which we are in possession. Our Jirst proposition, and that which we have hitherto been defending, was, " that in a vast plurality of instances, in which contrivance is perceived, the design of the contri- vance is beneficial." Our second proposition is, " that the Deity has added pleasure to animal sensations, beyond what was necessary for any other purpose, or when the purpose, so far as it was necessary, might have been effected by the operation of pain." This proposition may be thus explained. The capaci- ties, which, according to the established course of nature, are necessary to the support or preservation of an animal, however manifestly they may be the result of an organiza- tion contrived for the purpose, can only be deemed an act or a part of the sa-ne will, as that which decreed the exis- tence of the animal itself; because, whether the creation proceeded from a benevolent or a malevolent being, these capacities must have been given, if the animal existed at all. Animal properties therefore, which fall under this de- scription, do not strictly prove the goodness of God. They may prove the existence of the Deity ; they may prove a. high degree of power and intelligence ; but they do not prove his goodness : forasmuch as they must hare been Z :-i70 THE GOODXESS OP THE DEITY. found in any creation which was capable of continnance^ although it is possible to suppose^ that such a creation might have been produced by a being, whose views rested upon misery. But there is a class of properties, which may be said to be superadded from an intention expressly directed to hap- piness ; an intention to give a happy existence distinct from the general intention of providing tl'e means ot existence ; and that is, of the capacities for pleasure, in cases, where- in, so far as the conservation of the individual or of the species is concerned, they were not wp.iited ; or wherein the purpose might have been secured by the operation of pain. The provision which is made of a variety of objects, not necessary to life, and ministering only to our pleasures : and the properties given to the necessaries of life themselves, by which they contribute to pleasure as well as preserva- tion, show a further design, than that of giving existence.* A single instance will make all this clear. Assuming the necessity of food for the support of animal life, it is re- quisite that the ammal be provided with organs, fitted for the procuring, receiving, and digestiiig of its food. It may be also necessary that the animal be impelled by its sensa- tions to exert its organs. But the pain of hunger would do all this. Why add pleasure to the act of eating ; sv^'eetness and relish to food ? Why a new and appropriate sense for the perception of the pleasure ? Why should the juice of a peach applied to the palate, anect the part so different- ly from what it does when rubbed upon the palm, of the hand ? This is a constitution, v,'hich, so far as appears to me, can be resolved into nothing but the pure benevolence of the Creator. Eating is necessary ; but the pleasure at- tending it is not necessary : and that this pleasure, depends n u only upon our being in possession of the sense of taste, which is difiierent from every other, but upon a particular state of the organ, in which it resides, a felicitous adapta- tion of the organ to the object, will be confessed by any one, who may happen to have experienced that vitiation of taste which frequently occurs in fevers, when every taste is irregular, and every one bad. In mentioning the gratifications of the palate, it may be said that we have made choice of a trifling example. I am *See this topic considered in Dr. Balguy's treatise upon the Divine Benevolence. This excellent author. First, I think, proposed it ; and nearly in the terms in which it is here stated. Some other observations.. also, under this head, are taken trom that treatise. THE GOODNESS OP THE DEITY. 271 not of that opinion. They afford a share of enjoyment to man ; but to brutes, I believe, that they are of very great iraportaiice. A horse at liberty passes a great part of his waking hours in eating. To the ox, the sheep, the deer, and other ruminating animals, the pleasure is doubled. Their whole time almost is divided between browsing upon their pasture and chewing their cud. Whatever the pleas- ure be, it is spread over a large portion of their existence. If there be animals, such as the lupous tish, which swallow their prey whole, and at once, without any time, as it should seem, for either drawing out, or relishing, the taste in the mouth, is it an improbable conjecture, that the seat of taste with them is m the stomach ; or, at least, that a sense of pleasure, whether it be taste or not, accompanies the disso- Iuti(>n of the food in that receptacle, which dissolution in general is carried on very slowly ? If this opinion be right, they are more than repaid for their defect of palate. The feast lasts as long as the digestion. In seekincT for argument we need not stay to insist upon the comparative importance of our example ; for the observa- tion holds equally of all, or of three at least, of the other senses. The necessary purposes of hearing might have been answered without harmony ; of smell, without fra- grance ; of vision, withmit beauty. Now, " If the Deity had been indifferent about our happiness or misery, we must impute to our2:ood fortune (as all design by this supposition is excluded) both the capacity of our senses to receive pleas- ure, and the supply of external objects fitted to excite it." I allege these as two felicities, for they are different things, yet both necessary ' the sense being formed, the objects which v/ere applied to it, might not have suited it ; the ob- jects being fixed, the sense might not have agreed with them. A coincidence is here required which no accident can ac- count for. There are tiiree possible suppositions upon the subject, and no more. The first, that the sense, by its original constitution, was made to suit the object ; the second, that the object, by original constitution, was made to suit the sense : the third, that the sense is so constituted, as to be able, either universally, or within certain limits, by habit and familiar- ity to render every object pleasant. Whichever of these suppositions we adopt, the effect evinces, on the part of the Author of nature, a studious benevolence. If the pleasures which we derive from any of our senses, depend upon an original congruity between the sense and the properties perceived by it, we know by experience, that the adjust- ii'ri THE GOODNESS OF THE DEITY. ment demanded, with respect to the qualities which wein conferred upon the objects that surround us, not only choice and selection, out ot a boundless variety of possible qualities Avith which these x)bjects might have been endued, but apro- [wrtioning also of degree, because an excess or defect of in- tensity spoils the perception, as much almost as an error in the kind and nature of the quality. Likewise the de- gree of dulness or acuteness in t le sense itself, is no arbi- trary thing ; but in order to preserve the congruity here spoken of, requires to be in an exact or near corresponden- cy with the strength of the impression. The dulness of the senses forms the complaint of old age. Persons in fe- vers, and, I believe, in most maniacal cases, experience great torment from their pretcrndtural acutefiess. An in- creased, no less than an impaired sensibility, induces a state of disease and suiTering. The doctrine of a specific congruity between animal senses and their objects, is strongly favoured, by what is ob- served of insects in the election of their food. Some of these will feed upon one kind of plant or animal, and upon no other : some caterpillars upon the cabbage alone ; some up- on the black currant alone. The species of caterpillar which eats the vine, will starve upon the elder ; nor will that which we find upon fennel, touch the rosebush. Some insects confine themselves to two or three kinds of plants or animals. Some again show so strong a preference, as to afford reason to believe that, though they may be driven by hunger to others, they are led by the pleasure of taste, to a few particular plants alone ; and all this as it should seem, independently of habit or imitation. But should we accept the third hypothesis, and even car- ry it so far as to ascribe every thing, which concerns the question, to habit, (as in certain species, the human species most particularly, there is reason to aitribute something,) we have then before us an animal capacity not less perhaps to be admired, than the native congruities which the other scheme adopts. It cannot be shown to result from any fix- ed nec';issity in nature, that what is frequently applied to the senses cshould of course become agreeable to them. It is, so far as ic subsists, a power of accommodation, provided in these senses by the Author of their structure, and forms a part of their perfection. In whichever way we consider the senses, they appear t© be specific gifts, ministering, not only to preservation, but 10 pleasure. Bat what we nsaally call the senses ^re prob- THE GOODNESS OP THE DEITY. 273 ably themselves far from being the only vehicles of enjoy- ment, or the whole of our constitution,, which is calculated for tne same purpose. We have many internal sensations of the most agreeable kind, hardly referrible to any of the five senses. Some physiologists have holden, that all secre- tion is pleasurable : and that the complacency, which in health, without any external, assignable object to excite it, we derive from life itself, is the effect of our secretions go- ing on weil within us. All this may be true : but, if true, what reason can be assigned for it, except the will of the Creator ? It may reasonably be asked, why is any thing a pleasure ? and I know of no answer which can be returned to the question, but that which refers it to appointment. We can give no account whatever of our pleasures in the simple and original perception ; and even, when physical sensations are assumed, we can seldom account for them in the secondary and complicated shapes, in which they take the name of diversions. I never yet met with a sportsman who could tell me in what the sport consisted ; who could resolve it into its principle, and state that principle. I have been a great follower of fishing myself, and in its cheerful solitude have passed some of the happiest hours of a suffi- ciently happy life ; but to this moment, I could never trace out the source of the pleasure which it afL.)rded me. The " quantum in rebus inane !" whetiier applied to our amusements, or to our graver pursuits, (to which, in truth, it sometimes equally belongs,) is always an unjust com- plaint. If trifles engage, and if trifles make us happy, the true reflection suggested by the experiment, is upon the tendency of nature to gratification and enjoyment ; which is, in other words, the goodness of its Author towards his sensitive creation. Rational natures also, as such, exhibit qualities which help to confirm the truth of our position. The degree of understanding found in mankind, is usually much greater than what is necessary for mere preservation. The pleasure of choosing for themselves, and of prosecuting the object of their choice, should seem to be an original source of enjoy- ment. The pleasures received from things, great, beauti- ful, or new, from imitation or from the liberal arts, are, in ^ome measure, not only superadded, but unmixed gratifi- cations, having no pains to balance them.