AN INTRODUCTORY LECTURE TO A COURSE IN COMPARATIVE ANATOMY, ILLUSTRATIVE OF PALEY'S NATURAL THEOLOGY. BY JOHN*,KIDD, M. D. REGIUS PROFESSOR OF MEDICINE IN THE UNIVERSITY OF OXFORD. OXFORD, AT THE UNIVERSITY PRESS FOR THE AUTHOR. SOLD BY J, PARKER, OXFORD ; AND BY C. AND F. RIVINGTON, ST. Paul's churchyard, and Waterloo pi^ace, london. MDCCCXXIV. TO SIR ASTLEY COOPER, BART. F. R. S. SURGEON TO THE KING, &c. &c. &c. My dear Sir, . Jt is now nearly thirty years since I com- menced my professional studies under the joint auspices of yourself and Mr. Cline'; and if it were customary to unite the names of two persons on an occasion like the present, I should feel it difficult to separate the name of the one from that of the other ; for they are names which will necessarily be handed down together to posterity, as having contributed in a preeminent degree towards raising the science of Surgery to its highest pitch on the only solid and legitimate basis, the result, namely, of an extensive, long, and successful practice. Indebted to Mr. Cline, as well as to your- self, for much of the professional knowledge which I possess; and indebted equally to a 2 iv DEDICATION. each, in the persons of different individuals of my family, for the successful exertion of your' professional skill; I yet naturally address myself more particularly to you on the pre- sent occasion, because, in consequence of a nearer proximity in our ages, I have from the beginning been thrown more into the society of yourself, than into that of your colleague ; v^hich circumstance, though it could not di- minish my respect for the one, has necessarily strengthened the feelings of attachment to the other. If the expression of this attachment, and of gratitude for those favourable testimonials of my character which I have received from you on some important occasions of my life, be in any degree acceptable to you, I have a very great pleasure in thus publicly avowing my sentiments towards you, by the inscription of the following pages with your name. I am, my dear sir, With the truest respect and esteem, Your much obliged and sincere friend, J. KIDD. Oxford, April 12, 1824. PREFACE. A FEW words will be sufficient in explanation of some parts of the following Lecture. It will be at once known to every resident mem- ber of the University, that the individuals to whom I have referred in the first page, are the Rev. Dr. Lloyd, Regius Professor of Divinity ; and Mr. J. S. and Mr. P. B. Duncan, Fellows of New College : and I have discharged a most willing debt in speaking of them in terms npt only justified by my own senti- ments, but, which is more to the purpose, by the sentiments of the University at large. With respect to the translations from Galen, I believe they will be found, if not always literal, yet faithful representations of his language and opi- nions. I am well aware that in philosophical investiga- i tions the previous consideration of final causes, on \ which great stress is laid in the following Lecture, is usually and properly excluded : but I am equally vi PREFACE. aware, that the rule neither is nor ought to be with- out an exception ; and that in this, as on similar occasions, the reason of the exception corroborates the expediency of the general rule. I am also aware, that such observations as are introduced on the real nature of monstrous pro- ductions, are, in a mere physical point of view, rather calculated to get rid of, than to solve the difficulty. But if reason have its limits, it must be one of its highest prerogatives to know the exact boundary of those limits ; and though a relaxation in our exertions to ascertain the general laws of nature, because we may despair of success in some instances, would betray an ignoble or slothful indo- lence ; yet to me it seems in the highest degree pro- bable, that there are some questions, and that the real character of monstrous production^ is one of that number, the solution of which exceeds the powers of reason : and if so, impatience of ignorance will in such cases be an indication of intellectual weakness, rather than of strength. In speaking of Dr. Gall's theory, I have endea- voured to offer a fair statement ; and though at the conclusion I have expressed myself freely with re- spect to the opinion I entertain of its general merits, yet I have purposely abstained from every personal remark, and therefore feel myself clear from the risk PREFACE. vii of having given any personal offence. With Dr. Gall indeed I am perfectly unacquainted: but I have a gratification in taking this opportunity of ex- pressing the pleasure I experienced from the short acquaintance which I made some few years since, in Oxford, with his colleag'ue Dr. Spurzheim : of whom, in common with many of the first professional cha- racters in this country, I am disposed to think most highly. With respect to the following Lecture itself, I do not in the least deprecate the exercise of criticism, however severe, provided it be also candid: but I would beg leave to remind the general reader, that the Course of Lectures, to which the present was introductory, was delivered to an audience, com- posed chiefly of individuals to whom the pursuit of physical science both is and ought to be a relaxa- tion rather than a study. But I have now no fear of that jealousy which once existed towards this University, in the minds of those who had not had an opportunity of becoming acquainted with its in- stitutions. Oxford is now strong enough to say without boasting, that though clouds soon obscured her bright dawn of natural science, which, origi- ' nating in the labours and association of Boyle, i Hooke, Wallis, Sir Christopher Wren, and others ! of similar pursuits, subsequently led to the establish- viii PREFACE. ment of the Royal Society of England, that dawn has again revived : and I am happy in believing, that mutual communication has produced mutual respect bet\veen those who cultivate science in this place and in other parts of this kingdom. The natural theology 6f Dr. Paley is so generally recommended and read in this University, that I need not here insist either on the scope or the utility of the argument so powerfully and at the same time so beautifully enforced in that work. And if philo- sophy be on all occasions admissible as the handmaid of religion, I need not fear, in employing this argu- ment as the groundwork of a course of academical Lectures, that I have selected a subject unacceptable to an academical audience; especially as this sub- ject has been recommended to me by him, who, from the weight of his personal character and abilities, has within little more than a year been appointed to that chair, from which such a recommendation must come with peculiar propriety. Neither will that chair be disparaged, nor will he who fills it be displeased, if to his authority I add that of two other indivi- duals ; brothers not only by birth, and eminently in mutual affection, but still more eminently in their love and encouragement of taste and science, and of every thing that is amiable and virtuous in life. It will be remembered, that Paley states his argu- ■ment under the supposition ofthe different manner in kvhich the mind would be impressed, by meeting [with a mere loose stone on the one hand, or an in- mcate piece of machinery on the other, in the midst )f an unfrequented heath; that from the evident narks of contrivance in the latter, suppose it a watch or instance, a conviction would arise in the mind, -liat the several parts had been put together by de- { B 2 sign. And, further, supposing the mechanism of the watch such as to enable it by internal movements to produce another watch like itself, it would increase beyond measure our admiration of the skill which had been employed in the formation of such a ma- chine. He then applies this argument to the exa- mination of the eye and ear of animals, and to the power of propagating their species ; and shews from the infinitely superior proofs of skill and contrivance in the works of nature, that if we infer the existence of a contriver from the proofs of contrivance in the works of art, much more must we infer the existence of a Creator from the evidence of consummate skill in the structure and functions of natural objects, as plants and animals. He argues further, that the ex- istence of a Creator is not rendered questionable by occasional irregularities and imperfections ; nor by our ignorance of the operation or use of parts : and combats various atheistical notions concerning chance, or a principle of order, or the elTect of long continued habit, as equivalent to a creative power. He then proceeds to examine the mechanism and functions of the various parts of animals, and the connected assemblage of these parts in different individuals : and he instances several peculiarities of organization, as the air-bladder of fish, the fang of the viper, &c. He next considers what he calls prospective contri- vances, as the formation of teeth within the jaw long before the time of their being called into action, or even making their appearance externally : then the mutual relation of parts, as of teeth to the stomach : and particularly that species of relation called by him compensatioJi ; in which the defects of one part or of 3 one organ are supplied by the counterbalancing structure of another part or of another organ. Lastly he examines the instincts of animals: and every where he intersperses his observations with appeals to tlie understanding of the atheist, against the sup- position, that the various phenomena he has been considering are referable to chance, or any other principle independent of a creative power. As every subject is probably viewed by each indivi- dual in some peculiar light, in a light, that is, modified by his habitual train of reflection, I would beg permis- sion, in the commencement of these Lectures, to make a few observations on the application and va- lue of the argument employed by Paley in the work above mentioned. Being fully persuaded then that the supposition ^ of pure intellectual atheism involves an intellectual \ absurdity ; in other words, that the pure or unmixed j application of the intellectual powers, supposing them : to be in any degree sufficient for the process of rea- t soning, can never lead to a conclusion involving the J disbelief of a Creator ; being fully persuaded of this H point, I feel that so far it is unnecessary to hold any [i argument on the subject; and that Paley, without making an appeal to the understanding of a supposed atheist, might have simply held up to view the mani- festation of the power and wisdom of God, evidenced in the works of creation, as a subject worthy both of philosophical and religious contemplation. But athe- ism apparently exists and has existed in all ages of the world ; and is from time to time either openly 1 professed or insidiously recommended by those, whose I intellectual powers, however distorted or diseased, B 2 4 - give general proof of original strength and soundness. Nor is it difficult, whether to those who admit the original depravity of our nature, or to those who have simply by observation penetrated the recesses of the human heart, to discover the existence of mo- tives that would lead either to the profession of athe- ism^ or to a wish that the doctrine were true. For, without entering more minutely into a question, the discussion of which belongs rather to others, it is " evident from antecedent reasoning, that a profligate man, whose life is systematically at variance with what are generally acknowledged as the moral laws of God, would first wish to escape the punishment consequent on the infringement of those laws ; and would thus be led to hope, that the author of those laws had no existence but in the opinion of man- kind. And such a wish is probably implied in that passage of the Bible ; " The fool hath said in " his heart, There is no God:" for since m the language habitual to Scripture wickedness and folly are conver- tible terms, and as what we are affirmed to say in our heart may naturally be understood as expressing the object of our affections, rather than the conviction of our understandings ; hence those words may be interpreted as implying the hope, rather than the be- lief of the fool, or wicked man. On the other hand, the outward profession of atheism may be traced to many sources. Those men, for instance, who live a depraved life may choose to profess a disbelief in God, in order to obviate the accusation of inconsistency in living directly in opposition to his laws : or intel- lectual pride, that absurd yet baneful error of our nature, may lead some to the profession of a doctrine, 5 on the discussion of which more humble, and there- fore to them more contemptible minds may fear to enter. Some, again, may gratify their vanity by the invention or application of specious arguments, for the purpose of influencing others, less wicked per- haps, but still weaker than themselves ; while these their disciples may on their part be gratified by sup- posing, that they see the solidity of the arguments of a favourite leader : for that such reciprocal feeling may take place between opposite characters is mani- fested on various occasions. " Doubtless the pleasure is as great " Of being cheated, as to cheat." To us perhaps the evil of atheistical doctrines is ra- ther an object of wonder than of fear : for during a long period in which the cause of irreligion has been both openly and insidiously advocated, by writers neither unlearned nor unpopular, the infection hap- pily has reached a very few of the- thousands who -have been educated in this University. Of any fear to be entertained from the writings of ^ Lucretius, I, could never myself see any rational ground. But as I have known that fear expressed by one whose opinion ought not to be treated with ! indifference on any subject connected with intellect- ! ual education, I will take this opportunity of shew- : ing (in one instance for the present) how easily the i reasonings of the Epicurean philosophy, if they de- ' serve the name of reasoning, may be combated on this point. There is not perhaps in the whole poem of Lucre- tius a more beautifully poetical passage than that, in B 3 6 which the helplessness of human infancy is contrasted