^T^ 5W ^tv>\\^ IMAGE EVALUATION TEST TARGET (MT-S) ^ .4. , V 6^ *>, ,. y WITH A POSTHUMOUS ESSAY ON INSTINCT. BT OHAELES DARWIN, M.A., LL.D., F.rv.S. NEW YORK: D. APPLETON AND COMPANY, 78 FIFTH AVENUE. 1900. ^UG 2 6 1966 318940 PREFACE. It will be observed that the title of this volume is " Mental Evolution in Animals." The reasons which have led me to depart from my intention (as expressed in the Preface of " Animal Intelligence") to devote the present essay to mental evolution in man as well as in animals, are given in the introductory chapter. It may appear that in the following pages a somewhat disproportionate amount of space has been allotted to the treatment of Instinct; but, looking to the confusion which prevails with reference to this important branch of psychology in the writings of our leading authorities, I have deemed it desirable to consider the subject exhaustively. It is, I think, desirable briefly to explain the circum- stances under which I have been enabled to produce so much hitherto unpublished material from the MSS of the late Mr. Darwin, and also to state the extent to which I have availed myself of such of this unpublished material as came into my hands. As I have already explained, in the Preface of " Animal Intelligence," Mr. Darwin himself gave me all his MSS relating to psychological subjects, with the request that I should publish any parts of them that I chose in my works on Mental Evolution. But after his death I felt that the cir- cumstances with reference to this kind oflFer were changed, and that I should scarcely be justified in appropriating so much material, the value of which had become enhanced. I therefore published at the Linnean Society, and with the consent of Mr. Darwin's family, as much of this material as PBEFACB. could be published in a consecutive form ; this is the chapter which was intended for the " Origin of Species," and which, for the sake of reference, I have added as an Appendix to my present work. For the rest, the numerous disjointed para- graphs and notes which I found among the MSS I have woven into the text of this book, feeling on the one hand that they were not so well suited to appear as a string of disconnected passages, and on the other hand that it was desirable to publish them somewhere. I have gone through all the MSS carefully, and have arranged so as to introduce every passage in them of any importance which I find to have been hitherto unpublished. In no case have I found any reason to suppress a passage, so that the quotations which I have given may be collectively regarded as a full supple- mentary publication of all that Mr. Darwin has written in the domain of psychology. In order to facilitate reference, I have given in the Index, under Mr. Darwin's name, the numbers of all the pages in this work where the quotations in question occur. 18, CosywAXii Tebbace, Beqbnx'b Park, London, N.W., November, 1883. CONTENTS. Pbbfacb 1 Inteodpctiow 5 Chaptee I. The Cbitkeion of Mixd 16 „ II. The Steuctuee and Functions of Nebve-Tissce 24 „ III. The Phtsioal Basis of Mind 31 „ IV. The Root-peinciples op Mind 47 „ V. EXPIANATION OF THE DiAOEAU 63 „ VI. Consciousness 70 „ VII. Sensation 78 „ VIII. Pleasuees and Pains, Memout, and Association OP Ideas 103 „ IX. Peeception 123 „ X. Imagination 142 „ XI. Instinct 159 „ XII. Instinct (continued). Origin and Development of Instincts .. .. 177 „ XIII. Instinct (continued). Blended Origin, or Plasticity of Instinct. . . . 200 „ XIV. Instinct (continued). Modes in which Intelligence determines the Varia- tion of Instinct in Definite Lines . , . . 19 „ XV. Instinct (continued). Domestication ., ,, ',, ,, ,, 230 „ XVI. Instinct (continued). Local and Specific Varieties of Instinct .. ., 243 „ XVII. Instinct (continued). Examination of the Theories of other Writers on tlie Evolution of Instinct, with a General Sum- mary of the Theory here Set Forth .. .. 256 ^ CONTENTS. Chaptbb XVIII. lN8TiircT (continued). Oa«e» of Special Difflcultj with Regord to the Foregoing Theory of the Origin and Develop- ment of InstinotB 273 II XIX. Rbason ,, ,, 818 n XX. Animal Emotions, and Summabt of Intel* • LEOTCAt FaCCLTIBS 841 Apmndix „ 863 VAQM the op- • • 273 • t 818 • • • 841 • • 863 i2. 49 48 47 46 45 44 43 42 41 40 39 ir 36 3S 34 33 32 3' 30 PxoDUOTt OF Emotional OivcLorMtNT. 29 W 27 26 25 24 23 22 21 20 19 «7 16 'S 14 13 12 II 10 Shame, Kemorse, JJeceitrulnus, Liulicroiis. Revenge, Rag^. Grief, Hate, Cruelty, Benevolence. Kmtilation, Pride, Resentment, Aesthetic love of ornament. Terror. Sympathy. Aflection. Jealousy, Anger, Play. Parental aflection, Social feeiiags, Sexual selectioo, Pugnacity, Industry, Curiosity. Sexual emotions without sexual selection. Surprise, Fear. INTRODUCTION. In the family of the sciences Comparative Psychology may claim nearest kinship with Comparative Anatomy ; for just as the latter aims at a scientific comparison of the bodily structures of organisms, so the former aims at a similar com- parison of their mental structures .♦ Moreover, in the one science as in the other, the first object is to analyze all the complex structures with which each has respectively to deal. When this analysis, or dissection, has been completed for as great a number of cases as circumstances permit, the next object is to compare with one another all the structures which have been thus analyzed ; and, lastly, the results of such comparison supply, in each case alike, the basis for the final object of these sciences, which is that of classifying, with reference to these results, all the structures which have been thus examined. In actual research these three objects are prosecuted, not successively, but simultaneously. Thus it is not necessary in either case that the final object—that of classification- should wait for its commencement upon the completion of the dissection or analysis of every organism or every mental structure that is to be found upon the earth. On the con- trary, the comparison in each case begins with the facts that are first found to be comparable, and is afterwards pro- gressively extended as knowledge of additional facts becomes more extensive. Now each of the three objects which I have named affords • The word "structure" is used in a metaphorical sense when appUed to xoind, but the usage is convenient. 6 INTRODUCTION. in its pursuit many and varied points of interest, which are quite distinct from any interest that may be felt in the attain- ment of the ultimate end — Classification. Thus, for example, the study of the human hand as a mechanism has an interest apart from all considerations touching the comparison of its structure with that of the corresponding member in other animals ; and, similarly, the study of the psychological facul- •ties in any given animal has an interest apart from aU con- siderations touching their comparison with the corresponding faculties in other animals. Again, just as the comparison of separate bodily members throughout the animal series has an interest apart from any question concerning the classification of animal bodies to which such comparison may ultimately lead, so the study of separate psychical faculties throughout the animal series (including, of course, mankind) has an interest quite distinct from any question concerning the classification of animal minds to which such comparison may ultimately lead. Lastly, around and outside all the objects of these sciences as such, there lies the broad expanse of General Thought, into which these sciences, in all their stages, throw out branches of inference. It is needless to say that of late years the interest with which the unpre- cedented growth of these branches is watched has become so universal and intense, that it may be said largely to have absorbed the more exclusive sources of interest which I have enumerated. With the view of furthering these various lines of interest, I have undertaken a somewhat laborious enquiry, part of which has already been published in the International Scientific Series, and a further instalment of which is con- tained in the present volume. The two works, therefore, " Animal Intelligence " and " Mental Evolution in Animals," although published separately, are really one ; and they have been divided only for the following reasons. In the first place, to have produced the whole as one volume would have INTRODUCTION. *J been to present a book, if not of inconvenient bulk, at least quite out of keeping with the size of all the other books in the same series. Moreover, the subject-matter of each work, although intimately related to that of the other, is never- theless quite distinct. The first is a compendium of facts relating to Animal Intelligence, which, while necessary as a basis for the present essay, is in itself a separate and distinct treatise, intended to meet the interest already alluded to as attaching to this subject for its own sake ; while tlie second treatise, although based upon the former, has to deal with a wider range of subject-matter. It is evident that, in entering upon this wider field, I shall frequently have to quit the narrower limits of direct obser- vation within which my former work was confined ; and it is chieiiy because I think it desirable clearly to distinguish between the objects o^ Comparative Psychology as a science, and any inferences or doctrines which may be connected with its study, that I have made so complete a partition of the facts of animal intelligence from the theories which I believe these facts to justify. So much, then, for the reasons which have led to the form of these essays, and the relations which I intend the one to bear to the other. I may now say a few words to indicate the structure and scope of the present essay. Every discussion must rest on some basis of assumption ; every thesis must have some hypothesis. The hypothesis which I shall take is that of the truth of the general theory of Evolution : I shall assume the truth of this theory so far as I feel that all competent persons of the present day will be prepared to allow me. I must therefore first define what degree of latitude I suppose to be thus conceded. I take it for granted, then, that all my readers accept the doctrine of Organic Evolution, or the belief that all species of plants and aniniels have had a derivative mode of origin by ^^7-°^ ^^^^^'^i /'' ^^^^^'> and, moreover, that one great law or 8 INTRODUCTION. method of the process has been natural selection, or survival of the fittest. If anyone grants this much, I further assume that he must concede to me the fact, as distinguished from the manner and history of Mental Evolution, throughout the whole range of the animal kingdom, with the exception of man. I assume this because I hold that if the doctrine of Organic Evolution is accepted, it carries with it, as a necessary corollary, the doctrine of Mental Evolution, at all events as far as the brute creation is concerned. I'or throughout the brute creation, from wholly unintelligent animals to the most highly intelligent, we can trace one continuous gradation; so that if we already believe that all specific forms of animal life have had a derivative origin, we cannot refuse to believe that all the mental faculties which these various forms present must likewise have had a derivative origin. And, as a matter of fact, we do not find anyone so unreasonable as to maintain, or even to suggest, that if the evidence of Organic Evolution is accepted, the evidence of Mental Evolution, within the limits which I have named, can consistently be rejected. The one body of evidence therefore serves as a pedestal to the other, such that in the absence of the former the latter would have no locus standi (for no one could well dream of Mental Evolution were it not for the evidence of Organic Evolution, or of the transmutation of species) ; while the presence of the former irresistibly suggests the necessity of the latter, as the logical structure for the support of which the pedestal is what it is. It will be observed that in this statement of the case I have expressly excluded the psychology of man, as being a department of comparative psychology with reference to which I am not entitled to assume the principles of Evolu- tion. It seems needless to give my reasons for this exclusion For it is notorious that from the hour when Mr. Darwin and Mr. Wallace simultaneously propounded the theory which has exerted so enormous an influence on the thought of tha I! INTRODUCTION. 9 present century, the difiference between the views of these two joint originators of the theory has since been shared by the ever-increasing host of their disciples. We all know what that difference is. We all know that while Mr. Darwin believed the facts of human psychology to admit of being explained by the general laws of Evolution, Mr. Wallace does not believe these facts to admit of being thus explained. Therefore, while the followers of Mr. Darwin maintain that all organisms whatsover are alike products of a natural genesis, the followers of Mr. Wallace maintain that a distinct exception must be made to this general atement in the case of the human organism ; or at all events in the case of the human mind. Thus it is that the great school of evolutionists is divided into two sects ; according to one the mind of man has been slowly evolved from lower types of psychical exist- ence, and according to the other the mind of man, not having been thus evolved, stands apart, sui generis, from all other types of such existence. Now assuredly we have here a most important issue, and as it is one the discussion of which will constitute a large element of my work, it is perhaps desirable that I should state at the outset the manner in which I propose to deal with it. The question, then, as to whether or not human intelli- gence has been evolved from animal intelligence can only be dealt with scientifically by comparing the one with the other, in order to ascertain the points wherein they agree and the points wherein they differ. Now there can be no doubt that wlien this is done, the difference between the mental faculties of the most intelligent animal and the mental faculties of the lowest savage is seen to be so vast, that the hypothesis of their being so nearly allied as Mr. Darwin's teaching implies, appears at first sight absurd. And, indeed, it is not" until we have become convinced that the tlieory of Evolution can alone afford an explanation of the facts of human anatomy 10 INTRODUCTION. that we are prepared to seek for a similar explanation of the facts of human psychology. But wide as is the difference between the mind of a man and the mind of a brute, we must remember that the question is one, not as to degree, but as to kmd ; and therefore that our task, as serious enquirers after truth, is calmly and honestly to examine the character of the diff'erence which is presented, in order to determine whether It IS really beyond the bounds of rational credibility that the enormous interval which now separates these two divisions of mind can ever have been bridged over, by numberless inter- mediate gradations, during the untold ages of the past. While writing the first chapters of the present volume I intended that the latter half of it should be devoted to a con- sideration of this question, and therefore in "Animal Intelli- gence" I said that such would be the case. But as the work proceeded it soon became evident that a full treat- ment of this question would require more space than could be allowed in a single volume, without seriously curtailing both the consideration of this question itself and also that of Mental Evolution, as this is exhibited in the animal kingdom. I therefore determined on restricting the present essay^'to a consideration of Mental Evolution in Animals, and on reserv- ing for subsequent publication all the material which I have collected bearing on Mental Evolution in Man. I cannot yet say how long it will be before I can feel that I am justified in publishing my researches concerning this branch of my subject; for the more that I have investigated it, the more have I found that it grows, as it were, in three dimensions— m depth, width, and complexity. But at whatever time I shall be able to publish the third and final instalment of my work, it will of course rest upon the basis supplied by the present essay, as this rests upon the basis supplied by the previous ona It being understood, then, that the present essay is restricted to a consideration of Mental Evolution in Animals INTRODUCTION, 11 I should like to have it also understood that it is further restricted to the psychology as distinguished from the philo- sophy of the subject. In a short and independent essay published elsewhere .♦ I have already stated my views con- cerning the more important questions of philosophy into which the subject-matter of psychology is so apt to dip • but here it is only needful to emphasize the fact that these two strata of thought, although assuredly in juxtaposition, are no less assuredly distinct. My present enquiry belongs only to the upper stratum, or to the science of psycholocry as dis- tinguished from any theory of knowledge. I am in no wise concerned with " the transition from the object known to the knowing subject," and therefore I am in no wise concerned with any of the philosophical theories which have been pro- pounded upon this matter. In other words, I have every- where to regard mind as an object and mental modifications as phenomena; therefore I have throughout to investigate the process of Mental Evolution by what is now generally and aptly termed the historical method. I cannot too strongly impress upon the memory of those who from previous reading are abie to appreciate the importance of the distinction, that I thus intend everywhere to remain within the borders of psychology, and nowhere to trespass upon the grounds of philosophy. ^ On entering so wide a field of enquiry as that whose limits I have now indicated, it is indispensable to the continuity of advance that we should be prepared, where needful, to supple- ment observation with hypothesis. It therefore seems desira- ble to conclude this Introduction with a few words both to explain and to justify the method which in this matter I intend to follow. It has already been stated that the sole object of this work is that of tracing, in as scientific a manner as possible the probable history of Mental Evolution, and therefore, of ■^ Nineteenth Centurif, December, 1882, r .? I 12 INTRODUCTION. course, of enquiring into the causes which have determined it. So far as observation is available to guide us in this enquiry, I shall resort to no other assistance. Where, however, from the nature of the case, observation fails us, I shall proceed to inference. But though I shall use this method as sparingly as possible, I am aware that criticism will often find valid ground to object — ' It is all very well to map out the sup- posed genesis of the various mental faculties in this way, but we require some definite experimental or historical proof that the genesis in question actually did take place in the order and manner that you infer,' Now, in answer to this objection, I have only to say that no one can have a more lively appreciation than myself of the supreme importance of experimental or historical veri- fication, in all cases where the possibility of such verification is attainable. But in cases where such verification is not attainable, what are we to do ? We may clearly do either of two things. We may either neglect to investigate the sub- ject at all, or we may Jo our best to investigate it by employ- ing the only means of investigation which are at our disposal. Of these two courses there can be no doubt which is the one that the scientific spirit prompts. The true scientific spirit desires to examine everything, and if in any case it is refused the best class of instruments wherewith to conduct the examination, it will adopt the next best that are available. In such cases science clearly cannot be forwarded by neglect- ing to use these instruments, while her cause may be greatly advanced by using them with care. This is proved by the fact that, in the science of psychology, nearly all the con- siderable advances which have been made, have been made, not by experiment, but by observing mental phenomena and reasoning from these phenomena deductively. In such cases, therefore, the true scientific spirit prompts us, not to throw away deductive reasoning where it is so frequently the only INTRODUCTION. 13 instrument available, but rather to carry it with us, and to use it as not abusing it. And this, as I have said, is what I shall endeavour to do. No one can regret more than myself that the most interesting of all regions of scientific enquiry should happen to be the one in which experiment, or inductive verification, is least of all applicable ; but such being the case, we must take the case as we find it, use deductive reasoning where we clearly see that it is the only instrument available, but use it to as limited an extent as the nature of our subject permits. |l !i MENTAL EVOLUTION IN ANIMALS. CHAPTER I. The Criterion of Mind. The subject of our enquiry being Mental Evolution, it is desirable to begin by understanding clearly what we mean by Mind,* and then defining the conditions under which known Mind is invariably found to occur. In this chapter, therefore, I shall deal with what I take to be the Criterion of Mind, and shall then pass on in the next chapter to a consideration of the objective conditions under which alone Mind is observed to exist. It is obvious, then, to start with, that by Mind we may mean two very different things, according as we contemplate it in our own individual selves, or as manifested by other beings. For if I contemplate my own mind, I have an imme- diate cognizance of a certain flow of thoughts and feelings, which are the most ultimate things — and, indeed, the only things — of which I am cognizant. But if I contemplate Mind in other persons or organisms, I can have no such immediate cognizance of their thoughts and feelings; I can only infer the existence of such thoughts and feelings from the activities of the persons or organisms which appear to manifest them. Thus it is that by Mind we may mean either that which is subjective or that which is objective. Now throughout the present work we shall have to consider Mind as an object ; and therefore it is well to remember that our only instrument of analysis is the observation of activities • It was necessary in my work on Animal Intelligence briefly to touch on this question j therefore the parts of the analysis which are common to the two works I shall render as much as pobsible in the same words. 16 MENTAL EVOLUTION IN ANniALS. which we infer to be prompted by, or associated with, mental antecedents or accompaniments analogous to those of which we are directly conscious in our own subjective experience. That is to say, starting from what I know subjectively of the operations of my own individual mind, and of tlie activi- ties wliicH in my own organism these operations seem to prompt, I proceed by analogy to infer from the observable activities displayed by other organisms, the ftict that certain mental operauions underlie or accompany these activities. From this statement of the case it will be apparent tliat our knowledge of mental activities in any organism other than our own is neither subjective nor objective. That it -s not subjective I need not wait to show. That it is not objective may be rendered obvious by a few moments' reflec- tion. ^ For it is evident that mental aciivities in otlier organisms can never be to us objects of direct knowledge ; as I have just said, we can only infer their existence from the objective sources supplied by observable activities of such organisms. Therefore all our knowledge of mental activities other than our own really consists of an inferential inter- pretation of bodily act'vities — this interpretation being founded on our subjective knowledge of our own mental activities. By inference we project, as it were, the known patterns of our own mental chromograph on what is to us the otherwise blank screen ox another mind; and our only knowledge of the processes there taking place is really due to such a projection of our own subjectively. This matter has been well and clearly presented by the late Professor Clifford, who has coined the exceedingly appropriate term eject (in contradistinction to subject and object), whereby to designate the distinctive character of a mind (or mental pro- cess) other than our own in its relation to our own. I shall therefore adopt this convenient term, and speak of all our possible knowledge of other minds as ejective. Now in this necessarily ejective method of enquiry, what is the kind of activities that we are entitled to regard as indicative of ]\Iind ? I certainly do not so regard the flowing of a river or the blowing of a wind. Why ? First, because the subjects are too remote in kind from my own organism to admit of my drawing any reasonable analogy between them and it; and, secondly, because the activities which they present are invariably of the same kind under the same cir- THE CRITERION OP MIND. ^f^ Consciousness. In other wor^^^^^ L^. 'Tv "^^^^ ^' «"«»^- satisfied before wreven Teain f^- "'^'^'""r^'l"'^^ ^« be activities are indicat ^of Xd th?^fr \'^'' '^'''''''^^' played by a livino^ or^nism «..!%? ^"^^^^V^^^ must be dis- be taken as the criterion of consciousness ? S hi . "i'' ^^ criterion is either needful or possible Z I ^"^J^^^^^ely, no nothing can be more ultlm^tP £1 ' *° '"®' individually, and, th-erefore, my conscbtness cann"ot'"aLT r^'^'"""^^^' having a claim to a higher ceStv P^ ?^ 7 ^^^^^ such criterion is required and ^ ^"v ' ^^J^^^^^^^ly^ some come within the te/i^torv of « I ^ ^°^^sciousness cannot only appreciate ?he lattr th/oiK^^^^^^^^^ consciousness, I can -these ambassadors beTnarfV^^ ^^'^'^ °^ ambassadors the observable ^o^ittetlf :: l^^^^^^^ therefore, is, What acfiviHflr^? " • ^^? "^^^ question, as indicative of fnsc ousnS '^Cr''''' .T '' ^' '^^'^ readily is,-All aSirth.f ^"'T' ^^^^ ^^"^«« "^ost vvhereverwCaliSnL ^'^ indicative of Choice; tional choice we XfnSr^^^^ exerting inten-' therefore, that the omanil T^^ '' conscious choice, and, shows that t4 ans:S™not do' rtl -^^ f^^'^ whether there is any minr wS.^ / lu ' '"^^"^^ ''"^ disputing choice, physiology,l^wTsh. rl-n ,f' ^Tf °^ ^°"«^^°"^ lirm in denying that aTlannll^^^ I ^''"-"'f *^ "^'^P^^^- ^^ ^ery host of reilex actions t SvpH V ''!?. "^"^ *° "^^"^- ^he in view of such ZlnientallnTr'^ '^'' proposition, and, adjustments, we hnrtScL tv 1^ apparently intentional element as real or fictiSr ThI \ T' ^''^ ^^ ^^'^ ^^^ice- whether the adjTs ments 1--^^^^^ ''' ^'''^' ^' ^" '^^ under the samTc rc^2aST«l "'1 l"''''^"^''^ ^'^^ ^''^"^'^ tinction between ad Wivo stimulation. The only dis- and adjustivrmovein r^^ '' '''^'^ action, consists in the fSer L^nT^ '"^-^r"'"^'^ within the nervous system hpt"° ^'^ '"^''^^'^^ mechanisms ^«^-^ic.^«. adjiiS Totme^s^ ^^^ ^^ ^^^^^ stimulations, while thi Sr ! " Response to ii;«r^^•cM/ar fi! 18 MENTAL EVOLUTION IN ANIMALS. of a machine under the manipulations of an operator : when certain springs of action are touched by certain stimuli, the whole machine is thrown into appropriate action ; there is no room for choice, there is no room for uncertainty ; but, as surely as any of these inherited mechanisms is affected by the stimulus with reference to which it has been constructed to act, so surely will it act in precisely th^ same way as it always has acted. But the case with conscious mental adjust- ment is quite different. For, without going into the question concerning the relation of Body and Mind, or waiting to ask whether cases of mental adjustment are not really quite as mechanical in the sense of being the necessary result or correlative of a chain of psychical sequences due to a physical stimulation, it is enough to point to the variable and incalcu- lable character of mental adjustments as distinguished from the constant and foreseeable character of reflex adjustments. All, in fact, that in an objective sense we can mean by a mental adjustment, is an adjustment of a kind that has not been definitely fixed by heredity as the only adjustment possible in the given circumstances of stimulation. For, were there no alternative of adjustment, the case, in an animal at least, would be indistinguishable from one of reflex action. It is, then, adaptive action by a living organism in cases where the inherited machinery of the nervous system does not furnish data for our prevision of what the adaptive action must necessarily be — it is only in such cases that we recog- nize the element of mind. In other words, ejectively con- sidered, the distinctive element of mind is consciousness, the test of consciousness is the presence of choice, and the evidence of choice is the antecedent uncertainty of adjustive action between two or more alternatives. To this analysis it is, however, needful to add that, although our only criterion of mind is antecedent uncertainty of adjustive action, it does not follow that all adjustive action in which mind is con- cerned should be of an antecedently uncertain character ; or, which is the same thing, that because some such action may be of an antecedently certain character, we should on this account regard it as non-mental. Many adjustive actions which we recognize as mental are, nevertheless, seen before- hand to be, under the given circumstances, inevitable ; but; analysis would show that such is only the case when we have in view agents whom we already, and from independent evidence, regard as mental. THE CRITERION OP MIND. -^19 Tn positing the evidence of Choice as my objective (or ejective) criterion of Mind, I do not think it necessary to enter into any elaborate analysis of what constitutes this evidence. In a subsequent chanter I shall treat fully of what I call the physiology or objective aspect of choice ; and then it will be seen that from the gradual manner in which choice, or the mind-element, arises, it is not practically possible to draw a definite line of demarcation between choosing and non-choosing agents. Therefore, at this stage of the enquiry I prefer to rest in the ordinary acceptation of the term, as implying a distinction which common sense has always drawn, and probably always will draw, between mental and non-mental agents. It cannot be correctly said that a river chooses the course of its flow, or that the earth chooses an ellipse wherein to revolve round the sun. And similarly, however complex the operations may be of an agent recog- nized as non-mental— such, for instance, as those of a calcu- lating machine— or however impossible it may be to predict the result of its actions, we never say that such operations or actions are due to choice ; we reserve this term for operations or actions, however simple and however easily the result may be foreseen, which are performed, either by agents who in virtue of the non-mechanical nature of these actions prove themselves to be mental, or by agents already recognized as mental— i.e., by agents who have already proved themselves to be mental by performing other actions of such a non- mechanical or unforeseeable nature as we feel assured can only be attributed to choice. And there can be no reasonable doubt that this common-sense distinction between choosing and non-choosing agents is a valid one. Although it may be difficult or impossible, in particular cases, to decide to which of the two categories this or that being should be assigned, this difficulty does not aftect the validity of the classification —any more, for instance, than the difficulty of deciding whether Limulus should be classified with the crabs or with the scorpions affects the validity of the classification which marks off the group Crustacea from the group Arachnida. The point is that, notwithstanding special difficulties in assigning this or that being to one or the other class, the psychological classification which I advocate resembles the zoological classification which I have cited ; it is a valid classification, inasmuch as it recognizes a distinction where 20 MENTAL EVOLUTION IN ANIMALS. take' the mo^i^ T'"^?^- '' ^^^ti^.-^^h- For even if we cer a ^L oL ^ntemgence e.ists, and that prior o cercam act ions it is always affected n certain wavs ThorP nptV '"-i ^^«"PPo«e that the state of thTn % is so to proceed without, and those that proceed with this remaTkaWe jectivity are lacts at any rate no Ipss rpnl fiiov. fi,^ c atdS'n '' '^ """f''^^' -meV?rellt r™ iu'variaV/ and faithful y mirrored in those of the former such Theno mena, for this reason alone, deserve to he nln^., i„ „ j- .™ I scientific category, even though it we,^ pro^uhet™ connTitLtrSdrrd's, i^L roXna^!^t a e SmpaSedTvXr ''■"'""'J™ ^''''^*'" activities which we%rsSTrfnott':fcrpa';,ivirs r^'i^i/oC ^r tSrthl tm'cT "^'^^r to"co!»i;^«Sn^o" acton areTent^Z; "S™'!,*"' »<* able to c;«<„» their detZine?hStce "' ''"' '"^'^^ "'« »"™'' «■'>-!' gence . — it is, then, adaptive action by a livino- oranm-^^m rs'nTtaistdSt'''' """"'"^'^ "' "- Suri s uues not lurnish data for our prevision of what the adantivp action must necessarily be-it is only here th 't we recoSe h^Vforwhic-'t"" '' "^".'" ^'^^ criteria; ^r'm?:^ tneretore, whit i I propose, and to which I shall adhere throughou the present volume, is as follows --Does the organism learn to make new adjustments, or to modify old THE CRITERION OP MIND. 21 ones, m accordance with the results of its own individual experience ? _ If it does so, the fact cannot be merely due to reflex action m the sense above described ; for it is impossible that heredity can have provided in advance for innovations upon or alterations of its machinery durin.r the lifetime of a particular individual," Two points have to be observed with regard to this criterion, in whichever verbal form we may choose to express it. The first is that it is not rigidly exclusive either, on the one hand, of a possibly mental character in apparently non- niental adjustments, or, conversely, of a possibly non-mental character in apparently mental adjustments. For it is certain that failure to learn by individual experience is not always conclusive evidence against the existence of mind; such failure may arise merely from an imperfection of menify or from there not being enour/h of the mind-element present to make the adjustments needful to meet the novel circum- stances. Conversely, it is no less certain that some parts of our own nervous system, which are not concerned in the phenomena of consciousness, are nevertheless able in some measure to learn by individual experience. The nervous apparatus of the stomach, for instance, is able in so con- siderable a degree to adapt the movements of that or^an to the requirements of its individual experience, that were the organ an organism we might be in danger of regardintr it as dimly intelligent. Still there is no evidence to show that non-mental agents are ever able in any considerable measure thus to simulate the adjustments performed by mental ones • and therefore our criterion, in its practical application, has rather to be guarded against the opposite danger of denyinr^ the presence of mind to agents that are really mental For as I observed in "Animal Intelligence," "it is clear that lon^ before mind has advanced sufficiently far in the scale of development to become amenable to the test in question, it has probably begun to dawn as nascent subjectivity. In . other words, because a lowly organized animal does not learn by Its own individual experience, we may not therefore con- clude that m performing its natural or ancestral adaptations to anpropiate stimuli, consciousness, or the mind-element is wholly absent ; we can only say that this element, if present reveals no evidence of the fact. But, on the other hand, if a lowly organized animal does learn by its own individual 22 MENTAL EVOLUTION IN ANIMALS. pi i experience, we are in possession of the best available evi- dence of conscious memory leading to intentional adaptation. Therefore, our criterion applies to the upper limit of non- mental action, not to the lower limit of mental." Or, again adopting the convenient terminology of Clifford, we must always remember that we can never know the mental states of any mental beings other than ourselves as objects ; we can only know them as ejects, or as ideal projections of our own mental states. And it is from this broad fact of psycho- logy that the difficulty arises in applying our criterion of mind to particular cases — especially among the lower animals. For if the evidence of mind, or of being capable of choice, must thus always be ejective as distinguished from objective, it is clear that the cogency of the evidence must diminish as we recede from minds inferred to be like our own, towards minds inferred to be not so like our own, passing in a gradual series into not-minds. Or, otherwise stated, although the evidence derived from ejects is practically regarded a's good in the case of mental organizations inferred to be closely analogous to our own, this evidence clearly ceases to be trust- worthy in the ratio in which the analogy fails : so that when we come to the case of very low animals — where the analogy is least — we feel uncertain whether or not to ascribe to them any ejective existence. But I must again insist that this fact— which springs immediately out of the fundamental isolation of the individual mind— is no argument against my criterion of mind as the best criterion available ; it tends, indeed, to show that no better criterion can be found, for it shows the hopelessness of seeking such. The other point which has to be noted with regard to this criterion is as follows. I again quote from " Animal Intelli- gence : — " Of course to the sceptic this criterion may appear un- satisfactory, since it depends, not on direct knowledge, but on inference. Here, however, it seems enough to point out, as already observed, that it is the best criterion available ; and, further, that scepticism of this kind is logically bound to deny evidence of mind, not only in the case of the lower animals, but also in that of the higher, and even in that of men other than the sceptic himself. For all objections which could apply to the use of this criterion of mind in the animal kmgdom, would apply with equal force to the evidence of any THE CRITERION OF MIND. 23 mind other than that of the iaiividual objector. This is obvious, because, as I have already observed, the only evi- dence we can have of objective mind is that which is furnished by objective activities ; and, as the subjective mind can never become assimilated with the objective so as to learn by direct feeling the mental processes which there accompany the objective activities, it is clearly impossible to satisfy any one who may choose to doubt the validity of inference, that in any case, other than his own, mental processes ever do accompany objective activities. " Thus it is that philosophy can supply no demonstrative refutation of idealism, even of the most extravagant forrri. Common-sense, however, universally feels that analogy is here a safer guide to truth than the sceptical demand for impossible evidence; so that if the objective existence of other organisms and their activities is granted — without which postulate comparative psychology, like all the other sciences, would be an unsubstantial dream— common sense will always and without question conclude that the activities of organisms other than our own, when analogous to those activities of our own which we know to be accompanied by certain mental states, are in them accompanied by analogous mental states." r 24 MENTAL EVOLUTION IN ANIMALS. CHAPTER II. The Structure and Functions of Nerve-Tissue. Having thus arrived at the best available Criterion of Mind considered as an eject, we have now to pass on to the topic which has already been propounded, viz., to a consideration ot the objective conditions under which known mind is in- variably found to occur. Mind then, so far as human experience extends, is only certainly known to occur in association with living organisms and, still more particularly, in association with a peculiar kind of tissue which does not occur in all organisms, and even in those in which it does occur never constitutes more than an exceedingly small percentage of their bulk. This peculiar tissue, so sparingly distributed through the animal kinr^dom and presenting the unique characteristic of being associated with mind, IS, of course, the nervous tissue. It therefore devolves upon us, first of all, to contemplate the structure and the functions of this tissue, as far as it is needful for the purposes of our subsequent discussion that these should be clearly understood. Throughout the animal kingdom nerve-tissue is invariably present in aU species whose zoological position is not below that of the Hydrozoa. The lowest animals in which it has hitherto been detected are the Medusa, or jelly-fishes, and from them upwards its occurrence is, as I have said, invari- able. Wherever it does occur its fundamental structure is very much the same, so that whether we meet with nerve- tissue m a jelly-fish, an oyster, an insect, a bird, or a man, we have no difticulty in recognizing its structural units as everywhere more or less similar. These structural units are microscopical cells and microscopical fibres. (Figs. 1 2 ) Ihe fibres proceed to and from the cells, so servin" to THE STRUCTURE AND FUNCTIONS OF NERVE-TISSUE. 25 PiQ. 1.— Motor Nerve Cells connected by intercellular proceBses (b, b), and giving origin to outgoing fibres (c, c, c, and a). 4. Multipolar cell containing much pig- ment around nucleus. Diagrammatic, (Vogt.) Fio. 2.— Multipolar Ganglion Cell from anterior grey matter of Spinal Cord of Ox. a, Axis cylinder procesr : i, branched processes, magnified IBO dia- meters. (Deitera.) connect the cells with one another, and also with distant parts of the animal body. The function of the fibres is that of conducting stimuli or impressions (represented by mole- cular or invisible movements) to and from the nerve-cells, while the function of the cells is that of originating those of the impressions which are conducted by the fibres outwards. Those of the impressions which are conducted by the fibres inwards, or towards the cells, are originated by stimuli affecting tlie nerve-fibre in any part of its length ; such stimuli may be contact with other bodies or pressure arising therefrom (mechanical stimuli), sudden elevations of temperature (ther- mal stimuli), moleoular changes in the nerve-substance pro- '4 m 26 MENTAL EVOLUTION IN ANIMALS. duced by irritants (chemical stimuli), effects of electrical disturbance (electrical stimuli), or lastly, the passage of a molecular disturbance from any other nerve-fibre with which the one in question may be connected. Nerve-cells are usually found collected together in aggre- gates which are called ganglia, to and from which Tar^e bundles of nerve-fibres come and go. Tliese rope-like clusters of nerve-fibres constitute the white threads and strings which we recognize as nerves when we dissect an animal. (See Fig. 3.) Tiie relation of the clusters of fibres to the cluster of cells is now such as to supply the anatomical condition to the performance of a physiological FlQ. 3.