* " Balguy on the Divine Benevolence. Z2 '274 THE GOODNirsS OP THE PEIi^V. I do not know whether our attachment to properly (m; not something more than the mere dictate of reason, or even than the mere effect of association. Property communi- cates a charm to whatever is the object of it. It is the first of our abstract ideas ; it cleaves to us the closest and the longest. It endears to the child its plaything, to the peas- ant his cottage, to the landholder his estate. It supplies the place of prospect and scenery. Instead of coveting the beauty of distant situations, it teaches every man to find it in his own. It gives boldness and grandeur to plains and fens, tinge and colouring to clays and fallows. All these considerations come in aid of our second prop- osition. The reader will now bear in mind what our two propositions were. They were, firstly, that, in a vast plu- rality of instances, in which contrivance is perceived, the design of the contrivance is beneficial : secondly, that the Deity has added pleasure to animal sensations beyond what was necessary for any other purpose ; or when the purpose, £0 far as it was necessary, might have been effected by the operation of pain. Whilst these propositions can be maintained, we are au- thorized to ascribe to the Deity the character of benevo- lence : and what is benevolence at all, must in him be in-' finite benevolence, by reason of the infinite, that is to say, the incalculably great number of objects, upon which it i? exercised. Of the opaoiN of evil no universal solution has been discovered : I mean no solution which reaches to all cases of complaint. The most comprehensive is that which arises from the consideration of general rules. We may, I think, without much difficulty, be brought to admit the four following points : first, that important advantages may ac- crue to the universe from the order of nature proceeding ac- cording to general laws : secondly, that general laws, how- ever well set and constituted, often thwart and cross one another : thirdly, that from these thwartings and crossings frequent particular inconveniences will arise : and fourth- ly, that it agrees with our observation to suppose, that some degree of these inconveniences takes place in the works of nature. These points may be allowed ; and it may also be asserted that the general laws with which we yre acquainted, are directed to beneficial ends. On the other hand, with many of these laws we are not acquaint- ed at all, or we are totally unable to trace them in their THE 600DNESS OP THE »EITT?. 375 feraaehes and in their operation : the effect of which igno^ ranee is, that they cannot be of importance to us as meas.- ures by which to regulate our conduct The conservation of them may be of importance in other respects, or to other bemgs, but we are uninformed of their value or use : unin* formed consequently when, and how far, they may or may not be suspended, or their effects turned aside, uy a presiding and benevolent will, without iccurrnig greater evils than those xvhich would be avoided. The consideration, therefore, of general laws, although it may concern the question of the origin of evil very nearly, (which 1 think it does,) rests in views disproportionate to our faculties, and in a knowledge which we do not possess. It serves rather to account for the obscurity of the subject, than to supply us with distinct an- !?wers to our difficulties. However, whilst we assent to the above stated propositions as principles, v/hatever uncertain- ty we may iind in the application, we lay a ground for be- lieving, that cases, of apparent evil, for which ive can sug- gest no particular reason, are governed by reasons, which are more general, which lie deeper in the order of second causes, and which on that account are removed to a greater distance from us. The doctrine oi imperfections, or, as it is called, of evils of imperfection, furnishes an account, founded like the former, in views of universal nature. The doctrine is briefly this. It is probable that creation may be better re- plenished, by sensitive beings of different sorts, than by sensitive beings all of one sort. It is likewise probable, that it may be better replenished, by different orders of beings rising one above another in gradation, than by beings pos- sessed of equal degrees of perfection. Now a gradation of such beings implies a gradation of imperfections. No class can justly complain of the imperfections wiiich belong to its place in the scale, unless it were allowable for it to com- plain, that a scale of being was appointed in nature : for which appointment there appear to be reasons of wisdom and goodness. In like mdiUUQx,Jinitcness, or what is resolvable into finite- ness, in inanimate subjects, can never be a just subject of complaint, because, if it were ever so, it would be always so : we mean, that we can never reasonably demand that things should be larger or more, when the same demand might be made, whatever the quantity or number was. And to me it seems, that the sense of mankind has so far acquiesced in these reasons, as that we seldom complain t376 THE GOODNESS OF THE DErTY. of evils of this class, when we clearly perceive them to be such. What I have to udd therefore is, that v/e ought not to complain of some other evils, which stand upon the same foot of vindication as evils of confessed imperfection. We never complam that the crlobe of our earth is too small : nor ehould we complain, were it even much smaller. But where is the ditference to us, between a less globe, and a part of the present being uninhabitable? The inhabitants of an island, may be apt enough to murmur at the sterility of some parts of it, against its rocks, or sands, or swamps ; but no one thinks himself authorized to murmur, simply because the island is not larger than it is. Yet these arc the same griefs. The above are the two metaphysical answers which have been given to this great question. They aie not the worse for being metaphysical, provided they be founded, (which I think, they are,) in right reasoning ; but they are of a na.- ture too wide to be brought under our survey ; and it is of- ten difficult to apply them in the detail. Our speculations, therefore, are perhaps better employed when they confine themselves within a narrower circle. The observations which follow are of this more limited, but more determinate kind. Of hodlJy imia the principal observation, no doubt, is, that which we have already made, and already dwelt upon, viz. " that it is seldom the object of contrivance ; that, when it is so, the contrivance rests ultimately in good." To which however may be added, that the annexing of pain to the means of destruction is a salutary provision : in-^ asmuch as it teaches vigilance and caution ; both gives no- lice of danger, and excites those endeavours which may be necessary to preservation. The evil consequence, which sometimes arises from the want of that timely intimation of danger which pain gives, is knoun to the inhabitants of cold countries by the example of frost-bitten limbs. I have conversed with patients v.-ho had lost fingers and toes by this cause. They have in general told me, that they were totally unconscious of any local uneasiness at the time, Som.e I have heard declare, that, whilst they were al:>out their employ^^ent, neither their situation, nor the slate of the air, was unpleasant. They felt no pain, they suspect- ed no mischief, till, by the application of warmth, they dis- covered, too late, the fatal injury which some of their ex- tremities had suffered. I say that this shows the use of pain, and that we stand in need of such a monitor. I believe THE GOOPNESS OF THE DEITY. 277 sJso that the use extends further than we suppose, or can now trace ; that to disagreeable sensations, we, and all an- imals, owe, or have owed, many habits of action which are salutary, but which are become so familiar as not easily to be referred to their origin. Pain also itself is not without its alleviations. It may be violent and frequent ; but it is seldom both violent and long continued : and its pauses and intcrmij^sions become posi- tive pleasures. It has the power of shedding a satisfaction over intervals of ease, which, I believe, few enjoyments ex- ceed. A man resting from a fit of tl»e stone or gout, is, for the time, in possession of feelings which undisturbed health cannot impart. They may be dearly bought, but siill they are to be set against the price. And, indeed, it depends upon tlie duration and urgency of the pain, whether they be dearly ;)ought or not. I am far from being sure, that a man is not a gainer by suffering a moderate interruption of bod- ily ease for a couple of hours out of the four-and-twenty. Two very common observations favour this opinion : one is, that remissions of pain call forth, from those who experi- ence them, stronger expressions of satisfaction and of grati- tude towards both the author and the instruments of their relief, than are excited by advantages of any other kind : the second is, that the spirits of sick men do not sink ia proportion to the acuteness of their sufferings ; but rather appear to be roused and supported, not by pain, but by the high degree of comfort which they derive from its cessa- tion, or even its subsidency, whenever that occurs : and which they taste with a relish, that diffuses some portion of mental complacency over the whole of that mixed state of sensations in which disease has placed them. In connexion with bodily pain may be considered bodily disease, whether painful or not. Few diseases are fatal. I have before me the account of a dispensary in the neigh- bourhood which states six years' experience as follows : " admitted 6,420— cwm/ 5,476— dead 2;34." And this I suppose nearly to agree with what other similar institutions exhibit. Now in all these cases, some disorder must have been felt, or the patients would not have applied for a rem- edy ; yet we see how large a proportion of the maladies which were brought forward, have either yielded to proper treatment, or, what is more probable, ceased of their own accord. We owe these frequent recoveries, and, where re- covery does not take place, this patience of the human con- stituiion under mauy ©f the distempers by which it is ?isitv 278 THE GOODNESS OF THE DEITY. ed, to two benefactions of our nature. One is, that she works within certain limits; allows of a certain latitude, witliin which health may be preserved, and within the con- fines of which