with the early developement of the powers of brutes : and certainly I could not select one more fitted for the present occasion, because it will give me an op- portunity of introducing, and also of amplifying, one of Paiey's most favourite instances of contrivance in the structure of the human body. The passage to which I allude is in the 5th book, line 223. Tum porro Puer, ut S£evis projectus ab undis Navita, nudus humi jacet, infans, indigus omni Vitali auxilio, cum primum in luminis oras Nixibus ex alvo matris natura profudit ; Vagituque locum lugubri complet, ut asquum est, Cui tantum in vita restet transire malorum. At variae crescunt pecudes, armenta, ferseque, Nec crepitacula eis opus sunt, nec cuiquam adhibenda est Almse nutricis blanda atque infracta loquela : Nec varias quaerunt vesteis pro tempore coeli. Denique non armis opus est, non moenibus altis, Queis sua tutentur, quando omnibus omnia large Tellus ipsa parit, naturaque daedala rerum. The helpnessness above described arises in a great measure from the imperfect state of that bony column called the spine, on which the body principally de- pends for the due exercise of its powers. I wiU first therefore shew, how admirably this co- lumn is calculated for the intended puipose in the adult state ; and, in afterwards examining the state of the same column in the infant, we shall observe, that in the midst of the most decided marks of weakness and imperfection, there is an extraordinary instance of strength and perfect growth in precisely that part of the column, which could not have been left in an 7 incomplete state without manifest, immediate, and constant danger to the individual. And in reasoning on the subject, we soon perceive how that very help- lessness and imperfect state of the physical powers in infancy, so ill understood and appreciated by the Epicurean, contribute to the fuller developement of - the moral character, not only of the individual, but of his parents also, and of all his immediate connec- tions. The mutual affection, for instance, that takes place and is cemented between the infant and its mother during the lengthened period in which the latter nurses her offspring — the stimulus which is given to the exertions of the other parent in supply- ing the increasing wants of those who depend on him for support — and the general feeling and expression of good-will and attachment which binds together the numerous individuals of the same family — all co- incide to increase the sum of human happiness and virtue. Whereas, let the Epicurean infant be born with all his powers complete, and let him exert those powers as soon as born, independently of the assistance of parent, or sister, or brother ; and what would then remain of those endearing relations but the empty name? In considering the office of the adult spine, we find the following qualities requisite: — great strength com- bined with gi-eat flexibihty, together with a general convenience of form for the attachment and secure lodgment of many important organs. Let us then examine how these qualities are attained ; and first with respect to strength. To this end its pyramidal form is obviously con- ducive, and the arrangement of the solid matter of B 4 8 which it is composed is such as to contribute to the same effect : for that solid matter, instead of being collected into one compact mass, is diffused in such a manner as to resemble the structure of sponge ; and it is well known with reference to the strength of artificial columns, that the same quantity of matter being given for each, those columns which are hollow are stronger than those which are solid. Again, the whole column is made up of numerous parts, called vertebrae, which are so bound together by strong and elastic bands or ligaments, as to lessen the chance of its being broken in the act of bending ; and these vertebrae being applied to each other throughout by broad horizontal surfaces, are thus best calculated to support the perpendicular pressure of the superincumbent parts. The effect of general strength is further accom- plished by the mutual locking in of the projecting portions or processes of the several vertebrae ; and the same effect is accomplished to an additional extent among those vertebrae which belong to the thorax or chest, by the mode of articulation between the vertebrae and the ribs ; each rib being united, not entirely to the side of its corresponding vertebra, but partially to the upper and lower side of two contigu- ous vertebrae. The flexibility of the spine is secured to the utmost requisite extent by the number of articulations or joints which it possesses, and which amount to more than twenty, as well as by by the elasticity of the sub- stance constituting those joints : and the projecting parts or processes of the several vertebrae which serve for the insertion of the muscles and tendons which are 9 to move the whole, are differently disposed in the neck, the back, and the loins, so as to be accommo- dated to the degree and kind of motion in each : thus the vertebrae of the neck admit of a lateral mo- tion to a greater extent than those of the back ; and the vertebrae of the back admit of flexion and exten- sion to a greater degree than those of the neck ; while the vertebrae of the loins, being intended for support rather than flexibility, have their processes so distributed, as to contribute principally to the for- mer of those effects. The evidences of convenience in form with respect to the accommodation and protection of contiguous parts are not less obvious than of strength and flex- ibility. Thus while the anterior portion of each ver- tebra consists of an entire mass of bone, as being in- tended to constitute a portion of that part of the whole column that is to sustain the weight of the su- perincumbent and surrounding paj-ts, the posterior portion is hollowed out into a ring through which the spinal marrow passes ; the continued series of similar rings in the several vertebrae constituting a bony canal, which at the same time gives lodgment and protection to that important part of the nervous system. It will be readily seen upon examination that from the annular part of each vertebra three projecting portions, called processes, pass off, two in a lateral di- rection, the other advancing from the posterior part like a thorn, whence indeed the term spinous process |l by which it is distinguished. It is remarkable, that in the case of the cervical vertebrae the lateral pro- cesses are perforated, and in such a direction, as tliat 10 the several perforations form on either side of the neck a continued canal ; no such perforation taking place in the lateral processes either of the dorsal or the lum- bar vertebrae. Now as through this canal two large arteries are conveyed, which are destined to supply blood to the brain, there can be no doubt that these la- teral processes are thus perforated in order to form a se- cure passage for those important blood vessels. Equal proofs of design are observable in the specific differ- ences of form peculiar to the spinous processes of the vertebrae of the neck and of the back ; the ex^ tremities of those of the neck being bifid, in order to conduce ultimately to a greater freedom of lateral motion in that part ; those of the dorsal vertebrae overlapping each other in such a manner, that the pressure of burdens carried on the back occasions neither the pain nor the inconvenience which must be felt, did those processes project at right angles to the column, as they do in the loins : in which part, on the other hand, by so projecting, they afford a firmer surface of attachment for the insertion of pow- erful muscles, on whose action the support and mo- tion of the trunk of the body in a great measure de- pend. It has been stated, that the general form of ' the spinal column is pyramidal, and that the effective part of the pyramid is formed by the apposition of i the bodies of the vertebrae to each other ; and it will ; be observed, that of these bodies those of the neck are ) smallest in their dimensions, while those of the loins [ are the largest. Now these are respectively the con- [ ditions which would be antecedently expected, in- asmuch as the former have a much slighter weight pressing upon them than the latter. Again, in n comparing the dorsal with the lumbar vertebrae it •will be seen, that the bodies of the former are com- pressed in the direction of the lateral diameter, in order to give more room for the play of the lungs on either side of the chest, while those of the latter are ra- ther compressed in a direction from behind forwards, in order to give room to and facilitate the motion of the abdominal viscera. Nor will it escape observation, that while the pos- terior surface of the spinous column is broken into a series of projecting rugged points, which serve admi- rably for the support of the whole, and of the several parts of the column, as well as for insertion of nu- merous muscles ; the anterior part of the column throughout its whole extent affords a smooth surface, .over which the soft viscera both of the thorax and of all animals, possessing in his soul this " general and original capacity, is justly endued in " bis body with this general and original instrument." " Let us tben scrutinize this member of our body ; " and inquire, not simply whether it be in itself use- " ful for all the purposes of life, and adapted to an " animal endued with the highest intelligence ; but " whether its entire structure be not such, that it " could not be improved by any conceivable alteration. " In the first place, it possesses in an eminent degree " a leading quality of an organ of grasp ; since it rea- " dily applies itself to, and securely holds, bodies of " every form and size that are capable of being moved " by human strength. Shall we inquire then, whe- " ther it be better for this purpose that it should be " divided into several parts, or that it should be al- " together undivided : or is it not apparent without " further reasoning, that, had it been undivided, " it could have grasped only just such a portion of " every object presented to it as was equal to itself ; but being divided into many parts, it can both ea- " sily grasp bodies much larger than itself, and can " accurately search out and lay hold of the smallest " particles of matter. For to the former it is capa- " ble of generally applying itself so, as to encompass " them by the separation of the fingers ; while in lay- ing hold of very minute objects the entire hand is not employed, (from the grasp of which they would escape,) but only the tips of two of the fingers. I* Thus then the hand is framed in the manner most Lib. i. cap. 5. C 18 " convenient for laying a firm hold on objects ijoth " greater and less than itself. And, in order to enable " it to apply itself to objects of various shapes, it is " evidently most convenient that it should be di- " vided into many parts, as it is : and it seems to be " better constituted for this purpose than any similar " instrument ; for it not only can apply itself to sub- " stances of a spherical form, so as to touch them with " every part of itself ; but it also can securely hold " substances of a plane or of a concave surface, and " consequently it can hold substances of any form. " And, because many bodies are of too great a size " to be held by one hand, nature has therefore made " each hand an assistant to its fellow ; so that the " two, when together, laying hold of bodies of un- " usual bulk on opposite sides, are fully equivalent " to a single hand of the very largest dimensions : " and on this account, the hands are inclined towards, " and in every point are made equal to each other r " which is at least desirable, if not necessary in in-' " struments intended to have a combined action. " Take then any one of those unwieldy bodies,' " which a man can only lay hold of by means of both " his hands, as a mill-stone or a rafter ; or take one " of the smallest objects, as a millet-seed, or a hair; " or a minute thorn ; or, lastly, reflect on that vast " multitude of objects of every possible size, interme- " diate to the greatest and the least of those above " mentioned, and you will find the hands so exactly" " capable of grasping each particular one, as if they " had been expressly made for grasping that alone. " Thus the smallest things of all we take up witli *' the tips of the forefinger and thumb ; sul)stances a 19 " little larger we take up with the same fingers, but " not with the tips of them ; substances still larger " we take up with three fingers, and so on with four, " or with all the five fingers, or even with the whole " hand : all which we could not do, were not the " hand divided, and divided precisely as it is. For, " suppose the thumb were not placed, as it is, in op- " position to the other four fingers, but that all the " five were ranged in the same line, is it not evident " that in this case their number would be useless. " For in order to have a firm hold of any thing, it " is necessary either to grasp it all round, or at least " to grasp it in two opposite points ; neither of which " would have been possible, if all the fingers had been placed in the same line : but the end is fully " attainable, simply in consequence of the present " position of the thumb, which is so situated, and " has exactly such a degree of motion, as by a slight ** inclination, to be easily made to cooperate with " any one of the other four fingers. And no one can ** doubt, that nature purposely gave to the hands a " form adapted to that mode of action which they ** are observed to have: while in the feet, where extent of surface is wanted for support, all the toes " are arranged in the same line. ^ But, to return to " a point which we were just now considering, it is j" not merely necessary in laying hold of minute ob- jects to employ the extremities of two fingers op- " posed to each other, but that those extremities should be exactly of the character they are, namely soft, and round, and furnished with nails : " for if the tips of the fingers were of bone, and not Lib. ii. cap. 9. ^ lj^^ } ^ap. 6. « C 2 20 " of flesh, we could not then lay hold of such minute " bodies as thorns or hairs ; or if they were of a " softer and moister substance than flesh, neither " then could such small bodies have been secured : " for in order that a body may be firmly held, it is " necessary that it be in some degree enfolded in the " substance holding it ; which condition could not " have been fulfilled by a hard or l^ony material. On " the other hand, a material too soft would easily " yield to substances it attempted to lay hold of, and " would continually let them escape ; whereas the " extremities of the fingers are just of that interme- " diate degree of consistence which is calculated for " their intended use. " ^But, since tangible substances vary much in " their degree of hardness, nature has adapted the " structure of the extremity of the fingers to that " circumstance : for they are not formed either en- " tirely of flesh, or of the substance called nail, but. of " a most convenient combination of both : thus those " parts which are capable of being mutually brought " in apposition, and which are employed in feeUng *'* for minute objects, are fleshy ; while the nails are " placed externally, as a support to the former. For the fingers are capable of holding soft substances, " simply by the fleshy, or soft parts of their ex- " tremity ; but they could not hold hard substances " without the assistance of nails ; deprived of the " support of which the flesh would be forced out of " its position. " And on the other hand, we could not lay hold " of hard substances by means of the nails alone ; ' Lib. i. cap. 7. 