— SmaU Sympathetic Ganglion (hnman) with Multipolar Cells. Magnified about 400 diameters. (Leydig.) process, which is termed Eeflex Action. If we suppose the lett-hand bundle of fibres represented in the woodcut to be prolonged and to terminate in a sensory surface while the other three bundles, when likewise prolonged, terminate m a group of muscles, then a stimulus falling upon the sensory surface would cause a molecular disturbance to travel along the left-hand or in-going nerve to tlie ganglion- on reaching the ganglion this disturbance would cause 'the ganglion to discharge its influence into the right-hand or out- gwng nerves, which would then conduct this disturbance into the group of muscles and cause them to contract. This pro- cess 18 called reflex-action, because the original stimulus tailing upon the sensory surface does not pass in a direct line THE STRUCTURE AND FUNCTIONS OP NERVE-TISSUE. 27 to its destination in the muscles, but passes fir=(t to the ganglion, and is thence reflected from the sensory surface to the muscles.* This, which at first sight appears a round- about or cumbrous sort of process, is really the most economic that is available. For we must remember the enormous number and complexity of the stimuli to which all the higher animals are perpetually exposed, and the consequent neces- sity that arises for there being some system of co-ordination whereby these innumerable stimuli shall be suitably responded to. And such a system of co-ordination is rendered possible, and actually realized, through this principle of reflex action. For the animal body is so arranged that the innumerable nerve-centres, or ganglia, are all more or less in communica- tion one with another, and so receive messages from all parts of the body, to which they respond by sending appropriate messages down the nerve-trunks supplying the particular groups of muscles which under the given circumstances it is desirable to throw into contraction. In other words, when a stimulus falls upon the external surface of an animal, it is not diffused in a general way throughout the whole body of the animal, so causing general and aimless contractions of all the muscles ; but it passes at once to a nerve-centre, and is there centralized; the stimulus is dealt with in a manner which leads to an appropriate response of the organism to that stimulus. For the nerve-centres which receive the stimulus only reflect it to those particular nmscle-groups which it is desirable for the organism, under the circumstances, to throw into action. Thus, to take an example, when a small foreign body, such as a crumb of bread, lodges in the windpipe, the stimulus which it there cause? is immediately conveyed to a nerve-centre in the spinal cord, and this nerve- centre then originates, by reflex action, a highly complicated series of muscular movements which we call coughing, and which clearly have for their very special object the expul- sion of the foreign body from a position of danger to the organism. Now it is obvious that so complicated a series of muscular movements could not be performed in the absence of a centralizing mechanism ; and this is only one instance among hundreds of others that might be adduced of * The term, however, is not a hnppv one, because the procesB is some- thing more thiui the reliection of the original stimulus or moicuuliir disturb- ance ; the ganglion adds a new disturbance. if 28 MENTAL EVOLUTION IN ANIMALS. Of course we may wonder how it is that the nerve-centres which preside over reflex action, not being endowed wTth consciousi^ss, know wliat to do with the stimuli which U^ey receive The explanation of this, however, is that the ana^ tomical arrangement of ganglion and nerves in any particular case IS such as to leave no choice or alternative of action If the apparatus is called into action at all. Thus to benin'at he bottom of the series, in the Medusa the simple j^i^h a are distributed all round the margin of the animal, ad respond by reflex action to the stimuli which are applied at any other part of the surface. This has the effect of ^hicreas- mg the rate and the str.^ngth of the swimming-movements and so of enabling the animal to escape from tlie souZof diuiger. Now, although this is a true reflex action, and has an obvious purpose to serve, it does not involve any co-ordi nation of nuiscular movements. For the anatomical plan of a jelly-fish is so simple, that all the muscular tissue in the body IS spread out m the form of one continuous sheet: so tliat the only function which the marginal ganglia have to peiform when they are stimulated into^eflex ac'tion, iHhat tissur'""'"^ '" contraction one continuous sheet of muscular i. ^fir ^^ "'•'^y i"^^^ ^^^^ in its earliest stages reflex action IS nothing more than a promiscuous discharge of nervous energy by nerve-cells, when they are excited by a stimidu. passing into them from their attached nerve-fibres * But as animals become more highly organized, and distinct muscles are by degrees set apart for the performance of distinct actions vve can readi y understand how particular nerve-centres are piirnf I "'""' ''* ^P^'^ ^° P'^^i^*^ o^er these distinct actions; the nervous centres then perform the part of tri-. gers to the particular muscular mechanisms over which the'V Hon 'nf ";;^''°f ''i ""^"fl' .^^^'^ ""^y ^^ ^^'^■'^ened by the recep- tion of stimuli along their own particular lines of communi- cation, or nerves. Thus, for instance, in the star- fish-animals tuVlT somewhat higher in the zoological scale than the jelly-fish, and which have a more highly deA'eloped neuro- muscular system-the ganglia are arranged in a ring round * Fo';f'j^^"ll"ccountofrelIex.ictioninMeclu8,e,8eei'At7 Trans Crooning. Lecture, VSib; also mi. Trans., 1877 and 1880 ' ^'°°'"*** 'ii THE STRUCTURE AND FUNCTIONS OF NERVE -TISSUE. 29 tho bases of tho fivo rays, into which they send, and from whicli they receive, nerve-fibres; tho ganj/lia are likewise connected with one another by a penta<^onal ring of fibres. Now experiment shows that in this simple, and indeed geo- metrical plan of a nervous system, the constituent parts are able, when isolated by section, to preside over tho movements of their respective muscles ; for if a singlo ray be cut off at its base, it will behave in all respects just like tho entire star- fish — crawling away from injury, towards light, up perpen- dicular surfaces, and righting itself when turned upon its back. That is to say, the single nerve-centre at the base of a single separated ray is able to do for that ray what the entire pentagonal ring, or central nervous system, is able to do for the entire animal ; it is for that ray the trigger which, when touched by the advent of a stimulus, throws the mus- cular mechanism into appropriate action. Thus it is evident that each of the five nerve-centres stands in such anatomical relation to the muscles of its own ray, that when certain stimuli fall upon the ray, the process of reliex action leaves no choice of response. The beauty and delicacy of this mechanism is shown when in the unmutilnted animal all the nerve-centres are in communication as one compound nerve- centre. For now, if one ray is irritated, all the rays will co-operate in making the animal crawl away from the source of irritation; if two opposite rays are simultaneously irri- tated, the star-fish will crawl away in a direction at right angles to an imaginary line joining the two points of irrita- tion. And, more prettily still, in the globular Echinus, or sea-urchin (which is, anatomically considered, a star-fish whose five rays have become doubled over in the form of an orange, soldered together and calcareous so as to make a rigid box), if two equal stimuli be applied simultaneously at any two points of the globe, the direction of escape will be the diagonal between them ; if a number of points be simul- taneously irritated, one effect neutralizes the other, and the animal rotates upon its vertical axis ; if a continuous zone of injury be made all the way round the equator, the same thing happens ; but if the zone be made wider at one hemisphere than the other, the animal will crawl away from the greatest amount of injurij. So that in the Echinoderms the geometrical distribution of the nervous system admits of our making ex- periments in reflex action with very precise quantitative m »' 30 MENTAL EVOLUTION IN ANIMALS. «d' .tn n ! T? • ""' '' ""'''' P^'^^y "P°" t'^i^ beautifully adjusted mechanism, so as to produce at will the balancincr or this stimulus against that one-the results, as expressed in forces * "mechanical principle of the parallelogram of As we proceed through th. animal series we find nervous systems becoming more and more integrated ; nerve-centres multiply, become larger, and serve to innervate more numerous and more complex groups of muscles. It is, however, need- less for me to devote space to describing this advance of structure, because the subject is one belonging to compara- tive anatomy. It is enough to say that everywhere the nervous machinery is so arranged that, owing to the ana- tomical plan of a nerve-centre with its attached nerves there 18 no alternative of action presented to the nerve-centre other than that of co-ordinating the group of muscles over the combined contraction of which it presides The next question therefore, which arises is-How are we to explain the fact that the anatomical plan of a ganglion, with its attached nerves, comes to be that which is needed to direct the nervous tremours into the particular channels required ? Tlie following is the theory whereby Mr. Herbert Spencer seeks to answer this question, and in order fully to under- stand It we must begin by noticing the effects of stimulation upon undifferentiated protoplasm. A stimulus, then, api^Iied to homogeneous protoplasm, which is everywhere contractile and nowhere presents nerves, hos the effect of mvin.T rise to a visible wave of contraction, which spreads in all cUrections from the seat of stimulation as from a centre. A nerve on the other hand, conducts a stimulus without undergoincr any contmction, or change of shape. Nerves, then, are°func- t oually distinguished from undifferentiated protoplasm bv the property of conducting invisible or molecular waves of fitimula ion from one part of an organism to another, so establishing physiological continuity between such parts vvitliout the necessary passage of visible waves of contraction :Now beginning with the case of undifferentiated proto- plasm, Mr Spencer starts from the fact that every portion of the colloidal mass is equally excitable and equally contrac- Translmt^^ ^''''""' ""^ '''"' experiiDeuts, see Croonian Leclure, I>UU. THE STRUCTURE AND FUNCTIONS OF NERVE-TISSUE. 31 tile. But soon after protoplasm begins to assume definite shapes, recognized by us as specific forms of life, some of its parts are habitually exposed to the action of forces different from those to which other of its parts are exposed. Conse- quently, as protoplasm continues to assume more and more varied forms, in some cases it must happen that parts thus peculiarly situated with reference to external forces will be more frequently stimulated to contract than are otlier parts of the mass. Now in such cases the relative frequency with which waves of stimulation radiate from the more exposed parts, will probably liave the effect of creating a sort of polar arrangement of the protoplasmic molecules lying in the line through which these waves pass, and for other reasons also will tend ever more and more to convert these lines into passages offering less and less resistance to the flow of such molecular waves, — i.e., waves of stimulation as distinguished from waves of contraction. And lastly, when lines offering a comparatively low resistance to the passage of molecular impulses have thus been organically established, they must then continue to grow more and more definite by constant use, until eventually they become the habitual channels of communication between the parts of the contractile mass through which they pass. Thus, for instance, if such a line has been established l)etween the points A and B of a con- tractile mass of protoplasm, when a stimulus falls upon A, a molecular wave of stimulation will course through that line to B, so causing the tissue at B to contract — and this even though no wave of contractio,i has passed through the tissue from A to B. Such is a very meagre epitome of Mr. Spencer's theory, the most vivid conception of which may perhaps be conveyed in a few words by employing his own illustration, viz., that just as water continually widens and deepens the (-■ irxuel through which it flows, so molecular waves of the k.uid we are considering, by always flowing in the same tissue tracts, tend ever more and more to excavate for tliem- selves functionally differentiated lines of passage. When such a line of passage becomes fully developed, it is a nerve- fibre, distinguishable as such by the histologist ; but before it arrives at this its completed stage, i.e., before it is observable as a distinct structure, Mr. Spencer calls it a " line of dis- charge."* * A certain amount of experimental verification lias been lent to this 32 MENTAL EVOLUTION IN ANIMALS. arise in positions wWo'o- ™PP°'"=s nerve-cells, to tion^?rrtv;^-nn""v^?^^^^ plan of a ffan^lion wifli ifi Xni i *"® anatomical tion that " practice makes ,,ZZ?'^f^ ?,'-'^'"^l°^''""^ that the co-ordinations of Sf, !. .' ^ ""' ""'^ ""=*»« presided over hv tl?= <>' " "s"'Iar movement which are ^e^dy terZ.^a'r e l^X^^XTy t''"Y """' moi^rLdS'ty'Lf.h%h" fenXr'"" T^' '","^ ""^ uit case, that when an associated muscular i?o.va^/«*^Y«^-o«tWl877 on "SnfP fi^'^ '" '^ Proceedings of the are that when physiological contiSt of a «f ."T ' ^^^ P"""P"1 ^"^^^ interrupted by overj.pjing or;S^«. f ^^ of neuro-niuscular tissue is visible or n.us-'cularJ^r^f^'onCt on InTin:-M'' ""^ ^^^"^6 both of stimulation are blocked, after a lon° „""? ^''•".^ or molecular wares of allowed to break upon the 8hLorfLr'''r-°'^^'""'''«''^^°" ^^^^s are last begin to force a^passagerd very sol^S"""^ i^^terruption, they at free, so that neither the waves of Jr, ft f ^"'^"^0 becomes perfectly any longer hindered. Whether in such I °'' "^''.^i"^" ""^ stin.uhVtion are veloped. or only a "line o ItlL" 1 ean.^ot «" ^^1"^ "^rve-flbre is de- passage is effected through prcvi^usW exS fl^ ' but most probably the become more functionally develoDerrhv fV.i -^ ^^''' ?^ "'^ P^^^"« ^^'i^li • Less Batisfactory not ,In v^hl/ '''"''''^ °^ "^^"^i^^- whole weight of emSydogica" Ld w!^^ speculative, bilt because the opposed to the speculation^ iC the S°fi' ''," '"f ^PP^"^''^ *° '"^ *« be show that nerve-cells are ?ho resul of llf "f " ^* *'"^ ''^■'^'^'•'''' ^^^ ^o dermal cells-that is thntfLT • l^ specialization of epithelial or epi- but by way of a f uXr d feraUon oT' °' "-'''^-^"^^'^'''^ protoplas?;;. ferentiated tiaaue, where ^^^^^S^S^^^^^^ t^^^' m THE STRUCTUEE AND FUNCTIONS OF NERVE-TISSUE. 33 movement takes place with sufficient frequency, it cannot by any effort of the will become again dissociated ; as is the case, for instance, with the associated movement of the eyeballs, which does not begin to obtain till some days after birth, but whicli then soon becomes as closely organized as any of the associated movements in the muscles of the limbs * And if this is the case even in the life-time of individuals, we can scarcely wonder that in the life-time of species heredity with natural selection should still more completely adapt the anatomical plan of ganglia, with their attached nerves, to the performance of the most useful — i.e., the most habitual — actions. Thus we may see in a general way how such nei'vous machiner}" may at last come to be differentiated into specially distributed anatomical structures, which, on account of their special distribution, are adapted to minister only to particular co-ordinations of muscular movements. That is to say, we are thus able to understand the rise and development of Keflex Action. of * Mr. Darwin called my attention to the following passage in the writings Lamarck (FAil. Zool., torn, ii, pp. 318-19) : — " Dans toute action, lo fluide des nerfs qui la provo(|ue, subit un mouveraent de deplacement qui y donne lieu. Or, lorsque cette action a ete plusieurs fois repetee, il n'est pas douteux que le fluide qui I'a executee, ne se soit fraye une route, qui lui devient alors d'autant plus facile h parcourir, qu'il I'a eiJ'ectivement plus souvant francliie, et qu'il n'ait lui-meme une aptitude plus grand i auivre cette route frayee que celles qui le sout moina." '*?fe I i 34 MENTAL EVOLUTION IN ANIMAL* CHAPTER III. The Physical Basis of Mind. 1; f < Vi We have already taken it for granted that Mind has a physical basis m the functions of the nervous system or that every mental process has a corresponding equivalent in some neural process. I shall next endeavour to show how precise tnis equivalency is. We have seen that ganglionic action consists of waves of nervous tremours originating in the cells, coursing along the attached hbi-es to other cells, and there arousing fresh impulses ot the same kind. Moreover, we have seen that this coursincr ot nervous impulses through nervous arcs is not, as it were° promiscuous, but that, owing to the anatomical plan of a ganglion, it takes place in certain determinate directions, so that the result when expressed in muscular movement, shows the function of a ganglion to be that of centralizing nervous action, or of directing nervous tremours into definite channels Last y, we have seen that this directing or centralizinor' function of ganglia has probably in all cases been due to thS principle of use combined with that of natural selection JVow It 18 known from experiments on the lower animals, as well as from the effects of cerebral disease in man, that the part of the nervous system in all the Vertebrata which appears to be exclusively concerned in all mental operations is the so-called " large brain," or cerebral hemispheres This IS the convoluted part of the brain which appears imme- diately below the skull, and is above all the series of cran'dia or nerve-centres which occupy the rest of the cerebro-spfnal tract As some at least of the bewildering multitude of cells and fibres which constitute the cerebral hemispheres are in connection with these lower ganglia, there is no doubt that the hemispheres are able to "play down" upon these gano-lia as upon so many mechanisms, whose function it is to throw f ' I THE niYSICAL BASIS OF MIND. 35 this and that group of muscles into action. Much light is at present being thrown upon this subject by the researclies of Hitzig, Fritsch, Ferrier, Goltz, and others ; but we must pass on to consider that function of these great nerve-centres with which we shall henceforth be exclusively concerned, the function, namely, of being associated with the phenomena of Mind. As the cerebral hemispheres pretty closely resemble in their intimate structure ganglia in general, there can be no reasonable doubt that the mode of their operation is substan- tially the same ; and as such operation is here attended with the phenomena of subjectivity, there can be equally little doubt that such phenomena must constitute a sort of obverse reflection of ganglionic action. Looking, then, upon this obverse reflection, can we detect any fundamental principles of mental operation which may reasonably be taken to corre- spond with the fundamental principles of ganglionic opera- tion? The most fundamental principle of mental operation is that of memory, for this is the conditio sine qud non of all mental life. But memory on its obverse side, or the side of physiology, can only mean that a nervous discharge, having once taken place along a certain route, leaves behind it a molecular change, more or less permanent, such that when another discharge afterwards proceeds along the same route, it finds, as it were, the footprints of its predecessor. And this, as we have seen, is no more than we find to be the case with ganglionic action in general. Even long before move- ments involving muscular co-ordination have been repeated with sufficient frequency to become consolidated into one organized and indissoluble act, they become, in virtue of the principle which I have termed the principle of use, more and more easy to repeat ; in all but in the absence of a mental constituent the nerve-centre concerned remenibcrs the pre- vious occurrence of its OAvn discharges ; these discharges have left behind them an impress upon the structure of the ganglion just the same in kind as that which, when it lias taken place in the structure of the cerebral hemispheres, we recognize on its obverse side as an impress of memory. The analogy is much too close to be attributed to accident, for it extends into all details. Thus, a ganglion may funjet it3 previous activity if too long an interval is allowed to elapse 36 MENTAL EVOLUTION IN ANIMALS. between tlie repetitions of its activity, as every one must know who is in the habit of playing on a musical instrument, or performing any other actions entailing the acquirement of dexterity. It may also be observed that when such is the case the particular activity forgotten by the ganglion may be more easily re-acquired than oridnolly it was acquired, which is just what we find to be tht 'vfch mental attainments. As particular illustrations ■' '■. ,e facts I may state two or three cases, which will also ■ ..ve to show of how little importance (on the objective side) is the occurrence of con- sciousness to the memory of a ganglion. Eobert Houdin early in life practised the art of juggling with balls in the air, and after a month's practice was able to keep four balls in the air at once. His neuro-muscular machinery was now so well trained, or remembered so well how to perform the series of actions required, that he could attbrd to withdraw his attention from the performance to the extent of reading a book without hesitation while keeping up the four balls. Thirty years afterwards, on trying the same experiment, having scarcely once handled the balls between times, he found that he could still read with ease while keeping up three balls ; the ganglia concerned had partly forgotten their work, but on the whole remembered it wonderfully well. Again, Lewes gives the case of a waiter asleep at a coffee-house, with much noise of talking arouncl him, who was instantly aroused by a low cry of " Waiter ;" and Dr. Abercrombie gives the case of a man who had long been in the habit of taking down a repeater watch from the head of his bed to make it strike the last hour, and who was observed to do this when otherwise apparently uncon- scious from a fit of apoplexy. But perliaps the most remark- able of all the cases that can be adduced are the most familiar ones of walking and speaking. When we remember the immense amount of neuro-muscular co-ordination that is required for either of these actions, and the laborious steps by which each of them is first acquired in early childhood, it is indeed astonishing that in after life they come to be per- formed without thought of their performance ; the ganglia concerned have fully learned their work. So much for memory. But memory would be a useless faculty of mind if it did not lay the basis for another, and really the most important principle of subjectivity ; I mean / u THE PHYSICAL BASIS OF MIND. 87 the Association of Ideas. This is the root and branch of the whole structure psychological, and therefore, if mind has a physical basis, we should expect to meet with some very aeneral and essential feature of ganglionic action answering to tliis very general and essential feature of mental action. And this, beyond question, we do find. For the association of ideas is merely a development of simple memory. A mental impression, image, memory, or idea having once occurred in juxtaposition with another, not only are the two memories remembered, but also the fact of their juxtaposition, so that when one memory or idea is aroused, the other is aroused likewise. Let us, then, look at the matter a little more closely, in order to see how this great principle of psychology may receive its explanation, so far as the collateral principle of physiology is concerned. There can be no doubt that in the complex structure of the cerebral hemispheres one nervous arc (i.e., fibres, cells, and fibres) is connected with another nervous arc, and this with another almost ad infinitum ; and there can be equally little doubt that processes of thought are accompanied by nervous discharges taking place, now in this arc, and now in that one, according as the group of nerve-cells in each arc is excited to discharge its influence by receiving a discharge from some of the other nerve-arcs with which it is united. Again, as we have seen, it is practically certain that the more frequently a nervous discharge takes place through a given group of nervous arcs, the more easy will it be for sub- sequent discharges to take place along the same routes— these routes having been thus rendered more permeable to the pas- sage of subsequent discharges. And now a very little reflec- tion will show that in this physiological principle we no doubt have the objective side of the psychological principle of the association of ideas. For it may be granted that a series of discharges taking place through the same group of nervous arcs will always be attended with the occurrence of the same series of ideas ; and it may be further granted that the previous passage of a series of discharges through any group of nervous arcs, by making the route more permeable, will have the effect of making subsequent discharges pursue the same course when started from the same origin. And if these two propositions be granted, it follows that the tendency of ideas to rtcur in the same order as that in which they '1^ ; S8 MENTAL EVOLUTION IN ANIMALS. i seen,; o" r;-:^ t^^^ .^ tC t^ Sf initate^.^ Mu injily aue to a conscious association of ideas mnv liv <, euthciently long course of ganglionic instrucUon cS to^be conscious actions, and therefore become m no way distin guishable from reflex actions.* ^ ™°' IJut the proof of the fundamental correlation between f ? TiLr""" ?." "i^^""" ="=«» does not end Ive" here. There is another line of evidence which althom,?, perhaps not quite so dehnite, nevertheless seen s to me nS direaciy adduced. If we take ideation to be in tliP si ma sense an index of the higher or more complex «s Z cesses, as muscular movement is of the lower or less comHpv we shall find evidence to show that the developri t of ueveiopment ot the correspondmg nervous processes wh,Vh plCZ'fof ''"^. '" "^"^ ^^^^^^ whU on he lower plane (that of muscular movement) has led to the advanoini development of muscular co-ordination. In otW wo?ds f we consent to change the index from muscles to ideat;.^ shall find evidence that the method of nervous evolution has P X^ r ''^ been uniform ; we shall find that the ToCssi^e elaboration of nervous structures-which in the one SiS Z X"Td r Jh '"tr"^"-^ 'T^^^^^ '' ^mZZ system and m the other case has been reflected in fha advancing phases of mental evolution-we shall find thl^ th^! progressive elaboration has throughout been perv^^^ same principles of development. pervaaea Dy the while women Always spiTadtheirW *t "'^ objeotsuch as a coin! the difference of dress has IpH frT n rfff ^ /^''® ''^'''°" °^ ''°"^*'' i^ thab ia each case having becrorinanrfr'tr"' f ^-^g^'^^f habit-the habit Bt-arcelj distinguishable from a ^^^ ^ '"''"'^"" "^J"«'"»^'°t. but now ijt ; AX. THE PHYSICAL BASIS OF MIND. 39 Disregarding the philosophical question as to how nervous action IS associated with subjective ideation, and conceiniiicr ourselves only with the scientific fact that it is thus associatetf we may most clearly appreciate the parallel whicli I am about to draw if we regard tbe objective processes as the causes of the subjective. Whether or not such is really the case matters nothing to the exposition on which I am about to enter; for I throughout take it for granted that the association of neurosis and psychosis is as invariable and precise as it would be were it proved to be due to a relation of causality Placing therefore neurosis for the purposes of my arrrumerit as the cause of psycliosis, I desire to show that th °re is a very exact parallel between the ganglionic action which pro- duces subjective ideation and that which produces muscular co-ordination; I desire to show that if we interpret the phenomena of ideation in terms of the nervous activity which IS supposed to produce it, we shall find that tliis activity IS just the same in all its laws and principles as that winch produces muscular co-ordination. _ No doubt it sounds absurd, and from a philosophical point of view alone it is absurd, to speak of ideas as the psychological equivalents of muscles. So far as subjective analysis could teach us, it certainly does not seem that an idea presents any further kinship to a muscle than it does to a stoue, or to the moon ; but when we look at the matter from the objective side, we perceive tliat the kinship is most intimate. Taking it for granted that the same idea is only and always aroused during the activity of the same nervous structure, element, or group of cells and fibres, it follows that any particular mental change resembles any particular mus- cular contraction in so far as it is the terminal result of the activity of a particular nervous structure. The inconoruity of comparing a mental change to a muscular contraction arises, ot course, from the emphatic distinction which must always be felt to exist between mental and dynamical pro- cesses. Physiology, which is concerned only with the dyna- mical processes, can take no cognizance of anything that happens in the region of mind. It can trace nervous action leading to combined muscular movements of greater and greater nitricacy as we ascend to more and more elaborated mechanisms; but even when we reach the brain of man physiology can have nothing to do with the mental side of 40 MENTAL EVOLUTION IN ANIJIALS. ■|i ' H! the nervous processes. All that physiology can see in these processes is a greatly improved power of disrriniinating between stimuli, and of issuing impulses to a correspondingly greater numl)er and variety of adaptive movements ; the mental changes which accompany these nervous processes are as wliolly without the ken of physiology as these nervoua processes are without the ken of subjectivity. Therefore it is that when we speak of an idea as the analogue of a muscle, we feel the incongruity of confusing two things which are separated from one another by the whole interval that divides subject from object. But although in speaking of an idea as the analogue of a muscle, we do and ought to feel the incongruity, let it not be supposed that by thus speaking we are allowing ourselves to be betrayed into any confusion of thought. I speak of a mental change as the analogue of a muscular contraction only with reference to its being the ter- minal event invariably associated (whether by way of causality or not) with the activity of a nervous structure. And if we do not seek to press the analogy further than this, there is no fear of our confusing ideas which ought always to be kept fundamentally distinct. So much, then, by way of introduction to the point which I have to make plain. Now it admits of being abundantly proved that throughout the animal kingdom, so long as we regard the muscular system as our index of the structural advances taking place in the nervous system, we find this index to consist in the growing complexity of the muscular system, and the consequent increase in the number and variety of co-ordinated movements which this system is enabled to execute. Therefore the point which I have to prove will be proved if I can make it clear that the process of mental evolution bears some such resemblance to that of niuscular evolution as we should expect that it ought to bear, if they are both dependent on a similar process of nervous evolution. In other words, I have to show that the process of mental evolution consists essentially in a progressive co-ordination of progressively developing mental faculties, analogous to that which takes place in muscular movements. Beginning with the faculties of simple sensation, we know, for instance, that when a note of music is struck, it appears to produce a single vibration, and yet physical ana- lysis shows that the sound is not a single vibration, but a i ' THE PHYSICAL BASIS OF MIND. 41 liijilily complex structure of vibrations or harmonics, and that the ear takes in all tliese harmonics by as many separate nervous elements (whatever the elements may be which minister to the perception of pitch), although they are all blended into one compound sensation, which is so well com- pounded that the evidence supplied by it alone would never have led us to suspect that the sensation was other than simple. The same is known to be the case with sensations of colour, taste, and smell ; so that Lewes feels justified in going to the length of saying, " Every sensation is a group of eensible components."* And, taking the same view on the psychological side as I take, he further says in general terms, " The main fact on which our exposition rests is indisputable, namely, that sensation, perception, emotions, conceptions, are not simple undecomposable states, but variously com- pounded." To avoid being tedious, I shall not pursue the analysis through all the grades of the psychological faculties ; but, taking ideation in its widest sense, as including alike the mere memory of a sensation and the most complex process of abstract thought, I shall briefly show that it everywhere displays a grouping and compounding of subjective elements which, if translated into their objective counterparts, display precisely the same method of nervous evolution as that which obtains in the lower ganglia, as expressed by muscular co- ordination. As Bain observes, "Movements frequently conjoined become associated, or grouped, so as to arise in the aggregate at one bidding. Suppose the power of walking attained, and also the power of rotating the limbs, one may then be taught to combine the walking pace with the turning of the toes outward. Two volitions are at first requisite for this act, but after a time the rotation of the limb is combined with the act of walking, and, unless we wish to dissociate the two, they go together as a matter of course ; the one resolution brings on tlie combined movement Articulate speech largely exemplifies the aggregation of muscular movements and positions. A concurrence of the ch.est, larynx, tongue, and mouth, in a definite group of exertions, is requisite for each alphabetical letter. These groupings, at first impossible, Problems, ^c, p. 260. 42 MENTAL EVOLUTION IN ANIMALS. l! are, after a time, cemouted with aU the firmness of the strongest instinct." Precisely analogous to this process of Uendiri'^ many Beparato muscuhjr ir.ovements into one simultaneous and com- pounded movement, is the process of blending many simiile Kl-is into one complex or compounded idea. Just as mus- cular co-ordination is dependent on the simultaneous action ot a certain group of nerve-centres for the purpose of securinr» tlio combined action of a number of muscles, so wo must suppose that a general or a composite idea is dependent on the simultaneous activity of several nerve-centres which I muster to the several component parts of the blended idea, llie psychological side of this process has been so well ex- pressed by James Mill, that I cannot do better than render it in his words :— " Ideas which have been so often conioined tliat whenever one exists in the mind the other exists alon-r with It, seem to run into one another, to coalesce, as it wercT and out of many to form one idea, wliich idea, however in reality complex, appears to be no less simple than any one of tliose of which it is compounded The word • gold,' for example, or the word ' iron,' appears to express as simple an idea as the word ' colour,' or the word ' sound ' let it 18 immediately seen that the idea of each of those metals 13 made up of the separate ideas of several sensa- tions : colour, hardness, extension, weight. TJiose ideas, how- ever, present themselves in such intimate union, that they are constantly spoken of as one, not many. We say, our Idea of iron, our idea of gold; and it is only with an effort that reflecting men perform the decomposition." And simi- larly, of course, with the most highly complex ideas, except that the more complex they becon)«. the greater is the diffi- culty of securing the needful composition, and the more easily do they undergo disintegration. Thus it is that, in the words ot Mr. Spencer, " In the development of mind there iij a pro- gressive consohdation of states of consciousness. States of consciousness once separate become indissoluble. Other states that were originaUy united with difficulty, grow so coherent as to follow one another without difficulty. And thus there arise large aggregations of states, answering to complex external things— animals, men, buildings— which are so welded together as to be practically single states. But this integration, by uniting a large number of related sensations % :,. 1*1 THE PHYSICAL BASIS OP MIND. 43 into one state, does not destroy them. Though subordinated as parts of ii whole, they still exist."* Again, just as the principle of association is exhibited in the case of ideas not only with reference to the simaltanams blending of siniplu ideas into one complex idea, but also with reference to the succcssirc sequence or concatenation of ideas ; so in the case of muscular co-ordinations we acipiire, not only the power of a simultaneous co-operation of muscle- groups, but also that of a successive co-operation. For instance, as Professor Bain observes, ' In all mantud opera- tions there occur successions of movements so tirmly asso- ciated, that when we will to do the first, the rest follow mechanically and unconsciously. In eating, the action of opening the mouth mechanically follows the raising of the iworsel Although the learning of successions of movements involves the medium of sensation, in the first instance, yet we nuist assume that there is a power, in the system, for associating together movements as such." In fact, it miglit well have been added, there is such a power that manilests itself long before the dawn of any of the powers of the " will " ; it is as true of the polyp as of the man tiiat " in eating, the act of opening the mouth mechanically follows the raising of the morsel." So with the highest or most abstract powers of mind. For abstractly \ merely means the mental dissociating of qualities from objects, and, in its higher phases, blending these qualities, or conceptions of them, into new ideal com° binations. Lastly, just as innumerable special mechanisms of mus- cular co-ordinations are found to be inherited, innuraeiable special associations of ideas are found to be the same ; and in one case as in the other, the strength of the organically nuposed connection is found to bear a direct proportion to the frequency with which in the history of the species it has occurred. Thus, the simplest, oldest, and most constant ideas relatmg to time, space, number, sequence, &c., may be compared, in point of organic integrity, with the oldest and most indissolubly associated muscular movements, such as tliose concerned in breathing, deglutition, and visceral niotions. _ Again, inherited instincts have their counterparts in such inherited muscular co-ordinations as are not abso- • Principles of Psychology, vol. ii, p. 476. 44 MENTAL EVOLUTION IN ANIMALS. lutely indissoluble. And similarly, of course, associations of ideas acquired only during the life-history of the individual need to be more or less constantly maintained by repetition, just as muscular co-ordinations similarly acquired can only be maintained by practice. Upon the whole, therefore, it is impossible that there could be a more precise parallelism between these two manifesta- tions of nervous machinery, and it is one which for recog- nition in a general way does not require scientific analysis ; it has been perceived by the common sense of mankind — witness, for instance, the term " gymnastics " having become applicable to mental no less than to muscular co-ordinations. But, for the sake of systematic completeness, I shall conclude this exposition by briefly pointing out that all those patho- logical derangements which occur in the nervous centres that preside over muscular activities, have their parallels in similar derangements which occur in the nervous centres that are concerned in mental activities. Thus "nervous- ness," or a disturbance of the normal balance of nerve- centres, has a strikingly analogous effect in confusing the ideas and in perturbing muscular co-ordinations. Idiotcy has its parallel in inability to perform complex muscular move- ments, with which inability, indeed, idiotcy is itself almost invariably associated. Lunacy has it counterpart in an un- balanced, or badly correlated power of muscular co-ordina- tion, which in its graver manifestations is known as ataxy ; while mania is mental convulsion, and unconsciousness mental paralysis. I must not, however, take leave of this branch of our subject without briefly alluding to a difficulty which may occur to some minds, and which has been well stated by Professor Calderwood in his recently published work.