it only sutlers a graduated diminution. Dif- ferent quantities of food, different decrees of exercise, dif- ferent portions of sleep, different states of the atmosphere, are compatible with the possession of health. So likewise is it with the secretions and excretions, with many internal functions of the body, and with the state, probably, of most of its internal organs. They may vary considerably, not only without destroying life, but without occasioning any high degree of inconveniency. The other property of our nature to which we are still more beholden, is its constant endeavour to restore itself, when disordered, to its regular course. The fluids of the body appear to possess a power of separating and expelling any noxious substance which may have mixed itself with them. This they do, in erup- tive fevers, by a kind of despumation, as Sydenham calls it, analogous in some measure to the intestine action by which fermenting^ liquors work the yeast to the surface. The solids, on their part, when their action is obstructed, not only resume that action, as soon as the obstruction is remov- ed, but they struggle with the impediment : they take an action as near to the true one, as the difficulty and the disorganization, with which they have to contend, will al- low of. Of mortal diseases, the great use is to reconcile us to death. The horror of death proves the value of life. But it is in the power of disease to abate, or even extinguish this horror ; v;hich it does in a wonderful manner, and, of- tentimes, by a mild and imperceptible gradation. Every man who has been placed in a situation to observe it, is surprised with the change which has been wrought in him- self, when he compares the view which he entertains of death upon a sick bed, with the heart-sinking dismay with which lie should some time ago have met it in health- There is no similitude between the sensations of a man led to execution, and the calm expirin:i of a patient at the close of his disea.se. Death to him is only the last of a long train of changes : in his progress through which, it is possi- ble that he may experience no shocks or sudden transitions. Death itself, as a mode of removal and of succession, is so connected with the whole order of our animal world, that almost every thing in that world must be changed, to be able to do without it. It may seem likewise impossible to THE GOODNESS OF THE DEITY. 219 separate the fear of death from the enjoyment of life, or the perception of t.iat fear from ^rational natures. Brutes are in a great rueasure delivered from all anxiety on this account by the inferiority of their faculties : or rather they seem to be armed with tne apprehension of death just suf- ficiently to put them upon the means of preservation, and no further. But would a human being wish to purchase this immunity by the loss of those mental powers which enable him to look forward to the future 1 Death implies sejjaratio/i ; and the loss of those whom we love must necessarily be accompanied with pain. To the brute creation, nature seems to have stepped in with some secret provision for their relief, under the rupture of their attachments. In their instincts tov/ards their offspring and of their offspring to them, I have often been surprised to observe, how ardently they love, and how soon they for- get. The pertinacity of human sorrow (upon which time also, at length, lays its softenmg hand) is probably, there- fore, in some manner connected with the qualities of our rational or moral nature. One thing however is clear, viz. that it is better that we should possess affections, the sources of so many virtues au'l so many joys, although they be exposed to the incidents of life, as well as the interruptions of mortality, than, by t!ie want of them, be reduced to a state of selfishness, apathy, and quietism. Of other external evils (still confining ourselves to what are called physical or natural evils) a considerable part come within the scope of the following observation. The great principle of human satisfaction is engagement. It is a most just distinction, which the late Mr. Tucker has dwelt upon so largely in his works, between pleasures in which we are passive, and pleasures in which we are ac- tive. And, I believe, every attentive observer of human life will assent to his position, that, however grateful the sensations may occasionally be in which we are passive, it is not these, but the latter class of our pleasures, which con- stitute satisfaction ; which supply that regular stream of moderate and miscellaneous enjoyments, in which happi- ness, as distinoruished from voiujtuousness, consists. Now for rational occupation, which is, in other words, for the very material of contented existence, there would be no place left, if either the things with which we had to do were ab- solutely impracticable to our endeavours, or if they were too obedient to our uses. A world furnished with advantages on one side, ana beset with difficulties, wants, and incon- 280 THE GOODNESS OP THE DEITY. veniencics on the other, is the proper abode ot free, ration' al, and active natures, bring the fittest to stimulate and ex- ercise their faculties. The very refractoriness of the ob- jects they have to deal with contributors to this purpose. A world jn which nothing depended upon ourselves, how- ever it might have suited an imagmary race of beings, would not have suited manl^ind. Their skill, prudence, industry ; their various ans, and their best attainments, from the ap- plication of which tney draw, if not their highest, their most permanent gratifications, would be insignificant, if things could be eitner moulded by our volitions, or, of their owq accord, conformed themselves to our views and wishes. Now it is in this refractoriness that we discern the seed and principle o( p /it/ sical evil, as far as it arises from that which is external to us. Civil evils, or the evils of civil life, are much more easily disposed of than physical evils; because they are, in truth, of much less magnitude, and also because they result by a kind of necessity, not only from the constitution of our na- ture, but from a part of that constitution which no one would wish to see alteied. The case is this. Mankind will in every country breed up to a certain point of distress. That point may be different in different coi»ntries or ages according to the estailished usages of life in each. It will also shift upon the scale, so as to adnut of a greater or less number of inhabitants, according as the quantity of provision which is either produced in the country or supplied to it from other countries may happen to vary. But there must always be such a point, and the species will always breed up to it. The or- der of generation proceeds by something like a geometrical progression. The increase of provision, under circumstan- ces even the most advantageous, can only assume the form of an arithmetic series. Whence it follows, that the pop- ulation will always overtake the provision, will pass beyond the line of plenty, and will continue to increase till check- ed, by the difficulty of procuring subsistence.* >Such diffi- culty, therefore, along with its attendant circumstances, must be found in every old country ; and these circumstan- ces constitute what we call poverty, which, necessarily, imposes labour, servitude, restraint. It seems iinpossible to people a country with inhabitants who shall be all in easy circumstances. For suppose the thing to be done, there would be such marrying and giving in marriage amongst them, as would in a few years change * See a statement of this subjectj in a late treatise upon population. THE GOODNESS OF THE DEITY. 281 the face of affairs entirely ; i. e. as would increase the con- sumption of tliose articles, which supplied the natural or habitual wants of the countrj?, to such a degree of scarcity, as must leave the o;reatest part of tire inhabitants unable to procure them without toilsome endeavours, or, out of the dif- ferent kinds ofthese articles, to procure any kind except that which was most easily produced. And this, in fact, de- scribes tiie condition of the mass of the community in all countries; a condition unavoidably, as it should seem, re- sulting from the provision which is made in the human, in common with all aniuial constitutions, for the perpetuity and multiplication of tne species It need not however dishearten any endeavours for the public service, to know that popabition naturally treads up- on the heels of improvement. If the condition of a people be meliorated, the consequence wiil be either that t\ie?nea?i happiness wiii be increased, or a greater number partake of it ; or, which is most likely to happen, that both effects will take place together. There may be limits fixed by nature to both, bur they are limits not yet attained, nor even ap- proached, in any country of the world. And wnen we speak of limits at all, we have respect on- ly to provisions for aniuial wants. There arc sources, and means, and auxiliaries, and augmentations of human hap- piness, communicable without restriction of numbers ; as capable of being possessed by a thousand persons, as by one. Such are those which flow from a mild, contrasted with a tyrannic government, whether civil or domestic ; those which spring from religion ; those which grow out of a sense of security , those which depend upon habits of vir- tue, sobriety, moderation, order ; those, lastly, which are found in the possession of well directed tastes and desires, compared with the dominion of totmenting, pernicious, con- tradictory, unsatisfied, and unsatisfiabie passions. The distinctions of civil life are apt enough to be re- garded as evils, by those who sit under them : but in my opinion, with very little reason In the first place the advantages which the higher con- ditions of life are supposed to confer, bear no proportion in value to the advantages which are bestowed by nature. The gifts of nature always surpass the gifts of fortune. How much, for example, is activity better than attendance ; beau- ty, than dress ; appetite, digestion, and tranquil Oowels, than all the studies of cookery, or than the most costly compila- tion of forced or farfetched dainties ? A A •282 THE GOODNESS OF THE DEITY. Nature has a strong tendency to equalization. Habit, the instrument of nature, is a great leveller ; the familiari- ty which it induces, taking off the edge both of our pleasures and our suffernigs. Indulgencies which are habitual keep us in ease, and cannot be carried much further. So that, with respect to the gratifications of which the senses are capable, the diiference is by no means proportionable to the apparatus. Nay, so far as superfluity generates fastidious- ness, the difference is on the wrong side. It is not necessary to contend, that the advantages de- rived from wealth are none, (under due regulations they are certainly considerable) but that they are not greater than the V ought to be. Money is the sweetener of human toil, the substitute for coercion, the reconciler