21 " for these being themselves hard, would easily slip " from the contact of hard bodies. Thus then, the' " soft flesh of the tips of the fingers, compensating " for the unyielding nature of the nails, and the " nails giving support to the yielding softness of the " flesh, the fingers are hereby rendered capable of " holding substances that are both small and hard. " And this will be more evident, if you consider the " effect of an unusual length of the nails ; for where " the nails are immoderately long, and consequently " come in contact with each other, they cannot lay " hold of any minute object, as a small thorn or a " hair : while, on the other hand, if, from being " unusually short, they do not reach to the ex- " tremities of the fingers, minute bodies are inca- " pable of being held through defect of the requi- " site support : but if they reach exactly to the ex- " tremity of the fingers, they then, and then only, " fulfil the intention for which they were made. " The nails, however, are applicable to many other " purposes besides those which have been mentioned ; " as in polishing, and scraping, and in tearing and " peeling off the skin of vegetables or animals. And, " in short, in almost every art where nicety of exe- *' cution is required, the nails are called into action." In appealing to the sophists of his time, the lan- guage of Galen is as follows : — " s Whoever admires " not the skill and contrivance of nature, must either " be deficient in intellect, or must have some private " motive which withholds him from expressing his " admiration. He must be deficient in intellect, if he " does not perceive that the human hand possesses B Lib. iii. cap. lo. c 3 22 " all those qualifications which it is desirable it should " possess ; or if he thinks that it might have had a " form and construction preferable to that which it " has : or he must be prejudiced, hy having imbibed " some wretched opinions, consistently with which " he could not allow that contrivance is observable " in the works of nature." Galen adds : " Such per- " sons we are bound to pity, as being originally in- " fatuated with respect to so main a point ; while at " the same time it behoves us to proceed in the in- " struction of those hapj)ier individuals, who are not " only possessed of a sound intellect, but of a love of " truth." On another occasion, in reprobating the vices and the scepticism of the Epicureans, he says : " But if " I waste more time on such profligates, virtuous " men might justly accuse me of polluting this sa- " cred argument which I have composed as a sin- " cere hymn to the praise and honour of the Crea- *' tor ; being persuaded that true piety to him con- " sists not in the sacrifice of whole hecatombs of " oxen, nor in the offer of a thousand varieties of " incense ; but in believing ourselves, and in declar- " ing to others, how great he is in wisdom, power, " and goodness." Galen then sums up this part of the argument with the same sentiment, and nearly in the same words, which Solomon uses on a similar occasion. " ^The contrivances of nature," he says, " are so va- " rious and so consummately skilful, that the wisest " of mankind, in endeavouring to search them out, " have not yet been able to discover them all." ^> Lib. X. cap. lo. 23 Let us compare with the foregoing the following passage in Ecclesiastes^: " Then I beheld all the " work of God, that a man cannot find out the work " that is done under the sun : because though a man " laliour to seek it out, yet he shall not find it ; yea " farther ; though a wise man think to know it, yet " shall he not be able to find it." I will only detain you by one other extract, taken from the 7th chapter of the 11th book; in which chapter, after having noticed many evidences of de- sign in the construction of the human body, parti- cularly the adaptation, in the number and size of the parts, to the effect to be produced, he breaks out into this remarkable apostrophe : " How can a " man of any intelfigence refer all this to chance, as " its cause : or if he deny this to be the effect of fore- " sight and skill, I would ask, what is there that foresight and skill do efiect? For, surely, where " chance or fortune act, we see not this correspon- " dence and regularity of parts. I am not very " solicitous about terms ; but if you choose to call " that chance which has so nicely constructed and " so justly distributed all the parts of an animal " body, do so ; only remember and allow, that in " so doing you do not fairly exercise the privilege of " framing new terms : for in this way you may call " the meridian splendour of the sun by the name of " night ; and the sun itself, darkness. What ! was " it chance that made the skin give way so as to " produce a mouth ? or, if this happened by chance, " did chance also place teeth and a tongue within " the mouth ? For, if so, why should there not be ' Chap. viii. verse 17. c 4 24 " teeth and a tongue in the nostrils or in the ear ?" Or, to carry on a similar appeal'', " Did chance dis- " pose the teeth themselves in their present or- " der ; which, if it were any other than it is, what " would be the consequence ? If, for instance, the " incisors and canine teeth had occupied the back " part of the mouth, and the molar or grinding " teeth had occupied the front, what use could we " have made of either ? Shall we then admire the " skill of him who disposes a chorus of thirty-two " men in just order; and can we deny the skill of " the Creator, in disposing the same number of teeth " in an order so convenient, so necessary even for " our existence ?" He then extends the argument to the teeth of other animals, as corresponding with the nature of their food ; and also to the form of their feet, as having a relation to the character of their teeth. " Never," says Cuvier, one of the most philosophical physiologists of the present day, " never do you see in " nature the cloven hoof of the ox joined with the *' pointed fang of the lion ; or the sharp talons of " the eagle accompanying the flattened beak of the " swan." In corresponding expressions Galen exclaims, " How does it happen that the teeth and talons of " the leopard and lion should be similar ; as also the " teeth and hoofs of the sheep and goat ; that in " animals which are by nature courageous, there " should be found sharp and strong weapons, which " are. never found in those animals that are by na- " ture timid : or, lastly, that in no animal do we ^ Chap. viii. and chap. xi. the last sentence. 25 " meet with a combination of powerful talons with " inoffensive teeth ? How should this happen, but " that they are all the work of a Creator, who ever " kept in mind the use and mutual relation of parts, " and the final purpose of his work." Before we proceed to examine the proofs of con- trivance and of foresight in the structure of indi- vidual animals, let us consider what is the essen- tial character of an animal in the abstract — a point which is not so easily to be ascertained as at the first view might appear. All the objects of the material world are usually distributed into three kingdoms, as they are called ; the animal, vegetable, and mineral. To these might with propriety, I think, be added a fourth, and be called the atmospherical. In examining the general characters of the indi- viduals belonging to these kingdoms, we shall find that upon the whole they are very different from each other. In the atmosphere we have the air which we re- spire, a form of matter so subtle in all its states as to be invisible ; and, diffused through this, we have an aqueous vapour \ a portion of which is always retained in close combination with the air; and, like it, in an invisible state. We have also diffused through the atmosphere those still more subtle I agents, heat and electricity: these four, severally I and generally, existing in a loose state of aggrega- tion, in consequence of the mutual repulsion of their particles. But all these, though of so subtle a sub- stance, are in their effects the most powerful agents 26 of nature. For, omitting the silent but wonderful operation of air and moisture and heat and electri- city, as exhibited in the process of vegetation, and many other processes which are continually going on, let us consider the occasional effects of air in the violence of a tornado ; or of moifiture, in the inundation of a rapid river, produced hy protracted rain : or let us contemplate the effect of either an indefinite increase or diminution of heat — on the one hand, all the processes of nature stopped by the effect of cold, so that the imbedded mammoth re- mains at this moment in the same state that it was four thousand years ago, and in which it may be ten times that space hereafter : on the other hand, the possibility of the dissijiation of all the constituent parts of matter, or their fixation in the state of glass, resulting from the agency of intense heat : or, lastly, let us consider the awful effects of condensed elec- tricity in the form of lightning ; and we shaU ne- cessarily acknowledge, that, though in their usual state the constituents of the atmosphere are the most tranquil agents of nature, yet, when their power is concentrated, they are the most tremen- dously energetic. In the mineral kingdom, the most characteristic property of the several species appears to be a dispo- sition to a peculiar mode of mutual attraction among the particles composing the individuals belonging to them ; from which attraction, when exerted under the most favourable circumstances, result that sym- metry and regularity of form, to which the term crystal has been applied. The transparency and degree of hardness of crystals are various, and de- 27 pend upon external circumstances. The form is fun- damentally the same for each species, though ca- pable of being modified according to known laws ; and the substance is chemically the same through- out its whole extent. Every atom of a mass of gypsum consists of water, lime, and sulphuric acid, united in the same proportions, as those in which they exist in the whole mass. The individuals of the vegetable kingdom differ very remarkably from those of the mineral, both in form and substance. In their form we see nothing like the mathematical precision of crystallization ; and in their substance they differ widely according to the part of the vegetable wliich is examined : so that independently of previous knowledge of the species, we could hardly discover any natural rela- tion between the several constituent parts of the in- dividual. What is there in the insulated leaf of a peach tree, or a rose, that woidd lead us to expect the fruit of the one, or the flower of the other ? But the most remarkable line of distinction be- tween vegetables and the individuals of the preced- ing kingdom consists in their mode of increase and reproduction. Minerals can only increase as such by the apposition of particles specifically similar to themselves ; and can only be reproduced, when de- stroyed, by the immediate com]:)ination of their con- stituent elements. But vegetables have an appara- tus within them, by means of which they can assi- milate the heterogeneous particles of the surround- ing soil to their own nature ; and they have also the power of jn-oducing individuals specifically the same as themselves : in common language, they are ca- 28 pable of contributing to their own growth, and the propagation of their species. And as they pro- duce these effects by peculiar organs adapted to the purpose, they are hence denominated organized bo- dies. The individuals of the animal kingdom very close- ly resemble those of the vegetable in the two pro- perties just described. The respective organs differ, as we miglit expect, in their form and position ; but in their function or mode of action there is a strong analogy and even similarity throughout. But animals differ from vegetables more remark- ably than these do from every unorganized form of matter, in being endued with sensation and volition; properties which extend the sphere of their relations to such a degree, as to raise them immeasurably above all other forms of matter in the scale of ex- istence. In distributing the individuals of the material world among these four kingdoms of nature, there occasionally prevails considerable obscurity, not only with respect to the true place which an individual ought to occupy in the scale of a particular kingdom; but even with respect to the question, under which . of the four kingdoms it ought to be arranged ; this obscurity arising of course from the points of resem- blance apparently balancing, or more than balancing the points of difference. In the atmospherical king- dom, for instance, take a fragment of a perfectly transparent crystal of pure ice ; and, excepting from the effect of