* The difficulty to which I allude arises from there being an absence of such a constant relationship between the size or mass of the brain, and the degree of intelligence displayed by it, as the foregoing teaching would reasonably lead us to expect. Now, I do not deny that the relation of intelligence to size, mass, or weight of brain is a perplexing matter when we look to the animal kingdom as a whole ; for although there is unquestionably a general relation of a quantitative • Pp. 211—216. THE PHYSICAL BASIS OF MIND. 45 kind, it is not a constant relation. Even within the limits of the human species this relation is not so precise as is usually supposed; for, neglecting particular cases that might be quoted of men of genius not having particularly large or heavy brains, the converse cases are perhaps in this connec- tion more remarkable— viz., those of feeble-minded persons having large and apparently well-formed brains. I am indebted to Dr. Frederick Bateman of the Eastern Counties' Asylum for directing my attention to the observations of Dr. Mierzejewskis, which were published at the international congress of psychologists held in Paris in 1878. These observations, which appear to have been carefully made, seeing that casts of the brains were exhibited, went to show' that idiotcy is compatible with large and apparently well- developed brains — the amount of grey matter in one instance being " enormous." And, if we turn to the animal kingdom, we find in a still larger measure that the mere amount of cerebral substance furnishes but a very uncertain index of the level of intelli- gence which is attained by the animal. This is the case even when we eliminate the element of complexity that is introduced by the differences which obtain in different animals between the bulk of the brain and the bulk of the body— small animals requiring a greater proportional bulk of brains than large ones, because the nervous machinery which ministers to muscular movement and co-ordination has in both cases to be accommodated. But this element of com- plexity may be removed by considering the cases in which small animals exhibit remarkable intelligence ; and in this respect no animals are so remarkable as the more intelligent species of ants alluded to in my former work. As Mr. Darwin has observed, the brain of such an insect deserves to be regarded as perhaps the most wonderful piece of matter in the world. But if this whole question touching the relation between the mass of brain and degree of intelligence is felt to lie as a difficulty in the way of evolutionary theory, I should reply to it by the following considerations. In the first place, that there is a general relation between size of brain and degree of intelligence, both in the case of man and in that of animals, is unquestionable. It is, there- fore, only with the more special exceptions that wc iiave to J 111 ^ 46 MENTAL EVOLUTION IN ANIMALS. deal. But here we have to remember that besides size or mass, there must certainly be a no less important factor to be taken into account — that, namely, of structure or complexity. Now we really know so little about the relations of intelli- gence to neural structure, that I do not think we are justified in forming any very strong conclusions d- 'priori concerning the relation of intelligence to mere size or mass of brain. Know- ing in a general way that mass plus structure of brain is necessary for intelligence, we do not know how far the second of these two factors may be increased at the expense of the first. And, as a mere matter of complexity, or of multum in parvo, I am not sure that even the brain of an ant deserves to be considered more wonderful than the ovum of a human being. Lastly, in this connection it may be as well to observe that there is as good evidence to show the importance of cerebral structure as a factor in determining the level of mental development, as there is to show the importance of cerebral mass. Throughout the vertebrated series of animals the convolutions of the brain — which are the coarser expressions of more refined complexities of cerebral structure — furnish a wonderfully good general indi- cation of the level of intelligence attained ; while in the case of ants Dujardin says that the degree of intelligence exhibited stands in an inverse proportion to the amount of cortical substance, or in direct proportion to the amount of the peduncular bodies and tubercles. In view of these con- siderations, therefore, I do not feel that the supposed diffi- culty, which I have thought it desirable to mention, is one of any real solidity. THE ROOT-rKINCIPLES OF MIND. 47 CHAPTER IV. The Eoot-principles of Mind. Although the phenomena of Mind, and so of Choice, are both complex, and as to their causation obscure, I think we have now seen that we are justified in beheving that they all present a physical basis. That is to say, whatever opinion we may happen to entertain regarding the ultimate nature of these phenomena, in view of the known facts of physiology we ought all to be agreed concerning the doctrine that the mental processes which we cognize as subjective, are the psychical equivalents of neural processes which we recofr- mze as objective. As already stated, I have elsewhere con- sidered the various hypotheses concerning the nature and the various attempts at an explanation of this equivalency between mental processes and neural processes ; but here I desire to consider the fact of this equivalency merely as a fact It will therefore signify nothing to my discussion whether, with the materialists, we rest in this fact as final or endeavour, with men of other schools, to seek an explanation ot the tact of some more ultimate character. It is enouoh if we are agreed that every psychical change of which we have any experience is invariably associated with a definite physical change, whatever we may suppose to be the nature and significance of this association. Looking, then, at the phenomena of Mind as invariably presenting a physical, or, as we may indifferently call it a physiological side, I shall endeavour to point out what I con- ceive to be the most ultixnate principle of physiology which analysis shows to be common to them all. On the mental side, as we have already seen, we have no difficulty in dis- tinguishing this ultimate principle, or common characteristic as that which we designate by the term Choice. Now if the power of choice is the distinctive peculiarity of a mental m ' i iB MENTAL EVOLUTION IN ANIMALS. I! being, and if. as we have taken for granted, every chancre of latPdlnti ' ' ^'''^T^y ought to admit of being trans- ated into some pliysiological equivalent. Further if there exZJtfnJ^^r^''^T} ^^^i^lent to be found, we should expect to fina it much lower down in the scale of physio- logical development than in the functions of the human W ;i r''''* ^"i^^ ^^ *^^ ^^^^'^ ^^i«^al« manifest, in a long descending scale, powers of choice which gradually fade leT^'.'l.^T''' ^"^ ^n^r shn^lioity; but^e should be Led d prion to expect, if there is a physiolocrical nrincinle which constitutes the objective basis%f the^psycSoS principle, that t^ie former should manifest itself more early m the course of evolution than the latter. Tor, whatever InTlr^^i ";?^ entertain concerning the relation of Body pvnl ^^'^^V,^^^^^ «?n be no question, on the basis of the eyolu ion theory which I assume, thai, as a matter of his! tW n/'^"'''f 'i^^' P^^^^Plf of physiology were prior to those of psychology; and therefore, if in accordance with our original agreement we allow that the latter have a phv- sical basis m the former, it follows that the principles of Now I think that the d priori expectation thus briefly sketched IS fully realized in the occurrence of a physiologic^ principle, which first appears very low down in the worfd of lite, and which, in its relation to psychology, has not yet received the attention which it desen4 f Ly best state the principle by giving an example. I have observed that if a sea-anemone is placed in an aquarium tank, and allowed to fasten upon one side of the tank near the surface of the water and if a jet of sea water is made to play continuously and forcibly upon the anemone from above, the result of course is that the animal becomes surrounded with a turmoil of water an^ air-bubbles. Yet, after a short time, it becomes 80 accustomed to this turmoil tliat it will expand its tentacles in earch ot food, just as it does when placed in calm watei' If now one of the expanded tentacles is gently touched with a solid body, all the others close around that body, in iust the same way as they would were they expanded n calm THE ROOT-PRINCIPLES OF MIND. 49 of the water and tS whiVh t TJ'\^ ^^ ^^^ turmoil with the solid My^e^attrL'St^^^^^^ '.^^^ ^^^-^ notwithstanding^ that it :'z.f -^ ^^ , ^ ^'^"^r stimulus than the former And ii i. f^''''''"^'''^^^ ^^«« ^^^^n^ity between stimulf^Vrti^^ ^7'' of discriminating sities, that I re^ird afthrohl '"'•^''''•'^^ ''Mechanical Intel in search ; it Stutes the SlinF""T^' "^ ^^^^^ ^^ ^^^e A similar power of discriSn!^''"^ ^'P'? ^^ ^^^^°i^«- known to occur in Xnts thZr. l "''P^^'" ^"« ^^"S been facts with regard to ll'-„\S^ "^^.^ ^^^^"7 observed we owe to the later rZ^^Tr^l^^t^^ ^^^"^^^ -The extraordinary dehV-nv nf .r • . ^y^^ ^nd his son. researches show the S of t^^TT''"'' ^^"^^ ^^^^«« darkness and light of the feebW i ^ '^f''^?" ^^^^^^^^ wonderful than the delicn^v nf ^ .intensity, is not less show the roots of i^^J:^^ eL'rd^ITSn "'^l^' '""t^ moisture and lines of least rp.icf.!^ • 1 ""^ « ^^out for present connection the most si. S". '"^ f"^ '°^^- ^^^ ^^ the have been brought Tio it bf Mr ''ti ''' '>'' '^°^^ ^^^^^^^ searches on the dimbim^ nnd ,' .^'"^^^^^^ Previous re- from these researches it ^^^^^ that theT" ^^"'^ ^°^' nating between stimuli, inSpective of iT'' '^ ^^f ""^^- mtensity or amount o niechan cal rLf f "^^ mechanical proceeded to an extent tW rlf/f .1^ '^."'^''"^®' ^^^ here tissue, although tSltu^VhS^^rirh '' ""''''' structure passed beyond the cell, l«r^f mu ^''''^ ^°<^ ^^ eles of Drosera, 4ich 2sp ijf 'JT^' . Thus, the tenta- tentaoles of a seaTnemone will "^^^^^ '^ ^'"^ ^'^'' ^^'^ stimulation supplied TyTai^m '" ^}' ^^°^«"<^ Ji.--f-sor'.Slands,;irttT^^^^^^^ ceivably slight stimulus of the kindmsed hv nl ^ T""'" mmute particle of solid matter exert n!b/ "^:i'^^^^^««l3' tmuous pressure upon the samp ff^J'^'"^ by gravity a con- says, "Thepressurretted rTptSie oM ''^- ^'T^^ only T^ of a grain, and sup^rt^ed w a de^^^^^^^ ""^'^^'^""^ have been mconceivablv sli-^bf w? ^ ^^ ^"^^' ""^^t could hardly have equ (led Ihe milwr^/'^J'"-^"^*^ ^^'^^ i<^ shall hereafter see that f,r lei ^^ ?^^ of a gram ; and we of phosphate of ammonia in so t^n ' T^^''"^'^' '^ ^ ^rain gland, acts on it aTd^Uicef iTJe'r '''''''' i^/ -^ ' • • • XL IS -I 50 MENTAL EVOLUTION IN ANIMALS. extremely doubtful whether any nerve in the human body, even if in an inflamed condition, would be in any way affected by such a particle supported in a dense fluid, and slowly brought into contact with the nerve. Yet the cells of the glands of Drosera are thus excited to transmit a motor impulse to a distant point, inducing movement. It appears to me that hardly any more remarkable fact than this has been observed in the vegetable kingdom. ' ^ But the case does not end here. For m another insec- tivorous plant, Dionoea, or Venus' Fly-trap, the principle of discriminating between different kinds of stimuh has been developed in a direction exactly the opposite to that which obtains in Drosera. For while Drosera depends for captunng its prey on entangUng the latter in a viscid secretion from its olands, Dionoea closes upon its prey with the suddenness of a spring-trap; and in relation to this difi'erence m the mode of capturing prey, the principle of discrimination between stimuli has been correspondingly modified. In Drosera, as we have seen, it is the stimulus supplied by oontinuous pressure that is so delicately perceived, while the stimulus supphed by ivipact is disregarded; but in Dionoea the smallest impact upon the irritable surfaces, or filaments, is immediately re- sponded to, while the stimulus supplied even by compara- tively great pressure upon the same surfaces is wholly disregarded. Or, in Mr. Darwin's own words, " Although the filaments are so sensitive to a momentary and delicate touch, they are far less sensitive than the glands of Drosera to pro- longed pressure. Several times I succeeded m placing on the tip of a filament, by the aid of a needle moved with extreme slowness, bits of rather thick human hair, and these did not excite movement, although they were more than ten times as long as those which caused the tentacles of Drosera to bend ; and although in this latter case they were largely supported by the dense secretion. On the other hand the olands of Drosera may be struck with a needle, or any hard Sbiect, once, twice, or even thrice, with considerable force, and no movement ensues. This singular difference in the nature of the sensitiveness of the filaments of Dionoea and of the glands of Drosera evidently stands in relation to the habits of the two plants. If a minute insect alights with its delicate feet on the glands of Drosera, it is caught by the viscid secretion, and the slight, though prolonged pressure THE ROOT-PRINCIPLES OF MIND. 51 gives notice of the presence of prey, which is secured by the slow bending of the tentacles. On the other hand, the sensi- tive filaments of Dioncea are not viscid, and the capture of insects can only be assured by their sensitiveness to a momentary touch, followed by the rapid closure of the lobes." So that in these two plants the power of discriminating between these two kinds of stimuli has been developed to an equally astonishing extent, but in opposite directions. But we find definite evidence of this power of discrimina- tive selection even lower down in the scale of life than the cellular plants; we find it even among the protoplasmic organisms. Thus, to quote an instructive case from Dr. Car- penter : — " The Deep-Sea researches on which I have recently been engaged have not ' exercised ' my mind on any topic so much as on the following : — Certain minute particles of living jelly, having no visible differentiation of organs .... build up ' tests ' or casings of the most regular geometrical sym- metry of form, and of the most artificial construction . . . From the same sandy bottom, one species picks up the coarser quartz-grains, cements tliem together with phosphate of iron (?), which must be secreted from their own substance ; and thus constructs a flask-shaped ' test ' having a short neck and a single large orifice. Another picks up iho. finer grains, and puts them together with the same cement into perfectly spherical ' tests ' of the most extraordinary finish, perforated with numerous small tubes, disposed at pretty regular inter- vals. Another selects the minutest sand-grain and the terminal points of sponge-spicules, and works these up together — apparently with no cement at all, but by the ' laying ' of the spicules — into perfect spheres, like homceo- pathic globules, each having a single fissured orifice." * Thus, co-extensive with the phenomena of excitability, that is to say, with the phenomena of life, we find this func- tion of selective discrimination ; and, as I have said, it is this function that I regard as the root-principle of Mind. I so regard it because, if we consider all the faculties of mind, we shall observe that the one feature which on their objecix .'e side they present as common, is this power of discriminating among stimuli, and responding only to those which, irrespec- tive of relative mechanical intensity, are the stimuli to which * Coniem^orari/ Review, April, 1873 !1 ' — ^--yi — rni-J I : ill 62 MENTAL EVOLUTION IN ANIMALa responses are appropriate. In order to see this, let tis lake the principal faculties of mind in their ascending order, and consider what they are, in their last analysis, upon their physiological side. First we have the organs of special Sensation, the physiological functions of which clearly con- stitute the basis of the whole structure psychological. Yet no less clearly, these functions in their last analysis are merely so many specially developed aptitudes of response to special modes of stimulation. Thus, for instance, the struc- ture of the eye is specially adapted to respond only to the particular mode of stimulation that is supplied by light, the ear to that which is supplied by sound, and so on. In other words, the organs of special sense are so many structures ] which have been variously and extremely differentiated in several directions, for the express purpose of attaining a severally extreme sensitiveness to special modes of stimula- tion v/.'thout reference to any other mode. And this is merely to say that the function of an organ of special sense is that of sorting out, selecting, or discriminating the par- ticular kind of stimulation to which its responsive action is appropriate. Again, many of the nervous mechanisms which minister to various Eeflex Actions are only thrown into activity by special modes of stimulation. This is notably the case with those highly complicated neuro-muscular mechanisms which are thrown into activity only by the mode of stimulation which we call tickling. Such instances are of special interest in the present connexion from the fact that the distinguishing peculiarity of this mode of stimulation consists in its being a stimulation of low intensity. The comparatively violent stimulation that is caused by the passage of food down the gullet, or by contact of the soles of the feet with the ground, is unproductive of any response on the part of the mechanisms which are thvown into violent activity by the gentlest possible stimula- tion of the same surfaces. Similarly with regard to Instincts. These, physiologically considered, are the activities of highly differentiated nervous mechanisms which have been slowly elaborated, through successive generations, for the express purpose of responding to some particular stimulus of a higlily wrought character, and which, on its psychological side, is a recognition of the circumstances to which the instinctive adjustment is appropriate. And so with the Emotions. Tor, THE ROOT-PRINCIPLES OF MIND 63 physiologically considered, the emotions are the activities of highly wrought nervous mechanisms, and these activities are only excited by the very special stimuli which, on their sub- jective side, we recognize as the particular kind of ideas which are appropriate to call up particular emotions. We do not laugh at a painful sight, nor does a ludicrous sight cause us to weep; and this, physiologically considered, merely means that the nervous machinery whose action is accompanied by one emotion, will only respond to one kind of very specialized and complex stimulation ; it will not respond to another and probably in many respects very similar kind of stimulation, which, nevertheless, is competent to evoke re- sponses from another and probably very similar piece of nervous machinery. And thus, also, it is with Eeasoning and Judg- ment. Eeasoning, on its physiological side, is merely a series of highly complicated nervous changes, regarding which the only thing we certainly know is, that not one of them can take place without an adequate physical accompaniment, and therefore that on its physiological side a train of reasoning is a series of nervous changes, every one of which must be produced by physical antecedents. And hence on its objec- tive side every step in a train of reasoning consists in a selective discrimination among all those exceedingly delicate stimuli which, on their subjective side, we know as argu- ments. Similarly regarded. Judgment is likewise nothing more than the final result of the incidence of a vast number of very delicate stimuli ; and this final result, like all the intermediate steps of the reasoning which led to it, is nothing more than the exercise of a power to discriminate between the stimulus which on its subjective side we recognize as the right, and that which we similarly recognize as the wrong. Lastly, Volition, subjectively considered, is the faculty of consciously selecting motives ; and motives, objectively con- sidered, are nothing more than immensely complex and inconceivably refined stimuli to nervous action. If we turn from the ascending scale of mental faculties in man, to the ascending scale of mind in the animal king- dom, we shall meet with further and still more definite evi- dence that the distinguishing property of mind, on its physiological side, consists in this power of discriminating between different kinds of stimuli, irrespective of their degrees of mechanical intensity. But, before giving a brief I 11 1 I 54 MENTAL EVOLUTION IN ANIMALS. review of the evidence on chis point, I may here meet a difficulty which has already arisen. The difficulty is that 1 began by showing it necessary to define Mind as the power of exercising Choice, and then proceeded to define the latter as a power belonging only to agents that are able to teel. Yet, on looking at the objective side of the prob era 1 pointed out that the physiological or objective equivalent ot Choice is found to occur in its simplest manifestations at least as low down as the insectivorous plants which are certainlv not agents capable, in any proper sense of the term, of feelincT. Therefore it seems that my conception ot what constitutes Choice is in antagonism with my view that the essential element of Choice is found to occur among organ- isms which cannot properly be supposed to feel. And this antagonism, or inherent contradiction, is a real one. though I hold it to be unavoidable. For it arises from the fact that neither Feeling nor Choice appears upon the scene ot lite suddenly. We canaot say, within extensive limits where either can properlj' be said to begin. They both dawn eraduaUy, and therefore in our everyday use ot these terms we do not wait to consider where they are first applicable; we only apply them where we see their applicability to be apparent. But when we endeavour to use these same terms in strict psychological analysis, we are at once met with the difficulty of drawing the line where the terms are applicable and where they are not. There are two ways of meeting the difficulty. One is to draw an rbitrary line, and the other is not to draw any line at all; but to carry the terms down through the whole gradation of the things until we arrive at the te°rminal or root-principles. By the time that we do arrive at these root-principles, it is no doubt true that our terms have lost all their original meaning ; so that we might as well call an acorn an oak, or an egg a chicken, as speak of a Dioncea feeMna a fly, or of a Drosera cJwosing to close upon its prey. Yet this use, or rather let us call it abuse, of terms serves one important purpose if, while duly regarding the change of meaning which during their gradual descent the terms are made gradually to undergo, we thus serve to emphasize the fact that they refer to things which are the product of a gradual evolution-things which came from other things as unlike to them as oaks to acorns or chickens to eggs. And this is my justification for tracing back the root-prmciples of THE ROOT-PRINCIPLES OF MIND. 65 Feeling and of Choice into the vegetable kingdom. If it ia true that plants manifest so little evidence of Feeling that the term can only he applied to them in a metaphorical sense, it is also true that the power of Choice which they display is of a similarly undeveloped character ; it is limited to a single act of discrimination, and therefore no one would think of applying the term to such an act, until analysis reveals that in such a single act of discrimination we have the germ of all volition. Let it therefore be understood that the difficulty which we are considering arises merely from the gradual manner in v'^-lch the faculties in question u,ose. The rudimentary power of discriminative excitability which a plant dispKays is commensurate with the rudimentary power of selective adjustment which it manifests in its movements ; and, just as the one is destined by developmental elaboration to become a self-conscious subjectivity, so the other is destined, by a similar elaboration, to become a deliberative volition. I shall now briefly glance at the ascending scale of organisms, with the view of showing that this proportional relation between the grade of receptive and that of executive ability is manifested throughout the series. I desire to makti it plain that the power of discrimination which in its higher manifestations we recognize as Feeling, and the power of selective adjustment which in its higher manifestations we recognize as Choice, are developed together, and throughout their development are commensurate. Amoeba is able to distinguish between nutritious and non- nutritious particles, and in correspondence with this one act of discrimination it is able to perform one act of adjustment ; it is able to enclose and to digest the nutritious particles, while it rejects the non-nutritious. Some protoplasmic and unicellular organisms are a'3le also to distinguish between light and darkness, and to adapt their movements to seek the one and shun the other ; while in " Animal Intelligence " some observations are given which seem to show that the discriminative and adjustive powers of these organisms may go farther even than this. The insectivorous plants, as we have already seen, are able to distinguish, not only between nutritious and non-nutritious particles, but also between different kinds of contact ; and, in corresponc.ence with this advance in receptive power, we observe a commensurate 66 MENTAL EVOLUTION IN ANIMALS. ■7 / I ^^ \ advance in the mechanism of adaptive movement. Numhor- leas other cases of such simple powers among plants might here be noticed ; but none of thera rise above the level of distinguishing between one or two alternatives of stimula- tion, and supplying the correspondingly simple movements of response. Where nerve-structure first appears, we find that the animals wliich present it — the Medusa) — have organs of special sense whorewith to distinguish with comparative delicacy and rapidity between light and darkness, and probably also between sound and silence. They are also provided with an elaborate tentacular apparatus, wherewith they are able to distinguish quickly and accurately between moving and not moving objects coming upon them from various sides, as well as between nutritious and non-nutri- tious particles. And in con-espondence with this advance of receptive capacity we observe a considerable advance of executive capacity — the animals being highly locomotive, swimming away rapidly from sources of contact which they distinguish as dangerous, and manifesting several other retlex actions of a similarly adaptive kind. Tims, also, the higher organizations of Star-fish, Worms, &c., wh.ile serving to supply the neuro-muscular mechanisms with still more detailed information regarding the outer world, serve likewise to supply them with the means of executing a greater variety of adaptive movements. In the Mollusca, again, we observe another advance in both these respects; the animals feel their way with sensitive feelers, select varied kinds of food, choose mates of their own species to pair with, and may even remember a particular locus as their home, &c. Among the Articulata the lower forms present co-ordinated movements which are few and simple as compared with the many and varied movements of the higher members of the class ; and their powers of distinguishing between stimuli are propor- tionally small. But in the complicated anatomy of the Crabs and Lobsters there is a large provision for the co-ordina- tion of movements, and the selective actions are correspond- ingly nifinerous and varied; while among the Insects and Spiders the power of muscular co-ordination surpasses that of the lower Vertebrata, and the power of intelligent adapta- tion, assisted by delicate antennas and highly perfected organs of special sense, is also greater. And the same principles hold throughout the Vertebrated series. It has already been THE ROOT-PRINCIPLES OF MIND. 87 rpmnrkcd by Mr. Spencer that there is here a general corre- Bpondenco to be observed between the possession of organs capable of varied actions, and the degree of intelligence to wliich the a,ninial attains. Tims of Birds the Parrots are the most intelligent, and they, more than any other members of their class, are able to use tlieir feet, beaks, and tongues in tlie examination of objects. Similarly, the wonderful intelligence of the Elephant may be safely considered as correlated with the no less wonderful instrument of co-ordinated movement which he possesses in his trunk ; while the superior intelli- gence of the Monkey, and the supreme intelligence of Man may no less safely be considered as correlated with the ^ill more wonderful instrument of co-ordinated movement which has attained to almost ideal perfection in the human liand. Again, and more generally, we may say that throughout the animal kingdom the powers of siglit and of hearing stand in direct ratio to the powers of locomotion ; and the latter are conducive to the growth of intelligence.* We may now observe that this correlation between muscular and mental evolution — or, more generally, between power of discrimination and variety of adaptive movements — is only what we should expect to find d priori. For it is clear that the development of the one function could be of no use without that of the other. On the one hand, it would be of no use to an organism that it should be able to discern a stimulus as hurtful or beneficial, if at the same time it lacked the power of co-ordinated movement necessary to adapting itself to the result of its discernment ; and, on the other hand, it would be equally useless that an organism should possess the needful power of co-ordinated movement, if at the same time it lacked the power of discernment which alone could render the power of co-ordinated movement use- ful. Now we know that all the meclianisms of muscular co-ordination are correlated with mechanisms of nervous co- ordination, and, indeed, that the former without the latter would be utterly useless. Yet we know next to nothing of • The Dog and Cat seem at first sight to constitute an exception to the principle above set forth; but it must be remembered that both these animals, and all tlieir tribe, possess very efficient instruments of touch and movements in their tongues, lips, and jaws, as well as to some extent in the paws. I think the superior intelligence of tlie Octopus, among molluslts, is to be attributed to the exceptional advantages which are rendered by its large and flexible, sensitive and powerful arms. n\ ;if 't: i ) Vt -li 53 MENTAL EVOLUTION IN ANIMALS, i :? J ':': -7 >•'! the ultimate nervous mechanisms whicli play down upon the muscular mechanisms; we only see a mazy mexus of cells and fihres, the very function of which, much less their inti- mate mechanism, could not be guessed, were it not that wo have the grosser mechanisms of the muscular system whereby to study the effects of these finer mechanisms. Muscular co-ordinations, then, are so many indices, " writ large," of corresponding co-ordinations taking place in the nervous system. Now we have seen that mental processes may be regarded as indices in precisely the same way, and indeed that, like muscular movements, they are the only indices we have of the operations of the nervous mechanisms with which they are connected. Moreover, we have seen that when this new set of indices has reached a certain level of development, marking of course a corresponding level of development in the nervous system, it begins unmistake- ably to show that the functions of receptive discrimination and of adaptive movement are taking yet another point of departure in the upward course of their development — that the nervous system is beginning to discriminate between novel and enormously complex stimuli, having reference not only to immediate results, but also to remote contingencies ; we see in short that the nervous mechanism is beginning to develope those higher functions of discriminative and adaptive ability which on their subjective side we know as rational. Therefore it is clear that these two faculties not only do but must proceed together. Every advance in the power of discrimination will be followed, in the life of the individual and in that of the species, by efforts towards the movements of needful adaptation, and in all cases where such movements require an advance on the previous power cf co-ordination, such advance will be favoured by natural selection. Thus every advance in the power of discrimination favours an advance of the power of co-ordination. And, conversely, we may now remark that every advance in the power of co- ordination favours an advance of the power of discrimina- tion. For, as a greater pov^er of co-ordinated movement implies the bringing of nerve-centres into new and more varied relations with the outer world, there is thus afforded to the nerve-centres a proportionately increa,sed opportuni;.}' of discrimination— an opportunity which will sooner or later be sure to be utilized by natural selection. THE ROOT-PRINCIPLES OF MIND. 59 Thus the two facvlties are, as it were, necessarily bound together. But here another consideration arises. They are thus bound together only up to the point at which the adap- tive movements are dependent upon the machinery supplied by nature to the organism itself. As soon as the power of discrimination has advanced far enough to be, not only con- sciously precipient, but deliberatively rational, a wholly new state of things is inaugurated. For now the organism is no longer dependent for its adjustments upon the immediate results of its own co-ordinated movements. From the time that a stone was first used by a monkey to crack a nut, by a bird to break a shell, or even by a spider to balance its web, the necessary connexion between the advance of mental dis- crimination and muscular co-ordination was severed. With the use of tools there was given lo Mind the means of pro- gressing independently of further progress in muscular co- ordination. And so marvellously has the highest animal availed itself of such means, that now, among the civilized races of mankind, more than a million per cent, of his adjus- tive movements are performed by mechanisms of his own construction. Wonderful as are the muscular co-ordinations of a tight-rope dancer, they are nothing in point of utility as compared with the co-ordinated movements of a spinning- jenny. Therefore, although man owes a countless debt of gratitude to the long line of his brutal ancestry for bequeath- ing to him so surpassingly exquisite a mechanism as that of the human body— a mechanism without which it would be . impossible for him, with any powers of mind, to construct the artiiicial mechanisms which he does— still man may justly feel that his charter of superiority over the lower animals is before all else secured by this, that his powers of adjustive movement have been emancipated from their necessary alliance with his powers of muscular co-ordination. _ _ I say, from his powers of muscular co-ordination, because It IS evident that our powers of adjustive movement, and so of adaptation in general, have never been, and can never he, emancipated from a necessary alliance with our powers of nervous co-ordination. I shall now sum up the results of our enquiry so far as it has hitherto gone. First, we found the Criterion of Aliud, ejectively considered, to consist in the exhibition of ifni I! ; I t '■'}'< 60 MENTAL EVOLUTION IN ANIMALS. Choice, and the evidence of Choice we found to consist in the ■performance of adaptive action suited to meet circumstances which have not been of such frequent or invariable occur- rence in the life-history of the race, as to have been specially and antecedently provided for in the individual by the in- herited structure of its nervous system. The power of learn- InfT by individual experience is therefore the criterion of Mind. But it is not an absolute or infallible criterion ; all tlhat can be said for it is that it is the best criterion available, and that it serves to fix the upper limit of non-mental action more precisely than it does the lower limit of mental ; for it is probable that the power of feeling is prior to that of con- sciously learning. Having thus arrived at the best available criterion of Mind considered as an eject, we next proceeded to consider the objective conditions under which known Mind is invari- ably found to occur. This led us briefly to inspect the structure and functions of the nervous system, and, while treating of the physiology of reflex action, we found that everywhere the nervous machinery is so arranged that there is no alternative of action presented to the nerve-centres other than that of co-ordinating the group of muscles over the combined contractions of which they severally preside. The question therefore arose — How are we to explain the fact that the anatomical plan of a nerve-centre with its attached nerves comes to be that which is needed thus to direct the nervous stimuli into the channels required ? The answer to this question we found to consist in the property which is ** shown by nervous tissue to grow by use into the directions which are required for further use. This subject is as yet an obscure one— especially where the earliest stages of such adaptive growth are concerned— but in a general way we can understand that hereditary usage, combined with natural selec- tion, may have been alone sufficient to construct the number- less reflex mechanisms which occur in the animal kingdom. Passing from reflex action to cerebral action, we first noticed that as the cerebral hemispheres pretty closely re- semble in their intimate structure ganglia in general, there can be no reasonable doubt that the mode of their operation - is substantially the same. Moreover we noted that, as such operation is here unquestionably attended with mental action, . a strong presumption arises that the one ought to coustituta THE EOOT-PRINCIPLES OF MIND. 61 a kind of obverse reflection of the other. Turning, therefore, to contemplate this presumably obverse reflection, we found that in many respects it is most strikingly true that the fundamental principles of mental operation correspond with the fundamental principles of ganglionic operation. Thus, we found that such is the case with memory and the association of ideas both of which we found to have their objective counterparts in the powers of non-mental acquisition which are presented by the lower ganglia. For we found that these ganglia unconsciously learn such exercises as they are made frequently to perform, that they forget their exercises if too long an interval is allowed to elapse between the times of practising them, but that even when apparently quite for- gotten such exercises are more easily re-acquired than originally they were acquired. More particularly we found that the association of ideas by contiguity presents a remark- ably detailed resemblance to the association of muscular movements by contiguity. For, agreeing to take ideas as the objective analogues of muscular movements, we observed when we thus changed the index of nervous operation from muscles to ideas, that the strongest evidence was yielded of the method of nervous evolution being everywhere uniform. Thus we remarked that sensations, perceptions, ideas, and emotions all more or less resemble muscular 'co-ordinations in that they are usually blended states of consciousness, wherein each con- stituent part must correspond with the activity of some particular nervous element — a variety of such elements being therefore concerned in the composite state of consciousness, just as a variety of such elements are concerned in a com- bined movement of muscles. Further, just as the associa- tion of ideas is not restricted to a blending of simultaneous ideas into one composite idea, but extends to a linking of one idea with another in serial succession ; so we saw that mus- cular movements exhibit a precisely analogous tendency to recur in the same serial order as that in which they have previously occurred. Lastly, we noted that all the patholo- gical derangements which arise in the nerve-centres that preside over muscular activities, have their parallels in simi- lar derangements which arise in the nerve-centres that are concerned in mental activities. Having thus dealt with the Physical Basis of Mind, we passed on in the next chapter to consider the Eoot-principles 62 MENTAL EVOLUTION IN ANIMALS. i ir^i. ^ f n : S ■ ' i ,i| ^ of Mind. Here the object was to trace the ultimate principles of physiology that might be taken as constituting the objec- tive side of those phenomena which on their subjective and ejective sides we regard as mental. These principles we found to be the power of discriminating between different kinds of stimuli irrespective of their relative degrees of mechanical intensity, coupled with the power of performing adaptive movements suited to the results of such discrimina'^ tion. These two powers, or faculties, we saw to occur in •/ germ even among the protoplasmic and unicellular organisms, and we saw that from them upwards all organization may be said to consist in supplying the structures necessary to an ever-increasing development of both these faculties, which always advance, and must necessarily advance, together. Wlien their elaboration has proceeded to a certain extentj they begin gradually to become associated with Feeling, and when they are fully so associated, the terms Choice and Pur- pose become to them respectively appropriate. Continuing ,.^ in their upward course of evolution, they next become con° / sciously deliberative, and eventually rational. But although when viewed from the subjective or ejective side they thus appear, during the upward course of th ; development, to become transformed from one entity to another, such is not the case when they are viewed from their objective side. For, when viewed from their objective side, the most elaborate process of reasoning, or the most comprehensive of judg- ments, is seen to be nothing more than a case of exceedingly refined discrimination, by highly-wrought nervous structures, between stimuli of an enormously complex character ; while the most far-siglited of actions, adapted to meet the most remote contingencies of stimulation, is nothing more than a neuro-muscular adjustment to the circumstances presented by the environment. Thus, if we again take mental operations as indices whereby to study the more refined working of nervous centres, as we take muscular movements to be so many indices' " writ large," of the less refined working of such centres^ we again find forced upon us the truth that the method of nervous evolution has everywhere been uniform; it has everywhere consisted in a progressive development of the power of discriminating between stimuli, combined with the complementary power of adaptive response. EXPLANATION OF THE DIAGRAM. 63 ! J ii Ms CHAPTER V. Explanation of the Diagram. We have now sufficiently considered the sundry first prin- ciples and prehminary questions which lie at the threshold of our subject proper. It seemed to me desirable to dispose of these principles and questions before we enter upon our attempt at tracing the probable history of Mental Evolution. ±Jut now that these first principles and preliminary questions have been disposed of, so far as their nature renders possible the way is as clear as it can be for us to pursue our enquirv concerning the Genesis of Mind. In order to give definition to the somewhat laborious investigation on which we are thus about to embark, I have thought it a good plan to draw a diagram or map of the probable development of Mind from Its first beginnings in protoplasmic life up to its culmination m the brain ot civilized man. The diagram embodies the results of my analysis throughout, and will therefore be repeatedly alluded to in the course of that analysis— ee througaout the present and also my future work. I may theretore begin by explaining the plan of this diagram. ^ Ihe diagram, as I have just said, is intended to represent m one view the whole course of mental evolution, supposin^r m accordance with our original hypothesis, such evolution S have taKen place. Being a condensed epitome of the results ot my analysis It is in all its parts carefully drawn to a scale, the ascending grades or levels of which are everywhere determmed by the evidence which I shall have to adduce Ihe diagram is therefore not so much the product of my indi- vidual imagination, as it is a summary of all the facts whi