of labour with liberty. It is, moreover, the stimulant of enterprise in all projects and undertakings, as well as of diligence in the most beneficial arts and employments. Now did affluence, when possessed, contribute nothing to happiness, or noth- ing beyond the mere supply of necessaries ; and the secret should come to be discovered ; we might be in danger of losing great part of the uses, which are, at present, derived to us through this important medium. Not only would the tranquillity of social life be put m peril by the want of a motive to attach men to their private concerns ; but the sa- tisfaction which all men receive from success in their res- pective occupations, which collectively constitutes the great mass of human comfort, would be done away in its very principle. With respect to station, as it is distinguished from rich- es, whether it confer authority over others, or be invested with honours which apply solely to sentiment and imagin- ation, the truth is, that what is gained by rising through the ranks of life, is not more than sufficient to draw forth the exertions of those who are engaged in the pursuits which lead to advancement, and which, in general, are such as ought to be encouraged. Distinctions of this sort are sub- jects much more of competition than of enjoyment; and in that competition their use consists. It is not, as hath been rightly observed, by what the Lord Mayor feels in his coach, but by what the apprentice feels who gazes at him, that the public is served. As we approach the summits of human greatness, the comparison of good and evil, with respect to personal com- fort,becomes still more problematical ; even allowing to am- bition all its pleasures. The poet asks, *' What is grandeur, THE GOODNESS OF THE DEITY. 2B^ what is power ?" The philosopher answers, " Constraint and plague ; et in maxima qiiaque fortuna minimum licere.'' One very common error misleads the opinion of mankind upon this head, viz. that, universally, authority is pleasant, submission painful. In the general course of iiuman affairs, the very reverse of this is nearer to the truth. Command is anxiety, obedience ease. Artificial distinctions sometimes promote real equality. Whether they be hereditary, or be the homage paid to office, or the respect attached by public opinion to particular pro- fessions, they serve to confront that grand and unavoidable distinction which arises from property ; and whicii is most overbearing where there is no other. It is of the nature of property, not only to be irregularly distributed, bat to run into large masses. Public laws should be so constructed as to favour its diffusion as much a.s they can. But ail that can be done by laws, consistently with that degree of gov- ernment over his property which ought to be left to the sub- ject, will not be suflicient to counteract this tendency. There must always therefore be the difference between rich and poor : and this difference will be the more grinding, when no pretension is allowed to be set up against it. So that the evils, if evils they must be called, which spring either froni the necessary subordinations of civil life, or from the distinctions which have, naturally, though not necessarily, grown up in most societies, so long as they are tinaccompanied by privileges injurious or oppressive- to the rest of the community, are such, as may, even by the most depressed ranks, be endured, with very little prejudice to their comfort. The mischiefs of which mankind are the occasion to one another, by their private wickedness and cruelties ; by ty- rannical exercises of power, by rebellions against just author- ity, by wars, by national jealousies and competitions opera- ting to the destruction of their countri'^s, or by other instan- ces of misconduct either in individuals or societies, are all to be resolved into the character of man, as a/ree agent. Free agency in its very essence contains liability to abuse. Yet, if you deprive man of his free agency, you subvert his nature. You may have order from him and regularity, bat you put an end to his moral character, to virtue, to merit, to accountableness, to the use indeed of reason. To which must be added the observation, that even the bad qualities of mankind have an origin in their good -nes. The case is this. Human passions are either necessary to human wef* '284 THE GOODNESS OF THE DEITY. fare, or capable of being made, and, in a great majority of instances, in fact made, conducive to its haj)[)ines9 These passions are strong and general , and, perhaps, would not answer their purpose unless they were so. But strength and generality, when it is expedient that particular circum- stances should be respected, become, if left to themselves, excess and misdirection. From which excess and misdi- rection the vices of mankind (the causes no doubt, of much misery) appear to spring. This account, whilst it shows us the principle of vice, shows us, at the same time, the prov- ince of reason and of selt-government ; the want also of ev- ery support which can be procured to either from the aids of religion ; and that, without having recourse to any na- tive gratuitous malignity in the human constitution. Mr. Hume in his posthumous dialogues, asserts, indeed , o( idle- ness Of aversion to labour, (which he states to lie at the root of a considerable part of the evils which mankind suffer,) that it is simply and merely bad. But how does he distin- guish idleness from the love of ease ? or is he sure, that the love of ease in individuals is not the chief foundation of so- cial tranquillity ? It will be found, I believe, to be true, that in every community there is a large class of its mem- bers, whose idleness is the best qual ty about them, being the corrective of other bad ones. If it were possible, in every instance, to give a right determination to industry, we could never have too much of it. But this is not possi- ble, if men are to be tree. And without this, nothing would be so dang-erous, as an incessant, universal, indefatigable activity. In the civil world as well as in the material, it is the vis inertia? which keeps things in their places. Natural Theology has ever been pressed with this (juestion. Why, under the regency of a supreme and be- nevolent will, should there be, in the world, so much as there is, of the appearance of chance? The question in its whole compass lies beyond our reach, but there are not wanting, as in the origin of evil, answers which seem to have considerable weight in particular cases, and also to embrace a considerable number of cases. I. There must be chance in the midst of design : by which we mean, that events which are not designed, ne- cessarily arise from the pursuit of events which are design- ed One Bjain travelling to York meets another man trav- THE GOODNESS OP THE DEITP, 285 filing to London. Their meeting is by chance, is acciden- tal, and so would be called and reckoned, though the jour- neys which produced the meeting, were both of them, un- dertaken with design and from deliberation. The meeting, though accidental, was nevertheless hypotheticaily necessa- ry, (which is the only sort of necessity that is intelligible ;) for, if the two journeys were commenced at the time, pur- sued in the direction, and with the speed, in which and with which they were in fact begun and performed, the meeting could not be avoided. There was not, therefore, the less necessity in it for its being by chance. Again, the meeting n^ight be the most unfortunate, though the er- rands, upon winch each party set out upon his journey, were the most innocent or the most laudable. The by effect may be unfavourable, without impeachment of the proper purpose, for the sake of which, the train, from the operation of which these consequences ensued, was put in motion. Although no cause act without a good purpose, accidental consequences, like these, may be either good or bad. IT. The appearance of chance w^ll always bear a pro- portion to the ignorance of the observer. The cast of a die, as regularly follows the laws of motion, as the going of a watch ; yet, because we can trace the operation of those laws through the works and movements of the watch, and cannot trace them in the shaking and throwing of the die, (though the laws be the same, and prevail equally in both cases,) we call the turning up of the number of the die, chance, the pointing of the index of the watch, machinery, order, or by some name which excludes chance. It is the same in those events which depend upon the will of a free and rational agent. The verdict of a jury, the sentence of a judge, the resolution of an assembly, the issue of a con- tested election, will have more or less of the appearance of chance, mig'it be more or less the subject of a wager, ac- cording as we were less or more acquainted with the rea- sons which influenced the deliberation. The difference resides in the information of the observer, and not in the thing itself; which, in all the cases proposed, proceeds from intelligence, from mind, from counsel, from design. Now when this one cause of the appearance of chance, viz. the ignorance of the observer, comes to be apphed to the operations of the Deity, it is easy to foresee how fruit- ful it must prove of difficulties, and of seeming confusion. *i86 1*HE GdOBNirsS OF -PHE 6EITY, It is ©nfy to think of the Deity to perceive, what variety ©f objects, what distance of time, what extent of space and ac- tion, his counsels may, or rather must, comprehend. Caa it be wondeied at, that, of the purposes which dwell in such a mind as this, so small a part should be known to us ? It is only necessary therefore to bear in our thought, that, in proportion to the inadequateness of our information, will be the quantity, in the world, of apparent chance, III. In a great variety of cases, and of cases compre- liending numerous subdivisions, it appears, for many rea- sons, to be better, that events rise up by chance, or, more properly speaknig, with the appearance of chance, than ac- cording to any observable rule whatever. This is not sel- dom the case even in human arrangements. Each person's place and precedency in a public meeting may be deter- mined by lot. Work arid labour may be allotted. Tasks and burthens may be aliottcd. -Operumque laboi em Partibus aquabut justis, aut sorfe trahebat. Military service and station may be allotted. The dis- tribution of provision may be made by lot^ as it is in a sail- or's mess ; in some cases also, the distribution of favours may be made by lot. In all these cases it seerns to be ac- knowledged, that there are advantages in permitting events to chance, supeiior to those which would or could arise from regulation. In all these cases also, though events rise up in the way of chance, it is by appouitmeni that they do so. In other events, and such as are independent of human will, the reasons lor this preference of uncertamty to rule appear to be sti.Ii stronger. For example, it seems to be expedient, that the period of human life should be uncertain. Did