temperature, it would.be difficult, either by the sight or the touch, to distinguish it from a fragment of transparent quartz, or rock crystal : in- 29 deed the transfer of the original term KpvaraWo^, from the one to the other, shews the close resem- blance of the two. Some minerals again approach so nearly in form to vegetables, as to have given rise to specific terms of appellation, derived from the vege- table kingdom ; as flos ferri — mineral agaric, &lc : and even within the last few years, and in the pre- sent advanced state of science, one of the most splendid and gigantic flowers in the vegetable king- dom was mistaken for an animal, a species, namely, of sea-anemone. And, lastly, many of the animals called sea-anemones so far resemble the flower called by the same name, that their real character is at first very doubtful to those who are unacquainted with the animals of that genus. But, omitting these rare and equivocal instances, and avoiding the confinement of abstract definitions, which are scarcely applicable to any subjects but such as are mathematical, we may safely assume that animals in general are capable of being considered under three distinct points of view; namely, either simply as organized beings, endued with the powers of contributing to their own nutri- tion, and the reproduction of their species : or se- condly, as endued also with the powers of locomo- tion : or lastly, as possessing, in addition to the other two, the powers of sensation and volition. In grounding these Lectures then on Paley's work, pl shall so far deviate from his arrangement, as to distribute the examples intended to be produced un- der the three preceding heads. And in order to make the Lectures as comprehensive as possible, I shall exhibit the facts according to the classification of animals most approved at the present day. The 30 principle of this classification is the degree of simi- larity of their internal organization to that of the human body, disregarding the occasional dissimilarity of their external form : on which princijDle we find the bat and the whale placed in the same class with those animals that most nearly resem])le man ; though from their external form they are rather to be considered, the one a bird, the other a fish. On this principle of classification, the term " com-; " parative anatomy," to which Dr. Paley objects, (p. 241.) is perfectly appropriate ; since by compar-* ing the anatomy of each species with that • of man^ its true place in the scale is ascertained. It wiU be consistent with the intention of these Lectures, to give an outline of this classification ; but it is not ne- cessary to take uji your time, by giving more than a mere outline of it. Cuvier, who is in a great measure the author of this classification, distributes animals first into four great divisions ; each of which he successively subdivides into classes, orders, genera, and species : and where se veral genera in the same order are more than usual ly allied in the characters of their structure, he col lects them into one grouji, under the name of famil and tribe. The first great division comprehends only thos animals which have a brain and spinal marrow which spinal marrow being contained in a S23ine, o backbone made up of several vertebrae, has given ris to the term animalia vertebrata. This division con tains four classes, namely, the mammalia, or animal which suckle their young, birds, reptiles, and fish. The second great division consists of animals, whic 31 having neither a vertebral canal, nor a skeleton alto- gether, are caUed animalia moUusca. It contains six classes, which are described according to the situation of their feet, or those parts which serve the purpose of feet. The third great division comprehends all those ani- mals whose bodies are divided very regularly into distinct parts, hence called animalia articulata. It is distributed into four classes. The fourth great division comprehends, among others, all those animals which, from their branching or radiated form, are called zoophytes, and anima- lia radiata. It is distributed into five classes. Before we proceed to examine those instances of mechanism and contrivance which characterize par- ticular species of animals, it will be desirable to con- sider such points in the mechanism and contrivance of animal life in general, as from their almost uni- versal occurrence demand some previous attention : the common phenomena for instance, connected with I the three powers above enumerated; that is, diges- tion, and the propagation of the species ; the muscu- lar or locomotive powers ; and the nervous system. The process of digestion, as far as we are acquainted with it, is soon described : the organs in their simplest state consisting merely of a membranous bag, which «by means of a fluid that exudes from its internal sur- fface, has the power of reducing all the varieties of food on which animals live to a soft homogeneous pulp, from which the nutritive particles are absorbed into the system, and perfected into the state of blood. The instruments of the circulation of the blood \ are the heart, and the several systems of vessels con* 32 nected with it. The blood itself is primarily pro- duced, as was just now said, from the food on which the animal lives : but omitting for the present the con- sideration of the apparatus by which this is effected, I would only observe as worthy of admiration, and in- dicative of the uniformity and power of nature, (by which term, I mean the Deity, or controller of nature,) the similarity in the character of this fluid, through a long series of animals of very different orders, and living on very different kinds of food. And when we come to examine the mode of its distribution through the body, and the uses to which it is applied, we have equal cause of wonder in the artificial man- ner in which it is conducted from part to part, and in the varying character of the compounds that are separated from it. The resemblance between the distribution of the blood-vessels, and the distribution by a skilful engineer of the pipes and conduits which are to convey water to the several parts of a large city, has been often remarked : but in the distribution of the blood, there is this additional cause for admira- tion, that whereas, in the case of the artificial dis- tribution of water, the same unaltered fluid is drawn oflf from each individual reservoir to which it has been conveyed, in the case of the blood it is far other- wise : thus what passes into the kidney as blood., passes out as urine ; from the lacrymal gland it passes o\it as tears ; from the glands of the mouth, as sa- liva ; from the liver, as bile ; and so on with respect to all the glands of the body. And throughout all the species of the more per- fect animals, as quadrupeds, birds, reptiles, and fish, there does not appear to be one exception to this 33 mode of distribution ; so that, whether you examine the smallest of the fry of the smallest species of min- now, the aggregate quantity of whose blood would hardly be sufficient to leave a sensible moisture on the tip of your finger ; or whether you examine the largest of the whale tribe, the main vessel of whose body is a foot in diameter, and whose heart is said to throw out fifteen gallons of blood at a stroke; in either case the mode of distribution and the appara- tus by which it is effected are essentially the same, as well as the final result : the minutest fish has its heart and arteries as artificially arranged, and the se- cretions from the blood as distinctly elaborated, as those of the elephant or whale. And this is another instance of the truth of that observation, that great and little are as nothing in the hands of God. Those who have not considered the subject must be surprised at the quantity of blood which passes through the heart of any moderately sized animal in the course of twenty-four hours. In ourselves the quantity of iDlood existing in the body at any given moment is probably from 30 to 40 pints. Of this, an ounce and a half, or about three table spoonfuls are sent out at each stroke; which multiplied into 75 (the average rate of the pulse) is 112.5 ounces, or seven pints, in a minute ; i. e. 420 pints, or 52.5 gallons, in an hour ; and 1260 gallons, i. e. nearly 24 hogsheads, in a day. Now if we recollect that the whale is said to send out from its heart at each stroke 15 gallons, the imagination is overwhelmed with the aggregate of the quantity that must pass through the heart of that animal in twenty-four hours. It is a general D 34 law, that the pulse of the larger animals is slower than that of the smaller : but even if we put the pulse of the whale so low as 20 in the minute, the quantity circulated through the heart, calculated at 15 gallons for each pulsation, will be 432,000 gallons, equal to 8000 hogsheads in twenty-four hours. The consideration of this amazing quantity is how- ever a subject of mere empty wonder, if not accom- panied with the reflection, that in order to produce the aggregate amount, the heart is kept in constant motion ; and that in fact it is incessantly beating, as it is termed, or throwing out the blood into the ar- teries, from the first period of our existence to the moment of our death, without any sensation of fa- tigue, or even without our consciousness, excepting under occasional corporeal or mental agitation. With respect to the phenomena connected with the propagation of animals, the inconceivable extent of the result in some instances, and its limitation in others, open a wide field for contemplation : but nei- ther the time nor the data of which we are in pos- session permit me to do more than point out one or two of these instances ; much less to insist on the consequences dependent on the relative proportions of animal existence in different orders and genera, and in different parts of the globe. It is an old and a trite observation, that while the larger and fiercer animals produce only one or two at a birth, the smaller animals are much more prolific : and the final cause of this difference is considered as sufficiently obvious, inasmuch as the smaller animals are upon the whole the prey of the larger; and that without this ar- rangement, the larger animals would soon extinguish 35 the races of the smaller, and would then themselves fail for want of food. A favourite instance of the fecundity of animals is taken from the class of fish, and is estimated from the aggregate number of the ova in the roe of the cod. Lewenhoek reckoned, that in the roe of a cod- fish there were more ova, each destined to produce a fish, than there are human beings on the face of the earth. The most remarkable faqt with which I have yet met, connected with the present subject, relates to a minute species of medusa, an animal belonging to the class called sea-nettles. ' The number of these medusae in some parts of the Greenland seas is so -great, that in a cubic inch taken up at random there are no less than 64 ; in a cubic foot this will amount -to 110,592 ; and in a cubic mile (and there can be no doubt of the water being charged with them to that ■extent) the number is such, that allowing one person xould count a million in a week, it would have re- quired eighty thousand persons from the creation of the world to complete the enumeration. In this part of the subject will be properly consi- dered the case of those monstrous productions called lusus naturae. I This term is applied to those natural productions, llfehich vary in- any remarkable degree, with respect j to form, colour, structure, size, &c. from the general character of the individuals of the same species. '■ The term, literally taken, implies a sportive effort of the creative power of nature ; and, for the purpose ' Jameson's Journal, vol. ii. p. 12. D 2 36 of general description, there is no objection to this term ; being, as it now is, familiarized by long con- tinued use. But as we have no ground for supposing that nature, or, to use the more proper expression, that the providence of God, ever acts without some wise and beneficent purpose, we must consider the term, in a philosophical point of view, as expressing an effect, of the natural cause of which we are igno- rant. On the present occasion I propose to inquire briefly, and with that diffidence and caution which the subject demands, what is the real character of those unusual productions which are denominated lu- sus naturae, or monsters ; or in other words, for what end Providence ordains that such productions should be formed and subjected to our observation. It will be found then, upon even a cursory exa- mination, that in a lusus naturae the character of the species, however obscured, is never lost. An indi- vidual sheep may have two heads, or two bodies, or double the usual number of extremities : but you will never find that one of those heads shaU be the head of a sheep, the other the head of a horse. Nor will you ever find that the head shall be that of one species of animal, and the extremities those of an- other. There is no ground, in short, for supposing that nature has ever produced such an individual as a chimera or centaur. So that Lucretius's scepticism in this point is justified by a physiological truth : Sed neque centauri fuerunt, nec tempore in ullo Esse queat duplici natura et corporc bino Ex alienigenis menibris conipacta potestas. Lib. V. 8TC. 37 And we have good reason for believing, that these productions are regulated in their form and struc- ture by some previous design. In pursuing this investigation it will be natural to ask, what are the limits which separate a lusus naturae from the ordinary individuals of the same species? And we shall soon find that these limits are in the majority of instances undefinable. If indeed, in comparing the several organs, agree- ment with respect to number be the criterion, the limits are for the most part fixed. Thus the human hand so very generally consists of five fingers, that - an instance of an individual having more or less than five fingers would be justly esteemed an instance of a lusus naturae. But even number is not always an acknowledged criterion ; foi' with respect to the i teeth, though 321 is the usual number in the human subject, yet the instances of persons having only ' 28 are