  • l3 which renders possible the executive faculty of appropriately responding to stimuli. Not less deserving of similar treatment is the cognate principle of Discrimination, which, as we have seen, is destined to become the most important of the functions subsequently distinctive of nerve- cells and ganglia. But we have also seen that both Conduc- tility and Discrimination first appear as manifested by the cellular tissues of plants, if not even in some forms of apparently undifferentiated protoplasm. It is, however, only when these two principle^j are united within the limits of the same structural elements that we first obtain optical evidence of that differentiation of tissue which the histologist recognizes as nervous; therefore I have represented the function of nerve-tissue in its widest sense, Neurility, as formed by a confluence of these two root-principles. Neurility then passes into Eeflex Action and Volition, which I have repre- sented as occupying the axis or stem of the psychological tree. On each side of this tree I have represented the out- growth of branches, and for the sake of distinctness I have confined the branches which stand for the faculties of Intellect on one side, while placing those which represent the Emotions upon the other. The level to which any branch attains re- presents the degree of elaboration which the faculty named thereon presents; so that, for instance, when the branch Sensation, talcing origin from Neurility, proceeds to a certain level of development, it gives off the cuiiiiiioucement of Per- EXPLANATION OF THE DIAGRAIL 65 ception, and then continues in its own line of development to a somewhat higher level. Similarly, Imagination arises out of Perception, and so with all the other branches. Thus the fifty levels which are drawn across the diagram are intended to represent degrees of elaboration ; tliey are not intended to represent intervals of time. Such being the case, the various products of mental evolution are placed in parallel columns upon these various levels, so as to exhibit the comparative degrees of elaboration, or evolution, which thev severally present. One of these columns is devoted to the psycho- logical scale of intellectual faculties, and another to the psychological scale of the emotional. But for the danger of rendering the diagram confused, these faculties might" have been represented as secondary branches of the psycholooical tree ; in a model this might well be done, but in a diagram it would not be practicable, and therefore I have restricFed the branching structure to represent only the most generic or tiindamental ot the psychological faculties, and relegated those ot more specific or secondary value to the parallel columns on either side of the branching structure. In these two columns 1 have throughout written the name of the faculty at what I conceive to be the earliest stage, or lowest level of its elaboration ; i.e., where it first gives evidence of its existence m another parallel column I have given the grades of mental evolution which I take to be characteristic of sundry crroups m the animal kingdom, and in yet another column I have represented the grades of mental evolution which I take to be characteristic of different ages in the life of an infant In my subsequent work I shall fill up all the levels in . these vertica. columns which are now left blank, on account ' ot the text of the present work being restricted to the mental evolution of animals. At first I intended in this work to truncate the whole diagram at the level where mental evolu- tion in animals ends— ie., at the level marked 28— and to reserve the continuation of the stem and branches, as well as tnat ot the parallel columns, for my ensuing work. But a terwards I thought it was better to supply the continuation ot the stem and branches, in order to show the proportion which I conceive to obtain between the elaboration of the higher faculties as they occur in animals and the same taculties as they occur in man. Confining, then, our attention to the first twenty-eight m 11 PI li!! i' ii; ■ ! _jijaami ' 11 I 66 MENTAL EVOLUTION IN ANIMAL3. ^levels with which alone the present essay is to be concerned, if we pitch upon any one of them at random, we shall obtain a certain rough estimate of the grade of mental evolution which IS presented by the animals named upon that level. _ To avoid misapprehension I may add that in thus render- ing a diagrammatic representation of the probable course of mental evolution with the comparisons of psycholo.ses, it is impossible to avoid a certain amount of over- lapping with what has gone before. For example, in my chapter on the Physical Basis of Mind, it was clearly impos- sible not to allude to such leading principles of psychology as sensation, perception, ideation, and others. Therefore, in now undertaking an investigation of these various principles CONSCIOUSNESS. 71 in the order of their probable evohition, it may ofton appear that I am, as it were, going back upon, or in part repeating, what I have ahvady said. But this apparent defect in the method of my exposition will, I think, be seen on closer attention to be more than compensated for by the advantage of avoiding confusion between physiology and psychology. It would, lor instance, have been easy to have split up tlie chapter on the Physical Basis of Mind already alluded to, and to have apportioned its various parts to those among the succeeding chapters which treat of the psychological aspects of the pliysiological princii)les set forth in those various parts; but the result would have been largely to have obscured th(3 doctrine which I desired to make plain through- out — viz., that all mental processes must be regarded as pre- senting physical counterparts.* So much in explanation of my method being understood, I shall begin the psychology of mental evolution by con- sidering that in which the mind-element must be regarded as consisting — namely. Consciousness. Turning to the diagram, it wilt be observed that I have written the word " Con- sciousness " in a perpendicular direction, beginning at level 14 and extending to level 19. My reason for doing this is because the rise of Consciousness is probably so gradual, and certainly so undefined to observation, that any attempt to draw the line at which it does arise would be impossible, even on the rough and general scale wherewith I havp endea- voured to draw the lines at which the sundry mental faculties may be regarded as taking origin. Therefore I have repre- sented the rise of Consciousness as occupying a considerable area in our representative map, instead of a definite line. This area I make to begin with the first development of " Nervous Adjustments," and to terminate with the earliest appearance of the power of associating ideas. In now proceeding to justify this assignment of limits between the earliest dawn of Consciousness and the place where Consciousness may first be regarded as truly such, I may best begin by saying that I shall not attempt to define • It seems almost needless to add that the impossibility of entirely Bopa- raling psychology from physiology for the purposes of exposition will, mutatis mutandis, confinue to meet us more or less throughout the following, as it has throughout the preceding chapters ; but I sliall endeavour always to make it clear when I am speaking of mental processes and when of physical. i. M Jtf^i^^ m i,i : 'ill 72 MENTAL EVOLUTION IN ANIMALS What is meant by Consciousness. For, like the word " Wnd " any defiSn Tf .. ^^'\^^'^> cannot be comprehended in that of an ahnost unrecognizable affection ,,nS,tl't "J rZeirZT''"'r- ^"^ S^dual, that ev n wWnn L oi of objective analysis, to correspond; and this weTflSd.' i il! CONSCIOUSNESS. 73 For in our own organisms we know that reflex actions are not accompanied by consciousness, altliougli the complexity of the neuro-muscular systems concerned in these actions may be very considerable. Clearly, therefore, it is not mere complexity of ganglionic action that determines conscious- ness. What, then, is the difference between the mode of operation of the cerebral hemispheres and that of the lower ganglia, which may be taken to correspond with the great suijjective distinction between the consciousness which may attend the former and the no-consciousness which is inva- riably characteristic of the latter ? I think the only difference that can be pointed to is a difference of rate or time. We know by actual measurement, as we shall subsequently see in more detail, that the cerebral hemispheres work more slowly while undergoing those changes which are accom- panied by consciousness than is the case with the activities of the lower centres. In otlier words, tlie period between the fall of a stimulus and the occurrence of responsive movement is notably longer if the stimulus has first to be perceived, than it is if no perception is required. And this is proved, not only by comparing the latent period (or the time which elapses between t! ■. stimulation and the response) in the case of an action involvxng one of the lower centres and that of an action involving the cerebral hemispheres in perception ; but also by comparing the latent period in the case of one and the same cerebral action which from having originally involved perception has through repetition become automatic. An old sportsman will have his gun to the shoulder, by an almost unconscious act, the moment thit a bird unexpectedly rises; a novice similarly surprised wii, spend a valuable second in "taking in" the situation. And any number of similar facts might be given to show that if few things are " as quick as thought," reflex or automatic action is one that is quicker. Further, in a general v/ay it can be shown that the more elaborate a state of consciousness is, the more time is required for its elaboration, as we shall see more in detail when we come to treat of Perception. Now what does this greater consumption of time imply ? It clearly implies that the nervous mechanism concerned has not been fully habituated to the performance of the response required, and therefore tliat instead of the stimulus merely needing to touch the trigger of a ready- formed apparatus of !-,ii 1V m 74 rii m MESTAL ETOLOTIOS lU AOTMA13. response is jJddS JP'^f".^'™"'' before the appropriate this ph.y o/Suli iJ"t 'e Sence' o?'" J-'^,"""!" ».- "^ stances" is known a«in,l,:„-'^L " "difficult circmn- conscious^ess-rch 4 t?r^^^ '"' ,?™" " » »»»Pl« "«* ot time is reqnived by tto erebrlS"' J " P?'-«q«ion-more appropriate responseto a non haH Z "• '"PP'^^S an required by tlie lower np,t„ ^ "' experience, than is complicated of rX ac to^T' ^r performing the most habitual exper fence I^, ,„ ? !7 ™^ f '"'P"""" to thdr discharge Cittn wl ''^.i^^Vui'tZf/ ""™"' And this c„,n 1 X„f f»«s wh ch f 7''''?' 'f'"'-^*--- expression in a len'-tl enh, " .f t'b. "',' '" l'''.)'«i»l''Hi-al a psyehoh,gic„l e.^:^:\^l^ t^^i^'' -° deaH:^^;;;fr.';f::hfch''':,s,f:':;]iT''^T'^^^'^^ parative sense siinnlp nrp ,?,'''"-'' possibly and m a com- sciousness. Or, in th^ 3s "f a17 ^ plienomena of con- And th3 quid fuccession oT^i::^'^ • "'*^''-^' T^^^ '^'''^''- * Principles of Ps,/choloq,/, vol i n Aq^; t m • 1 i Spencer is not sw/Iioientlv evnlie fc o H .'..Fi-n .1 f '"^' ^'o^o^^'- t'lat Mr. where, in showing that ' t^^mS^^'lI^^J^'"' quoted passage or else- constituted bj the mere c^m^rrZof .r.nii;""'"""'' '"'* V' "^^^ "«'^^s^'i'-ily said, sucli complexity in i.self doe It ,.nn f! . 1' '''^'^"- , ^'"^'^'"^' «« ^ '>'^ve rise of consciousness! except n so for \sknav"h' ""^"""« '° ^''^ ^''^'^ »''« tera. the ganghoaic fri^tioi. wMchTa txireS brai^;X^^^^^^^^^^^^ ^^ "^^^ CONSCIOUSNESS. 75 them into more and more complex and varied relations with their environment), the primitive assignment of a special nervous mechanism to meet the exigencies of this or that special group of stimuli becomes no longer practicable, and the higher nerve-centres have therefore to take on the func- tion of focussing many and more or less varied stimuli, in order to attain to that higher aptitude of discrimination in which we have already seen to consist tlie distinctive attri- bute of Mind. And, as Mr. Spencer has observed, " the co- ordination of many stimuli into one stimulus is, so far as it goes, a reduction of difi'used simultaneous changes into con- centrated serial changes. Whether the combined nervous acts which take place when the fly-catcher seizes an insect are reg-arded as a series passing through its centre of co- ordination in rapid succession, or as consolidated into two successive states of its centre of co-ordination, it is equally clear that the changes going on in its centre of co-ordination have a much more decided linear arrangement than have the cliangcs going on in the scattered ganglia of a centipede." And this linear character of the change is, of course, one of the most distinctive features of consciousness as known to ourselves subjectively. It will have been ol)served that this interpretation of the rise of consciousness is purely empiiical. We know by immediate or subjective analysis that consciousness only occurs when a nerve-centre is engaged in such a focussing of varied or comparatively unusual stimuli as have been described, and when as a preliminary to this focussing or act of discriminative adjustment there arises in the nerve-centre a comparative turmoil of stimuli coursing in more or less unaccustomed directions, and therefore giving rise to a com- parative delay in the occurrence of the eventual response. But we are totally in the dark as to the causal connection, if any, between such a state of turmoil in a ganglion and the occurrence of consciousness. Whetlier it is tlie Angel that descends to trouble the waters, or the troubling of the waters that calls down the Angel, is really the question which divides the Spiritualists from the Materialists ; but with this question we have nothing to do. It is enough for all the objects of the present work that we never get the Angel without the troubling, nor the troubling without the Angel ; we have an empirical association between the two which is as valid for ( 'i ■■ 1^ MM ! :l - Ill 76 KENTAL EVOLUTION IN ANIMALS. the purposes of merely historical psychology as would be a full understanding of the causal connection, if there is any such connection to be understood. So much, then, for the physical conditions under which consciousness is always and only found to occur. It remains briefly to conclude this chapter by showing that these con- ditions may most reasonably he regarded as first arising within the limits between which I have represented the origin of consciousness. Eememberiug what has already been said concerning the gradual or undefined manner in which consciousness probably dawned upon the scene of life, and that I therefore represent its rise as occupying a wide area on the diagram instead of a definite line, I think it least objectionable to place the begin- ning of this dawn in nervous adjustments or reflex action, and the end of it in the association of ideas. For, on the one hand, it is clear from what has been said tliat it is impossible to draw any definite line between reflex and conscious action, inasmuch as, considered objectively or as action, the latter differs from the former, not in kind, but only in a gradual advance in the degree of central co-ordination of stimuli. Therefore, where such central co-ordination is first well established, as it is in the mechanism of the simplest reflex act, there I think we may with least impropriety mark the advent of consciousness. On the other hand, where vague memory of past experiences first passes into a power of asso- ciating simple ideas, or of remembering the connections between memories, there I think consciousness may most properly be held to have advanced sufficiently far to admit of our regarding it as fairly begun. In this scheme, therefore— which of course it is needless to say I present as a somewhat arbitrary estimate where no more precise estimate is possible— the Coelenterata are repre- sented as having what Mi. Spencer calls " the raw material of consciousness," the Echinodermata as having such an amount of consciousness as I think we ma- voasonably slip- pose that they possess, if we consider how multifarious and complicated their reflex actions have become, and if we reuie)nber that in their spontaneous movements the neuro- muscular adjustments which they exhibit almost present the appearance of being due to intelligence.* The Annelida I • See F/iU. Trans., Croonian Lecture, 1881. I :; ''H CONSCIOUSNESS. 17 the place upon a still higher level of consciousness, because, both Irom the facts mentioned in " Animal Intelligence"' and from those published by Mr. Darwin,* it seems certain that their actions so closely border on the intelligent that it is difficult to determine whetlier or not they should be classed as intel- ligent. Upon this level, also, I represent the period of the embryonic life of Man as coming to a close ; for although the new-born chi'd, from the immaturity of its experience, dis- plays no adjustments that can be taken as indicative of intelligence, still, as its nerve-centres arc so elaborate (embo- dying the results of a great mass of hereditary experience, which although more latent in the new-born child than in the new-born of many other mammals and all birds, must still, we should infer from analogy, count of something), that we can scarcely doubt the presence of at least as much conscious- ness as occurs among the annelids. Moreover, pain appears to be felt bv a new-born child, inasmuch as it cries if injured ; and althougli this action may be largely or chiefly reflex,, we may from analogy infer that it is also in part due to feeling. The remaining levels occupied by the dawn of consciousness may be considered as assigned to the lower Mollusca — an assignment which I think will be seen to be justified by con- sulting tlie evidence given in my former work ^i actions performed by these animals of a nature which is unques- tionably intelligent. • See bis work on Earthworms, ISSl. hi ,;' ; n r 3 78 MENTAL EVOLUTION IN ANIMAL3. CHAPTER YIl Mk f. (I \ ■ < Sensation. exclusive of the cnvpMUr ^^fi ""'Z ^^^^P'^ion- , -linis, too, it is felt (Reflex ActTonH'''^'T adjustments whic!i are un- ¥ i SENSATION. 79 faculties ; it only has to do with the question wliether such and such a faculty occurs in such and such an organism. Therefore, so long as the question is one of classifying psychical faculties, we can only say that wherever there is Feeling there is Sensation, and wherever there is no Feeling there is no Sensation.* But where the question is one of classifying organisms with reference to their psychical facul- ties, it is clear that the difficulty of determining whether or not this and that particular low form of life has the begin- nings of Sensation, is one and the same as the question whether it has the beginnings of Consciousness. Now we have already considered this question, and we have found it impossible to answer; we cannot say within broad limits where in the animal kingdom consciousness may first be re- garded as present. But for the sake of drawing the line somewhere with reference to Sensation, I draw it at the place in the zoological scale where we first meet with organs of special sense, that is to say, at the Coelenterata. In doing this, it is needless to observe, I am drawing the line quite arbitrarily. On the one hand, for anything that is known to the contrary, not only the sensitive plant which responds to a mechanical stimulus, but even the protopl; ,mic organisms which respond to a luminous stimulus by congregating in or avoiding the light, may, wliile executing their responses, be dimly conscious of feeling ; and, on the other hand, the mere presence of an organ of special sense is certainly no evidence that its activities are accompanied by Sensation. What we call an organ of special sei:se is an organ ailapted to respond to a special form of stimulation ; l»ut whether or not the pro- cess of response is accompanied by a sensation is quite another matter. We infer by a strong analogy that it is so accompanied in the case of organisinn like our own (whether of men or of the higher animals) ; but the validity of such inference clearly dimiuiyhes with the diminishing strength of the analogy — i.e., as we recede in the zookij^ical and psycho- logical scales from organisms like our own towards organisms less and less like. Having thus made it as clear as I can that it is only for the matter of convenience that I have supjiused the rise of Sensation to coincide with the rise of organs of special * Altliougli this sounds like a tniisui, it ia in direct opposition to t'le classification of Lewes, alluilud to aboTe. 1 lit I 80 MENTAL EVOLUTIOxV IN ANIMALS. r > sense I shall next proceed to take a brief survey of the s^nse In"f"" T/^' reference to the powers of' speck uXshn&p H l^^"''^^'''^''' '^ '' "^<^^^«'^«' ^'"1 indeed vv hi iL -1 /""T"'^''^" °'"^"« °f «P«cial sensation vMiich the animal knigdom presents. My object is merely to pve a genera outline of the j .wers of special sensaZn pro- bably enjoyed by different classes of animals; for, as these owers constitute the foundation of all the otl.er powers of n IP if f? "^^P°^^^"^« for us to have a general idJa of the foolti^il sS. ^^^^'^^^P"^-^ "^ ^^- -"-l^y g-les of the In some of his recently published experiments Enrrel- mann found tiiat many of the protoplasmic and unicflluhir organisms are affected by light that is to say, tlXmove- m n s are influenced by light, in some cases causing a cele- r tion in others slowing of their movements ; in some cases te organisms seeking the light, while in other cases they d <^ 1 V •• '^'- ^? ^^""'^ ^^'^^ ""^^ t^^e^e effects were re- dn? I .i"""? Z ^^^'f ''^ ^^'''^ ^''^"■^^^«-- (1) alteration pro- a Ipr Hnr ' ^t^ "' the interchange of gases (2) consequent alteration m the conditions of respiration, and (3) specific processes of luminous stimulation. It is with the latter o^y that we are concerned, and tlie organism which Engelmann names as exhibiting it typically is Unglena vrridi^ aC piecauions had been taken to eliminate causes 1 and 2 it was still found that this organism sought the light. More- over, It was f;>und that it would only do so if the' light were allowed to fall upon the anterior part of its body Here thrwo "" P;»"^^"t-«P'^^' ^''^ careful experiment showed that tnis was not the point most sensitive to light, a colourless ^ound'f'?'''"' 'tJ'" '^ protoplasm lying in fi-oAt of it behig tound to be so. Hence it is doubtful whether this piament^ spot is or is not to be regarded as an exceedingly prfmitive :S^S^:^Se/^ '''' '''' '' ''' spectrliJ:!!.^.^/.. The remarkable observation recorded by Mr. H. J. Carter, di.nlo";''! "^T from Jiim in my previous work,t seems to display almost incredible powers of special sense among the i Animal Intelligence, ^^. lQ-21. J II t 8ENSATI0N. 81 Rhizopoda; and Professor Hreckel observes, in his essay on tlie " Orij^inand Development of the Sense-Or-^ ) 84 MENTAL EVOLUTION IN ANIMALS. ;i with uninistakeable evidence of the occurrence of nil i\.. « of distiuo'in'qhin.T 1,-rri.f f J - J^^^ uueiius, capable onlv I SENSATION. 85 not correct. "We do not really see things reversed, for the inind IS not a perpendicular object in space, standing behind the retina in the manner that a photographer stands behind his camera. To the mind there is no up or down in the retina, except in so far as the retina is in relation to the external world ; and this relation can only be determined not by sight, but by touch. And if only this relation is constant, it can make no difference to the mind whether the images are direct, reversed, or thrown upon the retina at any angle with reference to the horizon ; in any case the corre- lation between sight and touch would be equallv easy to establish, and we should always see things, not in the position m which they are throivn upon the retina, but in that which they occupy with reference to the retina. Thus it reaUy re- quires no more 'practice' correctly to interpret inverted images than it does similarly to interpret upright images • and therefore the fact that some eyes of an ant are sup- posed to throw direct images, while others are supposed to throw inverted, is not any real objection to the theorv' that they do.* *' There is no one group in" the animal kingdom where we have so complete a series of gradations in the evolution of an organ of special sense as is presented by the organ of sif^ht in Worms "In the lowest Vermes,"— I quote from Prolessor Hseckelf— "the eye is only made up of individual pigment-cells. In others, refractive bodies are associated with these, and form' a very simple lens. Behind these refractive bodies sensory cells are developed, forming a retina of the simplest order presenting a single layer, the cells of which are in connection with extremely delicate terminal fibres of the optic nerve. Lastly, in the Alcipidse, which are highly organized Annelidte that swim on the surface of the sea, adaptation to this mode of life has brought about such perfection of the eye that this organ in these animals is in no way inferior to that of the lower vertebrata. In these creatures we find a large globular eye-ball, enclosing externally a laminated globular lens, internally a vitreous body of large circumference. Imme- diately investing these are rods of the usual cells sensitive to light, which are separated by a layer of pigment-cells from the outer expansion of the optic nerve or retina. The ex- • Quoted from an article of my own in Nature, June 8, 1882. t Jissai/ on Origin and Development of Sense-oi-yuns. ' I ;■ nt I % I , I I ; i ! II I ■ 1 I' -f' U'\ ivi 'It m f ''■ ' 1 H. f ' V , Ui Bi j ;il 1 ^1 : ! 1 1 i I i 1 ^ [ ^ u 86 MENTAL EVOLUTION IN ANIMALS. ternal epidermis invests the whole of the prominent eve-ball and forms m front of it a transparent hor^^ layer S cornea." Further, from the more recent obTervaSs o Mr. Darwin, it is certain that Earthworms, althouXSLte of eyes, are able to distinguish with much rar.idf/v n?rf n^! cisi^n between light and da^knes^; IHs helunJthat ft s" only the anterior extremity of the animal which disp avs this S^^/H•^' r"'^^^'.\^*^"* '^' ^'Sht affects the antS Janaha immediately, or without the intervention of a sense-Sr "an * Lastly, Schneider says that Serpul^ will suddenly withdraw their expanded tufts when a shadow falls upon them but th^ shadow must be that of an object moving wfth some r^^^^^^ Turmng now to the sense of hearing in the ArticXta wl find the simplest type of ear among %he Vermes where i? occurs as a closed globular vesicle containing S rwhich there is suspended an otolith + In snmp iS fhln 7 such as theWfish and lobster th^Tgat of\''eTri^^^^^^^ much more complex, and here, "if we give rise, by plS' Ob e^e the :.d7/" '' ^^W Pitch, afd at the sLfS Observe the aaditory organ under the microscope, we see that ttn 'f At '"\^ ' r'^'^^^ ^""^^'^y ^'^ i« seT in vib a- tion § Among Insects organs of hearing certainly occur at least m some species, although the experWents of sHibn Lubbock appear to show that ants are deaf. The evidence that some insects are able to hear is not only moXloS but also physiological, because it is only on the sSnnnJHnn hat they do that the fact of stridulatiL and otlXTeS sounds being made by certain insects can be expkSed and Brunelh found that when he separated a female gZho^ from the male by a distance of several metrertierairbTan to stridulate m order to inform hpr nf iiia '^''rt'^^^ "^S^^ which the female app:«ache?S.||'"l C mS^ubS observations proving the occurrence of a sense orhearino among the Lepidoptera.f Turning to the moZolticS of the subject, it is remarkable iat in the ArSafa the SENSATION. 87 ii auditory organs occur among different members of the group in widely different parts of "the body. Thus in the lobster and cray-fish they are situated in the head at the base of the antennules, while in some of the crabs {e.g., Mysis) they occur in the tail. Among the Orthoptera, again, they are found in the tibiae of the front legs, or, in other species, upon the sides of the thorax. In other insects, probability points to the organs of hearing being placed in the antennae. These facts prove that in the Articulata the sundry kinds of auditory organs must have arisen independently, and have not been inherited from a common ancestor of the group ; and it is remarkable that this should have been the case even within the limits of so comparatively small a subdivision as that which separates a crab from a crayfish or a lobster.* There can be no question that the sense of smell is well developed in at least many of the Articulata, although, save in a few cases, we are not yet in a position to deteimine the olfactory organs. Thus the account which I quoted in I' Animal Intelligence" (p. 24), from Sjt E. Tennent, concern- ing the habits of the land leeches of Ceylon, proves that these animals must be accredited with a positively astonishino- delicacy of olfactory perception, seeing that they smell the approach of a horse or a man at a long distance. In earth- worms the sense of smell is feeble, and seems to be confined to certain odours.f Sir John Lubbock has proved by direct experiment that ants are able to perceive odours, and that they appear to do so by moans of their antennae. The same remark applies to bees, and the general fact that many insects can smell is shown by the general fact that so many species of flowering plants, which depend for their fertilization upon the visits of insects, give out odours to attract them. That the Crustacea are able to smell is rendered evident by the rapidity with which they find food. I have recently been able to localize the olfactory organs of crabs and lobsters by a series of experiments which I have not yet published, and which would occupy too much space here to detail. I shall therefore merely say that they are situated in the pair of small antennules, the ends of which are curiously modified in order to perform the olfactory function. That is to say, the * Analogoiis facta are to be observed in the case of the Eye among Vermes, and also, as we shall presently aee, among Mollusca. t Darwin, loc. cit., p. 30. il \ h .( \ A 1 1 '; ;:i S^-: j j ' . j. ^^M ;j ■ . I i' "; '11 d ^ f 88 MENTAL EVOLUTION IN ANIMALS, terminal joint works in a vertical plane, and supports the sensory apparatus, which is kept in a perpetual jerking motion np and down, so as to bring that apparatus into sudden con- tact with any minute odoriferous particles which may be sus- pended in the water— just on the same principle as we our- selves smell by taking a number of small and sudden sniffs 01 air. Any one visiting an aquarium can have no difficulty m observing these movements upon any crab or lobster in a healthy condition. The sense of taste certainly occurs at least among some species of the Articulata (as, e.f/., among the honey-feedincr insects) and the sense of touch is more or less elaborately provided for m all. "^ Turning now to the MoUusca, we pass in a tolerably unitorm series from the simple eye-spots of certain of the Lamellibranchiata, through the Pteropoda, to the more com- pletely organized eyes of the Gasteropoda and the Heteropoda. 13ut when we arrive at the Cephalopoda, we encounter, as it were, a vast leap of development; for the eye of an octopus in point of organization, is equal to that of a fish, which it so closely resembles. And, while remembering that the resemblance, striking though it be, is only superficial, we must not tail to note that this enormous development in the organi- zation of the molluscous eye, which brings it so strangely to resemble the eye of a fish, is clearly correlated with the no less enormous development of the neuro-muscular system of the animal m which respect it more resembles a fish than it does the other Mollusca. This case is therefore analogous to the similarly high development which has been attained by the eye of the swimming worm previously described If we look to the Mollusca as a class, we meet with the same kind of variation in the position of the eye which we have already noticed with respect to the ear in the Articulata Ihus, while m the Cephalopoda and Gasteropoda the eyes a,re situated m the head, in some of the latter group there are supplementary eyes upon the back, which greatly differ in structure from the eyes in the head. In the LampUi- branchiata, again, the eyes occur in large numbers on the margin of the mantle. The sense of hearing is general to all the Mollusca, and the auditory organs exhibit a progressive elaboration as we ascend from the lower to the higher groups, which is analo- SENSATION. 89 goTis to that already noticed with reference to the organs of sight. Thus, among the lower Mollusca the organs of hearing consist of a pair of small vesicles attached to auditory nerves, and filled with fluid in which an otolith is suspended. In the Cephalopoda, however, while the same general plan of structure is adhered to, we find an approximation to the auditory apparatus of a fish ; for the vesicle or sac is now embedded in the cartilage of the head, is of larger size, and in general analogous to the organ of hearing of the Verte- brata. That at all events the majority of the Mollusca are able to smell, is proved by the readiness with which they find food, and the octopus is said to show a strong aversion to certain odours (Marshall). In the Cephalopoda the olfactory organs are probably two small cavitios near the back of the eye, and in the other Mollusca they are surmised to be situated in the small tentacles near the mouth. Touch is provided for both by these and by the larger tentacles (as well as by the general soft exterior) ; but in the Cephalopoda by the long, snake-like arms, which I think must be regarded as giving these animals a greater power of receiving tactile impressions than is enjoyed by any other marine animal. Among Fish sight is well developed. A trout will dis- tinguish a worm suspended in muddy water ; a salmon can • avoid obstacles when swimming with immense velocity ; and a Chelmon rostratus can take unerring aim with its little water projectile at a fly. The blind fish, which live habitually in the dark, have lost their eyes merely from disuse ; but in this connection it must be noted that we meet with a curious biological puzzle in the case of many of the deep sea fishes dredged by the Challenger. For although living at depths to which no light can be supposed to penetrate, some of these fisli have large eyes. It may be suggested that the use of these eyes is that of seeing the many self-luminous forms of life which, as the Challenger dredgings also show, inhabit the deep sea. But if this is suggested, the question immediately arises as to why these forms have become luminous ; for if thus rendered conspicuous to the fish, their luminosity must so far be a disadvantage to them. In the case of the lumi- nous animals which themselves have eyes, we may suppose that this disadvantage is more than compensated for by the advantage of enabling the sexes to find each other; but thia explanation does not apply to the blind forms. ! HI 90 MENTAL EVOLUTION IN ANIMALS. Fish, as we have already observed, are well provided with the organs both of hearing and of smell, Amphioxus being the only member of the class which is destitute of ears, and the oltactory lobes in the case of some species {e.g., the Skate) being of enormous size in relation to the other parts of the brain. The sense cf touch is provided for in many species by tentaculse in the neighbourhood of the mouth. The soft lips, and m some species the pectoral fins, are also tactile in lunction, and in certain gurnards there are digitate appendages connected with the latter which doubtless serve to increase their efficiency as organs of touch. It is doubtful whether taste, as distinct from smell, occurs in fish; but we must reinember, as before observed, that in the case of an aquatic animal there is no true distinction to be drawn between these two senses. For as there is here no gaseous medium (like the air) m question, the only distinction that can be drawn is a^ to whether the nerve terminations, which are affected bv the suspended particles in the water, happen to be dis- tributed over any part of the mouth where the food passes or over any other part of the animal. I say over any other part of the animal (and not only in the nasal fosste), because m some species of fish there are embedded in the skin along the sides of the body a number of curiously-formed papilla which on morphological grounds may reasonably be regarded as ministering to the sense of smell, or, as we may indifferently call It, of taste. Hackel, however, speculates upon these organs, and is inclined to think that they minister to some unknown sense. The sense of sight in Amphibia and Reptiles offers nothing specially worthy of remark, except that the crystal- line lens has not so high a refracting power as in Fish The transition from an eye adapted to see under water and an eye adapted to see in air, appears to be curiously shown by one and the same eye in the case of the Surinam Sprat. This animal has its eyes placed on the top of its head, so that when It comes to the surface of the water part of the eyes come into the air, and "the pupU is partly divided, and the lens is also composed of two portions, so that it is supposed that one part of this curious eye is adapted for aerial, and the other for aquatic, vision."* The senses of hearing, smell, taste, and touch, although all present in the • Marshall, Outlines of Fi.i/sioloff^, vol. i, p. 603. SENSATION. 91 Amphibia and Reptiles, are not much, if at all, in advance of these senses as they occur in Fish. Among Birds the sense of sight is proverbially keen, and in point of fact the animal kingdom has no parallel to the excellence of the organ of vision as it occurs in some species of this class. Whether we consider the eye of a Hawk, which is able to distinguish from a great height a protectively coloured animal from the surface of the ground which it so closely imitates ; or the eye of a Solen Goose, which is able from a height of a hundred feet in the air to see a fish at the depth of many fathoms in the water ; or the eye of a Swift, which is able so suddenly to form its adjustments ; we must alike conclude that the visual apparatus has attained to its highest perfection among birds. And in this connection it is of interest to note that protective colouring has attained its highest degree of perfection among animals which constitute the prey of birds. So surprising, indeed, is the perfection to which protective colouring has attained in some of these cases, that it has been adduced as a difficulty against the theory of evolution ; for it seems incredible that such perfec- tion should have been attained by slow stages through natural selec^on before the species exhibiting it had been extermi- nated by the birds. The answer to this difficulty is that the visual organs of the birds cannot be supposed to have been always so perfect as they are now, and therefore that a degree of protective colouring which might have afforded efficient protection at an earlier stage in the evolution of those organs would not supply such protection at the present day. In other words, the evolution of the eyes of birds and «f the protective coloration of their prey must be supposed to have progressed pari passu, each stage in the one acting as a cause in the succeeding stage of the other. The crystal- line lens is flat in birds which are remarkable for long sight, such as the vulture ; rounder in owls, which are very near- sighted ; and becomes progressively more spherical in aquatic birds, according to their aquatic habits. All birds are able to hear, and it is in this class that we first meet with definite evidence of an ear capable of appre- ciating with delicacy differences of pitch. Among many species of birds the delicacy of such appreciation (as well as that of timhre) is so remarkable that it may be questioned whether even human ears are more efficient in this respect. .' la ii I 'i, ; 1 l\ 1 1 I '111 :! ; ; i 5 h. : I ,:i H. «>| ; • 92 MENTAL EVOLUTION IN ANIMALS. The anatomical difficulty of accounting for this fact I need not wait to consider. I am myself inclined to think that the sense of hearing in birds (at all events of some species) is likewise higlily delicate with reference to the intensity of sound. My reason for so thinking is that I have observed Curlews dig their long bills up to the base into smooth unbroken surfaces of sea-sand left bare by the tide, in order to draw up the concealed worms. Under such circumstances no indication can be given by the worm of its position to any other sense of tlie curlew than that of hearing. Similarly, I suspect that the common Thrush is guided to the worm buried beneath tlie turf by the sense of hearing, and my suspicion is founded on the peculiar habits of feeding shown by the bird, which I have described elsewhere.* The sense of smell in Birds is in advance of that of Eeptiles, but not to be compared with its excellency in Mammals; for the old hypothesis that vultures find their prey by the aid of this sense has been abundantly disproved.f The sense of taste in Birds is likewise very obtuse as com- pared with this sense in Mammals ; and as compared with the same class they are also defective in their organs of touch. Indeed, the parrot tribe is the only one in which this sense is well or specially provided for, except the ducks, snipes, and other mud-feeding species, in which the bill is specially modified for this purpose. If we regard Mammals as a class we must say that, with the exception of the sense of vision which readies its greatest supremacy in Birds, all the special senses are more highly developed than in any other class. This is more particularly the case with the senses of smell, taste, and touch. The sense of smell reaches its highest perfection among the Carnivora and the Ruminants, and, on the other hand, is totally absent in some of the Cetacea. Any one accustomed to deer-stalking must often have been astonished at the pre- cautions which it is needful to take in order to prevent the game from getting the " wind " of the sportsman ; indeed to a novice such precautions are apt to be regarded as implying a superstitious exaggeration of the possibilities of the olfac- * Nature, vol. xv, pp. 177 and 292, where also see in more detail my observations on the feeding habits of the curlew, t See Animal Intelligence, pp. 286-7. BENSATION. 