mortality follow any fixed rule, it would produce a se- curity in those that were at a distance from it, which would lead to the greatest disorders, and a horror in those who approached it, simii-^r to that which a condemned prisoner feels on the night before his execution. But, that death be uncertain, the young must sometimes die, as well as the old. Also were deaths never sudden, they, who are in health, would be too confident of life. The strong and the active, who want most to be warned and checked, would live without apprehension or restraint. On the other hand ; were sudden deaths very frequent, the sense of constant jeopardy would interfere too much with the degree of ease / laiE ffOeONESS OF THE DBITV. iS^7 and enjoyment intended for us ; and human life be too pre.r earious tor the business and interests which belong to it. There could not be dependence either upon our ovvn lives, or the lives of those with whom we were coniiectedj suffi- cient to carry on the regular offices of human society. The manner, therefore, in which death is made to occur, con- duces to the purposes of admonition, without overthrowing the necessary stability of human affairs. Disease being the forerunner of death, there is the same reason for its attacks coming upon us under the appear- ance of chance, as there is for uncertainty in the time of death itself. The seasons are a mixture of regularity and chance. They are regular enough to authorize expectation, whilst their being, in a considerable degree, irregular, induces on the part of the cultivators of the soil a necessity for person- al attendance, for activity, vigilance, precaution. It is this necessity which creates farmers ; which divides the profit of the soil between the owner and the occupier ; which, by requiring expedients, by increasing employment, and by rewarding expenditure, promotes agricultural arts and ag- . ricultural life, of all modes of life the best, being the most conducive to health, to virtue, to enjoyment. I believe it to be found in fact, that where the soil is the most fruitful and the seasons the most constant, there the condition of the cultivators of the earth is the most depressed. Uncer- tainty, therefore, has its use even to those who sometimes complain of it the most. Seasons of scarcity then)selves are not without their advantage. They call forth new ex- ertions ; they set contrivance and ingenuity at work ; they give birth to improvements in agiicukure and economy; they promote the investigation and management of public resources. Again ; there are strong, intelligible reasons why there should exist in human society great disparity of wealth and station ; not only as these things are acquired in dif- ferent degrees, but at the first setting out in life. In order, for instance, to answer the various demands of civil life, there ought to be amongst the members of every civil soci- ety a diversity of education, which can only belong to an original diversity of circumstances. As this sort of dispar- ity, which ought to take place t>oin the beginning of life, must, ex hi/potJicsi, be previous to the merit or demerit of the persons upon whom it falls, can it be better disposed of than by chance ? Parentage is that sort of chance : yet it •388 tHB 600BNE39 OF THE BEITY. is the commandincr circumstance, which in general fixei^ each man's place in civil life, along with every thmg which appertains to its distmctions. It may be the result of a beneficial rule, that the fortunes or honours of the father devolve upon the son ; and, as it should seem, of a still more necessary rule, that the low or laborious condition of the parent be communicated to his family ; but with respect to the successor himself, it is the drawing of a ticket in a lot- tery. Inequalities, therefore, of foitune, at least the great- est part of them, viz. those which attend us from our birth, and depend upon our birth, may be left, as they are left, to chance, without any just cause for questioning the regency of a Supreme Disposer of events. But not only the donation, when by the necessity of the case they must be gifts, but even the acquirabiliUj of civil advantages, ought perhaps, in a considerable degree, to lie at the mercy of chance. Some would have all the virtuous rich, or, at least, removed from the evils of poverty, with- out perceiving, I suppose, the consequence, that all the poor must be wicked. And how such a society could be kept in subjection to government has not been shown ; for the poor, that is, they who seek their subsistence by constant manual labour, must still form the mass of the community ; otherwise the necessary labour of life could not be carried on ; the work would not be done, which the wants of man- kind in a state of civilization, and still more in a state of refinement require to lie done. It appears to be also true, that the exigencies of social life call not only for an original diversity o^ external circnxa- stances, but for a mixture of different faculties, tastes, and tempers. Activity and contemplation, restlessness and qui- et, courage and timidity, ambition and contentedness, not to say even indolence and dulness, are all wanted in the world, all conduce to the well going on of human affairs, just as the rudder, the sails, and the ballast of a ship, all perform their part in the navigation. Now since these characters require for their foundation, different orisfinal talents, different dispositions, perhaps also different bodily constitutions ; and since, likewise, it is apparently expedi- ent, that they be promiscuously scattered amongst the di^ ferent classes of society, can the distribution of talents, dis- positions, and the constitutions upon which they depend, bs better made than by chance ? The opposites of apparent chance, are constancy and sensible interposition ; every degree of secret direction be- THE €K)ODNESS OP THE DElTy. 289 ing consistent with it. Now of constancy, or of fixed and known rules, we have seen in some cases the inapplicabili- ty : and inconveniences, which we do not see, might attend their application in other cases. Oi seiibible mtorposition, we may be permitted to remark, that a Providence, always and certainly distinguisliable, would be neither more nor less than miracles rendered fre- quent and common. It is ditficult to jutli^e of the state into which this would throw us It is en )u^h to say, that it would cast us upon a quite different dispensation from that under which we live. It would be a total and rad- ical change. And the chan^je would deeply affect, or per- haps subvert, the whole conduct of human affiiirs. I can readily believe, that, other circumstances beiiig adapted to it, such a state mi^fht be better than our present state. It may be the state of other beings : it may be ours hereafter. But the question with which we are now concerned is, how far it would be consistent with our condition, supposing it in other respects to remain as it is? And in this question there seems to be reasons of great moment on the negative side. For instance, so long as bodily hi hour continues, on so many accounts, to be necessary for tlie bulk of mankind, any dependency upon supernatural aid, by unfixing those motives which piomote exertion, or by relaxing those hab- its which eriixender p-atient industry, misiht introduce negli- gence, inactivity and disorder, into the most useful occupa- tions of human life ; and thereby deteriorate the condition of human life itself. As moral agents we should experience a still groater al- teration, of which more will be said under the next article. Although, tiierefore, the Deity, who possesses tlie power of winding and turning, as he pleases, the course of causes which issue from himself, do, in fact, interpose to alter or intercept effects, which without such interposition, would have taken place, yet it is by no means incredible, that his Providence, which always rests upon final good, may have made a reserve with respect to the manifestation of his in-^ terference, a part of the very plan which he has appointed for our terrestrial existence, and a part conformable with, or, in some sort, required by, other parts of the same plan. It is at any rate evident, that a large and ample province remains for the exercise of Providence, without its being naturally perceptible by us ; because obscurity, when appli- ed to the interruption of laws, bears a necessary proportion fo the jraperfectioQ ©f our knowledge when applied to 290 THE GOODNESS OF THE DEITY. the laws themselves, or rather to the effects, which these laws, under their various and incalculable combinations, would of their own accord produce. And if it be said, that the doctrine of divine Providence, by reason of the ambigu- ity under which its exertions present themselves, can be attended with no practical influence upon our conduct ; that, although we believe ever so firmly that there is a Prov- idence, we must prepare, and provide, and act, as if there were none ; I answer, that this is adinixted : and that we further allege, that so to prepare, and sa to provide, is con- sistent with tlie most perfect assurance of the reality of a Providence : and not only so, but that it is, prohably, one ad- vantage of the present state of our information, that our provisions and preparations are not disturbed by it. Or if it be still asked, of what use at all then is the doctrine, if it neither alter our measures nor regulate our conduct ? I an- swer again, that it is of the greatest use, but tliat, it is a doctrine of sentiment and piety, not (immediately at least) of action or conduct; that it applies to the consolation of men's minds, to their devotions, to the excitement of grat- itude, the support of patience, the keeping alive and the strengthening of every motive for endeavouring to please our Maker ; and that these are great uses. Of all views under which human life has ever been con- sidered, the most reasonable, in my judgment, is that which regards it as a state of probation. If the course of the world were separated from the contrivances of nature, I do not know that it would be necessary to look for any other account of it, than what, if it may be called an account, is contained in the answer, that events rise up by chance. But since the contrivances of nature decidedly evince inten- tion ; and since the course of the world and the contrivan- ces of nature have the same author ; we are, by the force of this connexion, led to believe, that the appearance, un^ der which events take place, is reconcilable with the sup- position of design on the part of the Deity. It is enough that they be reconcilable with this supposition (and it is un- doubtedly true, that they be reconcilable, though we cannot reconcile them :) the mind, however, which contemplates the works of nature, and, in those works, sees so much of means directed to ends, of beneficial effects brought about by wise expedients, of concerted trains of causes terminat- ing in the happiest results ; so much, in a word, of counsel, intention, and benev dense, and