so frequent, that we scarcely class them as deviations from the common law. But if size, or colour, or form, be made the crite- rion, we evidently cannot then fix the limits ; for in all these points there is an endless variety in indivi- duals of the same species : so that it might perhaps be truly asserted, that out of the countless myriads of human beings that inhabit the earth, nay even )ut of all that have existed since the creation, no wo individuals would be found to resemble each )ther exactly in even any one of those points. And, n this, the infinite superiority of the Deity over luman power is seen: for the most accomplished irtist, as soon as he ceases to copy an actual indi- idual, falls into that general similarity of outline D 3 38 by which we are enabled to ascertain his style upon the first view. If, in the pursuit of our inquiry, we appeal to the distribution of the internal organs of the body, we shall find, that though with respect to many the position is determinable with considerable preci- sion, yet with respect to others the variation is end- less. If we consider the uses of the parts with refe- rence to the precision of their position, we shall find, that the position of those is most constant, the uses of which are most important ; while the distribution of those parts, the position of which may be varied to a considerable extent without inconvenience to the individual, is found to be continually varying. Now, as this law of nature does not seem at all to result from the construction of the parts' them- selves, and as the result is necessarily connected with the well being and even the life of the indivi- dual, we cannot consider this result us the effect of chance : for if chance could be admissible as the cause, why should one set of phenomena be so much more frequent than the other ? And with equal or still greater force we may apply the argument to the existence of those productions emphatically called monsters. Perhaps then, or rather assuredly, these monstrous productions are to be considered as proofs of a particular or constantly superintending Provi- dence ; and, like the storms that occasionally ravage the surface of the earth, may awfully recall to our minds the power of the Deity, while they at the same time convince us, by the rarity of their occur- rence, of the merciful beneficence of his nature. 39 Of such a constantly operating care and benefi- cence, the contemplation of physiological phenomena affords us frequent proofs ; from among which I shall, on the present occasion, mention only two. The first is taken from the history of a particu- lar tribe of insects. Insects in general are oviparous. The aphides, or "plant-lice, are, however, viviparous in the summer ; but in the autumn they are oviparous; and for the following reason, viz. The eggs which they lay are not hatched till the next season, and thus the spe- cies is preserved : for the eggs are capable of with- standing the winter's frost, which the animal itself would not"*. The second proof is derived from the history of our own species, and relates to the equality of the sexes; which equality is wonderfully preserved in reference to communities, though in individual fa- milies there shall be sometimes no children but of the male sex, in others none but of the female. : In the lying-in hospital of Dublin there have been delivered, from 1757 to 1807, i. e. in half a century, 39,354 women ; and the proportions of the sexes .were as follow : Boys - 31,559 Girls - 28,882 And male children appear in most, if not all parts of the earth to preponderate ; for men are more ex- posed to the accidents of life than women are°. . The second point of view under which it has been stated that animals may be considered, has a refe- rence to their power of locomotion ; of the organs of Lond. Med. Rep. vol. xi. p. 375. "Edinb. Med. J. vol.xv.p. 163. D 4 40 which I shall now offer such a general description as is applicable to the present purpose : but less need be said on this point, Paley having occupied that field so amply. These organs are the muscles, with their appendages the tendons ; and the bones, with the various articulations or joints, to the formation of which they contribute. It is clear that the motions of the several parts of the body could not be either produced or defined, were it not for the existence both of the bones them- selves, and of that mutual adaptation of the extre- mities of the bones called joints : and thus in those parts where protection and no motion is required, ~ the bones are applied to each other without the in- tervention of joints, as in the head; and although it might at first be asked, why, as in the case of the head, a number of distinct bones should contribute to the formation of that firm case which might have been of fully sufficient strength if formed of one bone, yet on a little consideration it will be seen, that two important points are gained by the present mode of formation : for in the original deposition of the osseous matter, the centre of each portion formed a separate- nucleus, round which ossification com- menced ; and the more of those nuclei there were, the sooner of course would the ossification of the whole skull be completed. And again, the lines of interrupted ossification often serve to arrest the pro- gress of a fracture occasioned by a violent blow, the force of the blow being diffused along the line of in- terruption. Where, on the other hand, any degree of motion is required, there the joint is constructed in such a manner as best to accomphsh the degree 41 of motion required : thus, in the arm, where very great extent of motion is required with comparative- ly little strength, there the extremity of one of the bones is a very large portion of a solid sphere, while the extremity of the other which is adapted to it, presents a small extent of surface, and that very slightly concave. But in the articulation of the thigh at the hip, where great strength is required with comparatively little motion, the hemispherical head of the one bone is completely hidden in a cor- responding cavity of the other. And in the remarkable instance of the articula- tion between the two jaws, where occasionally an unusual degree of force is required in the action of the joint, as in the biting some hard substance, the action of the lever is assisted by the interposition of a moveable piece of gristle, called the interarticu- lar cartilage. The muscles, with their appendages the tendons, which constitute the other branch of the locomotive apparatus, are to the bones what ropes in machinery are to the weights which are to be moved ; and for instances of their mode of action, Paley may be con- sulted. I would only observe by the way an occa- sional contrivance by which their line of action is changed from a parallel to an angular direction, in order to increase the force of their action. This is done by causing their tendons to pass over distinct insulated bones, which are often enveloped in the substance of the tendon. Such a mechanism is ob- servable in the anterior part of the knee, where the tendon of the rectus muscle of the thigh envelopes the bone called the kneepan ; and still more deci- 42 dedly in the case of the tendons, which move the hoof bones of the ox, where the bones which serve to change the line of direction of the tendons are perfectly distinct from the tendons which pass over them. Lastly, we have to consider the general character of the nervous system, or the organs of sensation and voHtion ; those mysterious instruments which are apparently the means of communication between the material world and the immaterial principle of our present existence. In ourselves, and in all the animals of the higher classes, these organs are the brain and nerves : and without at present deducing any conclusion from the observation, it may be stated as a fact, that the degree of approximation of the brain of brutes to that of man bears a very obvious relation to the degree of intelligence observable in the various classes of animals : so that, in just rea- soning, it must be admitted to be the instrument by which the various degrees of intelligence are mani- fested ; in those animals at least in which it exists. But it is of importance to observe, with reference to those physiologists who maintain, that the mate- rial condition of the brain is necessary to or actually confers the power of thinking, that the evidence of the exertion of that power is as strong, nay even stronger, in some animals that have no brain, as in those whose brains are developed in a very high de- gree ; I had almost said, as strong as in ourselves : and, if we look to the habits of many of the insect tribe, (the bee may be taken as instcu- omnium^ I should probably be justified in the assertion. 43 Every one present is doubtless aware, that at- tempts have frequently been made to build the doc- trine of materialism on the foundation of physiolo- gical observations ; and though it is not my inten- tion on the present occasion to occupy your time with a full examination of this question, yet to save myself from any misconception on the part of those who hear me, with respect to this subject, I beg leave to state, that the term materialism may be used, and appears to be so used actually, to imply the result of two very different modes of reasoning with respect to the phenomena of matter. Accord- ing to one mode it has been inferred, that there is an inherent and independent power, in certain mo- difications of matter, of exerting various energies; and those who make this inference maintain, among .other points, that the brain is capable of exerting the energy of thought, independently of any power communicated to it ah extra. Such an inference I for myself entirely disclaim. According to the other mode of reasoning, it is inferred, that where such and such modifications of matter are presented to view, they are merely to be acknowledged as evidence that the Deity manifests such and such powers : but though the terms em- •ployed in describing the phenomena and the results may be the same in both instances, yet they are only adopted in the latter instance for the purpose of preventing the delay and formality of a periphrasis. For instance, when I say that the magnet attracts iron ; that a piece of resin heated by friction attracts light bodies ; or that the planets attract each other ; I by no means intend to assert that these pheno- 44 niena are independent of the ])ower communicated by the Deity. And if I say that the brain has the power of thinking, I only mean, that I recognise in that organ the material instrument by which the process of thought is manifested. It was the opinion of Locke, that the Deity may probably have added to the brain, its parts being appropriately disposed for the purpose, the power of thought. This opinion was opposed by Stillingfleet, on the ground of the consequent difficulty of proving the immateriality of the soul. Such a difficulty is of too serious a character to be disregarded ; and on many occasions it would be better to avoid the question, and disregard the mi- nor difficulty which leads to it, namely, in what way animals exert the power of thought, than to incur the hazard of encountering one so much greater. But I will state the ground from which the ques- tion sf)rings ; and, though I see no intrinsic olijec- tion to the admission of Locke's opinion, and some good reasons for adopting it, yet I am happy in see- ing a way of getting rid of it in a manner unobjec- tionable to all who believe in the existence and power of God. The difficulty in which Locke's opinion originates is this. Brutes, as far as we can judge from theii* actions, have the faculty of think- ing : and the following dilemma naturally occurs to the mind on this subject. Either the brain of brutes is so constituted by the Deity as to have the power of thought ; or there is united with their bodies an immaterial principle, which uses the brain as an in- strument by which the power of thought is mani- fested. It does not appear to me that there is any 45 danger in the admission of either of those conclu- sions ; for, provided we do not make the power of thought independently and necessarily inherent in the brain, and provided we do not suppose the im- plied immaterial principle of brutes to be self-existent, and indestructible, and endued with moral responsi- bility, I do not see that the conclusions are either absurd, or in the slightest degree impious ; unless in- deed we dogmatically assert them. But we may avoid either conclusion, and solve the difficulty by the direct admission of the omnipotence -and universal presence of the Creator. Why may not every instinct and action of brutes be resolved into an immediate exertion of the power of God ? Some one perhaps may be scandalized at the supposition of such trivial interferences of God's power ; and may ask, " If then a horse start at a sud- " den sound, do you imagine that his muscles are set " in motion for that purpose by the hand of the " Deity ?" I would answer that I do ; and I see no absurdity or impropriety, even humanly speaking, in supposing, that he who in his. previous wisdom has determined to manifest a train of particular instincts and habits as characteristic of particular species of animals, should by his immediate power ordain, that the same instincts and the same habits should uni- formly be manifested in the same species and on si- milar occasions. We might ridicule as trifling, or doubt the common sense of that statesman, or that general, who should be at the pains of attempting to inform himself of the name and qualities and habits of every individual placed under his direction : and why? because from the natural limitation of our 46 powers we are unable to grasp in our comprehension or retain in our memories a vast multitude of objects; and therefore it behoves us to restrict the application of our faculties to those things that are of most im- portance. But this argument is completely annihilated, or rather absolutely excluded in the case of the Deity : and I feel convinced that Ave should do well con- stantly to keep in mind, and literally to believe, those words of our Saviour ; " that the very hairs of our " head are all numbered, and that not a