93 tory sense ; and it is not until he has himself seen the deer scent him at some almost incredible distance that he lends himseli' without disguised contempt to the discretion of the keeper. But among the Carnivora the sense of smell is even more extraordinary in its development on account, no doubt, of its being here of so much service in tracking prey. I once tried an experiment with a terrier of my own which shows, better than anything that I have ever read, the almost supernatural capabilities of smell in Dogs. On a Bank holiday, when the broad walk in Eegent's Park was swarm- ing with people of all kinds, walking in all directions, I took my terrier (which I knew had a splendid nose, and could track me for miles) along the walk, and, when his attention was diverted by a strange dog, I suddenly made a number of zig-zags across the broad walk, then stood on a seat, and watched the terrier. Finding I had not continued in the direction I was going when he left me, he went to the place where he had last seen me, and there, picking up my scent, tracked my footsteps over all the zig-zags I had made until he found me. Now in order to do this he had to distinguish my trail from at least a hundred others quite as fresh, and many thousands of others not so fresh, crossing it at all angles. Such being the astonishing perfection of smell in dogs, it has been well observed that the external world must be to these animals quite different from what it is to us ; the whole fabric of their ideas concerning it being so largely founded on what is virtually a new sense. But in this con- nection I may point out that speculation on such a subject is shown to be useless by the fact that the sense of smell in dogs does not appear to be merely our own sense of smell greatly magnified. For if this were the case it seems incredible that highly bred sporting-dogs, which have the finest noses, should be those which take the keenest pleasure in rolling in filth which literally stinks in our nostrils to the degree of being physically painful. The sense of hearing is acute in Mammals as a class, and it is worthy of remark that this is the only class provided with movable ears. As Paley observes, in beasts of prey the external ear is habitually directed forwards, while in species which they prey upon the ear admits of being directed back- wards. With the exception of the singing monkey (Hi/lobates agilis), there is no evidence of any mammal other than man 7 :|ii ¥ ),' ■ i J I I III 11'!-:; MENTAL EVOLUTION IN ANIMALS. 94 havin{» any delicate perception of pitch. I have, however, heard a tenier, wliich used to accompany a song by howling, follow the prolonged notes of the human voice with some approximation to unison ; and Dr. Huggins, who has a good ear, tells mo that his large mastiff " Kepler " used to do the same to prolonged notes sounded from an organ. The sense of taste is much more highly developed in the Mammalia than in any other class, and the same general statement applies to the sense of touch. Looking to tlie class as a whole, the principal organs of the latter are the snout, lips, and tongue ; the modified hairs, or " whiskers," are also very generally present. Among the Kodents, some of the Mustelido! and all tlie Primates, the principal organs of touch are the hands. And it would appear that the extreme modification which these members have undergone in the Cheiroptera has been attended with an extraordinary exalta- tion of their power of tactile sensation. For m the celebrated experiment of Spallanzani (since repeated and confirmed by several other observers), it was found that when a Bat is deprived of its eyes, and has its ears stopped up with cotton- wool, it is still able to fly about without apparent inconveni- ence, seeing that it avoids all obstacles in its flight, even though these be but slender strings stretched through the room in which the animal is allowed to fly. The only expla- nation of this surprising fact is that the membranous expanse of the wing, which is richly supplied with nerves, has developed a sensibility to touch, to temperature, or to both, so extreme as to inform the bat of the proximity of a solid body even before contact — either through the increase in the air-pressure as the wing rapidly approaches the solid body, or through the difference in the exchange of heat between the wing and the solid as compared with such ex- change between the wing and the air. When groping our way through a dark room we are ourselves able to feel a large solid body (such as a wall) before we actually touch it, especially, I have observed, with the skin of the face. Pro- bably, therefore, it is a great exaltation of this power which enables these night-flying animals to avoid so slender a solid body as a stretched string. But when we remember the rapidity and accuracy with which the sensation must here be aroused, we may well consider it ta equal, if not to surpass, in the domain of touch, the evolutionary development of i ;tt 1 \l SENSATION. 95 1 fii '. ' Bense-organs as it occurs in the sight of tho vultiim or tlie smell of the dog. Indeed, Hceckel and others have specu- lated whether the facts in this case do not call for the suppo-' eition of some additional and unknown sense, different in kind from any that we ourselves possess. But I think it is safer not to run into any such ohscure hypothesis unless actually driven to do so, and therefore I shall not here enter- tain it. For this reason, also, I shall not follow H.Tckel in his view that the "homing" faculty of certain animals is due to some additional and inexplicable sense, and therefore I shall reserve my treatment of this topic for my chapters on Instinct. After this rapid survey of the powers of Special Senpe as they severally occur in different classes of the animal kiuf;- dom, I shall conclude the present chapter by brieHy consider- ing certain general principles connected with Sensation. The muscular sense, the sense of hunger, thirst, satiety, and others of the like general kind need not detain us ; for although their causation is somewhat obscure, we know at least that they are dependent upon nervous adjustments, and, being of so much importance to animals, we infer that they have been developed under the general principles of neuro-muscular evolution already considered in previous chapters. My object here is rather to consider the mecha- nisms of certain more special senses from the point of view of those general principles. First as to the sense of Temperature, there is good evi- dence that in ourselves and at least in all the higher animals, thermal sensations can only be received by the nerve-endings in the skin and adjacent parts of the mucous membranes ; if the nerve-libres immediately above their terminations in these localities (as in the raw surface of a wound) be stimu- lated by heat or cold, the sensation produced is merely one of pain. There is strong evidence that not only the nerve- endings, but even the whole of the nerve-tracts of which they are the endings, are specialized for the purpose of re- ceiving thermal impressions. These impressions, when received, are not absolute, but relative to the temperature of the part receiving them — the greater the difference of tem- perature between the part and the object touching it, the greater being the impression. Moreover, the greater the til 1 .«» , 1 1 lU.rl 1. 1- >: ui u „ ti H ■i i If I- ( f/ ' ill ! • 'V' , ■ h '« ■ il- ■ -J' hi. i 1 . 96 MENTAL EVO1.UTION IN ANIMALS. extent of the receiving surface, the greater is the impression ; so that if the whole hand be immersed in water at 102°, the temperature of the water will be erroneously judged to be higher than that of another body of water at 104° the tem- perature of which is simultaneously estimated by a single finger of the other hand ; and, similarly, smaller differences of temperature can be appreciated by the whole hand than by a single finger. According to Weber, the left hand is considerably more sensitive to temperature than the right ; and it is certain that different parts of the body differ greatly in this respect. The more sudden the change of temperature, the greater is the sensory effect. We have no means of testing the truth of any of these statements with reference to any of the Invertebrata, or even with reference to the cold-blooded Vertebrata; but we can scarcely doubt that they apply in a general way to all the warm-blooded. The facts certainly show an elaborate provision for appreciating local changes of temperature occurring upon thia and that part of the external surface (the general, comfort or discom- fort arising from the body being kept at a normal tempera- ture or not is another matter, and one with which the special mechanism we are considering is not concerned) ; and there- fore we have to contemplate the probable cause of its origin and development. At first sight we appear to encounter a difficulty which I wonder never to have seen adduced by opponents of evolu- tion. For in nature the only differences of temperature which normally occur in objects with which animals Lave any opportunity of coming into contact, are those between ice and objects heated by a tropical sun ; and no one animal ever has the opportunity of experiencing changes of tem- perature extending through anything like so great a range ; for in the arctic regions there is no tropical sun, in the tropics there is no ice, and in the temperate zones the solar heat is moderate. Of course since the introduction of fire by man, the sense of temperature has become of much use to sundry species of animals for the examination of food, &c., and in this connection is of almost indispensable service to man himself ; but, looking to the antecedents of these animals and also to the antecedents of man, it may at first sight seem remarkable that such an elaborate provision should have been developed, and, as I have said, I wonder that no 1 'i SENSATION. 97 opponent of evolution has pointed to the fact. For it might be argued that here we have a complicated piece of special organic machinery constructed in obvious anticipation of the advent of cookery and warm baths. But I think the matter may be explained on evolutionary principles, if we remember that the only use of a sense of temperature is not that of exammmg food. Vie know that differences of temperature on the surface of the body (whether local or general) greatly modify the conditions of the circulation in the part or parts affected, and therefore it must always have been of use for animals to be provided with a sensory apparatus upon the surface of their bodies to give them immediate information of such differences. Its development along special lines (so that some parts of the body should be more sensitive to changes of temperature than other parts) is easily to be explained by the effects of habit or use. Thus, for example, the fact that the lips of man, although provided with a skin so dehcate and so sensitive to tactile impressions, are never- theless able to endure a sudden rise of temperature which would be painful to the skin of the face, must be taken to mean that habit has adapted the nerves in the lips to with- stand a sudden rise of temperature— and this certainly within the period since the invention of cookery. ^ Mr. Grant Allen takes a more general vifew of this sub- ject, and says: "To an animal, cold is death, and warmth is life. Hence it is not ar.tonishing that animals should very early have developed a sense which informed them of changes of temperature taking place in their vicinity ; and that this sense should have been equally diffused over the whole organism As soon as moving creatures ?J^?*^°m?^^ ^^ ^"' ^^^y probably began to feel hea. and cold. * _ The truth of such a general statement of this must be obvious, and the step between a sense of temperature equally diffused over the whole oiganism, and the specializa- tion of superficial nerve-endings to minister to this sense alone, is not a large step. Moreover, the step between this and the development of a rudimentary visual organ is like- wise not a large one. For the deposition of dark-coloured pigment m particularly exposed parts of the skin must have been of benefit to animals by enabling (in virtue of the increased absorption of heat thus secured) the nerve-endinga * Colour Sense, p. 13. I 1 m' ! M iMi ■' ■!i;;i ! I- A\ li: lill; ! I ■ 98 MENTAL EVOLUTION IN ANIMALS. in those parts to be more sensitive to changes of temperature. But the deposition of pigment in such localities constitutes a favouring condition to the origination of an eye, or of an organ whose sense of temperature becomes sufficiently developed to enable it to begin to distinguish between light and darkness. Thus, as Professor Hfeckel eloquently re- marks : " The ordinary nerves of the skin which pass to these dark pigment-cells of the integument, have already trodden the first steps of that magnificent march, at the end of which they have attained to the highest development of tl e nerves of sensation — the optic nerves." Turning next to the sense of Colour, it appears from the experiments of Engelmann already alluded to, that colour- sense of a kind occurs as low down in the zoological scale as the protoplasmic and unicellular organisms, inasmuch as particular species showed particulpr preferences for certain rays of the spectrum. But as in these organisms there are no organs of special sense, and probably no beginnings of consciousness, I do not think that any true analogy can be drawn between these cases and those in which there is a true sensation of colour. Nor have we any evidence of such a true sensation till we arrive at the Crustacea. Here we have proof, furnished by the direct experiments of Sir John Lubbock, that Daphnia pulex prefers certain rays of the spectrum to others,* and the Chameleon Shrimp (Mysis chcu- meleo) is known to change its colour in imitation of the surface on which it reposes, provided that it is not blinded or otherwise prevented from seeing that surface. Precisely analogous facts occur among the Cephalopoda {e.g., octopus), Batrachia {e.g.. Common Frog), Reptilia {e.g., Cam'eleon), and Pisces {e.g., Flounder) ; in all these cases, if the animals are blinded, the effects no longer occur. Moreover, Pouchet found that in the Pleuronectidee the mechanism whereby these imitative changes of colour are produced is bilaterally disposed, so that if only one eye of the animal is stimulated by coloured light, only one side of the animal changes colour. M. Fredericq afterwards found the same thing to be true of the Octopus, and in conjunction with Professors Burdon- • Journ. Linn. Soc, 1881. These observations have been adversely criti- cized bj Merejkowsky (Comptes Sendus, xciii, pp. 160-1), but his criticisms have been fully met by further experiments recently published by Sir John (Journ. Linn. Soc, 1883). ■ ^' ' s ■ i'r 1 !•: ! >■ iy ' i I ; , 1 ■► _ . SENSATION. 99 Sanderson, Cossar Ewart, and Mr. W. D. Scott, I have corroborated M. Fredericq's observations by a number of experiments ; stimulation of one eye alone by means of light produces immediate unilateral flushing of the whole of the same side of body, but no change of colour beyond the median line. As further proof that a well-developed sense of colour occurs in some of the Articulata, I may allude to the experi- ments of Sir John Lubbock on the Hymenoptera ; but as these have been already twice published in the International Scientific Series,* I need not here wait to recapitulate them, and shall therefore only remark that it is without any rea- sonable question to the presence of this sense in insects that we owe the beauty both of floral and of insect coloration. Again, as further proof that a well-developed sense of colour occurs in Fish, I may remark that the elaborate care with which anglers dress their flies, and select this and that com- bination of tints for this and that locality, time of day, &e., shows that those who are practically acquainted with the habits of trout, salmon, and other fresh-water fish, regard the presence of a colour-sense in them as axiomatic. And, with reference to the sea-water fish in general, we have the highly competent opinion of Professor H. N. Moseley to the effect that the great majority of the colours of marine animals have been acquired either for the protection or the allure- ment of prey, and that they refer particularly to the eyes of Fish, and also to those of Crustacea.! The fact that a sense of colour occurs in Birds is unques- tionable, and meets with its most general proof in the more or less conspicuous coloration of the fruits on which they feed ; for as in the analogous case of conspicuously coloured flowers depending on insects for their fertilization, so con- spicuously coloured fruits depend for the dissemination of their seeds upon being eaten by birds or mammals. Again, I have already mentioned the fact that nowhere in the animal kingdom does the protective and imitative colouring of animals atlfain to such nicety as it does where the eyes of birds are concerned. Lastly, the elaborate coloration of birds themselves, and the pleasure which some species take in the decoration of their nests, constitute supplementary • Viz., in Ants, Bees, and Wasps, and in Animal Intelligence. t (Quarterly Journ. Micro, Science, New Series, vol. xvii, pp. 19-22, i::;'H| I. I wm ;r' 1; T :-!> I M\ 100 MENTAL EVOLUTION IN ANIMALS. proof of the high development to which the colour-sense has attained m this class. All the remarks just made with reference to Birds, apply likewise though not perhaps in quite so high a degree, to Mammals, considered as a class. And here it becomes need- tul to consider the speculation of Dr. Magnus and Mr. Glad- stone, that the colour-sense of man has undergone a great improvement within the last two thousand yeaV inasmuch as before that time mankind are supposed by this specula- tion to have perceived only the lower colours of the spec- i,r°5'."'.r,'-T"^^' ^""^ yellow, and to have been colour- blind to the liigher,or green, blue, and violet. Professor Hackel lends his support to this speculation ; but to me it seems a highly improbable one, and this for the following reasons In the first place the speculation is based merely on etymological grounds, which in a matter of this kind are exceedingly unsafe. For the absence in a language of words denoting particular colours is, at best, but negative evidence that the men who spoke the language were blind to those colours; the absence of such words may quite as weU be due to the imperfection of language as to the imperfection of the visual sense. Thus, for instance. Professor Blackie tells us that the Highlanders call both sky and grass "gorm," and are nevertheless quite able to discriminate between the colours blue and green. In the next place, it is antecedently im- probable, upon the general principles of evolution, that a considerable change in the visual apparatus of man should have taken place within so short a period as the speculation in question assigns— especially in view of the fact that other Mammals Birds, and even some of the Invertebrata un- questionably distinguish the higher as well as the lower colours of the spectrum. Lastly, Mr. Grant Allen has taken the trouble to enquire, by means of a table of questions addressed to educated Europeans in all parts of the world whether any of the savage races of mankind now livin« display any inability to distinguish between the colours of the spectrum, and the answers which he has received have been uniformly in the negative.* I think, therefore, we may sately dismiss the speculation of Dr. Magnus and Mr. Glad- stone as opposed to aU the evidence which is at once trust- worthy and available. But in saying this I do not intend to • Colour-sense, Chapier X. 1 SENSATION. 101 dispute the probability, which indeed amounts almost to a certainty, that as civilization advances and the fine arts become developed, the colour-sense undergoes a progressive improvement in its power of distinguishing between fine shades, and also m its power of ministering to a more and more evolved condition of aesthetic feeling. And this I heheve is the true explanation of the class of facts aUuded to by Professor H^ckel as proof of the speculation which I have now discarded-the fact, namely, that "nowadays we see in the surviving savage races a crudity as to their sense of colour . . Our little ones, also, like the savages love assemblages of glaring hues which grate upon us, and susceptibility to the harmony of delicate shades of colour is the latest product of aesthetic education " Professor Preyer has published within the last year or two avery interesting theory touching the origin and development ot the colour sense, and as it has not, to my knowled^^e been no iced in any English publication, I shall here state the main Ki u^ 5®'''? '' *^^* *^^ colour-sense is a special and highly-exalted development of the sense of temperature To sustain this theory Professor Preyer first compares the sensi- bihty of the skm to temperature with that of the retina to light, and points out that the analogy has already been recognized by artists, who speak of colours as " warm " and cold. _ The warm colours arouse sensations of a character antagonistic to those which are aroused by the cold colours m just the same way as the hot and cold sensations of skin- temperature are antagonistic ; and the more this analosy is pursued, the closer is the agreement found to be." Therefore the suggestion arises, " that the sense of colour has been developed out of the sense of temperature," bespeaking a high refinement of functional activity which has its struc- tural correlative m the extremely differentiated and delicately organized expansion of nerve-endings which we find in the AC till 3(, A further analogy is that of contrasts. A finger that has been warmed or coo ed retains its change of temperature for some time after it has ceased to be warmed or cooled ; and this is taken to correspond with the phenomena of positive n w ir%'' .''' sensation: - colour. Moreover, while the after-effect of warming or cooling a portion of the skin remains, the temperature-sense of that portion is altered in ri I:. B.j. . : I ■ H ' , t| 102 MENTAL EVOLUTION IN ANIMALS. I : . ;-(! II I u it- \ r Buch wise that, if it has been cooled, it over-estimates the temperature of any object it may touch, and vice versd. This is taken to be analogous to the appearance of warm colours in the eyes when closed immediately after having been exposed to intense coM colours, and vice versd. So, too, it is with simultaneous contrasts. It is well known that if a small colourless surface is enclosed between two surfaces of cold or warm colours, the small surface will appear inversely coloured warm or cold, as the case may be ; and Professor Preyer has found by experiment, that if a small portion of the skin be enclosed by cold or warm surfaces on either side, the small enclosed area will feel cool if the neighbouring parts are heated, and vice versd. After showing that in his view illumination is to the sense of colour what contact is to the sense of temperature, and pointing out several subordinate analogies which I have no space to mention, Professor Preyer goes on to remark an important fact in relation to his theory, viz., that different parts of the skin manifest in their estimations of tempera- ture great differences in their estimates of what he calls the " neutral point," i.e., the point at which it cannot be said that a body is felt to be either hot or cold. The retina, then, being supposed to be merely a nerve-expansion having a much higher " neutral point " in the appreciation of temperature (ethereal vibrations) than has any nerve-expansion of the skin, colour-blindness is explained by supposing that the retina of the individual so affected has a neutral point either above or below the normal. " An over- warm eye must be blind to yellow and blue ; an over cool one must be blind to red and green." Total colour-blindness, which is a physio- logical characteristic among certain nocturnal animals, has its parallel in the pathological condition sometimes met with in man, of a total absence of the sense of temperature without impairment in the sense of touch. Lastly, it is observed that the first condition to the validity of any physiological hypothesis is that it should accord with morphological fact. But this is not the case with the theory of Young and Helmholtz, which ascribes the colour-sense to the functions of three retinal elements ; for it has been proved that the number of fibres in the optic nerve immediately before it enters the retina is much smxUer than the number of rods and cones in the retina. i ^ SENSATION. 108 In my opinion this theory, in its main outlines, seems a probable, as it certainly is a plausible one. I do not, indeed quite understand why, in accordance with the theory the '; neutral point" of the colour-blind should not merely be tound to be shifted to another part of the spectrum, nor am I quite clear about the explanation of the fact that the warm colours are those having the lowest and not the highest order of vibrations, as analogy would lead us to expect. But the theory has the merit of being antecedently probable, when we remember that in all likelihood the visual ^ense arose by the progressive elaboration of nerve-endings in particular parts of the skin, which before their special elaboration presumably ministered to the senses of touch and temperature. And this remark leads me to the last topic that I have to dwell upon in the present chapter. I refer to the body of morphological evidence which we now possess, showing that all the organs of special sense have had their origin in fecial elaborations of these nerves of the integument. For the uniform result of histological and embryological investigation is to show that all organs of special sense, wherever they occur and whatever degree of elaboration they present in the adult animal, are fundamentally alike in that their receptive surfaces are composed of more or less modified epithelium cells which originally constituted part of the external layer of the animal. Thus, the origin of the olfactory membrane m the embryo of the Vertebrata is found to consist in a pittincr of the skin of the fore part of the head— the pits, therefore'J being lined by the general layer of epidermic cells. The subsequent growth of the surrounding parts of the face eventually brings this lining to occupy the position which it does in the hollow parts of the nose. Similarly, the organs of hearing first begin as a pair of pits on the side parts of the head, situated somewhat far back, and likewise lined by the cells of the general integument. These pits rapidly deepen, so that their lining is pinched off or separated from the general integument of which it originally formed a part. The deep pit then becomes a closed sac, and the adjacent tissues becoming first cartilaginous and then osseous, this sac is enclosed well within the skull by bony walls. While its structure is undergoing further anatomical and histological changes, the drum, the chain of ear-bones, and the external ear are being formed, and thus eventually the auditory organ if rt-ti Yi 104 MENTAL EVOLUTION IN ANIMALS. •! is completed. In the case of the eye, again, the earliest sign of commencement consists in a similar pitting of the general integument, but the lining of this pit is not destined, as in the previous cases, to become the receptive surface of the sensory impressions. For, after it has deepened considerably it undergoes sundry changes which result in its forming the cornea, aqueous humour, and crystalline lens; while the retina arises as an offshoot from the brain in the form of a sac growing, as it were, upon a slender stalk towards the crystalline lens. At first the anterior surface of this sac is convex, but the posterior part afterwards becomes pushed into the cavity of the sac; so that the anterior surface eventually becomes strongly concave. Therefore the sac is now, as Professor Huxley graphically describes it, "like a double night-cap, ready for the head, but the place which the head would occupy is taken by the vitreous humour, while the layer of night-cap next it becomes the retina." Thus the rods and cones of the retina are not developed immediately out of the epidermic cells of the integument ; but inasmuch as the brain is itself begun as an infolding of the epidermic layer, the rods and cones of the retina are ultimately derived from those epidermic cells. Or, again to quote Professor Huxley, "the rods and cones of the vertebrate eye are modified epidermal cells, as much as the crystalline cones of the insect or crustacean eye are."* Therefore, in the words of Professor Hseckel, " the general conclusion has been reached that in man, and in all other animals, the sense-organs as a whole arise in essentially the same way, viz., as parts of the external integument or epidermis. The external integument is the original general sense-organ. Gradually the higher sense- organs detach themselves from this their primal condition, whilst they withdraw more or less completely into the pro- tecting parts of the body. Nevertheless in many [inverte- brate] animals, even at the present hour, they lie in the integument, as e.g., in the Vermes." I have entered thus fully into this general fact, because it is of importance, not only to the theory of evolution, but also to the philosophy of sensation, to know from such direct historical sources that all the special senses are differentiations of the general sense of touch. • Science and Culture, &.C., p. 271t it ' i 3 PLEASURES AND PAINS. 105 ''■ 11 mi CHAPTER VIII. .! ■ Pleasures and Pains, Memory, and Association of Idea^ In the diagram I have represented Pleasures and Pains as occupying in their first origin a level not far removed from that at which Sensation takes its rise. I have also repre- sented a short interval hetween Sensation and the origin of Perception, which is filled up in the lateral column by Memory and Primary Instincts. Therefore, before we pass on to consider the rise of Perception out of Sensation, I shall devote a chapter to a consideration of Pleasures and Pains, Memory, and Association of Ideas. Pleasures and Pains. On this topic I have little to add to the treatment which it has received at the hands of Mr. Herbert Spencer, and of his disciple, Mr. Grant Allen.* Pains, as Mr. Spencer points out, may be due to the want of action (" craving "), or to an excess of action. These two classes correspond largely, though not entirely, with the division of pains into massive and acute, which is formulated by Professor Bain. It also indicates the doctrine of Sir W. Hamilton and others, that Pain is due to excessive stimulation. But it is important to observe that the statement of Mr. Spencer, while " recognizing at one extreme the positive pain of excessive actions," recog- nizes also " at the other extreme the negative pains of in- actions ; the implication is that Pleasures accompany actions lying between these extremes." Mr. Grano Allen in the course of his able exposition of this subject, shows by many examples that "the Acute Pains, as a class, arise from the action of surrounding * See Principles of Pnychology and Physiological Esthetics, in both cases the chapter on " Pleasui-es and Pains." I II M 106 MENTAL EVOLUTION IN ANIMALS. yi:^] destructive agencies; the Massive Pdns as a class from '^aSpaTnfwh " "^^^^^"^ ^'^^' ^^o 'Z Ar.,f! PI » ' .?^'' P,""'^^^ ^° ^n extreme, merge into the fheriSr hi? '^'' " '?' '"^^ ^^^^^^^ ^^^ r^^^^r indefinite in their limits, heing simply a convenient working distinction ZL"^'ZV:lT':- ^^"^^ ^^^'^^^^-« ^hat PaS'of both Classes are the subjective concomitants of an actual disnm tion or disruptive tendency in some one (or moi^) ofthe cett Sr;f' \'T' ^' -PP^-dS^afferen cereDro-spinal nems m unbroken connexion with the brain" deferring the reader to Mr. Allen's own essay for all mat ers of detail and criticism, I shall merely say that in my ZinZ al \ZeTTF^' '^f "'^' this Vula as ap'pLXe to ail cases ot lam. His view concerning the phvsiolocrv of Pleasure is substantially the same as that of M^r Ker cte %r vti^"' l f ^?"^^^^^^ "^'^ extended a7dp. cise. 1 his view is that Pleasure is "the concomitint of a normal amount of activity in any portion or t^ wTole of the "XToirPpr"''^ with the'important aJ.S.ftha the strongest Pleasures result from the stimulation of the largest nervous organs, where activities are most intermittent " timber o? r^'fi^' ^''''T \' "'^ ^^^ direVt S ol'the number of nerve-fibres involved, and in the inverse ratio of the natural frequency of excitation." Hence "we ^e wherein Sflill n?y^ ^ 'T' ^f' ^^ ^' «^^^<^ly antitheticaUo tl e fan Vl ""'i^r^ "' *^'^ °^J^^^^^« antecedents similarly s^v ofZT-^ ^p''"'t '^° '^^^^"^ °^ ^«^«r attain the intend sity of Massive Pam, because the organism can be brought itTffil'nr'r^P"^^' of innutrition or exhaus ionX Its efficient working cannot be raised very high above the average. Similarly any special organ or plexus of nerves en undergo any amount of violent disruption orwastbJaway giving rise to extremely Acute Pains ; but organs a^reveiT seldom so highly nurtured and so long deprived of thek appropriate stimulant as to give rise to ve'ry Ac^Ie Pleasure » poin^rT^Tt f^^^^^^H^on do theL generaStions point ? They clearly pomt to the conclusion, Shich I do not thmk IS open to any one valid exception, th^t Pains are Sie cltantcf.T^^'^r'''^'" Pleasures are the^ubjective con- ore^, t^ '"'^ organic changes as are beneficial to the orgamsm-or, we must add, to the species. The more this PLEASURES AND PAINS. 107 doctrine is pursued m detail, the more unquestionable does Its truth become. Thus there is to be perceived, not merely a general qualitative, but also a roughly quantitative relation between the amount of pain and the degree of hnrtfulness as well as between the amount of pleasure and the degree of wMcsomeness.^^ As Mr. Allen observes, " nothing can more thoroughly mihtate against the efficiency of the mechanism than the loss of one of its component parts: and we find accordingly that to deprive the body of any one of its mem- Ders is paintul in a degree roughly proportionate to the general value of such member to the organism as a whole, lake, for example, the relative painfulness of severing from the body a leg, an arm, an eye, a finger-nail, a hair, or Apiece t \. Snmlarly with Pleasures, the least pleasurable are those attending activities of the organism which are least important for its welfare (or for that of its species), while the most pleasurable are those which attend the satisfaction of hunger, thirst, and sexual desire-especially if, in terms of Mr. Aliens formula, the needs to which these cravings minister have been long unsatisfied, so that the organism Is either in danger of enfeeblement and death, or in the most lit condition lor propagating its kind. Pleasures of the intel- lectual kind, although subservient to the same general laws ot nutrition and exhaustion, have referenee to such complex nervous states involving mental prevision of future contin- gencies, &c., that for the purposes of clear analysis they had best be here disregarded. ^ "■ The superficial or apparent objection to the doctrine we are considering which arises from the fact that feelinrrg of Pleasure and Pam are not infallible indices of what is respec- tively beneficial or injurious to the organism, is easily met by the consideration that in all such exceptional cases it is not the doctrine but its application which is at fault Thus again to quote Mr. Allen, who in my opinion has given in brief compass the best analysis of the philosophy of Pleasure and Pam that has hitherto appeared, "every act, so long as It IS pleasurable, is in so far a healthy and useful one • and conversely, so long as it is painful, a morbid and destructive ^"^■j . J , ^^"^^y ^^^^ ^^ ^^^® proleptic employment of the words deleterious ' and ' useful?^ To put it in a simple form. :"■! :'! f 1 : r ' ' i ■1 m « j j i .111 108 t|!|i 1 ■ , 1 ■ di- ■ f ^ 1 1 l:^ ; m.1 ■ MENTAL EVOLUTION IN ANIMALS. tlie nervous system is not prophetic. It informs us of what is its actual state at the moment, not what the after-effects of that state will be. If we take sugar of lead, we receive at first a pleasant sensation of sweetness, because the immediate effect upon the nerves of taste is that of a healthy stimu- lation. Later on, when the poison begins to work, we are conscious of a painful sensation of griping, because the nerves of the intestines are then being actually disintegrated by the direct or indirect action of the irritant." Now if the doctrine before us is found to apply generally to all cases of Pleasure and of Pain, the implication is suffi- ciently apparent; Pleasures and Pains must have been evolved as the subjective accompaniment of processes which are respectively beneficial or injurious to the organism, and so evolved for the purpose or to the end that the organism should seek the one and shun the other. Or, to quote Mr. Spencer, " if we substitute for the word Pleasure the equivalent phrase — a feeling which we seek to bring into consciousness and retain there, and if we substitute for the word Pain the equivalent phrase — a feeling which we seek to get out of consciousness and to keep out; we see at once that, if the states of consciousness which a creature endeavours to maintain are the correlatives of injurious actions, and if the states of consciousness which it endeavours to expel are the correlatives of beneficial actions, it must quickly disappear through persistence in the injurious and avoidance of the beneficial. In other words, those races of beings only can have survived in which, on the average, agreeable or desired feelings went along with activities conducive to the mainten- ance of life, while disagreeable and habitually-avoided feelings went along with activities directly or indirectly destructive of life, and there must ever have been, other things equal, the most numerous and long-continued survivals among races ^'n which these adjustments of feelings to actions were the best, tending ever to bring about perfect adjustments. " If we except the human race and some of the highest allied races, in which foresight of distant consequences intro- duces a complicating element, it is undeniable that every animal habitually persists in each act which gives pleasure, 80 long as it do'^A so, and desists from each act which gives pain. It is in ipife^t that, for creatures of low intelligence, there caa be u-o c aer guidance." PLEASURES AND TAINa 109 Thus, then, wo see that the affixing of painful or disncree- able states of consciousness to deleterious changes of the organism, and the reverse states to reverse changes, has been a necessary function of the survival of the fittest. We may further see that in bringing about this adjustment or corre- spondence, the zoological principle of the survival of the fittest must have been largely assisted by the physiological prmciple that Pleasure tends to accompany the normal activity of an organ and Pain to accompany its abnormal. For as organs are invariably of use to the organism, their normal activity must always be beneficial to it; while, con- versely, their abnormal activity, tending to cause or 'beincf caused by their own disintegration, must always be harmful to the organism. Survival of the fittest is thus provided with a ready-foi-med condition or tendency of psycho-physio- logy on which to work— a tendency which survival of the fittest may itself in earlier times have beer instrumental m producing ; but which, in any case, when once established must greatly assist survival of the fittest in apportioning the a,ppropriate state of consciousness to any particular organic process. ° Another principle of pyscho-physiology must likewise have greatly assisted natural selection in its execution of this work. This principle is that which obtains in so-called acquired tastes and distastes. Thus, as Mr. Spencer observes, •' Pleasures and Pains may be acquired—may be, as it were' superimposed on certain feelings which did not originally yield them. Smokers, snuff-takers, and those who chew tobacco, furnish familiar instances of the way in which long persistence in a sensation not originally pleasurable, makes it pleasurable— the sensation itself remaining unchanged. The like happens with various foods and drinks, which, at first distasteful, are afterwards relished if frequently taken Common sayings about the effects of habit imply recognition of this truth as holding with feelings of other orders. That acute pain can be superinduced on feelings originally agree- able or indifferent, we have no proof. But we have proof that the state of consciousness called disgust may be made inseparable from a feeling that once was pleasurable :" so that even in the life-time of the individual the states of consciousness as pleasurable or painful may reverse their character with reference to the same organic changes or sen- li'-ll |i ■'■■■ '' i 1 ■ i I ill! : i i|r- li m'\ 110 MENTAL BVOLUTION IN ANIMALS. ^ fil ti ;3 sations, and if this is the case it becomes evident with what plastic material natural selection has had to deal in moulding through numberless generations the form of consciousness which best fits, with refeience to the welfare of the organism, the circumstances of stiumlation. Thus we may well believe that survival of the fittest, acting always in co-operation with these principles of psycho- physioiog)-, must have been successful in accomplishing the adjustments here assigned to its agency— the adjustments, that is, between states of consciousness as agreeable or dis- agreeable and circumstances of stimulation as beneficial or deleterious. And thus it is that in the process of evolution organisms " have gone on establishing a consensus between the various organs of the body, so that at last, for the most part, whatever will prove deleterious to any organ proves deleterious also to the first nerves of the organism which it affects," and therefore disagreeable to ccnsciousness, although of course, as we should from these principles expect, this is only the case "when the deleterious object is found suffi- ciently often in the environment to give an additional point of advantage to any species which is so adapted as to discriminate and reject it."* Thus then, it seems to me, we have aa full a rationale of Pleasures and Pains as we can expect or need desire. The only difficulty is to understand the connection between the objective fact of injuriousness or the reverse, and the corre- sponding subjective state of consciousness; how is it that injuriousness or the reverse comes to be, as it were, translated into the language of Pleasure and Pain. But this is only the old difficulty of understanding the connection of Mind with Body, and has no reference to historical psychology, which ' takes the fact of this connection as granted. Possibly, how- ever — and as a mere matter of speculation, the possibility is worth stating— in whatever way the inconceivable connection between Body and Mind came to be established, the primary cause of its establishment, or of the dawn of subjectivity, • Grant Allen, loc. cit., p. 27. The latter consideration disarms any criti- cism which might be advanced against our doctrine on account of the agree- able tast*^ of certain poisons, both to ourselves and to the lower animals. But it is astonishing even here how rapidly the appropriate distaste arises after experience of the injurious effects : witness the dislike of wine which may fre- quently be caused, even in those who are addicted to excess, by Burreptitiouslr mixing it with nux-vomica. m ii'ip 1 f MEMORY AND ASSOCIATION OP IDEAS. Ill (Ml may have been this very need of inducing organisms to avoid the deleterious, and to seek the beneficial; the misan d'e'tre of Consciousness may have been that of supplying the con- dition to the feeling of Pleasure and Pain. Be tliis as it mav however, it seems certain, as a matter of observable fact, that the association of Pleasure and Pain with organic states and processes which are respectively beneficial and deleterious to the organism, is the most important function of Conscious- ness m the scheme of Evolution. And for this reason I have placed the origin of Pleasures and Pains very low down in the scale of conscious life..