thick adnata, which is designed to protect the eye \ and it seems especially necessary, as fish have no eye-lids. "XAlB.idl. Xtth. cf' Pf^nMeteri, CHAPTER III. Tab. IV. — THE LACHRYMAL APPARATUS AXD NICTITATUTG MEMBRANE. Fig. 1. a, the lachrymal gland, the source of the tears ; &, its sev- eral ducts, diffusing this fluid over the eye ; c, c, the puncta lachry- malia, which convey the tears into the lachrymal sac, terminating in the nostril. Fig. 2. The nictitating membrane, or third eyelid; it is a thin semi-transparent fold of the conjunctive, which, in a state of rest, lies in the inner corner of the eye, with its loose edge nearly vertical, but can be drawn out so as to cover the whole front of the>globe. In this figure it is represented in the act of being drawn over the eye. By means of this membrane, according to Cavier, the eagle is enabled to look at the sun. Fig. 3. The muscles of the nictitating membrane are very singular in their form and action, they are attached to the back of the sclerotic; one of them, a, which from its shape is called quadratus, has its ori- gin from the upper and back part of the sclerotic ; its fibres descend towards the optic nerve, and terminate in a curved margin with a cy- lindrical canal in it. The other muscle, h, which is called pyramida- lis, arises from the lower and back part of the sclerotic. It has a long tendinous chord, c, which passes through the canal of the quadratus, a, as a pulley, and having arrived at the lower and exterior part of the eye-ball, is inserted into the loose edge of the nictitating membrane. This description refers also to Fig. 4, a profile of the eye, and Fig. 5, the membrane and its muscles detached from the eye. ^P \\ TC) rr\23,]IV CHAPTER III. Tab. V. — THE HUAfAN ear, and tympanum of the ELEPHANT. Fig. 1. The organ of hearing; a, the external ear-, b, the meatus^ nnditorius externus, or outward passage of the ear ; leading to c, the membrana tympani, or drum ; d, the ossicula audiius, or little bones of the ear ; e, the semicircular canals ; f, the cochlea ; g, a section of the eustachian tube, which extends from the cavity of the tympa- num, to the back of the mouth or fauces. Fig. 2. The bones of the ear magnified, a, the malleus, or mal- let, connected by a process to the tympanum ; the round head is lodged in the body of, b, the incus, or anvil, and the incus is united to, c, the OS orbiculare, or round bone, and this to, d, the stapes, or the stirrup. These bones are named from their shape, and the names assist in con- veying an idea of their form. They are united by ligaments, and form an uninterrupted chain to transmit the vibrations of the atmosphere. Fig. 3. The labyrinth, so named from the intricacy of its cavities; it is situated in the petrous part of the temporal bone, and consists of (he vestibule, or central cavity, three semicircular canals, and cochlea^ so named from its resemblance to the windings of a snail shell, and is best explained by the plate, Fig. 1, and 3. The vibrations of sounds, striking against the membrana tympani, are propagated by the intervention of these four little bones, to the icater contained within the cavities ol the labyrinth ; and by means of this water the impression is conveyed to the extremities of the au- ditory nerve, and finally to the bra'n. Fish require no tympanum, nor external opening to the ear ; the fluid in which they live is the medium for conducting sounds through the bones of the head. Fig. 4. The tympanum of the elephant, of its natural size, showing its radiated fibres, supposed to bo muscular. TAIB 0 T J-UJi ^" 'J:^^idlc:t(>n CHAPTER VII. Tab. VI. — TROCHLEAR MUSCLE OF THE EYE, AND KIDXBY. Fig. 1. The trochlear or superior oblique muscle, arises with the straight muscles from the bottom of the orbit. Its muscular portion, a, is extended over the upper part of the eye-ball, and gradually as- sumes the form of a smooth, round tendon, b, which passes through the pulley, c, and is fixed to the inner edge of the orbit, d, then turn- ing backwards and downwards, e, is inserted into,/, the sclerotic mem- brane. The use of this muscle is to bring the eye forwards, and to turn the pupil downwards and upwards. Fig. 2. A section of the human kidney ; a, the einulgent artery, which conveys the blood to, b, the papillcB, where the peculiar fluid is secreted ; from whence it passes by tubes into, c, the pelvis ; d, the emulgent vein which returns the blood ; e, the ureter, or tube which conducts the secretion to its receptacle. TAB , TIo ^84,*te4 ^ Lu/i. (jf FenrUeii^H T-ILDEN FOUNDAHOK CHAPTER VIII. Tab. VIII. — BOPfEs of the arm. Fig. 1. a, the humerus ; the head, h, is a portion of a sphere, and exhibits an example of the ball and socket^ or universal joint ; c, the hinge joint, instanced in the elbow ; d, the radius ; e, the ulna. The radius belongs more peculiarly to the wrist, being the bone which sup- ports the hand, and which turns with it in all its revolving motions. The ulna principally belongs to the elbow joint, for by it we perform all the actions of bending or extending the arm. Fig. 2. a, the humerus : 6, shows the connexion of the radius, with e, the ulna, at the elbow. The mode of articulation at the wrist is »een, Fig. 1. '^e?id7eivnj- Z,it:k/ l^f^w"^^^ LlBRi^R CHAPTER VIII. Tab. IX. — THE SPINE. Fig. 1. The human spine, so named from the series of sharp pro- cesses projecting from the posterior part of the vertebrae. The spine consists of seven vertebrae of the neck, distinguished by the perfora- tions in their transverse processes ; of twelve belonging to the back, and marked by depressions for the heads of the ribs ; and, lastly, of Jive belonging to the loins, which are larger than the other vertebrae. Fig. 2. A separated dorsal vertebra: a, the body of the vertebra; 6, the ring through which the spinal marrow passes : c, c, the articu- lating surfaces to which the ribs are united. Fig. 3. The vertebra of a very large serpent, drawn from a speci- men belonging to the Anatomy School of Christ Church, Oxford. This figure shows the socket of the vertebra. Fig. 4. The ball or rornded joint, evidently calculated for extensive motion. Fig. 5. A part of the spine of the same reptile ; it is exceedingly strong, each bone being united to the other by fifteen surfaces of ar- ticulation. & .'H ^ CHAPTER VIII. Tab. X; — THE CHEST, PATELLA, AND SHOULDER-BLADE. Fig. 1. The spine, ribs, and sternum, constitute the frame work of the chest or thorax. Referring, however, to the plate, or to nature, we observe that the ribs are not continued throughout from the spine to the sternum, but intervening cartilages complete the form of the chest, by connecting the end of the rib to the breast bone. This is a further provision, relative to the mechanical function of the lungs, de- serving notice. The muscles of respiration enlarge the capacity of the chest by elevating the ribs ; and during the momentary interval of muscular action the cartilages, from their great elasticity, restore the ribs to their former position. Fig. 2. Represents the true shape of the patella, the anterior sur- face convex. Fig. 3, the posterior surface, has two concave depres- sions adapted to the condyles of the thigh bone. The projection of the patella, as a lever, or pulley, removes the acting force from the centre of motion, by which means the muscles have a greater advantage in extending the leg. That this bone is " unlike any other in the body," is a mistake ; such bones are numerous, though less obvious, for they do not exceed the size of a pea : these are called sesamoid hones, and are formed in the flexor tendons of the thumb, and sometimes in the fingers. They are frequently found under the tendons of some of the muscles. Two of these sort of bones are constantly found under the articulation of the great toe with the foot. Fig. 4. The shoulder-blade (scapula) is joined to the collar bone by ligaments, and to the thorax by powerful muscles which are capa- ble of sustaining immense weights, and whose action gives the vari- ous directions to the arm, and enables it freely to revolve at the shoulder joint. ''TAE.X j THE NEW POBUC " AStOR, LENOX AN. CHAPTER VIII. Tab. XI. — THE HIP, KNEE AND ANKLE JOINTS. Fig. 1. The capsular ligament is here opened in order to show the ligament of the hip, named the round ligament. It allows considera- ble latitude of motion, at the same time that it is the great safe-guard against dislocation. Fig. 2. and 4. The crucial or internal ligaments of the knee-joint arise from each side of the depression between the condyles of the thigh bone ; the anterior is fixed into the centre, the posterior into the back of the articulation of the tibia. This structure properly Urn- its the motions of the joint, and gives the firmness requisite for violent exertions. Viewing the form of the bones, we should consider it one of the weakest and most superficial, but the strength of its ligaments renders it the most secure, and the least liable to dislocation of any joint in the whole body. Fig. 3. One of the interarticular cartilages of the knee, from their shape called semilunar ; it is also represented in situ, Fig. 2. The outer edge of each cartilage is thick, the inner concave edge thin; the sockets for the condyles of the thigh bone are thus rendered deep- er, and the cartilages are so fixed as to allow a little play on the tibia, by which the joint moves with great freedom. A moving cartilage is not common, but is peculiar to those joints whose motions are very frequent, or which move under a great weight. It is a contrivance found at the inner head of the collar bone and the articulation of the wrist, as well as at the knee. The obvious use is to lesisen friction and facilitate motion. Fig. 4. Exhibits the formation of the ankle joint ; a, the fibula ; b, the tibia. a]!A"-B,X.T J^enriS 2^ Li// fTFPE NEV:' CHAPTER IX. Tab. XII. — THE SART0RIU3 AND OBLIQUE MITSCIiES OF THB HEAD. Fig. 1. a, a, the sartorius, is the longest muscle of the whole hu- man fabric : it is extended obliquely across the thigh from the fore part of the hip, to the inner side of the tibia. Its office is to bend the knee, and bring the leg inwards. Fig. 2. There are two pairs of oblique muscles; a, a, the ohliquus capitis superior, arising from the transverse process of the atlas, and inserted into the occipital bone ; h, b, the ohliquus capitis inferior^ arising from the spinous process of the dentata, and inserted into the transverse process of the atlas. These muscles roll the head on one side, and draw it backwards. T_AIB.Xai. ■rfl^sfe CHAPTER XI. Tab. XIII. — THE MUSCLES OF THE ARM. Fig. 1. a, the biceps, (biceps flexor cubiti) arise by two portions Irom the scapula ; they form a thick mass of flesh in the middle of the arm, which is finally inserted into the upper end of the radius ; h, the brachicBUS internus, arises from the middle of the os humeri, and is inserted into the ulna. Both these muscles bend the fore-arm. c, the longus et brevis brachicBus externus ; these are better named aa one muscle, triceps extensor cubiti. It is attached to the inferior edge of the scapula, and to the os humeri, by three distinct heads, which unite and invest the whole back part of the bone , becoming a strong tendon which is implanted into the elbow. It is a powerful extensor of the fore-arm. d, the anconaus, a small triangular m\iscle, situated at the outer side of the elbow : it assists the last muscle. FiG.l and 2. e, e, the annular ligament of the wrist, under which pass the tendons of the muscles of the fingers. Fig. 1. /, the deltoid muscle ; the muscle at the shoulder by which the arm is raised. t:!