sparrow falls " to the ground without the knowledge and permis- " sion of our heavenly Father." The question respecting the nature of the soul, and even respecting its existence, which has been mixed up with the foregoing, and which has been discussed occasionally with a degree of freedom that makes one shudder, I leave to the examination and defence of abler advocates. With respect to myself, satisfied of its incorporeal nature, and separable ex- istence from the body, however mysteriously united to it for a specific time and purpose, I should in the first place throw the onus prohandi on those who maintained the identity of the two : but, even if I thought the proof of their identity could be esta- blished, I should have no fear for the consequences ; for unless the materialist could also prove that the incongruous compound were self-existent and inde- structible, I do not see that he would have gained any ground on which he might take his stand with more assurance than before. With respect to the attempts of those to whom I have alluded, I would observe, that if ridicule or 47 irony were weapons which the defence of so funda- mental a truth as the existence of the. Deity required, they might be employed with peculiar force against such sophistry as has disgraced the cause of science on this point : but while I deprecate the use of those weapons on any, but especially on such an occasion, I know no terms of honest indignation too severe to mark our abhorrence of the profligacy of the attempts in question, provided they have been deliberately made. But on this point I beg leave to offer a few observa- tions, which, if made with a conciliatory spirit, may come with propriety from the person who holds the appointment of Lecturer in Anatomy and Physiology in this University. I have already stated the intention of these Lec- tures ; namely, to set before you the indications of wisdom and power in the Creator deduced from the skill and contrivance observable in his works. And I at the same time added, that although it should be admitted, that intellectual atheism had no real exist- ence in the world, and that the profession of it was an evil scarcely to be apprehended in this place ; yet the simple manifestation of the power and wis- dom of God, evidenced in the works of creation, is a subject worthy both of philosophical and religious contemplation. I shall not presume to insist farther on this topic, than to point out what appears to me an occasional deficiency in the mode of conducting the discussion respecting the question of professed or implied athe- ism. As far as my observation has gone, those who attack the positions of atheistical writers satisfy 48 themselves by an exertion of theii' power in expos- ing the fallacies of their opponents and reprobating the tendency of their conclusions : and it must be granted that the cause of religion, and consequently the good of society, has been essentially benefited by their exertions : nor does the occasion, logically con- sidered, call for an extension of the argument. But it will not, I think, be denied in this place, that however important the establishment of natural religion may be, the advancement of revealed reli- gion should be constantly the leading object of all our endeavours. Now it is very possible to conceive, and they must be very young, or must have inattentively made their observations on mankind, who are not convinced, that, in the process of reasoning on any subject, an ardent feeling and imagination may incautiously en- tertain opinions, the conclusions from which were nei- ther anticipated, nor would have been antecedently admitted by their author. It is possible also to con- ceive, that from the mere vanity and weakness of human nature, and without any sinister or malevo- lent intention, a writer might be induced to admit a conclusion which he would have originally ab- horred, rather than give up a position which he had once maintained : and in order to give authority to this assertion, I would call to your minds an observa- tion of Bishop Stillingfleet applicable to the present point. He says, that there are two great dangers in philosophizing ; namely, either for the sake of error, to disregard the truth; or through the fear of injur- ing truth, to admit or retain an error. The first of these dangers has been represented in the case abo\ e 49 supposed ; the second was exhibited to the world at the time that the papacy condemned formally and imprisoned the philosopher who maintained the motions of the heavenly bodies to be such as they- are now universally acknowledged to be. And some of the positions of geology which are now ac- knowledged, without any fear of their being at va- riance with the scriptural history of the creation and the universal deluge, were once in the same predica- ment. It is also very possible to conceive, that if a writer who has maintained a position that may involve an atheistical or any less objectionable conclusion, should be harshly taxed with the intention of insidiously re- commending such a conclusion, an opposition to the cause of truth might arise in his mind simply from the offensive manner in which his intentions had been represented ; a feeling of resentment to the per- son of his accuser might be converted into an oppo- sition to, or hatred of, the cause. I do not justify, I even wonder at the contracted feelings of any one engaged in philosophical investigations, which would lead to such an expression of resentment ; what I mean to insist on is, that if, by avoiding to give of- fence unnecessarily, we may be enabled to prevent the rise of any misconception, or any angry feeling in the breast of another, it is our duty to do so. Although therefore, to return to a former point, we are not called upon, in the logical conduct of our argument, to extend the subject from the considera- tion of atheism to that of revelation ; yet if, by con- ducting it in a mode recommended by the principles of revealed religion, we can be instrumental in recall- E 50 iiig another from a feeling of hostility to revelation, we are, in my opinion, bound to do so. It is due to the cause which ought ever to be up- permost in our minds, openly to state, that in mak- ing these remarks I have in my view a well known physiological work, which has given, and justly given, much regret, if not offence, to all those who are sin- cerely desirous of maintaining that cause. Though personally unacquainted with the author of that work at the time of its publication, I naturally perused it, and not without a considerable degree of attention ; and the brief opinion of it which I am about to ex- press, I am so far from fearing should rtieet the au- thor's eye, that did I think this representation would prevail more with him than his own reflections, I would not hesitate to make a personal appeal to him ; satisfied that the mode and terms in which I should make that appeal could not possibly be con- strued as an intention of giving offence. Of the ge- neral language and style of that work ; of the ex- tensive acquaintance which it evinces with the nu- merous writers on the subject of which it treats ; of the clear exposition of the facts there recorded ; and of the author's mode of arguing in general, it would be superfluous for me to say more, than that on those points he deservedly enjoys the approbation of the scientific world. I have a pleasure also in stating that in many parts he directly asserts, not only the existence, but even the power and wisdom, and I may add the beneficence of God ; and he maintains, with a constancy and an ardour which would do credit to the most zealous defender of the scriptures, the po- sition, that all mankind have descended from two in- 51 dividuals : and though I admit that this conclusion is a necessary consequence of his own physiological views, yet an uncandid reasoner might have kept that conclusion out of sight, or at least might have avoided to bring it so prominently forward, had he w^ished to invalidate the authority of the scriptures". But here I am constrained to add, O si sic omnia: and his most devoted admirers and even advocates must admit, that in some parts of his work there is a levity, and even apparent malevolence of expres- sion, on occasions where every word and even every tone ought to be in unison with feelings of good-will to our fellow-creatures, and of reverence to God. Bishop Butler, a writer more powerful perhaps in argument than has ever existed, has said of the Bi- ble, "that a book received as a revelation, by a great *' part of the civilized world, demands, as if by a " voice from heaven, to have its claims most serious- " ly examined into ; and that, before such examina- " tion, to treat it with any kind of scoffing and ridi- " cule, is an offence against natural piety." Now as the author whose physiological work I am consider- " ing admits the existence of the Deity, it is not beg- ging the question, and certainly he cannot be of- fended with me, if I presume that he possesses the feeling of natural piety. Since then the Bible affirms the divine origin of a priesthood, and inculcates the lief of the separate existence and the immortality of he soul, to insinuate that the teaching of such a belief is merely the trick of priestcraft, is certainly, both in itself and in its terms, a species of scoffing offensive to natural piety. And to ridicule the belief n the existence of the soul as united to the body, E 3 52 merely from the natural difficulty that must occur in the attempt to ascertain the precise moment when that mysterious union takes place, is equally un- worthy, not only of the feeling of natural piety or of philosophical seriousness, but even of good sense and good taste. I purposely abstain from bringing forward the passages or expressions to which I here allude, because from their total want of harmony with the style and spirit of this place, I might be supposed, in so doing, to be desirous rather of esta- blishing a triumph over an enemy, than of ingenu- ously reminding one, whom I would wish to consider as a friend, of his error. But I do not hesitate to say, that the passages to which I allude have been seri- ously detrimental to the good order of society : for it is a fact too well known, that the work contain- ing them has been edited in a form, and disseminated with an industry, that shew some general end was expected to be attained from its distribution : and it is clear, that that end was likely to tend towards the subversion of morality and religion, from the mere character of its editors ; even if we did not consider that, with the exception of the passages in question, there is scarcely a fact or a sentence in the whole book that would interest or even be intelligible to any one 'of that mass of readers before whom it has been so industriously brought. Too late for the remedy of this part of the mischief, it is not yet too late for tlic confession of his error : and if the author be not averse to the noble humiliation of acknowledging a fault, he may still prevent much of the future evil which may otherwise result to the junior members of his profession, from the perusal of new editions of that 53 work ; and, to suggest no higher motive, may secure the undivided approbation of his seniors and equals. But to return to our subject, namely, the consi- deration of the nervous system, we are under the necessity of confessing, that there is no part of ani- mal physiology involved in greater obscurity than this. For we cannot infer the use of the brain and nerves, either from their structure or from any changes apparent in them during their action ; whereas the uses of the bones, the muscles, the blood-vessels, and many other organs, are easily de- ducible from the circumstances above mentioned, i Nor can we, from the effects ostensibly produced by the action of the brain and nerves, collect any data I which are calculated to elucidate the nature of that j action. And, to complete the difficulty, the effects iiproduced are frequently of directly opposite charac- I ters. Thus apoplexy is sometimes fatal without any apparent deviation from the healthy state of the brain ; while speedy recovery sometimes succeeds jthe severest apoplectic symptoms. And again, with respect to paralysis, though commonly the diseased appearance in the brain is on the opposite side to that of the paralysed parts of the body, yet some- times the paralysis is on the same side with the dis- eased appearance in the brain. Neither are we assisted in our inquiry by the Contending theories of different physiologists. The functions of the nervous influence, as stated by Dr. Wilson PhiHp, are, to convey impressions to and Prom the sensorium ; to excite the muscular fibre ; :o separate and recombine the elementary parts of ;he blood in the formation of the secreted fluids ; E 3 54 I and to evolve caloric from the blood. Dr. Philip finds, moreover, experimentally, that after all signs of sensation and voluntary power have disappeared, and the animal is what we call dead, the nerves are still capable, by artificial stimuli, of conveying im- pressions to the muscles, and the muscles of per- forming their functions. The nerves also still pos- sess the power of decomposing and recombining the elementary parts of the blood, and also of evolving caloric from that fluid. Dr. Allison, on the other hand, says, that it ap- pears to be established, that no muscle of voluntary or involuntary action derives any thing from the nervous system which enables it to contract : so that the terms " nervous influence," and " nervous ener- " gy," in this their commonest sense, are absolutely without meaning. There is evidently, however, a close connection between the nervous and arterial systems ; for we continually see that they reciprocally alFect each other : and it is an anatomical fact, that the arte- ries in general are surrounded by a net-work of nerves. The evolution of animal heat is also apparently under the control of the nervous system ; for respi- ration has no power of generating heat, unless the functions of the brain are entire : and yet respira- tion, even though artificially suppoi'ted, produces the usual change in the colour of the blood, and the usual proportion of carbonic acid also, although the functions of the brain