^ Indeed, if we contemplate the subject we shall find it difficult or impossible to imagine a form of consciousness, howevcf' dim, which does not present m a correspondingly undeveloped condition, the capacitv of preferring some of its states to others— that is, of feeling a distinction between quiescence and vague discomfort, which with a larger accession of the mind-element, grows into the vivid contrast between a Pleasure and a Pain. I think therefore, it is needless to say more in justification of the level on the diagram at which I have written these words. Memory and Association of Ideas. It is obvious that Memory must ne, and is, a faculty which appears very early in the development of Mind. A priori, this must be so, because consciousness without memory would be useless to the animal possessing it, and d posteriori we find that this is so whether we contemplate the scale of mental evolution in the animal kingdom or in the growing child. _ I have therefore assigned the rise of Memory to the level immediately succeeding that which is occupied by the rise of Pleasures and Pains. In a previous chapter* I have endeavoured to show that, even before the dawn of Consciousness, nervous actions of adjustment when frequently repeated present conclusive evidence that the nervous machinery concerned in them becomes more or less organically adapted to perform them, and so exhibits the objective aspect of memory. This objec- tive aspect I spoke of as the memory of a ganglion. Since that chapter was written, M. Ribot has published his excel- • On " the Physical Basis of Mind." i'l i'. if ! i! 1 f 1 , J 'J r fi ii 1 i f I. I : ■ ; i i .i ■■ > ! ! ,1 H 1 : ' f 112 MENTAL EVOLUTION IN ANIMALS. Hi lent work on the "Diseases of Memory," which has now been translated, and forms a member of the International Scientific Series. In this work M. Eibot deals fully with the complete analogy that obtains on the objective side between ganglionic memory— or, as he caUs it, organic memon^— and the physical changes in the cerebral hemispheres which are concerned in true or conscious memory. I should like to express my satisfaction at finding so singularly close a corre- spondence between the views of M. Eibot and myself upon these matters, which extends into so many detaUs that I have left my chapter already referred to verbatim as it was oricd- naUy written; for it speaks in favour of the truth of one's results when they have been independently arrived at by another worker in the same field.* ^ And here I may observe that I also agree with M. Eibot in his view that the phenomena of memory, whether "organic" or "psychological," present no point of true analogy with any such purely physical phenomena as the permanent effects upon a photographic plate of a short exposure to light, or any other phenomena where living organisms are not concerned. I further agree with him in his view that the earliest analogy we can find to memory is to be sought in living tissues other than nervous, and that it occurs m protoplasm. Thus he quotes Hering to the effect that muscular fibre " becomes stronger in proportion to its use." To this It may, I think, be objected that there is no evidence of individual muscular fibres thus gaining in strength by use. I think a better, because a more unexceptionable, parallel IS afforded by the fact that when a constant galvanic current IS allowed to pass for a short time through a bundle of mus- cular fibres, in the direction of their length, and is then opened a change is found to have been produced in the excitability of the fibres such that they are less excitable than before to a stimulus supplied by again passing the current in the same direction, and more excitable to the stimulus sup- plied by passing the current in the opposite direction. This memory of a muscle touching the direction in which a gal- vanic stimulus has passed endures for a minute or two after the current has ceased to pass (Frog). I have found this • Any one who cares to trace the correspondence may do so by comparinff my chapter above aUuded to with the first chapter of M. Eibot'a work. MEMORY AND ASSOCIATION OF IDEAS. 113 curious fact to hold in the case of muscular tissues of various animals, from the Medusae upwards.* " Again I concur with M. Eibot in h's opinion that the physical basis of memory consists partly in a more or less permanent molecular change or "impress" produced upon the nervous element affected by the stimulus which is re- membered, and partly upon " the establishment of stable connections between different groups of nervous elements" 1 do not think that the view can be too strongly reprobated which crudely supposes that the first of these physical con- ditions IS alone sufficient to explain all the facts of memory and therefore_ that a given remembrance is, as it were stored upm a particular ceU, as a particular "impression" upon the substance of that cell. On the contrary, as M. Eibot SHOW'S, Lach of these supposed unities (memories) is com- posed of numberless and heterogeneous elements ; it is an association, a group, a fusion, a complexus, a multiplicity; .... Memory supposes not only a modification of nervous elements, hut the formation among them of determi- nate associatiom for each particular act. We must not how- ever, forget that this is pure hypothesis— the best available one no doubt, but still not to be taken as implying that we really know anything definitely concerning the physical sub- stratum of memory." ^ "^ Profound however, as our ignorance unquestionably is concermng the physical substratum of memory, I think we are ut least justified in regarding this substratum as the same botfi m ganglionic or organic, and in conscious or psycholo- gical memory— seeing that the analogies between the two are so numerous and precise. Consciousness is but an adjunct which arises when the physical processes— owing to infre- quency of repetition, complexity of operation, or other causes— myolve what I have before caUed ganglionic friction. And this view IS confirmed by the large and general fact noted in Pm %lanT'vfj\^l^'"^'T' ^^ t^^^'O'^o'^otor Sj«tem of Medusa." vlL pI V AT • }^^^' ^^^'^ °" "Modification of Excitability," ic Zty. A Z ^^^ "n'^ ^""h >'«°' '^°«''««^ of Anatomy an/hysio'. log,/, yol. X. Another equally good instance of what mar be termed nroto- stimuli, which occur more or less in aU excitable tissues, i e wherever 1 ving protoplasm is concerned. These facts are that if ^ successfon of moT«„nr^^'^'^'''^V*^° ^'',?*^^^« «««"«• the latter becomes piSe si^e?y more and more quick as well as more and more energetic, in its fesoonse^ each stimulus leaves behind it an organic memory of itf occurrence ^ ' lip : 1 1 ii.' ■1 1 t p 1 f if'! 1 1 ,f I I. 3 I ' 114 MENTAL EVOLUTION IN ANIMALS. our chapter on the Physical Basis of Mind, that conscious memory may become degraded into unconscious memory by repetition; associations originally mental lapsing into asso- ciations that are automatic. Thus much being premised touching the physical basis of memory, we may next pass on to consider the evolution of memory on its psychological side. +T,- P^ earliest stage of true or conscious memory may I think, be regarded as consisting in the after-eflect produced upon a sensory nerve by a stimulus, which after-effect so long as it endures, is continuously carried up to the sensoriura feuch for instance, is the case with after-images on the retina the after-pain of a blow, &c.* ' The next stage of memory that it appears to me possible to distinguish by any definite interval from the first-named IS tfiat of feeling a present sensation to be like a past sensa- tion. In order to do this there may be no memory of the sensation between the two successive occasions of its occur- rence, and neither need there be any association of ideas Unly this takes place ; when the sensation recurs the second third, or fourth time, &c., it is recognized as like the sensa- tion when It occurred the first time— as like a sensation which is not unfamiliar. Thus, for example, accordincr to bigismund, who has devoted much careful attention to the psychogenesis of infants, it appears that the sweet taste of milk being remembered by newly-born infants, causes them to prefer sweet tastes in general to tastes of any other kind Ihis preference of course endures long after the time of weaning IS past, and generally continues through childhood; but the interesting point in the present connection is that it occurs too early in the life of the child to admit of our sup- posing that any association of ideas can take part in the process. For Sigismund says that the memory of the taste of milk becomes attached to the perception " immediately," and Preyer states, from independent observations of his own that the preference shown for sweet tastes over tastes of all oth^ kinds may be clearly seen as early as the first day. The next distinguishable stage of memory is reached when, still without any association of ideas, a present sensa- tionis perceived as unlike a past one. Thus, again turnincr to the observations of Sigismund and Preyer, it appears from ♦ Compare Wundt, Qrundzuge der philosophischen Pst/chologie, p. 791. MEMORY AND ASSOCIATION OF IDEAS. 115 them that after the accustomed taste of milk has become well fastened m the memory by several successive acts of suckincr the child when a few days old is able to distinguish a chancS of milk. Similarly, I find among Mr. Darwin's MSS the lollowing note : — " It is asserted (by Sir B. Brodie) that if a calf or infant has never been suckled by its mother, it is very much easier to bring It up by hand than if it has sucked only once So again, Kirbyaiid Spence state (from Reaumur, ' Entomolocry ' vol. 1, p. 391) that larvae after having ' fed for a time on Sne plant will die rather than eat another, which would have, been perfectly acceptable to them if accustomed to it from the first.' " It will be observed that in dealing with these stages of memory m very young inllmts, where as yet no association of Ideas can either be supposed to be present or is needed to explain the facts, we at once encounter the question whether the memory is to be considered as reaUy due to individual experience, or as an hereditary endowment, i.e., an instinct And here it becomes apposite to refer to the old and hicrhly interesting experiment of Galen, which definitely ans?vers, this question with reference to animals. For soon after its birth, and before it had ever sucked, Galen took a kid and placed before it a row of similar basins, filled respectively with milk, wine, oil, honey, and flour. The kid, after examin- ing the basins by smell, selected the one which was filled with milk. This unquestionably proves the fact of hereditary memory, or instinct, in the case of the kid ; and therefore it IS probable that the same, at all events in part, applies to the case of the child. In proof of which I may allude to the experiments of Professor Kuszmaul, who found that even prior to individual experience derived from suckinf^ milk newly-born children show a preference for sweet tastes over all others. For, on their tongues being wetted with sugar or salt solutions, vinegar, quinine, &c., the new-born infants made all manner of grimaces, being pleased with the suoar solution, but with the others showing displeasure by a " sour face," a " bitter face," and so on. But although we freely admit that the memory of milk is at aU events in large part, hereditary, it is none the less memory of a kind, and occur* without the association of ideas. In other words, hereditary memory, or instinct, belongs to !i.'i ' \ ^: .* I i * t" m >:R| ( I •■ ft . I i. I 'Ui' ■.\'i ilV! 116 MENTAL EVOLUTION IN ANIMALS. I ' ! I .'! .(« I? What I have marked off as the second and third stages of conscious memory m the largest acceptation of the term-the stages, that IS, where, without any association of ideas a pre- sent sensation is perceived as like or unlike a past one It makes no essential difference whether the past sensation was actually experienced by the individual itself, or bequeathed to It, so to speak, by its ancestors. For it makes no essential difference whether the nervous changes which constitute the rtrfnTfif' P?? .°^ ^H Pf ^^^P^^ve aptitude were occasioned during the hfe-time of the individual, or during that of the species and afterwards impressed by heredity on the indi- vidual. In either case the psychological as well as the physiological result IS the same ; a present sensation is alike perceived by the individual as like or unlike a past sensation. It IS not easy at first to grasp the truth of this statement; but the source of the difficulty is in not clearly distinauish- ing between memory and the association of ideas. MSmorv inits lower stages which we are now considering has in mv opinion nothing to do with the association of ideas. It only has to do with perceiving a p^-esent sensation as like or unlike a past sensation, which never can have formed the object of an idea between times, and which does not even arise as an Ideal remembrance when the sensation again occurs In other words, there is no act of conscious comparison between tlie two sensations ; there is not even any act of ideation • but the past sensation has left its record in the nervous tissues ot the animal m such wise that when it again occurs it emerges into consciousness as a feeling that is familiar~or if another unlike sensation takes its place, this emerges into consciousness as a feeling that is not familiar. And whetlier such feelings of familirrity or unfamiliarity arise in the experience of the individual or in that of the species, makes as I have said, no essential difference either in the physiolo- gical or m the psychological aspect of the case. As showing how close is the connection between here- ditary memory, or instinct, and memory individually acquired. 1 shall briefly state some very interesting experiments which were made by Professor Preyer on newly-hatched chickens. ±le laid before a newly-hatched chicken some cooked white ot egg, some cooked yolk of egg, and some millet seed. The chick pecked at all three, but no more frequently at the two latter than it did at pieces of egg-shell, grains of sand, or the MEMORY AND ASSOCIATION OP IDEAS. 117 spots and cracks of a wooden floor on which it was placed. But at the yellow yolk it pecked often and earnestly. He then removed all three substances, and after the lapse of an hour replaced them. The chick instantly recognized them all as proved by its immediately beginning to devour them while flowing a complete disregard of all other and inedible objects, whip nf A ^^P^:^°^fnt the chick only once tasted the white of egg, and only took a single millet seed. The experi- ment therefore shows how apt a young chicken is to learn by Jp..rV 'Ir^ experience, while in the opinion of Pro- fessor Preyer the original preference shown to the yolk of egg proves an inherited faculty of taste-discrimination. Ihese experiments serve to introduce us to the sta^e of Memoryat which the Association of Ideas is first concern'ed- tn^'^^Pl" "? throughout all subsequent stages consti- tutes what may be termed the vital principle of Memory- for the chickens which first pecked at inedible objects in the presence of edible ones, and an hour later were able to dS SL^Tlf-^'"' two classes of objects, must have estabhshed a dehnite association of ideas between each of the tSl^tu^^^^''''Ai^\^'''^'' ^^P^^^«^^« ^ith reference 1^ tlli H rV"""^'^^^ '?''"'^''- ^^^ '^ '' noteworthy that, as these definite associations were established so quickly and as the result of only a single individual experience i/each case, we can scarcely avoid concluding that heredity must as'In thP.'^''^''r ?'* the largest, part^n the proceX^u as m the case of distinguishing from the first the boiled yolk IJf' Y^T'^ J^PP^f" ^^^^ ^^^^dity had the exclusive part * And this shows how closely the phenomena of heie- atthT,fH^'^r '^^f^^ '\'^'''' °^ ^^^ividual memory; a socfation^ n^ "7^1''''' "^ mnemonics, where the simpi' assoc ation of ideas first occurs in very youncr animals it i I ^1 ' ■ •,■: i •1 In J 122 MENTAL EVOLUTION IN ANIMALS. if ii .' ifiii • 1^^ I ' of memory IS also present in the division of the Mollusca. ino Kazor-fish, likewise, shows memovv, and this in a hi"h deforce, inasmuch as if only once alarmwl upon comin^ to the surtace of its burrow, it cannot be aj,'ain in(hiced to approach the surface for a long time, even by the application of irri- tants btiU more remarkable is the level of development to which memory has attained in the Snail, if the observation of Mr. Lonsdale is to be accepted of the Ildix pomatia, which, atter leaving its sickly mate and crawling over a garden wall returned next day to the place where it had left its mate.f Hut the hii/hest level to which the development of memory attains in the Mollusca is unquestionably in the Cephalopoda. tor according to Hollniann an Octopus remembered its en- countivr with a lobster in a remarkable manner,! while according to Schneider these animals learn to know their keepers.J Seeing that memory in various stages of development thus unquestionably occurs among the Mollusca, I thought it worth while to try some experiments in tliis connection with the Jb^chinodermata, but they all yielded negative results. It has however, been alleged that if a star-fish be removed from its' eggs, It will crawl back again to the place where they were- and if this statement were confirmed, it would of course prove memory in the Echinodermata. Hitherto I have myself had no opportunity of testing it, and therefore my expe- riments were confined to endeavouring to teach star-fish a tew simple lessons, which, as I have already implied, they would not learn. I am more surprised with my failure in this respect with the higher Crustacea; for although I have tried similar experiments with them, I have never been able to teach them the simplest things. Thus, for instance, I have taken a hermit crab, put it into a tank filled with water, and when he had protruded his head from the sheU of the whelk in which he was residing, I gently moved towards him a pair ot open scissors, and gave him plenty of time to see the glistening object. Then, slowly including the tip of one of his tentacles between the open blades, I suddenly cut off the tip Of course the animal immediately drew back into the Shell, and remained there for a considerable time. When he again came out I repeated the operation as before, and so on • Animal Intelligence, p. 26. f Ibid., p. 27. J Ibid., p. 30. :l % It I' i: ASSOCIATION OF IDEAS. 123 fntfl crrmtnnmhcT of timoH. till all the tentnclos hnd been progressively cut away little by little. Yet the ai.in ,1 m-vpr earnt to associate the appenince of the s i sZ t tl o eflect which always followed it. and so never drew n ur i^ the snip had been given. Nevertheless, that inen.orvdoea quoted in Aiiiinul Intelligence" (p. 233). concerning a bbster mounting guard upon a heap of shhJo beneath which It had previously hidden some food ° ^ In another class of the Articulata. liowover. the faculty of memory has been developed to an extrac.rclinaryde.ne7 and far surpasses that which han been attained by any otl er'c ass of Invertebrata. The class of the Articulata t^o which I alliuL are the Insects, and, more particularly, the 11^^^" Without quoting in ..7m.o the evidence on thi Yi ul vvh ch has already been given in my previous work, it is enough to say in general terms that ants and bees are unquestionably able to remember the places where many months^ befme they have obtained honey or sugar, &c.; and will also w en occasion requires, return to nests and hives which tlievTmve deserted the year before. Many interesting oSrvations ave also been made on the rate of acquisition and the en' th or duration of particular memories in these animals which however it is needless for me again to quote." PeSmps the mos interesting of these are the observations of sTr^John Lubbock on bees gradually learning to know the difference between an open and a closed window, and the observations of Messrs. Bates and Belt on the sand-wasps carefulirteac ng themselves (by taking mental notes of landmarksrtl e ocalities to whic3h they intend to return in orSer to sture the prey which they have temporarily concealed Incidenal evidence of memory in other orders of Insects wial^ be PP ^^r'otrT" '° "^^ rr'""' ^yon^^yi'^., for BceUes %; p 230 '^'' ^' ' ""''^ ^°' ^^'^ '^^"^"^^^ House- Turniug now to the Vertebrata, we find that in Fish memory is certainly present, although it never reaches S than such a degree of development°as is implied by rerem! bering in successive years the locality for spiwnin/leamrc. to avoid baits, removing young from a nesUvhidrhas beef ^f m i m ; 1 ' I i i : !■ t 124 MENTAL EVOLUTION IN ANIMALS. •f n' disturbed, and associating the sound of a bell with the arrival ■ or lood,* Batrachians and Reptiles are able to remember localities and also to identify persons.f The annual migration of lurtles further proves the duration of memory for at least a year. In Birds the power of memory has ac'vanced considerably beyond that of remembering, as in the case of the swallow, the precise locality of their nests from season to season, and even beyond that of identifying persons from year to yeart ± or the facts which I have previously detailed at length touching the acquisition by talking birds of tones, words and phrases, show not only an exceedingly high development of the powers of special association, but even the power of genuine recollection to the extent of kno^ving that theie is a missing hnk in the train of a previously formed association, and of purposely endeavouring to recover it. Quotations from Dr. Wilks, Mr. Venn, and Mr. Walter Pollock were also ?w^V"^ °^^®^' *° ®^^^ ^^^^ ^^^®^* ^^^ careful observation that the process of forming special associations is in such cases identical with that which occurs in man.§ Among Mammals the highest development of memory is presented by the Horse, Dog, and Elephant. Thus there is unexceptionable evidence of a horse remembering a road and a stable after an interval of eight years ;|| of a dog remem- bering the sound of his master's voice after an interval of five years,! and the sound of a clinking collar after an interval of three years ;f and of an elephant remembering his keeper alter having run wild for an interval of fifteen years.** It is probable, also, that if observations were made, the memory of Monkeys would be found to be very retentive, as it certainly IS most minute, and largely assisted by the intentional efforts 01 the animals themselves.tt • See Animal Intelligence, pp. 248-51. f Ihid., pp. 254-62. : Ihid p. 266. § For all these facts, see ibid.,x>p. 266-70. PERCEPTION. 125 ii i '^1 CHAPTER IX. Perception. At the level marked 18 I represent the rise from Sensa- tion to Perception. By this term I mean, in accordance with general usage, the faculty of cognition. " The contrast between Sensation and Perception is the contrast between the sensitive and the cognitive, intellectual, or knowledge- giving functions." (Bain.) " Perception is an establishment of specific relations among states of consciousness ; and this is distinguished from the establishment of these states of consciousness themselves," which constitutes Sensation. (Spencer.) " In Perception the material of Sensation is acted on by the mind, which embodies in its present attitude all the results of its past growth." (Sully.) Sensation, then, does not involve any of the powers of the intellect as distinguished from consciousness, but Percep- tion implies the necessary occurrence of an intellectual or cognitive process, even though it be a process of the simplest possible kind. The term Perception, therefore, may be applied to all cases where a process of cognition occurs, whether such process arises directly or indirectly out of sen- sation ; thus it is equally correct to say that we perceive the colour or the scent of a rose, and that we perceive the truth or the probability of a proposition. Other, .'se phrased we may state the distinction between Sensation and Perception thus. A sensation is an elementary or uudecomposable state of consciousness, but a perception involves a process of mentally interpreting the sensation in terms of past experience. For instance, there is a closed book lying on the table before me ; my eyes have been resting on its cover for a considerable time while I have been thinking how I should arrange the material of the present chapter. All that time I have been receiving a visual sensation of » ,1' i ■il ; r' ■ihil: H r ■' i • ! I 1 1 i 1 ' J i s j 1 ' ' . ; ■ '1 " j ^1 126 MEXTAL EVOLUTION IN ANIMALS. I ft uu i 'ii I I particular kind; but. as I did not attend to it. tlie sensation did not involve any element of cognition, and therefore did not minister to any act of perception. All at once, however I became conscious that I v.as looking at a book and in cognizing that the particular object of sensation was a book tJllZr^ f ''. T "^ P«^.«^Pti°n- In other words. I men- tally interpreted the sensation in terms of past experience • I made a mental synthesis of the qualities of the object and assigned it o the class of objects which had pSusly produced a like sensation. pieviousiy teiJs'JSnl?'.*^'''''' ^ "^fntal classifying of sensations in teimsof past experience, whether ancestral or individual • it IS sensation 2^lus the mental ingredierL of interpretation. Now as a condition to the possibility of this incrredient it is clearly essential that there should be present fhe power of ^r^^'h ^'' '^^^ ^l ^ ^'^"°^^ °^ P^^t experience can the process be conducted of identifying present sensations or experiences as resembling past oSes". Therefore in the diagram I have placed the dawn of Memory on the level Se tnTh%'' ^^^^"^^^"cultyof Perception ^akesTts Itfni.inc o ^^^«.f "^^.^nd Perception are represented as attainmg a considerable vertical elevation from base to apex, te., from their first origin to their completed evolution. nl l^ j'i"'S^'* ^? ^^'° represented is evident if we reflect on the difference m the sensuous faculties of a medusa and an eagle, or between the perceptive faculties of a limpet and a man. It may, indeed, be thought that in my representative diagram I have not allowed enough for such differences, and therefore have made the vertical elevation of these branches too low. But here we must remember that in the case of Sen- sation as already shown, the advance of the faculty from its earliest to its latest stages consists essentially, on its morpho- logical aspect, of a greater and greater degree of specializa- tion of end-oi;gans of nerves; and I think that the degree of such advance is sufficiently expressed by the vertical elevation Which I have given to the branch in question, seeing how much more intricate must be the morphological development ot the nerve-tissues which are concerned in ministering to the next and to all succeeding faculties. And, as regards Perception, we must remember that in its more hTahly elaborated phases this faculty shades off into the higher representative branches marked "Imagination," &c.; so that PERCEPTION. 127 the branch marked " Perception " is not intended to include all that might possibly be included by the term if we did not eeparately name the higher faculties to which I allude. Now concerning the development of Perception, I may here make a general remark, which is first applicable at this stage of mental evolution, and which continues to be appli- cable to the development of all the faculties which we have subsequently to consider. This remark is that we have ceased to possess any data of a morphological kind— such as we had m the case of Sensation and the pre-mental faculties of adjustment— to guide us in our estimate of the degree of elaboration to which the faculty has attained. That morpho- logical evolution has here, as in the coarser instanc3 of Sen- sation, always gone hand in hand with psychical evolution, is amply proved in a general way by the advancing complexity of the central nerve-organs ; but just because this complexity IS so great, and the steps in morphological evolution which it represents so refined, we are totally at a loss to follow the process on its morphological side ; we are unable even dimly to understand the mechanisms which we see. Therefore, in order to estimate the ascending grades of excellence which these mechanisms present, we require to look to what we may most conveniently regard as the products of their operation ; we have to use the mental equivalents as indices of the mor- phological facts. We have seen that Perception is essentially a process of mentally interpreting Sensation in terms of past experience, ancestral or individual. The successive steps in the elabora- tion which this process undergoes in the course of its evolution must now be considered. The first stage of Perception consists merely in perceivin« an external object as an external object, whether by the sense of touch, taste, smell, hearing, or sight. But confining our- selves, for the sake of brevity, to the sense of sight, in this stage Perception simply amounts to a cognition of an object in space, having certain space relations with otlier objects of perception, and especially with the percipient organism. The next stage of Perception is reached when the simplest qualities of an object are re-cognized as like or unlike the qualities presented by such an object in past experience. The most universal of such qualities in objects pertain to size form, colour, light, shade, rest, and motion ; less universally |i ''4 : I ';i< i^l Wi> _ ,1 Ij :, In-.: i ■'J I:; I «- 1, - f 123 MENTAL EVOLUTION IN ANIMALS. such qualities pertain to temperature, hardness, softness, roughness, smoothness, and other qualities appealing to the sense of touch, as well as qualities appealing to the senses of smell, taste, and hearing. In the case of these more universal qualities, the part which the mind takes in the process of cognizing them as belonging to the objects is immediate and automatic, and, as Mr. Sully observes, " may be supposed to answer to the most constant and therefore the most deeply organized connections of experience." The third step in the advance of Perception consists in the mental grouping of objects with reference to their quali- ties, as when we associate the coolness, taste, &c., of a particular fruit with its size, form, and colour. Here the more frequently a certain class of qualities has been con- joined with another class in past experience, the more readily or automatically is the perceptive association established ; but m cases where the conjunction of qualities has not been so frequently or so constantly met with in past experience, we are able by reflection to recognize the perceptive association "as a kind of intellectual working up of the materials supplied us by the past." A further development of the perceptive faculty is re- quired to meet cases in which the qualities of objects have become too numerous or complex to be all perceived simulta- neously. In meeting such cases the faculty in question, while perceiving some of the qualities through sensation! supplements the immediate information so derived with information derived from previously formed knowledge ; the qualities which are not recognized immediately through' sen- sation are inferred. Thus, in my perception of a closed book I have no doubt that the covers are filled with a number of printed pages, although none of these pages are actually objects of present sensation. Or, if I hear a savage growl, I immediately infer the presence of an object presenting so complex a group of unseen qualities as are collectively com- prised in a dangerous dog. In a later chapter I shall have to dwell more minutely on this, which I may term the inferential stage of perception, and I shall therefore not deal more with it at present. It will be evident that the various stages which I have named in the development of Perception shade into one another, so as not really to be distinguishable as separata 1 ) 1 L 1 i j PERCEPTION. 129 Btages ; tliey constitute rather one uniforni growth on which, as in the case of Memory, I have arbitrarily marked these several grades of evolution. Moreover, it will be evident that the term " Perception " is really a very wide one, and may be said to cover the whole area of psychology, from the confines of an almost unfelt sensation up to the recognition of an obscure truth in science or philosophy. On this account the term has been condemned by some psychologists as too extensive in its application to be distinctive of "any particular faculty ; but nevertheless it is clearly impossible to do without it, and if we are careful to remember tlie sense in which we employ it— whether with reference to the lower or to the higher faculties of mind— no harm can arise from its use. I have just said that in the highest stage of its develop^ ment Perception involves Inference ; and I have previously said that in its lowest stages it involves Memory. I must now point out more particularly that in its ascending stages Perception involves Memory of ascending sta* 11 .111 - 1 i t 130 MENTAL EVOLUTION IN ANIMALS. H ■ I I'l : '7 slimes, and in all the habitual phenomena of experience such memories as tliis become so blended with our perceptions of the phenomena that the memories may be said to form intef^ral parts of the perceptions. Suppose, for instance, we see a man whose face we know, but cannot remember who the man is. Here the perception tliat the object which we see IS a man, and not any other of the innumerable objerts in Nature, is so intimately bound up wit'- •<'! organized association of ideas, that we do not thiin- .3 perception thus far as really depending on memory. L .0 only wh:n we turn to tlie incompletely organized association of ideas between the particular face and the particular individual, that we recognize the incompleteness of this part of the perception to depend upon the incompleteness of memory. Now these considerations, obvious though they appear, constitute the first stage in a disagreement on an important matter of principle, which will become more pronounced when I have to deal with the higher faculties of mind, and which, I regret to say, has reference to the writings of Mr. Spencer. In Ins chapter on Memory Mr. Spencer takes the view that, so long as " psychical changes are completely automatic, memory, as we understand it, cannot exist— there cannot exist these irregular psychical changes seen in the association of ideas." Now, I have already given my reasons for nob restricting the term Memory to the association of ideas ; but, passing over this point, I cannot agree that if psychical changes (as dis- tmguished from physiological changes; are completely auto- matic, they are on this account precluded from being regarded as mnemonic. Because I have so often seen the sun shine, that my memory of it, as shining, has become automatic, I see no reason why my memory of this fact, simply on account ot Its perfection, should be called no-memory. And similarly with all those well-organized memories which constitute integral parts of perceptions. In so far as they involve true " psychological changes," and therefore imply the presence of conscious rccogmtion as distinguished from reflex action, so far, I think, no line of demarcation should be drawn between them and any less perfect memories. I shall recur to this point when I come to consider Mr. Spencer's views on Instinct and Eeason. Another point wliich we have here to consider is the part which heredity has played iu forming the perceptive faculty PERCEPTIOIf. 131 of the individual prior to its own experience. We have already seen that heredity plays an important part in forming memory of ancestral experiences, and thus it is that many animals come mto the world with their powers of perception already largely developed. This is shown not only by such cases as those of Galen's kid, and Preyer's chickens before mentioned, but by all the host of instincts displayed by newly-born or newly-hatched animals, both Vertebrate and Invertebrate. This subject will be fully considered when I come to treat of Instinct, and then it will be found that the wealth of ready-formed information, and therefore of ready- made powers of perception, with which many newly-born or newly-hatched animals are provided, is so great and so precise, that it scarcely requires to be supplemented by the subsequent experience of the individual. In different classes of animals these hereditary endowments vary much both in kind and in degree. Thus, with mammals as a class, heredi- tary perception has reference in its earliest stages to the senses of smell and of taste ; for while many mammals are born blmd, some probably deaf, and all certainly very deficient in powers of locomotion, they invariably show more or less perceptive powers of taste, and very frequently well-advanced perceptive powers of smell. This we have already seen in the case of Galen's kid, and in the case of the do*^ (whose ancestors have depended so largely upon the perfection of smell) the same thing occurs in so high a degree, that so special an olfactory impression as is produced by the odour of a cat will cause a Utter of newly-born puppies to " pulf and spit."* ^ Birds come into the world with better endowments of perception than animals of any otlier class. For they are in full possession of every sense almost immediately after they are hatched, and, as we shall see later on, they are then able to use their senses nearly as well as they are ever eHe to use them. Reptiles are likewise hatched with their powers of percep- tion alniost as highly developed as they are ever destined to become,T and the same as a rule is true of invertebrated animals. I must now say a few words on the physiology of Percep- • See p. 164. f See Animal Intelligence, pp. 256-7. .".J-l. , m I ( I ;i .i is n .11 Ail „ •Hi ill ..^pllrf IllllfEd 132 MENTAL EVOLUTION IN ANIMALS. If :nli I'H tion— -or, more correctly, on what is known touching the physiological processes which accompany Perception. ° In earlier chapters I have already stated that the only distinction which is known on the physiological side between a nervous activity which is accompanied by consciousness, and a nervous activity which is not so accompanied, consists m a difference of time. I shall now give the experimental data on which the statement rests. Professor Ex.ner has determined the time which is occu- pied by a nerv(i-centre of man in executing its part in the performance of a reflex action. That is to say, the rate of transmission of a stimulus along a nerve beinf» known, and the length both of the afferent and efferent nerves concerned in a particular reflex act being known, as also is the "period of latency " of a muscle ; the time occupied by the nerve-centre in conducting its operations was determined by subtracting the time occupied by the passage of the stimulus along the afferent and efferent nerves, plus the period of latency of a muscle, from the total time between the fall of the stimulus and the occurrence of the muscular contraction. This time was found in the case of the reflex closure of the eye-lid to vary between 0-0471 and 0-0555 of a second according to the strength of the stimulus.* By a similar process Exner has estimated the time required for the central nervous operations which are together comprised in having a simple sensation, perceiving the sensation, and the volitional act of signalling the perception. That is to say, an electrical shock being administered to one hand, and as quickly as possible signalled by the other, the time occupied by the nerve-centre in performing its part of the process was esti- mated as in the previous case. This time in the case of this experiment was found to be 00828", which is nearly twice as long as that which, as we have just seen, is required for a nerve-centre to perform its part in a reflex action.f Acts of perception in which different senses are concerned occupy different times. This interesting topic has been investigated by a number of physiologists.^ According to Bonders the total "reaction-time" (i.e., between stimulus and response) is, roughly speaking, for touch |, for hearing ^, * Arch./, d. ges. Physiol., xliii, 526 (1874). t Ibid., vii, p. 610. X See Herman, Eandb. d. Physiol, Bd. II, Th. 2, 8. 264. PliRCErTION. 133 and for sight ^ of a second * The ohsei'vations of Von Wit- tichf, Vintschgau, and Honig-Schnied+ show tliat the reaction- time lor taste varies between 0-1598" to 0'23r)l" according to the kind of taste ; being least for salt, more for sugar, and most for quinine. A constant electrical current applied to the tongue gives a reaction-time for the resulting gustatory impression of 01 67". I am not aware that any experiments have been made with regard to smell. Exner has more minutely determined on himself the reaction- time for touch, sound, and sight, with the results which are emlwdied in the following table. The signal was in all cases given by the right hand depressing an electrical key ; — Direct electrical stimulation of retina Electrical shock on left hand . . Sudden sound . . . . Electric shock on forehead. . Electric shock on right hand "Visual impression from electric spark Electric shock on toe of left foot . . 01139" 01276 01300 01370 01390 01506 0-174ti§ It is thus noticeable that although the sensation of light pro- duced by vision of an electric spark is much greater than that produced by electrical stimulation of the optic nerve, the interval between the stimulation and the perception is much longer in the former case. Seeing that the optic nerve is so short, this difference cannot be attributed to the time lost in transmission along the nerve, and must therefore be supposed due to the time rec^uired for the nerve-endings in the retina to complete all the changes (whatever they may be) in which their response to luminous stimulation consists. Thus in the case of hearing, as the above table shows, some- what less time is consumed in the whole act of perception than is consumed in the case of sight by the peripheral changes taking place in the retina. _ According to Helmholtz and Baxt, the more complex an object of visual perception is, the greater must be tlie dura- tion of its image upon the retina, in order that the perception may be made ; while, within certain limits, the intensity of the image does not affect the time required to make the per- • Arch.f. Anat. und Physiol, 1868, p, 657. t Qt. Set. Med. (3), xxxi, p. 113. J Arch.f. Anat. und Phi/siol., x, p. 1. § PJliiger'a Archiv., Bd.'VII, p. 620. I : ' » u S ! 