^^,.XiJiii TenclJjpjcrt^L.ydi CHAPTER IX. Tab. XIV. — the muscles that raise the eye-lids, and SPHINCTER OR CIRCULAR MUSCLES. Fig. 1. A front view of this muscle, named levator palpebrcB supe- rioris : Fig. 2. a profile of the same in its natural position. This mus- cle arises within the orbit, and is inserted by a broad tendon into the upper eye-lid. Its name is expressive of its use. Fig. 3. Exhibits examples of sphincter muscles : a, a, the orbicu- laris palpebrarum, encircling the eyelid ; it closes the eye, and com- presses it with spasmodic force, when injured by particles of dust, &c. b, the orbicularis oris, surrounding the mouth ; it chief use is to con- tract the hps. i\\H,...\:i'\*'« r J ^.#«t*. ^** ;U CHAPTER IX. Tab. XV. — the digastric muscle. Fig. 1 and 2. The digastric muscle has its origin, a, at the lower part of the temporal bone ; it runs downwards and for- wards, and forms a strong, round tendon, 6, which passes through a perforation in the stylo-hyoideus,/; it is then fixed by a strong hgament, c, to the os hyoides, d ; it again becomes fleshy, runs upwards, and is inserted into, e, the chin. This description differs from Dr. Paley's, and it will be found by reference to dissections or the plate, that the os hyoides fur- nishes a stay or brace instead of a pulley, and that the loop or ring is in the stylo-hyoideus muscle. a'A]B.XT. T/'-Tu^/ftvn. Z/trh . CHAPTER IX. Tab. XVI. — the tendons of the toes. Fig. 1. a, the tendon of the long Jlexor of the toes, which divides about the middle of the foot into four portions, pass- ing through the sUts in, b, the short Jlexor tendons. Fig. 2. ex- plains a similar contrivance belonging to each finger : a, a tendon of the Jlexor suhlimis ; b, a tendon of the Jlexor profun- dus, passing through it. Fig. 3. a, b, tendons of the extensor muscles of the toes ; c, a tendon of a flexor of the foot. These are bound down and retained in situ by, e, the annular ligament of the instep, which consists of two distinct cross bands, going from the outer ankle to the inner ankle and neighbouring bones. a'A:K,:xyi ' /> CHAPTER X. Tab. XVII. — the heart. Fig. 1. A section of the human heart ; a, a, the superior and inferior vena cava, the veins which convey the blood to the, 5, right auricle ; and thence into, c, the corresponding ventricle ; from this ventricle the blood is impelled through, e, the pul- monary artery into the lungs ; and returning by /,/, the pul- monary veins, it is received into, g, the leji auricle ; it flows next into, h, the left ventricle ; which by its contraction dis- tributes the blood through the general arterial system -.—j, the aorta, the great artery which transmits blood to the different parts of the hoAj, from whence it is returned by veins to the cavace ; k, the tight subclavian ; I, the right carotid arteries, originating from one common trunk ; m, the lejl carotid; n, the left subclai^an ; d, the valves of the right ; i, the valves of the left ventricle. Fig. 2. The valves of the right side [tricuspid valves) sep- arated from the heart ; a, a, a, the carnace columnce, or muscu- lar fibres of the valve ; b, b, b, the chordce tendinece, or tendi- nous filaments which are attached to, c, the valves. Fig. 3. Exhibits the artery cut open with the form of the semilunar valves. Fig. 4. A portion of the artery filled, showing how effect- ually the valves prevent the retrograde motion of the blood in the aorta and pulmonary artery. W ' ~.-^\ J^e7teflear,7rs Lihf CHAPTER X. / Tab. XVIII. — the stomach, gall bladder, &c. Fig. 1. a, the stomach ; h, the cardia ; c, the pylorus. ' The gastric juice is a secretion derived from the inner membrane of the stomach, and digestion is principally performed by it. In the various orders of animated beings it differs, being adapt- ed to the food on w^hich they are accustomed to subsist. The food, vrhen properly masticated, is dissolved by the gastric fluid, and converted into chyme ; so that most kinds of the in- gesta lose their specific qualities ; and the chemical changes to which they would otherwise be liable, as putridity and ran- cidity, &c. are thus prevented. In this plate, h, the liver is turned up, in order to show the gall-bladder which is attached to its concave surface ; d, the duodenum ; e, part of the small intestines ; /, the pancreas ; and g, the spleen. Fig. 2. Explains the several ducts and their communica- tion with the duodenum; a, the gall-hladder ; &, the ductus cysticus ; which uniting with, c, the ductus hepaticus, forms, d, the ductus communis ; which, after passing between the mus- cular and inner coats of the intestine, opens into it at c. /, the pancreatic duct. The bile is said to become more viscid, acrid, and bitter, from the thinner parts being absorbed during its retention in the gall-bladder. T/v^/xxm:, Ttiu Tif ra/i.\ Lith CHAPTER X. Tab. XIX. — the lacteals, and thoracic duct. '' The figure in this plate represents the course of the food, from its entrance at the mouth to its assimilation with the blood ; a, the (esophagus, extending from the pharynx to, 6, the stomach ; where the alimentary matter, having undergone the digestive process, is coverted into chyme, a soft, homogeneous substance, and escapes at c, the pylorus, into, d, the intestines. In this plate a large portion of the latter is spread out to show a part of the absorbent system, called lacteals : these collect and imbibe the chyle, or milky juice from the chyme, and transmit it through e, e, the mesenteric glands, into one general receptacle,/, [receptaculum chyli,) from which, g, the thoracic duct ascends in a more or less tortuous direction to the lower vertebrae of the neck, and after forming an arch, it descends and enters h, the left subclavian vein, at the point where that vein is united with the internal jugular. The absorbents of the right side frequently form a trunk, which enters the right subclavian vein. TAH . XIX . / '■-v-safi*^^ CHAPTER X. Tab. XX. — the parotid gland. Fig. 1. A dissection to exhibit the parotid gland. Fig. 2. Explains the former ; a, a, the integuments turned back ; b, the parotid gland ; c, its pipe or duct passing over the masseter, then perforating, d, the buccinator muscle, and opening into the mouth opposite the second molar tooth. The flow of saliva intothe mouth is incessant, and it is one of the most useful digestive fluids. It is favourable to the maceration and division of the food, it assists it in deglutition and transforma- tion into chyme ; it also renders more easy the motions of the tongue in speech and singing. #1 'f'^-'i/i, ::?<%, CHAPTER X. Tab. XXI, — the larynx. Fig. 1. The larynx, pharynx, &c. a, the os hyoides, 6, the epiglottis pressed down, thus covering the glottis, or opening of the larynx ; as it does in the act of deglutition. Fig. 2. Exhibits the larynx, and trachea ; which is a contin- uation of the former ; h, the epiglottis ; g, the arytenoid carti- lages ; e, the thyroid cartilage, exceedingly strong, for the pro- tection of the upper part of the air tube ; d, the cartilaginous ringlets of the trachea or wind-pipe, each forming nearly two- thirds of a circle, and completed by a soft membrane, which, from its apposition to, e, Fig. 1, the cesophagus, accommodates itself to the substances passing into the stomach. Fig. 3. The larynx or upper part of the wind-pipe of a bird. TAB.XXr CHAPTER XI. Tab. XXII. — package of the viscera, and mesentery. Fig. 1. In this plate the parietes of the chest and abdomen, with the omentum, are removed to show the visc^era in situ ; a, the heart; b, the aorta; c, the descending vena cava; d, the lungs divided by the mediastinum into two portions ; three lobes belong to the right, and two to the left portion of the lungs ; e, the diaphragm, or that muscle which separates the thorax-from the abdomen ; /, the liver ; g, the gall-bladder ; h, the stomach ; i, the spleen ; k, the large intestines ; Z, the small intestines ; m, the bladder. The viscera of the thorax and abdomen, i. e. the viscera of organic life, are irregularly disposed. The agents of volition are double, but the instrmiients of involuntary motion, namely, the interior life, are single, and at least are ii^-egular in their form. The several viscera are correctly described in the Theol- ogy, and sufficient is said for the purposes for which they are introduced. To the supposed use of the spleen only an objec- tion must be taken : various hypotheses have been entertain- ed as to its office, but none are conclusive ; the most probable is, that it is a source of supply of blood for furnishing the gastric secretion, or that the blood undergoes some important change in it. Fig. 2. The mesentery. This membrane is formed by a re- flection of the periton(Eum from each side of the vertebrae ; it connects the intestines loosely to the spine, to allow them a certain degree of motion, yet retains them in their places ; and furnishes their exterior covering. Between the laminae of, a, the mesentery, are received the glands, vessels, and neryc*; and its extent admits of a proper distribution of each. CHAPTER XII. Tab. XXIII. — nerves of the bill of a duck, valvulje CONNIVENTES. CHAP. XIII. AIR-BLADDER OF A FISH, AND FANG OF THE VIPER. Fig. 1. The upper mandible of the duck, on which are dis- tributed the first and second branches of tiie fifth pair of nerves ; the former passing through the orbit to the extremi- ty of the bill, and, together with the latter, supplying the whole palatine surface. Fig. 2. A small portion of the human intestine cut open in order to show the valvules connicentes. Fig. 3. The air-bladder in the roach. This vessel differs in size and shape, in different species offish ; generally commu- nicating, by one or more ducts, either with the oesophagas or stomach ; by which means the fish receives or expels the air, thus sinking or rising witliout effort : but as some are desti- tute of this organ, it is considered as an accessary instrument of motion. Fig. 4. The head of a viper of the natural size. Fig. 5. The fang magnified, at the root of which is the gland which secretes the venom: a hair is represented in the tube through which the poison is ejected. TAB .XXOT. ^-^^QTwa-JSa^ , jP^t-/ dlef^ryjz.) ' J^ loJi ■ l^mU'^^o,^ I CHAPTER XIIL Tab. XXIV. — the opossum. Fig. 1. The American opossum ; [didelphis marsupialis.) The body of the animal is of a greyish yellow colour, some hairs entirely black, with others entirely white ; the tail fur- nished with scales ; the hands, nose, and ears naked. The female has the whole length of the belly cleft or slit, and ap- pears like a person's ^raistcoat buttoned only at the top and bottom. This cavity the animal has the power of lirmly closing. Within are thirteen teats, extremely small, one in the centre, and the rest ranged round it. i Fig. 2. One of the young of the opossum. Fig. 3. The pelvis of the opossum ; a, a, the two bones (ossa marsupialia) placed on the anterior part called the ossa pubis. The kangaroo and several other animals of New Holland have a similar structure. TAIB.IDLW. ?'