are entirely suspended. It is evident, moreover, that the nerves are the medium of sensation : for if a nerve be divided, the ■0 OO paii; to which that nerve is distributed becomes in- sensible : or if a nerve be mechanically compressed, the same effect is produced during compression. We know also that habit renders nervous impressions dull; and hence the love of novelty. And, lastly, we know that we can voluntarily augment the vivacity of our sensations : for who is not conscious of the difference between simply hearing and listening, and between simply seeing and gazing ; in other words, between the active and passive exertion of the senses ? - The nervous system is capable of a threefold di- vision, consisting of the brain ; the spinal marrow ; and the ganglia, as they are called, of the viscera : and these three parts respectively correspond to that division of the animal character which was adopted in a former part of this Lecture : the visceral gan- glia being principally appropriated to those parts^ with reference to which we may be considered as simply organized beings ; the spinal marrow, to our locomotive powers ; the brain, to our powers of sen- I sation and volition. Of the ganglial and spinal system, I do not pro- pose to speak more at large at present : but I shall enter a little more minutely into the consideration I of the cerebral system, from the obvious superiority of its importance. Of all the parts of the nervous system, taken col- lectively, the brain has been most generally consi- dered as the organ of the intellectual powers : and it has long been a favourite speculation, to endea- vour to ascertain what part of the brain is subser- vient to the existence and exercise of that degree of intellect and mental feeling which, in a greater or E 4 r 56 less degree, is possessed by many other animals as well as man. Of the existence of intellectual powers in brutes, no one, I conceive, can doubt, who has been at all accustomed to observe the characters and habits of animals : so that when in common lan- guage it is asserted, that man differs from other animals in possessing reason, while they are irra- tional, the term reason must be taken in its most extended sense, as implying the aggregate faculties of man, both moral and intellectual. I will not here insist on the evidence of the intel- lectual powers of brutes, as deducible from the ef- fects of what we call instinct ; because, in all those actions which are the result of instinct, animals ap- pear to be guided by a natural and irresistible im- pulse from within, which leads them to seek or to avoid that which will be either useful or injurious to them, and enables them to perform the most complicated acts, as the building of a nest, or the construction of a hive, though they may never even have seen the same acts performed by other indivi- duals of their species. I would rather insist on that evidence of their intellectual powers, which is de- rived from their conduct, when, in consequence of having been removed from their natural sphere of action, they are impelled by external and accidental circumstances. Thus the wariness of old animals in avoiding the pursuit or arts of an enemy, and the sagacity with which a practised hound wiU cut off an angle in order to shorten his distance, may be considered as proofs of a considerable degree of in- tellect in brutes. The playfulness of the young of most quadrupeds 57 may be regarded as no obscure proof of the exercise of the intellectual faculty which we call imagina- tion ; for the play of such young animals almost al- ways consists in the representation of mutual hosti- lity, though the real disposition at the time is any thing but hostile. A young puppy, under such cir- cumstances, snarls and bites, but with evident inten- tion not to hurt. ' Of the existence of mental feelings in brutes, there is still more decided proof than of the exist- ence of intellect. Thus the expression of joy in a dog at sight of his master is not to be mistaken ; the expression of fear in a horse at the sound of the Whip is equally unequivocal in its character. Again, ani- mals become attached not only to individuals of their own species, but to individuals of even a different Order or Class : and they evidently feel regret upon separation from their companions. On the supposition that the brain is the organ of the intellectual powers, physiologists have been led to compare the proportions of the whole and of va- rious parts of this organ in man and brutes. It has been supposed by some, that the intellectual facul- ties may be in proportion to the absolute size of the brain ; such an opinion being grounded on the fact, that the human brain is larger than that of the horse nr ox. But, on the other hand, the brain of the whale and of the elephant is larger than that of man ; though the intelligence even of the elephant bears no proportion to that of the human mind. Again, the Ijrain of the monkey and of the dog is smaller than that of the ox or the ass ; yet the former come much nearer to man with respect to their intellec- 58 tual faculties. Neither do the dispositions or quali- ties of animals appear to be connected with the ab- solute size of their brain ; for animals most different and even opposite in disposition may be ranged in the same class in respect to the size of their brain. For instance, the tiger and the deer ; and, among birds, the hawk and the pigeon. It would appear at first sight, that the comparison of the size of the brain with the size of the body would give a more uniform result. Thus, a croco- dile 12 feet in length, a serpent 18 feet in length, and a turtle that weighs from 300 to 5001bs. have each of them scarcely a sufficient quantity of sub- stance in their brain to weigh one drachm ; and the slight degree of intellectual power manifested by these animals corresponds with tliese proportions. But it will presently be shewn, that the proportional size of the brain is not a more certain criterion than the absolute size. Cuvier considers the brain in the human subject as equalling from about — to 3V of the bulk of the whole body. Dr. Gall thinks it equals from to of the bulk of the whole body. If we take the mean of those numbers, it wiU be about qr'o- In comparing the inferior animals with man in this respect, it appears that the proportion of the size of the brain to the size of the body is, Among the mammalia. In the orang-outang, as 1 to 96. In some species of monkey, 1 — 35. In the bat, - - - .1 — 96. mole, - - 1 — 36. dog, - - - 1 — 50—800. 59 In the fox, rat, mouse, elephant, ox, sheep, horse, - ass, dolphin, us ^mong birds. eagle, - - - goose, - - - duck, - sparrow, Among reptiles. tortoise, turtle, - - - snake, frog, Among fish. shark, tunny, pike, carp. to 200. — 76. — 43. — 500. — 860. — 270. — 400. — 254. — 50. 160. 360. 250. 30. 2240. 5688. 800. 170. 2496. 37440. 1300. 560. It appears from the foregoing statement, that not only do different genera of the same order differ very widely from each other in the proportion of their brain to their body, as the bat and the fox ; but that the proportion is sometimes inversely as the degree of intellect of the animal : thus, as far as we are ca- pable of judging, the intellect of the fox is infinitely greater than that of the bat, and yet the brain of the former, proportion ably to its body, is only one half 60 the size of the latter. The brain of the elejDhant, again, is smaller, in proportion to its body, than that of almost any other quadruped ; and yet what qua- druped exceeds the elephant in sagacity ? In some instances the disproportion is still greater in different species of the same genus, and even in different va- rieties of the same species : thus, in some dogs the brain compared with the body is as one to fifty, while in others it is as one to three hundi'ed ; a dispropor- tion six times as great as that between the bat and the fox. Again ; animals having been classed by modern physiologists in a scale regularly graduated from man, according to the degree, of their resemblance to him in some of the most important organs, it ap- pears that the brain of some of the genera of the lowest orders is proportion ably larger than that of some of the genera of the highest orders. Thus, in the first class, or the mammalia, the brain of the dolphin, which animal is in the lowest order of that class, is in proportion to its body four times as large as the brain of the fox, which is an animal of one of the highest orders. And the brain of the mouse and of the mole are nearly if not quite as large, in propor- tion to their body, as that of man. And the same circumstance occurs even in the second class, or birds ; for the brain of the sparrow is in proportion to the body as large as, nay even larger than that of man. Lastly, though it is unnecessary, and would be tedious to enter further into the detail of this part of the subject, there does not appear to be any con- nexion between the degree of the intellectual facul- 61 ties and the mutual proportions of the two consti- tuent parts of the brain, the cerebrum namely, and the cerebellum ; or between the degree of the intel- lectual faculties and the mutual proportions of the brain and the nerves. So that it appears, from a re- view of what has been advanced, that no criterion of the degree of intellect is found in the relative size of the brain of different animals ; nor in the size of the brain compared with that of the body ; nor in the relative size of the cerebrum either to the cerebel- lum or to the nerves. In the midst of these difficulties, a new theory, or at least a newly modified theory, arose, a few years since, under the auspices of Dr. Gall, a physician of Vienna : and as the consideration of his system ex- cited a great degree of attention among physiolo- gists, it will be right here to mention it. The simple enunciation of Dr. Gall's theory is this, that " the brain in general is the instrument by " which the intellectual faculties, and the moral " sentiments and propensities, are manifested ; par- " ticular parts of it being the organs of those several " faculties, sentiments, and propensities: and that ac- " cording to the state of these organs at any given " period of a man's life will be the faculties, senti- " ments, and propensities of each individual." To those who have objected to this theory, that it leads towards the doctrines of fatalism, and the ma- terial nature of the soul, it has been answered ; first, that as, according to the theory, no individual who is endued with intellect is deficient in the organs of those moral sentiments, which if cultivated will be sufficient to counteract whatever bad propensities 62 he may have^ the theory cannot consistently he ac- cused of inculcating the doctrine of fatalism : and se- condly, that without inquiring what the soul is, or in what manner it is united to the body in this life, (which Dr. Gall considers as questions not only be- yond the comprehension of human reason, but totally unconnected with his inquiries,) the theory merely investigates the material conditions of that part of the body by which the soul is affirmed to manifest itself to our observation. In examining the theory of Dr. Gall, I shall first state his opinions respecting the anatomical struc- ture of the brain and nerves ; and then, some of the facts on which his theory is founded. He rejects the terms cortical and medullary, as applied to the substance of the two distinct parts of the cerebrum and cerebellum ; and calls the former, simply from its colour, the grei/ substance ; in which he is justified from the fact, that it occurs in several parts in the interior of the brain, and thus therefore loses its analogy to the bark of a tree : the latter, or medullary part, he calls ^b7'ous substance, from its structure ; of the character of which he has satisfied other anatomists as well as himself; and which, in some parts of the brain, may be readily demonstrated even to those who have never been previously accustomed to dissection. The grey substance he considers as the matrix or source of the fibrous ; and he draws tliis conclusion from the analogy of gangha, whicli, being themselves of the same nature as the grey substance, he finds are always large in proportion to the white nervous fibres which issue from them ; which statement is corroborated bv Scarpa and otiier I 63 able anatomists : and he supports his opinion by the additional fact, that in other parts of the nervous system, both in the spinal marrow and in the brain, wherever the fibres are enlarged or multiplied, there is a correspondent supply of the grey substance. With respect to the several nervous systems of the body, namely, the visceral ganglia, the spinal marrow, the nerves of voluntary motion, the nerves of the senses, and lastly, the great mass of the brain, he supposes that, though all connected by branches of communication, they are otherwise independent of each other. His arguments relating to the independence of these several parts are as follow : first, as the visce- ral ganglia are the only part of the nervous system, in general, possessed by some animals, they cannot in those animals be derived either from a spinal marrow or a brain : and as the visceral ganglia are distributed to the same parts in those animals which they supply in man, and in numerous orders of other animals, it hence becomes probable, that they are in man also independent of the spinal marrow and brain: besides which, the fibres of the visceral sys- tem are evanescent both at their upper and lower extreme points, and thus do not appear to arise from any other source than themselves. That the spinal marrow is not a continuation of the brain, he argues both from the want of propor- tion in the brain to the spinal marrow, and from the irregularity of its diameter in different parts : whereas were it a continuation of the brain, it ought to diminish in its diameter in proportion as it sent off fresh branches of nerves. 