'I 'I Ml . i I! 1 1 4 m ■. : ^!l::! ]l' Mil 134 MENTAL EVOLUTION IN ANIMALS. M i accordingly. The sfate of ma ter thusTrese^^^^^^^^ f hT "'.' IS called by Bonders a " Dilemma "^nHf if fn -^^^ .""'"^ table of results ;— -^^^mma, and the following is his DUemma of hearing , t„„ Towele .udd.nb °Sed • 'i„.I V^ "" be made on hearing one only ' ' ^ "' *** Dilemma between five yoweU;,ig„alU beta " ."I JJ^ bet Jt te^oo^^^rArtirf • ™' ^."''^"'» p^"-" required Jr:;tf mee^ng f d-Uemmri^f '^ .'?^ J"»? o J'le^^rrr; bf I'rrdtrtr-^'^ ^ following results :--$ ^ ^ Auerbach, with the Jun*e, m?- *^- ''• ^''- -^'^^''''•' ^**- 1^' P- 329; Jfo«a..i«.. e^. Ser. Acad., pp. 657-5l''"'^"'' investigations, see ArcMv. f. Anat. und Pkysiol, 1868. t Archiv.f. d. ges. Fhysiol, 1877, pp. 298-380. PERCEPTION. Locnlization by Bight UiHtinpjmshing colour . . Localization by hearing (least interval) l)i»tingui8hing pitch (high notes) . . Localization by touch . . I)i8tinguiMhing pitch (low note's) Localxzation by hearing (greatest interval) 135 0011*' 0-01 a 0-015 0019 0021 0-034 0062 T.rJ!^ * ff^^"" ^"'""^^^ °^ alternatives are allowed bv tho Ttrrfs^ir^^^^^^^^^^ ' '''^^'-'"^^^ -^-^ ^ « car.^'^ ^^^^ required for perception in the case of all tli« ''Zl2rL:lni^^^^^^ ^"^' underthe' name'o aickness,and sundry Ss of Sfu^s "EltTt^ ^/"^^ °^ people of less vigorous or lively temperaments Accoid^n! to Exner persons who are accustomed to aUow theh^Tde.,^! run slipshod are relatively slow in forming thdrpertptJons or spondiL r ' ^T' T''''^'"^' ^^^"^- rece'fvhi'rd're: show tTp ^i^ '^™''^-'- J^^ ^^^' ^^^ following'table to vdTals * ^'''"'' "" ^^' reaction-time of seven hi61. Age. 26 23 Beaction-time. 1337 -3311 76 0-9952 24 1751 20 -2562 22 1295 85 1381 Remarks. Rough, lively labouring-man. S/'' ™°''^°'^°*«' ^"* '^tlier slow in apprehen- Infirm and not intelligent. Slow and deliberate in movements, blow and somewhat uncertain in movements blow and very precise in movements. Accustomed to manual work. Concerning the effects of drugs it is enou-h to sav thaf Exner found two bottles of Shine-wine increased hs react on WftjJe shooting that an amount of alcohol not sufficient tr£^'C/-T'''^'t^iy'^'''^ ^^^^t«'i« apt to make one shoot behind one's birds. And here, with reference to the personal equation, I may briefly 'aUude t^ some m r • Zoc. cit., p. 612. t Loc, cit., p. 628. II III -• r 1 ! li - ,- i ^.1 i : ; 1 \ ; i ■ { ] , ''; 186 MENTAL EVOLUTION IN ANIMALS. I I hitherto iininiiaislu'd observations of my own, which has served to display a positively astonishing difierence between (litterent individuals with respect to tlie rate at whicli they are able to read. Of course reading implies enormously intricate processes of perception botli of the sensuous and of the mtelleotual order; but if we choose for these observa- tions persons who have been accustomed to read much we may consi.ler that they are all very much on a par with respect to the amount of practice which they have had, so that the differences in their rates of reading may fairly be attributed to real dillerences in their rates of forming com- plex perceptions in rapid succession, and not to any merely accidental difterences arising from greater or less facility acquired by special practice. ' My experiments consisted in marking a brief printed paragrapli m a boc\k which had never been read by any of the persons to whom it was to be presented. The pararrraph which contained simple statements of simple facts! was marked on the margin with pencil. The book was then placed before the reader open, the page however being covered with a sheet of paper. Having pointed out to the reader upon this sheet of paper what part of the underlying pa^e the marked paragraph occupied, I suddenly removed the sheet of paper with one hand, while I started a chronograph with the other Twenty seconds being allowed for reSdiU the paragrapli (ten lines octavo), as soon as the time was up I again suddenly placed the sheet of paper over the printed page, passed the book on to the next reader, and repeated the experiment as before. Meanwhile the first reader, the moment after the book had been removed, wrote down aU if .1, ?[ ^ '"^ ^""^^"^ remember having read. And so on with all the other readers. Now the results of a number of experiments conducted on this method were to show, as I have said, astonishing differ- ences m themaximim rate of reading which is possible to different individuals, aU of whom have been accustomed to extensive reading. That is to say, the difference may amount to 4 to 1 ; or, otherwise stated, in a given time one indi- vidual may be able to read four times as much as another. Moreover, it appeared that there was no relationship between slowness ot reading and power of assimilation ; on the con- trary, when all the efforts are directed to assimilating aa 'I ■ ^ '. 1 I'' ■ -■'- : \ : iii 1 142 MENTAL EVOLUTION IN ANIMALS. 'J'. jr ' H CHAPTER X Imagination. We have already considered the psychology of Ideation to the extent of defining the sense in which I employ the word " Idea" or " Image," and also to the extent of tracing, both on the side of physiology and on that of psychology, the prin- ciple of the association of ideas* We have now to analyze the psychology of Ideation somewhat more in detail. The simplest case of an idea is the memory of a sensa- tion. That a sensation may be remembered even when there has been no perception is proved, not only by the fact before mentioned that an infant only a day or two old can distin- guish a change of milk, but also by the fact, which must be familiar to all, that several minutes after an unperceived sensation is past, we are able by reflection to remember that we have had the sensation. For example, a man reading a book may hear a clock strike from one to five strokes (or perhaps more) without perceiving the sound, yet a minute or two afterwards he can recall the past sensation and tell the number of strokes which have occurred. And in simpler instances the memory of a sensation may extend over a much longer time. The simplest case of an idea, then, being the memory of a past sensation (as distinguislied from the memory of a past perception), it follows that the earliest stages of ideation must be held to correspond with those earlier stages of memory which we have already described, wherein as yet there is no association of ideas, but merely a perception of a present sensation as like or unlike a past one. Hence in its most elementary form an idea may be said to consist in the faint revival of a sensation. Tliis view has already been advanced with much clearness by Mr. Spencer, Professor • Sje ChcipLers II and III, K.. ■II IMAGINATION. 143 past sedation is thTZelrHndTnTr'"^^''''' '"«" "^ « degree of intensity, as ™s the CMebml 1 ""'' *?"l'' ""' '■» panied the origin J sensatfcn* ""«'' *'""'» '"='>°"'. gar/^d t thfmXVnlS"' "^f"" ^^ ^ - diately after this the^rtacfnW? Perception, and imme- comes in. Later on thZ^ ■ '"^"".""■"n by contiguity and from tht point oSdsMlr""''/"'' ^^ """""'y^ tion. generalizat^oranr^mMctn" tr^^^^^^^^^ '^ '''""^ degrees which will constitCone Tthe tZc,' M? '^"'^ sidered in my next work ^ *" ** ^o- alreaXmStedlhelfwest'r " 1't i"^ ^'^^ *»' "« h*™ of MeLry andCltciat S^ Ide^^'Tes::'-^ 'T'"^ (ore, the analysis at the noint whsr, „ ;i, ^e™™"& Uiere- devote this chapter to a cmsMm?SnTf ^'"" i'^', ''' ^ =•>"" of the idea-forming powers Shi '""" '"S'"'"' Ph^'^es elude under the gen'erTlte™ t'^^^LT^ "™^^"™''^' ""- menW ^taTe rVhiSiThifdl 7 '"^'"t^ » ™"^'y «« xxc&t^SSr'r---^^^^^ of the origiUlLp'rTSnT' ." TW^rfiira nT^'f', ^"^ ^^''^^ -P««tion Tivid order, and then, afterwards, there mafc^ff''*''^ manifestetiorof the that 18 hke It except in being much ImlTtinT" JT'l^l^"^ manifestation And Professor Bain says, " What is thp n,«n * ^^""^^ Principles, p. 145 ) a resusdtated feeling Jf 'resVstonce a snTelf o^n "''"^f °" ""^'^^ ^^ with answer that seems admissible. Ser'S/^.!/- *"""'* ^ ^^^'^ '« "'^Jy one i'ar^,, and in the same manner, astheoTotSn- '''"^^'* *^' "^''^ *«'«« ''°^. ^n am, other assignable manner" (^l^f^' "'"^ «" other parts qmte assenting to thif view of ideation io f ^ Z\t*'''''*^ P" ^3«) Wl,ile ject 18 concerned, I think we aSfir too i.nn .P'^/^°^°8^ °*' ^^^^ «'''b. cerebration to indulge in any such confid.S 'S"°.''^°^ o^ the physiology of seat and manner of the f«L ofldet'" A^"°' 'TJ'="°^ ^^« ?>---« Spencer's views, it is needless to repeat the nn,^f-"' ^^%^^^^^^r,^^^ Mr. him touching the earliest stages of memorv ^r M '° T.^i"'' ' ^''''^^^^ 'vith the association of ideas. Only I may pS^? fl .'" ^f^°"° *^« ^^^v. nt of Idea IS held to consist in a faint revSf of ! seLn ,V //' "'^^ ''^"^^^'^ P°««iblo a perception), it follows that the occurrence of /h ^^' ^^r^inguished from precedes the occurrence of its assSirwin/f ".uP^"'* P^^^'^le idea the wemory of the sensation or t^« +■ T • f^^ °*'^'''' idea; and if so the idea is'held to eons st must also n^. '"^'^^^ "^ "^« ^'-"n^^tion in whic?a revivttls of the same kind!' ^'''"^' ''''^ association with other fS .1 ,.' ii! !'fi •1.1' 144 MENTAL EVOLUTION IN ANIMALS. i u I'l I (1 ' taken to mean the highest development of the faculty in the intentional imaging of past impressions. In this sense we speak of the imaginations of the poet, imaginations of the heart, scientific use of the imagination, and so on ; in all of which cases we presuppose the powers of high abstraction as well as tliose of intentional ideal combinations of former actual impi I ssions. It is needless to say that even in man, long before the faculty in question attains to this degree of development, it occurs in lower degrees. Indeed, this highest degree may be said to bear the same relation to the lower degrees that recollection bears to memory ; it implies the introspective searching of the mind with the conscious purpose of forming an ideal structure. But just as recollec- tion is preceded by memory, or the power of intentional association by that of sensuous association, so is imagination of the intentional kind preceded by imagination of the sensuous. After considering the subject I think we may, for the purposes of analysis, conveniently divide the grades of Imagination into four classes : — 1. On seeing any object, such as an orange, we are at once re-minded of the taste of an orange — have an imagina- tion of that taste ; and this is called up by the force of mere sensuous association. This is the lowest stage of mental imagery. 2. Next we have the stage in which we form a mental picture of an absent object suggested to us by some other object, as when water may suggest to us the idea of wine. 3. At a still higher stage we may form an idea indepen- dently of any obvious suggestion from without, as when a lover thinks of his mistress even in spite of external dis- tractions ; the course of ideation is here self-sustained, and no longer dependent for its mind-pictures (ideas) upon the suggestions of immediate sense-perceptions. At this stage we have dreaming in sleep, where the course of ideation runs on in a continuous stream when all the channels of sense are closed. 4. Lastly we have the stage of intentionally formirg mind-pictures with the set purpose of obtaining new ideal combinations. Such being the great differences in the degrees to which the faculty of Imagination may attain, I have made the \l IMAGINATION. i^k , 145 the origin of PefleSr Of 1. .? '^^'°''' ^"^ ^^^^^d mates are intended here as p1. '^ ^^''! comparative esti- with some rouX approx'i'ni T^f ?' *° '^'^''^^ °^«^ely relative amount o^aSmt on ^ ^^' ^/^^^^^ *^«th the mental species wh ch weTenomiL^^^^^^^^^ T^ ^^ ^^e indeed, as I have said ^£0^?^^ \ i.^'"^*'"'-. ^ ^^^^^^^r selves of an artificial or Innt' .^ ?^'f 'P^^'^« ^^^ them- we call facultLstrlTr^^^^^^^^^^ character-that what than objective or indenenden? Lf iT °^^,"^aking rather the classification of tCe f!cSf k''' ^^^.^herefore thau deserves in some remote sense to t ^ Py^>^^«gi«ts only one. Still it is thTbest cLlf ''^^'^'^, "^ ^ ^^^"ral purpose of comparing onf grtde ff^.r^^"^^^ ^'' '^^ another, and there can be no hari T^I k'^"'^°^ ^''^ remember, what I desire alwo v. flv. ^^^P^^^^g it if we representative tree is des3 n.l ^^^^"^J^^bered, that my relation between the faculties o?-' ^ ^^"^ *^' ^""^'^^ formulated by psycholoS ' ^' *^''' ^^^^ ^^^^ reql^e ::^Z^ ^^ TetelfaV^ 7^T^^^^ ^^ tion as attaining to the same S !1 .1,^ '^P®'' °^ Imagina- for psychologists mt h natSv nf/ T^^ '^ "^^^^^^^^^^ that I^am inadvertenti; Tntr^^. h "docrne^S ReT '' 'owever, is not the case. %n. i?w"l 1 ^.^^1^«°»- that, if we were able tn 1; • ■^^'' ^^^^^^S^ ^^ is true would become thf only rS^^^^^^^^^ 't'^?'''''^"' ^'^^^^^ diagram to favour any sV£rd a Z7' ^ ?' "°^ ^^^^""^ '^^ when I shall have occasion To pt.T • "^l ^^ .^7 next work, of the representative tSelwillTpr*^' ^'^^'' ^^^^^h«« do not intend Abstr7c ion ^ .Sf apparent that, as I I pK^P^n^aTv^^^^^^^^^^^^^ ^^. Win be seen that Mollusca. Insecta, Arrchnida Cri,!'"''^!"'''^ ^^^ «^^«««« bef.und,a3in:ti:^ef2^ir«SS^-^^^^^ In 146 MENTAL EVOLUTION IN ANIMALS. mil iiv i ' F 1|M:, the octopus which followed a lobster with which it had been fighting into an adjacent tank, by labcriously climbing up the perpendicular partition between the two tanks, must have been actuated by an abiding mental image, or memory, of its antagonist ; the spiders which attach stones to their webs to hold them steady during gales must similarly be actuated by a faculty of Imagination ; and the same is no less true of the crab which, when a stone was rolled into its / burrow, removed other stones near its margin lest they should roll in likewise. The limpet which returns to its home after a browsing excursion, must have some dim memory or mental image of the place. So much, then, for proof of Imagination of the first degree. Imagination of the second degree — or that wherein one object or set of circumstances suggests another and similar object or set of circumstances, occurs first, so far as my evidence goes, among the Hymenoptera. But here the cases of an association of ideas leading to the establishment of a mental imagery more or less remote from the immediate circumstances of perception are much too numerous to quote. I shall therefore merely refer to the headings " General Intelligence " in the chapters on Ants, Bees, and Wasps.* Among the higher animals imagination of this grade is of frequent occurrence and strong force. Thus, to supply only one example, Thompson, in his " Passions of Animals " (p. 59), gives the case of a dog " which refused dry bread, and was in the habit of receiving from his master little morsels dipped in gravy of the meat remaining in the plate, snapped eagerly after dry bread if he saw it rubbed round the plate, and as, by way of experiment, this was re- peatedly done till its hunger was satisfied, it is evident that the imagination of the animal conquered for the time its faculties of smell and taste." To tins order of imagination also belongs the wariness of wild animals. Thus Leroy, who in his capacity of Eanger had a laige experience, says, " In the first hours of the night, when th(} countenance of darkness is in itself a fertUe source of hope to the fox, the distant yelping of a dog will check him in the midst of his career. All the dangers which he has on various occasions passed through rise before him ; but at dawn this extreme timidity is overborne by the calls of • Animal Intelligence, pp. 122-40, and 181-19. IMAGINATION. 147 appetite; the animal then becomes bold by necessity He even runs to mftfif. Hnnaot. t»,«,„; — r.- ./ i-^ ./' . even runs to meet danger, knowing rie.", forecasthig by by return of light." imagmation] that it will be redoubled by re.urn or iiant" And again, speaking of the wolf where rendered timid by mni L''^'^^'''•^? '^y^ ^^^^ '^ "becomes subject to Illusions and to fa se judgments, which are the fruit of the n^.'n£"V'"^r^'n^^^' J"^S"^^°^« b^«««^e extended to a sufficient number of objects, he becomes the sport of an Illusory system, which may lead him into infinite mistakes t in f •'\'*^^ '°T^??* ^'^^ ^^^ P""^ipl«« ^hich have taken root in his mind. He wiU see snares where there are nrT.'nf'l-'"'^^-"^^'^"' ^''^^'^'^ ^y ^^^^' WiU invert the order of his various sensations, and thus produce deceptive danger/' &c.^ ""'" '"''^' '" ^^'''''' ""''^^^ of Tm^m^iL-''^^ IT ^""^ ''*!''' ^^'* *^ P™ve t^e existence of Imagination of the second order in animals, but I think It IS a good one, because showing that this faculty exists in this degree m an animal not having a very high grade of ntel igence-I mean the wild rabbit. Every oSe who has ferreted wild rabbits must have noticed that if the warren has been ferreted before, the rabbits are very unwilling to ' bolt " rathrtLn f?r7 !? ^' ''"°"^?^ ^"^"^^^ ^^ ^^e ferrets rather than face the dangers awaiting them outside. This shows that the rabbits associate (owing to past experience? the presence of a ferret in their burrows wL the prience of a sportsman outside them (for it does not signify how careful the sportsman may be to keep silent), and so vivid il the loss of h,s chickens His hounds had succeeded in captuS seveSf thi 1 he wolf soon approached the ocean with the other detachment of hounds^n woul/foZwfl.^*^"* t'T^'^ *^^* ^ '^' waves recededTrom the Zre he iTthe sand thaw ^' °f^ as possible, and in no instance made forprints h^i!/T * ^""^ r* 'l"'"''^-^ obliterated by the sweU. When fiSlv he^ha^d^^gone far enough, a. he supposed, to destroy the Bcent, he tried' INM if :i 1:1 -I 148 r . ">ntoms or And, moveov;r. "it \ll7?pZ^?f T'' ;?""* " *mgs. spectral imaged that occur ff!,,,. ''■ *'i'' ™"«^ ''i"'' »f canine rallies for in,,on„? " i""" •""""'' «» in man in this subjecSl^in'fSs"' ^uT" ''>'tT';obia.»t On thing o the .ioor::"nd^^x:!:j»^Xs;r:^-^^^^^ P- 74. ./ 'O.nimais, p. 60 j and Descent of Man et *«?.). Thus Guor asferts ^hat^Z «!!'''" ^fl- ^"'•^^^^' ^''^ «C 97 Bearch of imaginary stranger^S fbe^ anT^T-K^'"'' wafch-dog pr^vi sin .ones of panto,^^^^^^^^ towards th//, .,,j, L,i!i -it 150 MENTAL EVOLUTION IN ANIMALS. l\v\ I ('(If "ii II I :' r ■|!f at the vacant air, as if pursuing something against which it had an enmity." And, indeed, this peculiarity of being liable to optical delusions is so usual and well marked a feature in rabid dogs, that it generally constitutes the earliest and most certain symptom of disease.* My friend Mr. Walter Pollock sends me the following account of a Scotch terrier bitch which he possessed :— " She had a curious hatred or horror of any thing abnormal— for instance, it was long before she could tolerate the striking of a spring bell, which when I first knew her was a new experience to her. She expressed her dislike and seeming fear by a series of growls and barks accompanied by setting her hair up on end. She used from' tmie to time to go through exactly the same performance after gazing fixedly into what seemed to be vacancy. This attracted my attention, and I used to be on the look out for it, but carefully avoided in any way tempting her to make any display of this peculiarity. I simply watched her when- ever I was alone with her. The constant repetition in these circumstances of her seeming to see some enemy or portent unseen by me, and giving vent to her feelings in the way already described, led me to the conclusion that at these tunes she was the victim of optical illusion of some kind. I could, as I have already hinted, produce the same effect upon her by doing some unexpected and irrational thing, until she had become accustomed to this kind of experiment But after this the seeing, as it seemed to be, of some sort of phantom remained unabated. I had no opportunity of dis- cerning whether the phenomena occurred at any regular intervals, or whether they were more frequent after sleep than at other times." Pierquin describes a female ape which had a sun-stroke, and afterwards use to become terror-struck by delusions of some kind. She also used to snap at imaginary objects, and " acted as if she had been watching and catching at insects on the wing."t It seems needless for our present purpose to give more evidence on the fact of animals being subject to delusions, and so I sliall pass on to the third class of facts on which I rely as evidence that animals present Imagination of what I have called the third order. This class of facts consists o\ * See Youat, On the Bog, under Rabies, t Traite de la Folie des Animaux, ^c, tome i, p. 93. IMAGINATION, jgj fpint with which jaded hor^s return nn ^^ ' t^ ^''^*"' repose. AgS The Tsire wlnT""'"'"""''!'' "' '<""• "'"i picture, or imagination of E S them to retain a mental Tlie primptS of h?; L!^ Previously happy experience, as to indTthe anima s to W '\T T ^^^^""^tly so strong hundreds of mTles T? avel fo/n ^ '' ^"°''' ""^ ^^^^g"«« «f to the scenerw^iich occur, v /hi • °^' ?"'^''' "^ '^^"^"^"g dogs. cats. anrToLrXn ^m^r^^^^^ homes, give repeated IS ^ai^ ^^}^^J^^ "oni their former crushes and oveChelms Jhe fao^„ir'''"/'l '^ ^^' ^''^- ^^ trates the energies of he bo^^T^^^^^ -' ^^^ ^""" encaged, become so utterly spTrLbro^en 2?V''^% ^^^^ nourishment, pine for a f e wTys and dV T v ^- ''^"''. ^" larly the case Mith song-S' ^'"' J^Z'T"']'''- Monkey is caught wlipn f„ii -1 / "^^ *"® Howling reuses;;!, fo^d^^dlTtaa'ff;":^^^^^^^^ with the Puma- nnrt K,„»i„ !,».,' "'« "so the same ensues so Lmed'iatdv S"*.?/"""', "">'. death sometimes and violent p" stJeti Ihe .ni„d".°"'^ '™^ """^ » »■"'<'» Pini^u^nt confinTm'e^ttrttla't'"^ '"'^-P^'^'-n of ■nere absence of liberty or ^ht„^ fe^ inay be due to the any mental and coSsted n2r. nr"^" •" "' ^''"^ ""><"" think that this ob/ection^s pSded in"'^;r' 'T"?"' ^ cases to which I shall next refer and wh.Vh '""^- "'i'^''^'"'' except the sudden withLwfi"? *''" <'™ditions of life, whiei the Inima" " stS/'aLchT °I T'^""" f i^nown a case in which a ^r^J^^ ^^^d, 7t Thompson, Passions of Animals, pp. 64-5. -A i f! 1 ! i i: ' :■::;!:: i r. ■:":r!::arrLrar.:ar:;-rj _ I! 152 MENTAL EVOLUTION IN ANIMALS. k ■ I in I! ' I W' if: U v \\\ IMil « 1 <" sudden removal of his mistress, refused all food for a number of days, so that it was thought he must certainly die, and his life was only saved by forcing him to eat raw eggs. Yet all his surroundings remained unchanged, and every one was as kind to him as they always had been. And that the cause of his pining was wholly due to the absence of his beloved mistress, was proved by the fact that he remained perma- nently outside her bedroom door (although he knew she was not inside), and could only be induced to go to sleep by giving him a dress of hers to lie upon. No one could have seen this dog without being persuaded that he had a constant mental picture of his mistress in his imagination, and suffered the keenest mental anguish from her continued absence. Similarly there are numberless anecdotes on record, most of which are probably true, of dogs actually dying under such circumstances. All these facts, then, taken together — ^viz., dreaming, de- lusions, "home sickness," and pining for friends— clearly prove the presence among higher animals of Imagination in v/hat I have called the third order. A question may here arise as to whether I have not in the diagram placed the rise of Imagination too low. I place the first origin of this faculty on level 19, which corresponds with that of the MoUusca and an infant seven weeks old. This question, like all others of line-drawing among the psychological faculties, is confessedly a difficult one ; but the reasons why I have placed the dawn of Imagination so low in the psychological scale are as follows : — It will be remembered that the kind of Imagination which we have recently been coi^.sidering belongs to what I consider a high level of development. That is to say, I con- sider the power of dreaming to occupy a place about one third of the distance between the first dawn of the imagina- tive faculty and its maximum development in a Shakespeare or a Faraday. I so consider it because I believe that to pass through what I have called the first three stages, so as to arrive at the power of forming mental pictures independently of sensuous suggestions from without, the imaginative faculty has made so enormous a progress from its earliest begin- nings, that the rest of its development along the same lines is really nothing more than a function of the faculty of Abstraction. Superimpose upon the psychology of a IMAGINATION. 153 terrier which pmes for its absent mistress an elaborate structure of abstract ideation, and the terrier's imaginative faculty would begin to rival that of man. Of course it will j^ u. *ha^ abstraction presupposes imagination, and so undoubtedly it does ; still the two are not identical, as is proved by the fact that for the building up of abstraction to any exalted height, language, or mental symbolism of some kind, IS indispensable ; and mental symbols are so many artitices for the saving of imagination. Now if at first sight it seems absurd to accredit a mollusk with imagination, we must remember exactly what we mean by imagination in the lowest possible phase of its develop- ment. We mean merely the power ol forming a definite mental picture, or of retaining a mt iory, no matter of how rudimentary a kind ; provided that the memory implies some dim idea of an absent object or experience, and not, as in the case of an infant disliking the taste of strange milk, merely an immediate perception of contrast between an habitual and a present sensation. And that we find such a level of mental development as low down in the zoological scale as the Crasteropoda, would seem to be proved by the fact already alluded to of hmpets returning to their homes in the rocks after feeding. Of course the mental image which a limpet forms of Its home m a rock cannot be supposed to be com- parable m point of vividness or complexity with the mental image that a horse retains of its stall, or a dog of its kennel • still, such as It is, It is a mental image, and therefore betokens imagination. More vivid, and therefore more definite, is the mental image that a spider forms of her lair, who when dis- lodged and carried away to a short distance again returns to her old home. (Level 20.) With a still further advance in the power of mental imagery (level 21) we find supplied the psychological conditions for the ideation of cold-blooded Ver- tebrata, such as the determination displayed by mif^ratory Inshes (notably the salmon) to visit particular localities in tlie spawning season. On the next level (22) we reach the higher Crustacea, which, as we have already seen, are able to imagine m a high degree. Next we come to Eeptiles. con- cerning which I may quote the following anecdote from Lord Monboddo: "I am well informed of a tame serpent in the East Indies, which belonged to the late Dr. Vigot once kept by him in the suburbs of Madras. This serpent was I]' I fkWU ■ 1 i ' i|i 1 1 . . ! i |n 1 ! i ' ,jM 1 MENTAL EVOLUTION IN ANIMALS. taken by the French, when they invested Madras, in the late war, and was carried to Pondicherry in a close carriage. But from thence he found his way back again to his old quarters, though Madras is over one hundred miles distant from Pondicherry." If we substitute yards for miles, similar cases are on record with regard to frogs and toads — which from being so numerous can scarcely all be false. And that some reptiles have an imagination passing into what I have called the third stage is proved by the case of the python mentioned in "Animal Intelligence," which, when sent to the Zoological Gardens, pined for its previous master and mistress. The Cephalopoda and Hymenoptera have already been alluded to. Lastly, on the next level (25) we attain in Birds to imagination proved to be unquestionably of the third degree by the phenomenon of dreaming. Above this level it is not of so much interest to trace the improvement of the faculty. Such improvement throughout the subsequent levels tUl man, probably consists only in a progressive advance through imagination of the third degree — it being I think highly improbable, and cer- tainly not betokened by any evidence, that imagination in any animal attains to what I have called the fourth degree, which I therefore consider distinctive of man. *' For know that in the soul Are many lesser faculties that servo Reason as chief. Among these. Fancy next Her office holds. Of all external things, Which the five watchful senses represent. He forms imaginations, airy shapes ; Which Reason joining or disjoining, forms All that we affirm, or what deny, And call our knowledge." — Miltoit. Before taking leave of Imagination there are two branches of the subject which I should like briefly to consider. One is the opinion held by Comte that the higher animals present ideas of Fetishism. On this topic I cannot more briefly convey the material which I have to render than by quoting a previous publication of my own from " Nature."* " Mr. Herbert Spencer in his recently published work on the ' Prin- ciples of Sociology ' treats of the above subject. He says, * I believe M. Comte expressed the opinion that fetichistic conceptions are formed by the higher animals. Holding, as I • Vol. xvii, p. 168, et seq. IMAGINATION. 165 have given reasons for doing, that fetichism is not original but derived. I cannot, of course, coincide in this ^ew Nevertheless I think the behaviour of intelligent LS elucidates he genesis of it. I have myself witnessed in dogs two illustrative cases.' One of thirconsistld Tn ^ a'o?e eidtf f ^^^p^fr^ fth r^irSe'ntdi; tnrust one end of it against his palate, when 'giving a vein he dropped the stick, rushed to a distance from^t ^and betrayed a consternation which was particularly W^^^^^^^^ m so ferocious-lookmg a creature. Only after cautiou?flT the stick wh^^^H-^^^^^^^ ^^^^\^ ^'^y '^'^^^y the fa Jt that tne stick, while displaying none but the properties he was SiTth'/f 'T ^t^T^ded by him as anVt^^e ageT but that when it suddenly inflicted a pain in a way nevei' before experienced from an inanimate object, he was led Z a moment to class it with animate objects, and tTreiard it as capable of again doing him injury. 'similarly,in thfi^nd of the primitive man, knowing scarcely more of natural causation than a dog, the anomSlous behLour of an S previously classed as inanimate suggests animation The dea of voluntary action is made nascent; and there arises a tendency to regard the object with al'arm, lestTt should act in some other unexpected and perhaps m'ischievous way The vague notion of animation thus aroused will obviouslv thTr %T' ^1"^'" r'^°"' ^ f^^t ^« the developr^nt of the ghost-theory furnishes a special agency to whkh the anomalous behaviour can be ascribed.' ° "^ ^'^''"^ ^He • . "?"h^, other case observed by Mr. Spencer was that of an intelligent retriever. Being by her duties as a retriever leS to associate the fetching of game with the pleasure of the person to whom she brought it, this had become in her mind an act of propitiation; and so, 'after wagging her tail "nd grinmng, she would perform this act of propitiatil as neail v as practicable in the absence of a dead bV Sing abou she would pick up a dead leaf or other small object and would bring It with renewed manifestations of fSSiness Some kindred state of mind it is which, I believe, prompts tiie^sava,ge to certain fetichistic observances of an anSous " These observations remind me of several experiments I made some years ago on this subject, and which Le periiapa I ■. ■ 1 ' I r ;1 J ( ;. 1 i> nn ( '; ■li ti.l!Lii ij :h] \\ \\ I' 156 MENTAL EVOLUTION IN ANIMALS. ( , i M i ' worth publishing. I was led to make the experiments by reading the instance given by Mr. Darwin in the ' Descent of Man' of the large dog which he observed to bark at a parasol as it was moved along a lawn by the wind, so presenting the appearance of animation. The dog on which I experimented was a Skye terrier — a remarkably intelligent animal, whose psychological faculties have already formed the subject of several communications to this and other periodicals. As all my experiments yielded the same results, I will only mention one. The terrier in question, like many other dogs, used to play with dry bones, by tossing them in the air, throwing them to a distance, and generally giving them the appearance of animation in order to give himself the ideal pleasure of worrying them. On one occasion, therefore, I tied a long and fine thread to a dry bone, and gave him the latter to play with. After he had tossed it about for a short time, I took the opportunity, when it had fallen at a distance from him and while he was following it up, of gently drawing it away from him by means of the long invisible thread. Instantly his whole demeanour changed. The bone which he had pre- viously pretended to be alive now began to look as if it were really alive, and his astonishment knew no br ads. He first approached it with nervous caution, as Mr. Spencer describes; but as the slow receding motion continued, and he became quite certain that the movement could not be accountec. for by any residuum of the force which he had himself communicated, his astonishment developed into dread, and he ran to conceal himself under some articles of fur- niture, there to behold at a distance the 'uncanny' spectacle of a dry bone coming to life. " Now in this and all my other experiments I have no doubt that the behaviour of the terrier arose from his sense of the mysterious, for he was of a highly pugnacious disposition, and never hesitated to fight any animal of any size or fero- city ; but apparent symptoms of spontaneity in an inanimate object which he knew so well, gave rise to feelings of awe and horror, which quite enervated him. And that there was nothing fetichistic in these feelings may safely be concluded if we reflect, with Mr. Spencer, that the dog's knowledge 9f causation for all immediate purposes being quite as correct and no less stereotyped than is that of 'primitive man,' when an object of a class which he knew from uniform past experience to be inanimate suddenly began to move, he must i- IMAGINATION. 157 have felt the same oppressive and alarming sense of the mysterious which uncultured persons feel under similar cir- cumstances. But further, in the case of this terrier, we are not left with d, priori inferences alone to settle this point for another experiment proved that the sense of the mysterious in this animal was sufficiently strong in itself to account for hehayiour. Taking him into a carpeted room, I blew a soap-bubble, and by means of a fitful draught made it inter- mittently glide along the floor. He became at once intensely interested, but seemed unable to decide whether or not the fitful object was alive. At first he was very cautious, and foUowed It only at a distance; but as I encouraged him to examine the bubble more closely, he approached it with ears erect and tail down, evidently with much misgivin^^, and the moment it happened to move he again retreated."' After a time, however, during which I always kept at least one bubble on the carpet, he began to gain more courage, and the scientific spirit overcoming his sense of the mysterious, he eventually became bold enough slowly to approach one of the bubbles and nervously to touch it with his paw. The bubble of course, immediately burst, and I certainly never saw astonish- ment more strongly depicted. On then blowing another bubble, I could not persuade him to approach it for a crood while; but at last he came, and carefully extended his paw as before, with the same result. But after this second trial nothing would induce him again to approach a bubble and on pressing him he ran out of the room, which no coaxinrr would persuade him to re-enter. ® "One other example will suffice to show how strongly developed was the sense of the mysterious in this aninml When alone with him in a room I once purposely tried the effect on him of making a series of hideous grimaces. At first he thought I was only making fun ; but as I persistently disregarded his caresses and whining while I continued unna- turally to disturb my features, he became alarmed; slunk away under some furniture, shivering like a frightened child. He remained in this condition till some other member of the family happened to enter the room, when he emerged from his hiding place in great joy at seeing me again in my ritrht mmd. In this experiment, of course, I refrained from makmcr any sounds or gesticulations, that might lead him to think I was angry. His actions therefore can only be explained by his horrified surprise at any apparently irrational behaviour, '1 i; ■i 'III 1 i i.l f )'> ' 158 MENTAL EVOLUTION IN ANIMALS. .* ' ii t.e., by the violation of his ideas of uniformity in matters psychological. It must be added, however, that I have tried the same experiment on less inteUigent and lees sensitive terriers with no other eflTect than causing them to bark at me. i. wiU only add that I believe the sense of the mysterious to be the cause of the dread which many animals show of thunder. I am led to think this, because I once had a setter winch never heard thunder tiU he was eighteen months old and on then hearing it I thought he was about to die of inght, as I have seen other animals do under various circum- stances. And so strong was the impression which his extreme terror left behind, that whenever afterwards he heard the boom of distant artiUery practice, mistaking it for thunder he became a pitiable object to look at, and, if out shootin-' would endeavour to bury himself or bolt home. After having heard real thunder on two or three subsequent occasions hi? dread ot the distart cannon became greater than ever: so that eyentuaUy, though he keenly enjoyed sport, nothing would induce him to leave his kennel, lest che practice might begin wlien he was at a distance from home. But the keeper who had a large experience in the training of dogs, assured me it I allowed this one to be taken to the battery in order that he might learn the true cause of the thunder-like noise he would again become serviceable in the field. The animal' however, died before the experiment was made."* Thus I think we may safely set down the sense of the mysterious as thus undoubtedly displayed by intelligent doers —and also, I may add, by many horses when going aloncr^a dark road, hearing strange sounds, or seeing unaccustomed ^•u-1 • ~" . ®^^*^ ^^ imagination in suggesting vague pos- sibilities m circumstances perceived to be unusual; just as with children under similar circumstances the undefined imagination of possible harm springing out of such circum- stances in some unthought-of manner, engenders that feelincr of unreasonable dread which we may in both cases call I sense ot the mysterious. on 1™ '""^ T""^^ have been the case, however, I have little doubt, for ^LZ T T ^^^"^ ^ ''"J^''"" °^ ^PP^"^ ^*^r« being shot, out of baf^s i pon th9 wooden floor of an apple-room, the sound in the house as each bLTaa shot closely ivsembled that of distant thunder. The setter, therefore hSume terribly alarmed; but when I took him to the apple-room and sho;S S to the house he listened to the riuubling with all cheerfulness ^''^^"» DTSTINCT. 159 CHAPTER XL Instinct. Definition. I SHALL begin this important and extensive part of mv subject by repeating the definition of Instinct which I iSd down m my former work. It will be remembered that for folW-- ^'''''^'^ ^ '^''' ^"^'"'^ '^' '^"^ Instinct as "Instinct is reflex action into which there is imported the element of consciousness. The term is therefore a generic one, comprising all those faculties of mind which are dS^nl '^ '^'^''^^^^ "\^ "^^P^i^^ ^'^^^^^^ antecedent to Z dividual experience, without necessary knowledge of the relation between means employed and ends attained but similarly performed under similar and frequently recuiW circumstances by aU the individuals of the same specfes " ^ Keterring the reader to the context for my iustification of this definition M shall here only further ZLIT^J^ statement. It follows from the above definition of iSnct that a stimulus which evokes a reflex action is, at mSa sensation ;t but r. stimulus which evokes an instS've a^nte^M^^'^'P'""- .t'^'l^''^' I ^^-^ alreadylaTd L and^a Lr? '^'''"'"^ *^' distinction between a sensation and a perception, my meaning now will be clearly under- stood. For If a perception differs from a sensation in that it presents a mental element, and if an instinctive action differs IZVt^"'' '.tT ^^ '^^\ '' P^^^^^^« ^ ^^^t^l element tS.tr ^\'\' ''r'^^ '"PP^^^^ by a sensation is to a reflex action what a stimulus supplied by a perception is to an instinctive action; because if a sensation^ could act as a * Animal Intelligence, pp. 10-17. in X I -^^ "'^*' ™°'*''" ^^<^'i"se such a stimulus may be less tlian a sensaHon m that It may never cross the field of consciousness: sensation, nil If ii Mi.liJi: tt }U i » . i 160 5fc ! 1:'' Ml 11* Hi \ I [If < ' • -'i . I ' MENTAL EVOLUTION IN ANIMALS. Stimulus to an action apparently instinctive, ex hypothed the acton could not be (according to my definition) really instmctive ; and conversely, if a perception could act as a stimulus to an action apparently reflex, the action could nob be (according to my definition) a true reflex. Therefore if we agree to limit the term Instinct to nervous processes involving a mental element, it follows that this element is perception, and that it is always involved in every stimulus leading to instinctive action. nT.lJ!.l^r w """ ^"^ f "1?'^^ principles of classification it is only needful for me further to quote the following extract Iroiii my previous work : — ^ io 171'^- 'T^ ™Port,ant point to observe in the first instance IS that icstmct involves mental operations; for this is the only point that serves to distinguish instinctive from reflex action. Eeflex action, as already explained, is non-mental neuro-muscular adaptation to appropriate stimuli; but in- stinctive action 18 this and something more; ther^ is in it the element of mind. No doubt it is often difficult or even impossible, to decide whether or not a given action implies t^Ulfr" "^ '^' «^ind.element-i.., conscious as distin! guishedfrom unconscious adaptation; but this is altoc^ether a separate matter, and has nothing to do with the question ot defining instinct in a manner which shall be formally exclusive, on the one hand of reflex action, and on the other of reason. As Virchow truly observes, 'it is difficult or impossible to draw the hue between instinctive and reflex action; but at least the difficulty may be narrowed down to deciding in particular cases whether or not an action falls wTvtt'dS.^lf category of definition; there is no reason Jp Ii, /i ?^^^ '^°''^'^ ^"'^ ^^ account of any ambiguity of the definitions themselves. Therefore I endeavour to draw as sharply as possible the line whf. h in theory should be .aken to separate instinctive fromrehex action; and this line, as I have already said, is constituted by the boundary ot non-mental or unconscious adjustment, with adjustment in wnich there is concerned consciousness or mind " T.1..