.. ^^.j^ ^r. %><*'^~ V ^fe7i.-d/,^Ccri,s LUA CHAPTER XIII. Tab. XXV. — claw of the heron, and bill or the SOLAND GOOSE. Fig. 1. The middle daw of the heron. Fig. 2. The head of the Soland goosey {pelicanus hassanus) drawn from a specimen in the Ashmolean Museum, Oxford, lliis bird inhabits the coldest parts of Great Britain, more especially the northern isles of Scotland- TA.B .XXY ..*?aSF^ ■msim'-l Tirni.7lerc>'r>.i lirh. CHAPTER XIII. Tab. XXVI. — stomach of the camel. The figure in this plate exhibits the cells in the stomach of the camel, fi'om a prepai*ation- in the museum of the Royal College of Surgeons, London. In the camel, dromedary, and lama, there are four stomachs, as in horned ruminants ; but the structure, in some respects, differs from those of the lat- ter. The camel tribe have in the first and second stomach nmnerous cells, several inches deep, formed by bands of mus- cular fibres crossing each other at right angles ; these are constructed so as to retain the water, and completely exclude the food. In a camel dissected by Sir E. Home, the ceils of the stomach were found to contain two gallons of water ; but in consequence of the muscular contraction, wliich had taken place immediately after death, he was led to conclude this was a quantity much less than these cavities were capable of receiving in the hving animal. See Lectures on Compara- tive Anatomy, by Sir E. Home, vol. i. p. 168. Mr. Bruce states, in his Travels, that he procured four gal- lons of water from a camel, which from necessity he slaugh- tered in Upper Egypt. T.-^rfi , XXYI , PUBLIC UBRARYJ CHAPTER XIII. TjLB. XXVII. TONGUE OF THE WOODPECKER, AlfD 6KULX. OF THE BABTROUESSA. Fig. 1. The head of the woodpecker f (picas viridis.) Fig. 2. The tongue, the natural size. Fig. 3. The claw of the same bird, referred to in Chap. V, Fig. 4. The skvJl of the hdbyrouessa, from a specimen in the Anatomy School, Christ Church, Oxford. taib/^xt:ii CHAPTER XIV. Tab. XXVIII. — temporary and permanent teeth. Fig. 1. The gums and outer plate of the bone are removed, showing the teeth of the mfant, as they exist at the time of its birth; they are with ut roots, and contained in a capsule witliin the jawa. Fig. 2. In this figure, also, the outer alvelolar plate of the jaws has been removed to show the succession of teeth. This is the state at six years of age. The temporary teeth are all shed between the ages of seven and fourteen, and are suppli- ed by the permanent teeth, already nearly perfectly formed, and situated at the roots of the former. T/rK xx^'l: -^^f>^ MTORa ^^^'^ ^ ¥i«0 iy i^tt 'rgfc^^^'^^^^^ CHAPTER XIV. Tab. XXIX. — foramen ovale, and ductus arteriosus. Fig. 1. A view of the foetal heart ; a, the ascending, 6, the descending vena cava ; c, the right auricle ; rf, e, /, mark the elevated ring of the foramen ovale, or the opening between the two auricles. Fig. 2. The foetal heart ; a, the pulmonary artery ; 6, 6, its branches ; c, the ductus arteriosus, or canal for transmitting the blood into, d, the aorta. As the lungs are useless in the foetus, unless as a " prospective contrivance," the heart has to carry on a single circulation only : the free communication between the two auricles identifies them as one cavity ; and the ventricles also force the blood into one vessel, the aorta. TAB , _i:xix: CHAPTERS XV. & XVI. Tab. XXX. Fig. 1. Is the fore extremity of the mole; a, the os humeri, is pe- culiar, not only for its shortness, but in being artici^lated by &, one head to the scapula, and by c, another to the clavicle ; it is altogether of such a nature as to turn the palm outwards for working. The foot, or we may name it the hand, has eleven bones in the carpus or wrist, which is two more than in the carpus of man. One of which, d, is remarkable, and from its shape is called the falciform bone; it gives the shovel form to the hand. Fig. 2. The head of the Elephant. Fig. 3. and 4. The digitated extremity of the proboscis. Fig. 5. A transverse section of the proboscis, showing, a, a, the two tubes or nostrils. Between the external integum.ents and the tubes are two sets of small muscles ; an inner one running in a transverse, and an outward one in a longitudinal direction : h, h, the transverse faciculi of muscles, some of which run across the proboscis, others in a radiated, and some in an oblique direction : c, c, the radiated, and d, d, the oblique fibres approximate the skin and the tubes, without con- tracting the cavity of the latter. The others, which pass across the proboscis, contract both the surface of the organ, and the canals it contains ; they can, at the same time, elongate the whole or a part of it : e, e, the longitudinal faciculi, forming four large muscles, which occupy all the exterior of the organ. Fig. 6. The extended wings of the Jaf. Ostrologically considered, they are hands, the bony stretches of the membrane being the finger bones extremely elongated : a, a, the thumb, is short, and armed with a hooked nail, which these animals make use of to hang by, and to creep. The hind feet are weak, and have toes of equal length, armed also with hooked nails ; the membrane constituting the wing, is continued from the feet to the tail. Fig. 7. The upper mandible of the parrot, which is articulated with the cranium by an elastic Ugament, admitting of a considerable degree of motion. Fig. 8. An eye compounded of a number of lenses. The eyes of insects differ widely from vertebrated animals, by being incapable of motion ; the compensation, therefore, is a greater number of eyes, or an eye compounded of a number of lenses. Hook computed the lenses in a horsefly to amount to 7,000, and Leuwenhoek found the almost incredible number of 12,000 in the dragon-fly. Fig. 9. The eyes of a spider, drawn from nature. The number of eyes in insects varies from two to sixteen. The spider here referred to answers the description of the garden spider, {Epeira Diadema,) the eyes of which are planted on three tubercles, four on the central one, and two on each side of the lateral ones. \f^ (TA"B,:X1X 7^:^'<.^ ^t^na^Z^t^'nj- ^i^^ CHAPTER XIX. Tab. XXXIII. Fig. 1. The organs for forming the silk consist of two long vessels. They unite to form the spinneret (fusulus) through which the larva draws the silken thread eraploj'-ed in fabricating its cocoon, a, a, the silk bags, b, the spinneret. Fig. 2, The web of spiders is also a kind of silk, remarkable for its lightness and tenuity ; it is spun from four or six anal spinnerets, the fluid matter forming the web being secreted in adjacent vessels, a, b, c, d, the spinnerets. Fig. 3. Panorpa communis, (Linn.) is an insect frequently seen in meadows during the early part of summer. It is a long-bodied fly, of moderate size, with four transparent wings, elegantly variegated with deep brown spots. Fig. 4. The female glow-worm. Fig. 5. The male of the same insect. Fig. 6. The larva of some dragon-flies {ashna and libellula, F.) swim by strongly ejecting water from the anus. By first taking in the \vater, and then "expelling it, they are enabled to swim. This may be seen by putting one of these larva into a plate with water. We find that while the animal moves forward, a current of water is produced by this pumping in a contrary direction. Sometimes it will raise its tail out of the water, when a stream of water issues from it. Fig. 7. The spiracula, or breathing pores of insects, are small ori- fices in the trunk or abdomen, opening into a canal called the trachecB ; by which the air enters the body, or is expelled from it. In the larvae or caterpillars, a trachea runs on each side of the body, under the skin, and generally opens externally by nine or ten apertures or spira- culffi ; from these the same number of air-vessels of a silver colour pass off to be dispersed through the body, a, a, spiracula ; b, b, tra- chea. Fig. 8. The pupse of gnats suspend themselves on the surface of the water, by two auriform respiratory organs on the anterior part of the trunk, their abdomen being then folded under the breast ; when disposed to descend, the animal unfolds it, and with sudden strokes which she gives with it and her anal swimmers to the water, she swims from right to left, as well as upwards and downwards, with the great- est ease. FjG. 9. This is a well known fly, (stratyonis chamcdeon, F.) chame- leon fly. In its first state it inhabits the water, and often remains supported by its radiated tail, consisting of beautiful feathered hairs or plumes, on the surface, with its head downwards. But when it is disposed to seek the bottom or to descend, the radii of the tail is formed into a concavity including in it an air bubble ; this is its swim bladder, and by the bending of its body from right to left, contracting itself into the form of the letter S, and then extending itself again in- to a straight line, it moves itself in any direction. *V I ^^ W 7'iS7/.cZ/^u~n ' Zi/A CHAPTER XX. Tab. XXXTV. — the capsule, pistil, stamina, nigella, plumule, and radicle. Fig. 1. The capsule or seed-vessel of the poppy : (papaver somnifeniin :) it is divided to exhibit its internal structure. Fig. 2. Is an instance of an erect flower, the agave Ame- ricana ; in which the pistil is shorter than the stamina, a, the pistil ; b, the stigma ; c, the stamina ; d, the antherae. Fig. 3. A flower of the crown-imperial. The relative length of the parts is now inverted, a, the pistil ; 6, the stamina. Fig. 4. A blossom of the nigella. Fig. 5. A grain of barley, showing the plumule and radiclt growing fnym it. :cA.b„JiXXiy /^Wi,£/^W7is Zir?/ CHAPTER XX. Tab. XXXV. — vallisneria. Fig. 1. Valisneria spiralis. The female plant, the flowers of which are purple. This is drawn from a specimen in the possession of Dr. Ogle. Fig. 2. The male plant, producing white flowers ; these when mature rise hke air bubbles, and suddenly expanding when they reach the surface of the water, float about in such abundance as to cover it entirely. "Thus their pollen is scattered over the stigmas of the first mentioned blossoms, whose stalks soon afterwards resume their spiral figure, and the fruit comes to maturity at the bottom of the water." Fig. 3. One of the separated male flowers magnified. A '«V' CHAPTER XXII. Tab. XXXIX. Fie. 1, 2. The remarkable ring which surrounds the planet Saturn. Fig. 3. The earth an oblate spheroid. See p. 221. Fig. 4. See p. 224. Fig. 5. See p. 226. Fig. 6. Centripetal forces illustrated, pp. 222, 229. 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