64 With respect to the several pairs of nerves which are seen upon exposing to view the lower surface of the brain, it is admitted by many anatomists of ac- knowledged accuracy, that none of them, excepting the olfactory and optic, originate from the hemi- spheres of the cerebrum or cerebellum : l3ut Gall thinks that even these are not derived from either of those parts. By anatomists in general the olfactory nerves are supposed to originate from the corpora striata ; the optic nerves from the thalami nervorum opticorum : but it is asserted by Dr. Gall, that in some animals, even of the higher orders, which have not the sense of smelling, the corpora striata are yet present; in which case it cannot be said that those parts are destined to supply the nerves of smell : and with re- spect to the thalami nervorum opticorum he ob- serves, that in the horse, ox, and stag, the thalami themselves are much smaller than in man, though the optic nerves of these animals are much larger, which would hardly happen were those parts the source of those nerves : besides which, it may be clearly shewn from the brain of birds, that the optic nerves do not belong to the parts called the thalami. j Experiments also have been made on living animals, shewing that the loss of those parts from which the nerves of smell and sight are supposed to originate does not affect those senses. Thus the greatest part of the hemispheres of the brain was cut out in the , instances of some hens, pigeons, and rabbits, and yet I the animals manifested distinctly the sense of hear- : ing and seeing. It appears then, that, with the doubtful exception 65 of the olfactory and optic nerves, not a single nerve of the whole body is derived from the hemispheres of the cerebrum or cerebellum ; for the organs of the other senses, and all the muscles of voluntary mo- tion, together with the whole mass of the intestines, and the heart, and the lungs, &c. are supplied either by the visceral ganglia or the spinal marrow, or that portion of it called the medulla oblongata. . Either then the great mass of the brain is allotted in a most anomalous disproportion to the two senses of smelling and seeing, which in many animals are comparatively weak ; or, if it does not supply the nerves of seeing and smelling, there is no part of the body which it does apparently supply with nerves : and then the conclusion, which is by no means pe- culiar to Gall, and which the best and wisest men have admitted, presses upon us with peculiar force, that the brain is exclusively the instrument of the immaterial part of our present existence. In examining the various orders of animals, it is observable that there are some in which not any nerves are discernible : there are others in which only visceral ganglia are found : as we rise in the scale of animal life, nerves of voluntary motion are added; afterwards a spinal marrow and a brain of very simple construction, which by the superaddition of parts becomes gradually more complicated, till at length it closely resembles that of man : but still there are parts of the brain in man which are not found in other animals ; though man has all those essential parts which the most perfect animals pos- sess. Whatever be the cause, it is very evident, that, while F 66 in most of those animals which have no hrain, there are few if any signs of intelligence ; in those animals which have a brain, the signs of intelligence are stronger and more obvious in proportion as they re- semble man in the structure of their brain. And in man himself, if those parts by which he essentially differs from the brutes in the structure of his brain be defective, the manifestations of his feelings and intellectual faculties are also in general defective, as is the case with idiots. But if the brutes ap- proximate in the degree of their intelligence to man, in proportion as they approximate to him in the structure of certain parts of their brain ; is it not fair to infer, or rather does it not necessarily follow, that those parts of the human brain which are not found in other animals are subservient to the peculiar faculties of man ? It is in the hemispheres that the huriian brain exceeds in size the lirain of all other animals, even of the elephant ; the total size of the brain of which animal is only greater than that of man, because certain nervous fasciculi which are ap- propriated to particular parts, are enlarged corre- spondently to the energies of those parts. Thus tlie nerve communicating with the trunk of the elephant is nearly as thick as a man's arm. There are many interesting conclusions, particu- larly with respect to paralytic affections, which Gall has drawn from his view of the anatomical structure of the brain, the consideration of which belongs not particularly to the present subject : but as from Gall's dissection it appears that the several organs of the faculties are double, corresponding organs being found in each of the hemispheres of the brain, it has 67 been objected to his system, on that ground, that facts militate against' his theory, inasmuch as con- sciousness, or the exercise of any particular faculty or sentiment is single, while the organs are double : but his answer appears satisfactory ; for is it not so with the senses of hearing and seeing, the organs of which are double, but the impressions on the mind single ? There are many phenomena connected with the moral and the intellectual faculties of man, both in , a healthy and diseased state, which by shewing the mutual influence of the two distinct parts of our na- ture, the soul and the body, render it probable that the energies of the one, although it be itself im- material, may be manifested by means of a material instrument. The existence of that mutual influence above men- tioned, which indeed we might expect from their close though mysterious union, cannot be denied. Thus, grief or expectation destroys appetite ; mental application to any favourite pursuit makes us insen- sible of the want of food ; insanity renders us insen- sible of cold : and on the other hand, a disordered state of the digestive organs evidently impedes the free exercise of the mental powers. Intoxication confuses the memory and judgment; and the re- peated abuse of wine permanently debilitates the mind, and often terminates in confirmed insanity. The state of the air affects many individuals to a de- gree inconceivable to those who are not thus subject to its influence. Endemic ague and epilepsy have been j each cured by the effect of fear, j The idea that this connexion of the soul and body I may be traced in the conformation of the latter is F 2 68 by no means new ; as is evident from the anecdote of the unfavourable judgment passed on the disposi- tion of Socrates from the character of his counte- nance, which is too generally known to need a repeti- tion. And Aristotle has even entered into some de- tails on the forms and shades of colour in the hair and features, as indicative of particular temperaments or constitutions of the mind. And it is hardly a ques- tion, whether every individual is not accustomed in some degree to decide on character from the fea- tures, the colour of the hair, &c. independently of that expression of the countenance which rather marks the actually existing state of the mind than the latent disposition of it. Shakespear has several references to indications of personal character, as de- pending on the form of the countenance, or colour of the hair, &c. " In attempting to point out distinct organs for the several intellectual faculties and moral sentiments and propensities. Dr. Gall has advanced much be- yond his predecessors. And though, as far as I can judge, he has failed in all but one or two instances, yet he has supported the general principle of his theory by arguments which it seems difficult to re- fute : and that principle indeed, namely, that there are distinct organs for the several faculties, had been previously admitted by Haller, and also by Willis, who was of tliis University in the reign of Charles the First ; both of them not less distinguished for their private virtues and religious character, than for their knowledge and intellectual talents. Th( " Vide Tempest, Act IV. Scene 3. Two Gentlemen of N'eronfi, Aci IV. Scene 4. Ant. and Cleop. Act III. Scene 4. with Steevens's note 69 same doctrine appears to have been broached also long ago by the Arabian physicians. Dr. Cooke, in his Treatise on Nervous Diseases, has a note in page 20, vol. i. in which this fact is stated on the authority of Laurentius in the following words : " Universa Ara- " bum schola mansiones multas in cerebro statuit, et " singulis facultatibus singulas sedes assignat." It appears from Gall's own account that he was originally led to his peculiar train of thought by ob- serving the difference of talents and character in his own brothers and sisters, and in other children with whom he happened to be at school ; some of whom, though under perfectly similar circumstances of edu- cation with the rest, were much quicker in appre- hending what was taught them : and further, by observing in different individuals of the same spe- cies of animals, as dogs, that some were fierce, some mild. Again, in birds of the same species, that some , continued to sing their own notes only, while others would listen to and imitate artificial music. In the last mentioned instance particularly he ar- gued, that the difference could not arise from the gi-eater or less degree of perfection in the organ of hearing, which was the same in both, but must be looked for in the brain, to which the organ of hear- ing conveys sounds; which are judged of in the brain, and not in the ear itself. There are, more- over, numerous instances which shew, that the sense of hearing is by no means in proportion to the de- gree of perfection in the construction of the ear. The dog hears with indifference the sweetest me- lody ; and yet the construction of his ear is more perfect than that of any, even the most musical 70 birds. And on this point Gall asks, if the organ of hearing determined the power of singing, why should the female bird be mute, seeing that in this part of its bodily construction it differs not from the male ? It is equally observed, that in men the talent for music is not in proportion to the delicacy of the or- gan of hearing. In aUuding to such manifestations of partial ta- lent as are occasionally exhibited in certain indivi- duals at an early period of life, who have been ob- served to be children in every thing but in the ex- ertion of their peculiar talent. Dr. Gall asks, how should the different faculties of the mind be in un- equal proportions in the same individual, if there were only one and the same organ for all the facul- ties ? Dr. Spurzheim on the same point observes, " One " man has an excellent verbal memory, but is inca- " pable of combining two philosophical ideas. An- " other is a great painter, but a bad musician : and " so on. But if the same organ manifested every " faculty, how should the mind, by means of the " same instrument, manifest one faculty in its per- " fection, and another in a very limited manner ?" Partial insanity and partial idiotcy are among the circumstances which Gall considers as favouring his doctrine. The frequency of the former must be a fact well known to all ; the latter is not uncommon ; and even persons of considerable intelligence occa- sionally exhibit very obscure traces of this or that particular faculty. He also draws an argument in support of his the- ory, from the partial fatigue produced on the mind 71 by long protracted study , which fatigue is relieved by changing the object of study. Now, if the brain, he adds, were a single organ performing all the func- tions of the mind, why should not the organ be more fatigued by this new form of study ? Other arguments in favour of his system he draws from the temporary effects produced by inflamma- tion on the state of the mental powers : in the case, for instance, of idiots, who, during the inflamma- tory action, have manifested a considerable degree of understanding ; but after the cessation of the in- flammatory action, have relapsed into their former state of fatuity. In such instances the mental fa- culties, which had been previously in a state of fa- tuity, are possibly rendered for the time rational in consequence of a degree of excitement which, in in- dividuals not labouring under fatuity, would have probably produced delirium : but, as a rational state of the faculties may be considered, to use a mathe- matical expression, as a mean proportional to fa- tuity and delirium, it might be expected that the same cause which would raise a rational state of the faculties to delirium, would raise an idiotic only to a natural state. In the same manner, wine is ob- served to modify the characters of individuals of dif- ferent temperatures. " It keeps the unhappy from sinking, " And makes e'en the valiant more brave." It would require many hours to enter into the detail of this most interesting part of Dr. Gall's sys- tem. I must be content, therefore, to have intro- duced the subject to the minds of those who happen 72 not to have reflected on it before : and with respect to the merits of that system, I think it may be af- firmed with truth, that, considered as an abstract philosophical speculation, it is highly ingenious and interesting, and founded upon unobjectionable prin- ciples ; that in the extent to which the author has carried those principles, the doctrine becomes ridi- culously absurd ; and that in its general applica- tion, it is not only useless, but of a positively mis- chievous tendency : for without the help of this sys- tem every man of common sense has sufficient data from which to judge of the character of those with whom he associates ; and it is evidently more safe to judge of others by their words and actions, and conduct in general, than to run the risk of con- demning the character of an individual from the indication of some odious organ, the activity of which may have been subdued by the operation of religious motives. With respect to ourselves indeed, the study of the system may be attended sometimes with the hap- piest consequences : for if, from the contemplation of it, we can be strengthened in our conviction of the fact, which both reason and revelation teach us, that each individual is liable to particular tempta- tions depending on his specific temperament, we shall thus have one additional memento of our frailty, one additional incentive to watch over and combat the sin which doth so easily beset us.