^ '^^^ r"^ P'^iT"? *^ '^^'^' ^y ^ ^^^ selected examples, what has been called the Perfection of Instinct; next I shall similarly Illustrate the Imperfection of Instinct; and lastly, I shall discuss the important question of the Origin and Development of Instinct. wi tuo v^ii^ia PERFECTION OP INSTINCT. 161 Perfection of Instinct. An instinct may be said to be perfect when it is nerfertlv adapted to meet those circumstances in the life of an aniS for the meeting of which the instinct exists ami ?f ffT instmct this perfection must be exhTbi eTls'iXendent of mL? f 1' "^^^'^dual experience. We may therefore best d ful^^^^^^^^^^^^ '' ^"^^\^^ ^y eonsii" wot S aStm/nt. wTY ^""""^ '^f ^"^^^y ^^«"«^ ^«d com. on tWs I'S ?r ^^^n ^^'1^^'"? ^^ ^^^ ^""^^«t researches ?als ty of"£;?ew "^^^^^^^^^ f'""'^ >-^ ,^-'^ti- the mnv io t,„;i • , "" ""* supposed examples of instinct SstmSrS E"'™ ""'f ■°'' -^P'" '«»™"S. toitSn comes in o the 1^M° '"T'' """ " y°™S ''»■'•<«■ "»■""•» inj of chickens which he liberated from tlie'e^-^and hided" before their eyes had heen able to perform anVact of vWon fto,^"^'' "l"' r ''^'"°""S *e hood aft"r aL, od ™S beyond their reL. as babies arsaidTrLs^Hh: moof and they may be said to have invariahlfhit^he obleXat tro,;iTcMikrwT.e''lll'',t°':,,i,'' *"''7'««»''. if«i"«ion«rj vie.- of i )-\ j i ; : ! ■ i ^ ! ! ; • ■ ■ { ■ , f 1 i ; 1 ■ , i 162 MENTAL EVOLUTION IN ANIMALS. i ;>! ( Hil \^ which they struck— they never missed by more than a hair's breadth, and that, too, when the specks at which they aimed were no bigger, and less ■ ii te, ih..n the smallest dot of an i 10 seize between th^ ^, .nts uC the mandibles at the very instant of striking seemed a more difficult operation. I have seen a chicken seize and swallow an insect at the first attempt ; most frequently, however, they struck five or six times liftmg once or twice before they succeeded in swallow- ing their first food. The unacquired power of followinrr by sight was very plainly exemplified in lue case of a chiJken that, after being unhooded, sat complaining and motionless tor six minutes, when I placed my hand on it for a few seconds On removing my hand the chicken immediately followed It by sight backward and forward, and all round the table. To take, by way of example, the observations in a single case a little in detail :— A chicken that had been made the subject of experiments on hearing, was unhooded when nearly tnree days old. For six minutes it sat chirpin" and looking about it; at the end of that time it followed with its head and eyes the movements of a fly twelve inches distant • at ten minutes it made a peck at its own toes, and the next instant it made a vigorous dart at the fly, which had come withm reach of its neck, and seized and swallowed it at the farst stroke ; for seven minutes more it sat calling and looking about It, when a hive-bee coming sufficiently near was seized at a dart and thrown some distance, much disabled. For twenty minutes it sat on the spot where its eyes had been unveiled without attepipting to walk a step. It was then placed on rough ground within sight and call of a hen with a brood of its own age. After standing chirping for about a minute, it started off^ towards the hen, displaying as keen a perception of the qualities of the outer world as it was ever likely to possess in after life. It never required to knock its head against a stone to discover that there was ' no road that way. It leaped over the smaller obstacles that lay in its path and ran round the larger, reaching the mother in as nearly a straight line as the nature of the ground would per- mit. This, let it be remembered, was the first time it had ever walked by sight." Further, "When twelve days old one of my little proteges, while running about beside me, gave the peculiar chirr whereby they announce the approach of danger. I looked PERFECTION OP INSTINCT. 1P3 np, and behold a sparrow-hawk was hoveriim at a ereat height over head. E.iually striking was the ef!ect of the hawk 8 voice when heard for the first time. A youn- turkey whieh I had adopted when chirping within the uncracked shell vyas on the morning of the tenth day of its life eating a comfortal^e l.roaklast from my hand, when the youn^ hawk in a cupboard just beside us, gave a shrill chip, chrp. chip! Like an arrow the poor turkey shot to the other side of the room, and stood there motionless and dumb with fear, until fnr.^tf'f. "" '^"'"'^ ''>^' ^^^^" it ^^^rted out at the open door right to the extreme end of the passage, and theiv, silent and cv mched in a corner, remained for ten minutes. Several times during the course of that day it again heard these trSoTS:-'"' " every instance with similar mani- fin ^^""!. f ^^™"S, *o yo^^"S chickens, Mr. Spalding con- dr^Tir'^'"''' " ''''''' ^ ^•'^^^ '^^«» then/attempt to dress their wings when only a few hours old-indeed as soon as they could hold up their heads, and even when denied the use of their eyes. The art of scraping in search of food, which, If anydnng, might be acquired by imitation-for a hen with chickens spends the half of her time in scratching for wih^/ ""^^^'^''^^^f ^"other indisputable case of instinct. Without any opportunities of imitation, when kept ouite t^lff -^T '*";'. ^'''^' ^^"^^'^"^ ^^Sa^ t« ««rape win from two to SIX days old. Generally, the condition if the ..round was suggestive; but I have several times seen the S a sZthTab^:..~^^ °' ' ''''' °^ ^^^^°^« ^--' -^^ - In this connection I may here insert an interestin.. obser- Thomsol FKS 'h"7 communicated to me by Dr. ATen iiiomson, f .E.S. He hatched out some chickens on a carnet inclination to scrape, because the stimulus supplied by the to caU into action the hereditary instinct; but when s^inJeTtr '^"""^'^^ " ^^'^' gravel on the carpet, and so SedfatP^v JPT/"^' '' customary stimulus, the chickens immediately began their scraping movements -But to return to Mr. Spalding's experiments, he snys — fT.,f f» example of unacquired dexterity, I may niention that on placmg four ducklings a day old in the opL aii for i i ■ ^ I ' 164 MENTAL EVOLUTION IN ANIMALS. !! '!' i iH tlie first time, one of them almost immediately snapped at and caugiit a fly on the wing. More interestini, however is the de]il)erate art of catdiing flies practised l.y the turkey When not a day and a half ohl I observed the young turkey already spoken of slowly pointing its beak at flies and other small insects without actually pecking at them. In doing this, Its head could be seen to shake like a hand that is attempted to be held steady by a visible effort. This I ob- served and recorded when I did not understand its meanin^r J^orit was not until after, that I found it to be the invariable liabit of the turkey, when it sees a fly .settled on any ol))ect to steal on the unwary insect with slow and measured step until sufficiently near, when it advances its head very slowly and stendily till within an inch or so of its prey, which is then seized by a sudden dart." Mr. Spalding subseijuently tried similar experiments, with similar results, on newly born mammals. He found, for instance, that new-born pigs seek to suck almost immediately after birth. If removed twenty feet from the mother, they wriggle straight back to her guided apparently by her grunt- ing. He put a pig into a bag immediately it was born, and kept It m the dark till seven hours old, and then placed it outside the sty ten feet from its mother. It went straight to lier although it had to struggle for five minutes to squeeze under a bar. A pig blindfolded at birth went about freely, though tumbling against things. It had the blinder taken off next day, and then " went round and round as if it had had sight, and had suddenly lost it. In ten minutes it was scarcely distinguishable from one that had had sight all along. When placed on a chair, it knew the height to require considering, went down on its knees, and leaped down. . One day last month, after fondling my dog, I put my hand into a basket containing four blind kittens three days old. The smell my hand had carried with it sent them puflin" and spitting m a most comical fashion."* Here I may quote an observation of my own from the succeeding issue of " Nature." " Apropos to what Mr. Spalding says about the early age at which the instinctive antipathy of the cat to the dog becomes apparent, I may state that some months ago I tried an experiment with rabbits and ferrets somewhat similar to Into an out- that which he describes v/ith cats and dogs. • Natttre, vol. xi, p. 507. hi PERFECTION OP INSTINCT. 1G5 , house winch contained a doe rabbit with averyyounrr family I turned loo.se a ferret. The doe ral.l.it left her young ones and the latter, as soon as they smelled the ferret, be^an to' crawl about in so enerj^etic a manner as to leave no'doubt that the cause of the commotion was fear, and not merely motht!'*" "^ ""''"° ^''''"' ^^'" temporary absence of the With reference to the instinctive endowments of this kind in kittens. I may also quote the followin- which I find amon s "i«. ,HI • i-^ 1 ■;*'' m m i t I 11] 111^ If i; t • ,: !i„ , hi V.}, \\\ Miil 168 MENTAL EVOLUTION IN ANIMALS. "!l,f''''?^® ^ sea-aneraone (realia crassicornis), which wag into the centre of the disk, " and though it struggled a good deal to get free was retained tiU it was drowned and was tvm,r thl ,*^'^ r't''' °^ ^^« humble-bee attempt to a remarlnhl'f ' ''^/'^ *^^' """^^ ^"^^^' ^PP«^^« ^° «°««titute bee Teo-n'rif "^ imperfect instinct. Again, Huber saw a to BiPOP. V \ "' ^ T".^ ^"'"'*^^°°' ^^d °t^^«r bees tear it to pieces. Bees have also been observed to collect rye-flower when damp instead of pollen.f " Pollen-getting, accordinTto Gebien, is the weak point in the characte^r of bees;" fo^th s ^^t^ ff"""'"'' ^P- '^^ '^''' '^'^y "% up useless hoards ofit I nt n '!f] '^"l Z """"Smenting every year, and this is the only point on which they can be accused of want of prudence." numW ?rr"' ?^^ ^'^'' '""^'"^ ^ brief Record of a number of observations on ants (F. rufa) carrying pupa itourTf ' ^T ""? 'PP^^^^^^^ "«^1^«« expenditure of labour, far away from the nest, and even up trees. He tried taking away the skms from some of the cariders, and replacing l!^ T" *^' ^''^' *^^^'^* ^°^« that happened to fall in with them again carried tliem off. This, as the notes observe, appears to be a case of "blundering instinct;" and w!T' epitliet may be appliec. to mistak'es made by the ^fnl/ %r^' '^'''^'^ ^y ^^'' Moggridge, which carefully TnLV}l7 ^'^''''■'' ^^^\g«ll-^PPle« of\ small species o^ Ci/mps, clearly imagining that they were nuts ; and also nnder a, simihtr delusion, stored small beads whSi Mo '-' faltSiiigfSd:^'' *"' '^"^ ^^^^^^^> -^"-'^d - thei. Among Birds we find mistaken instinct exhibited by the Z^ZT'"''' u^! '^^ ^-^ ^" '^' '^^^ nest, withM eS tt oS '^\r '^ '^' y°^"« ^''^' ^ill ^ft^rwards eject ttie other. In the same category we mav nlaop thp sCauTiXf "'"PP;?* "' ""r ^86' on the paHf Zt-h* f^ 1^ ? . frequently mistaking a lai^er and unfamiliar bird for a hawk, as shown by their mobbing it; and numberless maSrn r'T".-"^ ^jven of mistaW instinct i„ tie SSL m:S::&:: ot "'^""°" "^ ""^-'^^'^ ^''^'• niPERFECTION OF INSTINCT. 169 by Mr Darwin^n f ho A }-^ shrewmouse, also mentioned InteUirrence » Tn S^Qwf* • *"' ^ «^erve in "Animal praSd hv if 1 '*•' lu^''^ witnessed the mode of capture S the ibbir-S.;^ ^^'."P'^ ^'^'^' ^"d i^ «°"«i«ts "merely behind unS t.n,°i iT ^^°"?' ^^^^ ^^' ^^^^^l toddling Denmd, until tamely allowing itself to be overtaken ^r^l i7 ','"'• ''°"'^«''' ■^'''<='' time would doubtless remedy rf weasels were sufficiently numerous in relation to *p~rtlt/ or^rff r" 't''- '" ?™ -^u-l'lectionth: pSSnemyr °" '"' "'"™' °' ^^^"^ f™"" *is mi"Se^™Sr,'r°'' f .*' imperfection of instinct VIZ., that although weU established instincts are as a rule \^! IS sumcient to lead the instinct astray It is also nf T'tt^""' 5? °°'' ^^"' ^^^^"« **^ b« ^ compLentarytuth vu.. that small variations taking place in the or^ar ism itself when not m normal converse with its environment Z S are not at first at home in them), but is brou^it ou ?n a mueh "Uefore passing to the theory of instinct, it may be . ! I ■ ' i I i \ 'I 11 ri:: •■H: 1.5 ; i ■ lJ| II 170 MENTAL EVOLUTION IN ANIMALS. M ill i ! ' worthy of remark that, unlocked for, I met with in the course of experiments some very suggestive, but not yet sufliciently observed, phenomena ; which, however, have led me to the opmion that not only do the animals learn, but they can also forget— and very soon— that which they never practised. Further, it would seem that anv early interference with the established course of their lives may completely derange their mental constitution, and give rise to an order of manifestations, perhaps totally and unaccountably different trom what would have appeared under normal conditions. Hence I am inclined to think that students of animal psychology should endeavour to observe the unfoldin^r of the powers of their subjects in as nearly as possible the ordinary circumstances of their lives. And perhaps it may be because they have not all been sufficiently on their guard in this matter, that some experiments have seemed to tell against tlie reality of instinct. Without attempting to prove the above propositions, one or two facts may be mentioned. Untauoht the new-born babe can suck— a reflex action ; and Mr. Her- bert Spencer describes all instinct as 'compound reflex action ; ' but it seems to be well known that if spoon-fed, and not put to the breast, it soon loses the power of drawin^^ milk Similarly, a chicken that has not heard the call of the mother until eight or ten days old then hears it as if it heard it not. 1 regret to find that on this point my notes are not so full as 1 could wish, or as they might have been. There is, however an account of one chicken that could not be returned to the mother when (? until) ten days old. The hen followed it, and tried to entice it m every way; still it continually left her and ran to the house or to any person of whom it caught si^ht Ihis It persisted in doing, though beaten back with a small branch dozens of times, and invlecd cruelly maltreated. It was also placed under the mother at night, but it again left her in the morning. Something more curious, and of a diff'erent kind, came to light in the case of three chickens that T kept hooded until nearly four days old— a longer time than ^ lyl have yc^ spoken of Each of these on being unhooded evinced the greatest terror of me, dashing off in the opposite direction whenever I sought to approach it. The table on which they were unhooded stood before a window, and each in Its turn beat against the glass like a wild bird. One of them darted behind some books, and, squeezing itself into a IMPERFECTION OF INFsTINCT. 171 comer, remained cowering for a Imgth of time. We mi=ht f^s3 but theTw'Y^"'-'"^ ''Tf'"^ exceptional wflS- ness , but the odd fact is enough for my present numntiP Whatever might have been the meaning of Lrmarked^cCe m their mental constitution-had the^been unCoded on the previous day they would have run to me instead of from me -It could not h^ve been the effect of experience iSm^s? have^ resulted wholly from changes in theFr Twn irgaZ- keenw'T'"*^"^ ^r ^^"^^^"^ *"^^ ^he experiment of keeping young duckhngc away from the water for several days after they were hatched; on then bringing them to a pond they showed as much dislike to the v^atfr as V^n' and partjcu arly the tendency which is thus iitduced among hen I nL^tTp'^'- ^"?^''^"° ^"^ other habits of tfif brbr /w s/;Ld fT^^'w ^r''""'^^ P"^^^^«^^d article by UT J W. Stroud of Port Elizabeth, who has devoted a good deal of attention to the subject of caponizi i. -1 Aristotle, more than two tliousand years a-*" aceurate general sltem^n I c^^TiVe™ th'; Xv f' ""'' =i^L-?rt?S-ir^^^^^ S;S;3et'..'''^-™'^"''-.-«'K Mr IZS' l;"'^,''''™^ .the life-time of the indivi, IMAGE EVALUATION TEST TARGET (MT-3) ^/ '^'^ K 1.0 I.I 11.25 1.4 18 1.6 V] <^ /] / ^^^ Photographic Sciences CoiporaUon 23 WEST MAIN STREET WEBSTER, N.Y. M580 (7<6) 872-4503 \ ^^ m V ''<\><.^> ^:v^ ^. >^ ^>i>^ 4' &. [A I A 178 MENTAL EVOLUIION IN ANIMALS. . t- h : if W. f < i:ni IH: manent instincts. Just as in the life-time of the individual adjustive actions which were originally intelligent may by Irequent repetition become automatic, so in the life-time of the species actions originally intelligent may, by frequent repetition and heredity, so write their effects on the nervous system that the latter is prepared, even before individual experience, to perform adjustive actions mechanically which m previous generations were performed intelligently. This mode of origin of instincts has leen appropriately called the " lapsing of intelligence."* ^ For the sake of subsequent reference, I shall allude to instincts which arise by way of natural selection, without the intervention of inteUigence, as Primary Instincts, and to those which are formed by the lapsing of intelHgence as Secondary Instincts. Let us now consider the reasons which d 'priori lead us to assign the probable origin of instincts to these principles, laking first the case of primary instincts, these reasons may be briefly rendered thus : — (1.) Many instinctive actions are performed by animals too low in the scale to admit of our supposing that the adjust- ments which are now instinctive can ever have been intel- ligent. (2.) Among the higher animals instinctive actions are performed at an age before intelligence, or power of learning by individual experience, has begun to assert itself, (d.) Considering the great importance of instincts to species we are prepared to expect that they must be in large part subject to the influence of natural selection. As Mr. Darwin observes, " it wiU be universally admitted that instincts are as important as corporeal structures for the welfare of each species under its present conditions of life. Under changed conditions of life it is at least possible that slight modifica- tions of instinct might be profitable to a species ; and if it can be shown that instincts do vary ever so little, then I can see no difiiculty in natural selection preserving and con- tinually accumulating variations of instinct to any extent that was profitable." That instincts may arise by way of lapsed intellitrence is rendered probable d ipriwi by all the facts which show the resemblance between instincts and intelligent habits. To take only a few of these facts for the present purpose, I • By Lewes, see Problems of Life and Mind. ORIGIN AND DEVELOPMENT OF INSTINCTS. 1*79 cannot do better than confine myself to making a quotation from Mr. Darwin's MSS ; for this will show how^ deep seateS and detailed is the resemblance between habit and instinct 'In repeating anything by heart, or in playing a time ZTl.TJm'n^^'ii if «^^"Pt«d, it is easy to back a little but very difficult suddenly to resume the thread of thoucrht or action a tew steps in advance. Now P. Huber has described a caterpillar which makes by a succession of processes a very complicated hammock for its metamorphosis; and he found that If he took a caterpillar which had completed its ham- mock up to, say the sixth stage of construction, and put it into a hammock completed up only to the third stage, the caterpillar did not seem puzzled, but repeated the fourth htth, and sixth stages of construction. If, however, a cater- pillar was taken out of a hammock made up, for instance, to the third stage, and put into one finished to the ninth staae so that much of Its work was done for it, far from feeliSg the benefit of this, it was much embarrassed, and even forced to go over the already finished work, starting from the third stage which it had left off before it could complete its Hammock. So, again, the hive-bee in the construction of its comb seems compelled to follow an invariable order of work M Fabre gives another curious instance how one instinctive' action invariably follows another. A Sphex makes a burrow flies away and seeks for prey, which it brings, paralyzed b^ having been stung, to the mouth of its burrow ; but alwavs enters to see that all i. right within before dragging in Us prey; whilst the Sphex was wit^un its burrow M Fabre removed the prey to a short distance ; when the Sphex came out t soon found the prey and brought it again to the mouth of the burrow; but then came the instinctive necessity of reconnoitering the just reconnoitered burrow; and as often as M. Fabre removed the prey, so often was all this gone ZZn^Tl 'l^^^^ *^' unfortunate Sphex reconnoitered its burrow forty times successively ! When M. Fabre altogether T^'^A fi^ P''^'.'^' ^P^^^' i^^^^^d °f searching for fresh prey and then making use of its completed burrow, felt itself and befor/'T^'^ '^ ^'"^^^ the rhythm of its insttcl ana before making a new burrow, completely closed up the d one as If it were all right, although in fact utterly useless as containing no prey for its larva.* ^ • Anf^. des Sci. Nat., 4 ser.. tome vi, p. 148. With respect to Bees, .ee i :\ 'X 180 .*,•! ; I'i i MENTAL EVOLUTION IN ANIMALS. 'II » ' i- r *'"" ^ In another way we perhaps see the relation of habit and instinct, namely in the latter acquiring great force if practised only once or twice for a short time ; thus it is asserted that It a calf or infant has never sucked its mother, it is very much easier to bring it up by hand than if it has sucked only once. So again Kirbyf states that larva, after having ' fed tor a time on one plant, will die rather than eat another, which would have been perfectly acceptable to them if ac- customed to it from the tirst.' " Such, then, are some of the d priori reasons for believing that instincts must have arisen from one or other of these two sources— natural selection or lapsing intelligence ; it now remains to prove, a posteriori, that they have so arisen I may first give a brief sketch of how this proof ought "to proceed. ° The proof, then, that instincts have had a primary mode of origin re(juires to show : — ' ~ I. That non-intelligent habits of a non-adaptive character occur in individuals. II. That such habits may be inherited. III. That such habits may vary. J7'rrF^^^-7'^®" *^^^^^^y ^^^ variations may be inherited. V. Ihat if such variations are inherited, we are justified in assuming, in view of all that we know concerning the analogous case of structures, that they may be fixed and intensified in beneficial lines by natural selection. The proof that instincts have had a secondary mode of origin requires to show : — VI. That intelligent adjustments when frequently per- formed by the individual become automatic, either to the extent of not requiring conscious thought at all, or, as consciously adjustive habits, not requiring the same degree of conscious effort as at first. • VII. That automatic actions and conscious habits may be inherited. Primary Instincts. ^ Proceeding, then, to consider these sundry heads of proof, It IS easy to establish Proposition I, inasmuch as the fact Kirby and Spence, Entomology, vol. i, p. 497. For the hammock caterpiUar. Bee Mem. Soc. Phys. de Qenive, tome vii, p. 154. ^ * Zoonomia, p. 140. f Intro, to Entomol, vol. i, p. 391. _, — - — ORIGIN AND DEVELOPMENT OF INSTINCTS. 181 which it states is a matter of daily observation. " Tricks of manner," indeed, are of such frequent occurrence in the nurseiy and schoolroom, that it usuaUy entails no small labour on the part of elders to eradicate them, and when not eradicated m childhood they are apt to continue throuoh- lite, miless afterwards conquered by the efforts of the indi- vidual himself. But in cases where the trick of manner isi not obnoxious, or sufficiently unusual to call for checkin^T it is allowed to persist, and thus it is that almost every one presents certain slight peculiarities of movement which we recognize as characteristic * Such peculiarities of movement as we meet with them in ordinary life are slightly marked ; but their significance in relation to instinct has been obtruded on my notice by observing them in the much more striking form in which they are presented by idiots. This is a class of persons which, as we shall find in my next work, is of peculiar interest m relation to mental evolution, because in them we have a human mind arrested in its development as well as deflected in its growth— therefore in many cases supplying to the comparative psychologist very suggestive material "for study. Now one of the things which must most strike any one on first visiting an idiot asylum, is the extraordinary character and variety of the meaningless tricks of manner which are everywhere being displayed around him. These tricks, often ludicrous, sometimes painful, but usually meaningless, are always individual and wonderfully per- sistent. Generally speaking, the lower the idiot in the scale ot idiotcy, the more pronounced is this peculiarity ; so that if one sees a patient moving to and fro continually, or otherwise exhibiting " rhythmical movements," one may be pretty sure that the case is a bad one. But even among tlie hii^her idiots and " feeble-minded," strange and habitual movements of the hands, limbs, or features are exceedingly common. Among animals similar facts are to be noticed. Scarcely any two sporting dogs "point" in exactly the same manner, ,,.•?'• 5*T^?*«' says (Mental PJiysiology, p. 373), " Wliat particular tnck each individual may learn, depends very much upon accident. Thus, in the old times of dependent watch-chains and massive bunches of seals these were the readiest playthings," &c. In view of the relation which such _ tricks bear to the formation of primary instincts, this remark has some importance ; it shows that even aimless movements may be determined and rendered habitual by the conditions of the environment. % siT ■: 1' i: 1 |i' : :'■ ij'-: i 182 MENTAL EVOLUTION IN ANIMALS. ml t • ' ' ,'H /: *',!! me'''fjZ^i^l ^^^'''' **^ ^'' particular attitude through when they are threatened, when at plav &o ^r,7 rll ' and indeed domestic animals of any kind^mL^l'"" noticed the diversity of their dispositions in "esTeTnf tf^ boldness, amiability, &c. : and Mr W T?f^? ,1^1?^ P^^^' large experience, if sure^St the d^;S/5^^^^^^^^ ^^^^ la^^s^and canaries is displayed bytSyl'aSrtS Almost innumerable instances might be given of indi vidual variations m the instincts of nelt-buildinlf Event conLctnt MTSrSrMSs''''' ^^ '''' ^^^^ " ^^^-^ to in ihi, for many years occupied a hole in a walWlS ;' "S-^^'l"*^ * P'^^'" ^^^^^ deseribesanother nest placedTu the sideotll7''1"^u'^-)' '^"^ ^'•- ^^^^ of clay weighing no les^s than eleven VonlaJtet.^Z^' "^ "'*\^. "'^^^ mehes in height (Zoologist, 2nd ser r 285nV T) 1/ "'^•^«"'-i"g thirteen frequently exhib ts variations in th^^^rn.f^" f goWen-crested Wren, also, crags of rock ; but Mr D E Wv rJ / '^^^ ?''^''' ''"'^'^^ i° precipitous describes a nest which he Welf if "^"T "" '^l'^^^-''' 1«72, pp. 141-3)! feet from the ground Coucrsri th'T'^f'* "'^ f/^'^''^^' °°* ^bove twenty 8ometimes unii in occuS one nest anHth ^° "^? ^'^ of birds wij men, or one of them will surrender thetnful % !f ' *^"^ ^"''"^^ ^° "om- trations of Instinct, p 233) Mr S sJ^^ 'l'' ''^ *i'T ^^^ *^^ «t'^«'' (^^^«*- " From what has be;n wrSen ifaDnears n^« ' 7w ^ '^^ the Missel-thrush says, plast<.r in the construction o?'theSSt;ht„^^^^^^ which agrees with my own leSion L ^ff'h' '"'"^Tt^ ^o without it, which did not contain plaster tKel^^; rl, ^^f °"^^ \ ^"^^ ^"""d ^^sts my way-and they have bein not? few P^"* •^^t^^^^^ ^hi^h have fallen in Fome kind betwee J tlie twi^s and 110^" t"^'"^^ ^^''^ ^'^^ ^ plastering of invariably consti'te th Zngf tS^^^e^mnr'"^ *^^ ^'^ f'^'' ""^^'^ 11 hi OKIGlN AND DEVmoPMENT OF INSTINCTa. 183 low down in the psychological scale as the insects we are not without evidence of individual variations of instinlt tC, for instance, Forel observed great diveSt m nf \,.-m- ' among the il <«««W«_the nZ^b^Sg^'J^Z^eslo^:! sometimes made under stones, and sometimS excavaW t' :^ wTitiiet,fnruu'rx''S'iy tr^^^^^^ which she holds, while another wIlT let them f^'and^'Z .li.w!-'^ shoi^ing strongly marked individual differences of dispasition in animals, and also that such differeuMs mav lead to useless or capricious actions having all the stren^h a e tEt' wh" h'- ' '""!= » g°«i cl«« of cies telfet pe7The%t*'f ■ ""i ' "'» -t it-i^gl C/i T. pet. Ihe bird soon became perfectly tame and then rnn ceived a strong, persistent, ar/unremitting atLchment to a peacock which also belonged to the establisliment WW^^^^^^ wasnoTTnr '11"^?'^ ^emarkable^rom the fact that k was not m the smallest degree reciprocated by the peacock ?or Tnred'td'bV'^'^'t '^^'-^^ ^^« constant Zp it behind hi'm t - f.T *° ^^^'"" ^^'^^ «^« ^^^ always just CO tai ?hp tn " ^'' ""''^^J" ^"°«^ ^P°" the gable of a and e^ven I^Jf widgeon could not fly to accompany him; aiu upon me gable; but she always kept as near him a^ oiv cumstances wou d permit, for as soon as he flewTp to h s" gable she would squat herself down upon the groTnd just :t7£bt\*r^CtftS^^^^^^^^ be multiplied indefinitely., but a, Mr. Darwin's essay at the end of ?2 shook it L'''"-;^?^ T'' ^'^ g'^«° i° anj further illustrations ° ' '* '^ ''^^^^^'^^ ^"^ ""^ to adduce ; J 1 ^ 1 * 1 im 1 r ^ w i ' I 1 i i f :.l ■'I'-^^ir-! ! ■ j J 1 ; 1 i !■ ( t ii - » 'i^M 184 MENTAL EVOLUTION IN ANIMALS. i '-Hi iky L Jiil;.., . ^ !l .T '^n ^^^°t^o" ^Iiich eventually cost her her life as she thus feU a prey to a prowling cat/ Now here we have^ curious case of a bird that had%een wild, takiL a ylZnt fancy for the wholly useless companionship of afothS and very dissimilar bird; for it should be added that shechose the peacock as the object of her persistent regard out of a isrp^r ^'^^' ^'^ ^^ ''--'"^ birds whicrii;'ed^ Similarly, cats often like to associate with horses and in some cases with dogs, birds, rats, and other unliLwea^^^^^^^^ Dogs not unfrequently make friendships with a vSfetv of animals, and in a case recorded by F. Cuvier a terrier fnLr5 80 much delight in the companionship of a ca-e^^^^^^ when the lion died the dog pined away and died also trprr'^f^'iT^' ?'^' ^° ^^^^^ ^°^««« ^^^^ become C* tremely attached to dogs and to cats, and seemed pleased to have them placed on their backs in their staUs."* Een-er mentions a monkey which was so fond of a dog that it cried with grief during the absence of its friend, carSssed it on Tts 'iTp^r-'^l''^^ '' ^^^^^ ^'' quarrels'with ol r doS A peccari m the menagerie at Paris formed a stron- attach- ment with one of the keeper's dogs, and a seal in the ame place allowed a little water-dog tS play with it Tnd to take fft Ta 'u !?°"*\ which it always resented if this were attempted by the other seals in the same tank. Do4 have lived on terms of friendship with guUs and ravens " waLV'&c Icr"" ^''''^'' ^° accompany his master in his Colonel Montagu, in the Supplement to his "Ornitho- logical Dictionary," p. 165, relates the following Sular instance of an attachment which took place between a Srd anf r^'t ' P"'^^? " ^^^ ^"» ^^d ^^^^^ the male bud, and had been most severely punished for the mis- fm tl 1 .?^ ''^'^^'^ ^'''''^ ^'^^^^ extremely distressed for the loss of her partner and only companion ; and probably having been attracted to the dog's kennel by the sight of her dead mate, she seemed determin^ed to persecute the dog by «^Ir'«T.fTV^"'''^f^''/^^ "°"t^^"^l vociferations; but after a little time a strict friendship took place between these incongruous animals. They fed out of the same trough, lived • Thompson, Passions of Animals, pp. 360-1. f Ibid. 't'l,' ORIGIN AND DEVELOPMENT OF INSTINCTSp 185 under the same roof, and in the same straw bed kept each other warm ; and when the dog was taken to the field, the lamentations of the goose were incessant," The same author gives ases of attachment between a pigeon and a fowl, a terrier and a hedgehog, a horse and a pig, a horse and a hen, a cat and a mouse, a fox and harriers, an alligator and a cat, &c., all as having fallen under his own observation. {Ihid.y p. 162.) It is not impossible that the so-called " domestic pets " which are kept by many species of ants* may really be use- less adjuncts to the hive, capricious love of association having perhaps in these ants become by inherited habit truly instinctive. This, at any rate, must be the explanation of the fact that birds of different species will, even in a state of nature, occasionally associate, as is the case with Guinea- fowls and partridges, and, according to Yarrell, with par- tridges and landrails. Such unusual cases among birds in a state of nature are of special interest, because they may then properly be regarded as the beginnings of such a firmly set and truly instinctive association as that which obtains between rooks and starlings, &c.t ;•!# Enough has now been said in support of Proposition I, viz., that non-intelligent habits of a non-adaptive character occur in individuals. We shall next proceed to Proposition II, viz., that such habits may be inherited. That this is the case with tricks of manner in man is a matter to be observed in almost every family, and was long ago pointed out by John Hunter. Mr. Darwin in his MSS gives a case which he himself observed, " and can vouch for its perfect accuracy." " A child who as early as between her fourth and fifth year, when her imagination was pleasantly excited, and at no other time, had a most peculiar trick of rapidly moving her fingers laterally with her hands placed on the side of her face ; and her father had precisely the • See Animal Intelligence, pp. 83-4. t Prof. Newton, F.R.S., informs me that "bands of the Golden-crested Wren may frequently be observed in winter consorting with bands of the Coal-Titmouse, and in a less degree with those of the Long-tailed Titmouse ; while parties of Redpoles and Siskins will for a time join their company, or vice versa. The flocking together of Rooks and Daws is, of course, an everyday occurrence, as is also for some months the association of Starlings with them, and in umny cases the combination of all with Lapwings. , .:i ( i i !M .1 i-i; ] J I I I ■':. 189 )h «;in. j'MJ: l;i ' il Mn: :i MEXTAL EVOLUTION IN ANIMALS. n'hrr'^^^^- instance there man;efwth"a?:mrnSL'h^ P^^^^^^^^ ^"«ks of seen; her puppy' wl^^h neveVouH h«^ ""^''^ ^^ ^'^ ''^' beg, now when f lU grow^SoTm. .i.^«^^^ ''"" ^"" ^^^^^r ment exactly in the ''same w^ay "f '''^' ^''''"'' ^°^'- differences of thirS nfnvl °'-*^ ''" ^°^ "^^rked different breeds Itlni hf ''''T '^-"''^^^y distinctive of are only concerned She X'> ^'^^^^ '' ^''''''' ^« gent, or non-adrptivThabits and H ? ^^ "^eless, unintelli- to do with the iisefS andii ^^^^^^" ^^'^ nothing into our various'^ces otlgf fc^„3^,ttr^^^ are bred combined with training \„7 °^^^"? ^^^/^^ificial select on meaningless traits of "htractefw^^^^^^ ?r '^' '''' '^ ^^^^^^ the animals themselvpcrnr ff ' ^^® ""^ ^° "«« either to heredity at woT Thus for ."n'^f"' ^' ^"^ ^^^ ^^A^^^ces of annoying habifof ba kin' round"'"' '^' "'^^^^'^ ^^^ ^^«^ among sundry breedVnf ?i^ ^ ^ carnage, which occurs the coUie, anJ is t^uiylnZ' '' ^ff^^^^^Y pronounced In This is shown by the ta tw'^^ T ^T^.^^^°^ «^ ^^^i^^tion. W never seenCthertof ^^^^^^^^ '^^ P™^^°°^ spontaneously begin to do so-? V ^^""f^^"^'^ nevertheless of character o^rdisposilnpeeuliano'^^^^ '''^'''. '''''' -ntioned; butlLnpasr^nt^^o^rrm^^^^^^^^^^ ^^*;^'^^^^^^^^ -'«^ - '---^^ o/^„,.„^ ,„, perfomteTo^Slie'nraT^^^^ s^JlZT?"^ ^^^^"'l Syke terriers to somerace-distiuction of a psychl5'J,\ if ^^' ^°''°° ''^"^^ *» be due vidual peculiarity. It thereJe leads on t .1? ' f "** ?°' "^^'^'^ *« "^n iudi. in the text. ^^""^^ o° to the class of cases uekt considered J See Mature, toI. xix, p, 234. ORIGIN AND DEVELOPMENT OP INSTINCTS. 187 I have met with in dogs of the inheritance of a thoroufflily sense- less psychological pecuharity. I refer to the instance which was comniunicated some years ago to Mr. Darwin by Dr. Huggins. IRS., and which I shall quote in his own words {nT,.r.LT' ? communicate to you a curious case of an inherited mental peculiarity. I possess an English mastiff by name Kepler a son of the celebrated Turk out of Venus.' 1 brought the dog, when six weeks old, from the stable in winch he was born The first time I took him out he started back in alarm at the first butcher's shop he had ever seen 1 soon found he had a violent antipathy to butchers and butchers' shops. When six months old a^ervant took him with her on an errand. At a short distance before coming to the house she had to pass a butcher's shop ; the dog threw himself down (being led with a string), neither coaxin" oT threats would make him pass the shop. The dog was too heavy to be carried and as a crowd collected, the servant had to return with the dog more than a mile, and then go without .i-m'.i "' ^^^"^fl about two years ago. The antipathy still continues, but the dog will pass nearer to a shop than on ZT^ TTm ^-^ u ^'^^ ^^'^ "^^^^^^ ^SO, in a little book on dogs, published by Dean, I discovered that the same strange antipathy is shown by the father. Turk I then v^rote to Mr. Nicholls, the former owner of Turk to ask tm tor any information he might have on the point. He replied ofTnvv'?^T v 'r"\^"^^P^^^^^^^^«^« ^^ King, the sire of Turk, in Turk, in Punch son of Turk out of MeS), and in Pans (son of Turk out of Juno). Paris has the greatest an ipathy, as he would hardly 'go into a street where a butchers shop ls. and would lun away after passinc. it When a cart with a butcher's man came into the place where the dogs were kept although they could not see him, they all were ready to break their chains. A master-butcher tiTZJ'Tih'f'i °"' '^'^^"S on Paris' master to see the dog. He had hardly entered the house before the do- (though shut in) was so much excited that he had to be put into a shed, and the butcher was forced to leave without seeing the dog The same dog at Hastings made a spring at a gentleman who came into the hotel. The owner caught the dog and apologised, and said he never knew him to do so betore, except when a butcher came to his house The gentleman at once said that was his business ' " ! i it, % i|;:j • i 11' 1 .;.:. h i ■ ■ a . i 1 ' - ' 1 iiiii LJ I: I 8 188 MENTAL EVOLUTION IN ANIMALS. We see, then, tliat non-intellirrent habits of non-nrlnnf iv« anim^rAfr"" r^'.^ «tro'ngly inherited b7 dots animals As showing tlmt the same is true of breeds or strain. strong „„e„stral instinct, is one which is communicated to Mr IJarwm ma letter from Mr. Thwaits, who S from mTX^^Vmss'' T' 7^ -'-'' '-^'ter I iiXm^^ ^"Si"li^? '--- »™™' i^XSii'fei todTwhl^tSbrplaceTt :tb or °; '^''^ ^™"« alarmed" and have i t";'ickVtatV Ln^L'-^o fi v^^ould drown in their struir-'liuf^" Mr ThJolf. aa \\,Z this pecdiarity does not IS to eSi Ihe tcto la the island, but only occurs in one particular breed or strain In Mr. parw,„'s MSS I also iind the folIowiL remarks • difeent^JrtsTM™' ""^-^h^ve stated that Wsef a trtl'e'' ;';r r""»' P^™^ have bjracti e'd S ^bLr'vSLlh^ \r?rhe"ittdT' ^■" ^"1^ "'»" " ?:;drs$-SE«h^i^:sSSS • personal Narrative, vol. iii, p. 383. Btruck by no horse on the grL y P S'^ LaX'*'^ *^'\u^ """^ ^""""^l^ action of some English horses '' For 1 nn v> J" ^V"- ^^"^ "'^t"™! ^'igh ditar, transmission^f qual t ts in the ca a^nf H ^ t^'' '"'*"""«^ "^ '^^^• ^nma/« a«d Plants. &l. vo ? pp iVg "'"' ''^ ^'"•*«''o» «/ OUIGIN AND DEVELOPMENT OP INSTINCTS. 189 ■'M ancient times in the East, when flying pigeons was much esteemed. Tumblers have the habit of flying in a close flock to a great height, and as they rise tum'bling hoad over tail. I have bred and flown young birds, which could not possibly have ever seen a tumbler; after a few attempts even they tumbled in the air. Imitation, however, aids the instinct, for all fanciers are agreed that it is highly desirable to fly young birds with firat-rato old ones. Still more remarkable are the habits of the Indian sub-breed of tumblers, on which I have given details in a former chapter, showing that during at least the last 250 years these birds have been known to tumble on the ground, after being slightly shaken, and to continue tumbling until taken up and blown upon. As this breed has gone on so long, the habit can hardly be called a disease. I need scarcely remark that it would be as impossible to teach one kind of pigeon to tumble as to uMch another kind to inflate its crop to the enormous size which the pouter pigeon habitually does."* This case of the tumblers and pouters is singularly interesting and very apposite to the proposition befove"us, for not only are the actions utterly useless to the animals them- selves, but they have now become so ingrained into their psychology as to have become severally distinctive of different breeds, and so not distinguishable from true instincts. This extension of an hereditary and useless habit into a distinction of race or type is most important in the present connection. If these cases stood alone they would be enough to show that useless habits may become hereditary, and this to an extent which renders them indistinguishable from true instincts.f In the Appendix several instructive cases of the same kind will be found, such as that of the Abyssinian pigeon, which, when fired at, " plunges down so as almost to touch the sportsman, and then mounts to an immoderate height ;"J the biscacha, which " almost invariably collects all sorts of * For further particulars on the instinct of tumbling, see Variation of Am mail and Plants, vol. i, p. 219, and 230. T Some years ago the Ratels wliicb were confined in one cage at the Zoological Gardens acquired the apparently useless habit of perpetually tumbling head over heels. If their progeny were to be exposed for a number of generations to similar contiitions of life, they would probably develope a true instinct of turning somersaults analogous to that of the tumbler- pigeon. I I have frequently noticed a similar propensity in the Lapwing. 13 ^e generations;" and in his own "family there occurred a curious case of a gentleman who inherited a constitutional character of hand-writing, and lost his richt arm by an accident; "in the course of a few months he learnt to write with his left hand, and before long the hand- wnting of the letters thus written came to be indistinguish- able from that of his former letters." This case remSr^e of a fact which I have frequently observed-and which has doubtless been observed by others-viz., that if I write in any unusual direction as for instance, on the perpendicular face of a recording cylinder), the hand-writing is unaltered in character, although both the hand and the eye are working i^ ^31^'''^^°'^"?' '"^ '*'^"g ^« ^h« mm^a^ element in hand-writing. Similarly, as observed in a previous chapter f one takes a pencU m each hand and writes the same word Z^hi ,fi I ' simu taneously-the left hand writing from right to left--on holding the backward written word before a mirror, the hand- writing may at once be recognized Many other instances might be given of the force of inheritance m the mental acquisitions of man.* But turning Idves t^e^7T^Jhf:^*''\^J^^ff^y' PP.- 39^-4' "'^'^^ h« discusses and pves caaes ot hereditary aptitude for music and painting. Also Galfon'« tfnt '^ ©^"^f*. for high mental qualities running in fammes eithe! in the same or m analogous lines of activity ; and Spencer (PsSo2 i p S or « E?" in'f ™''"^. -^ psychology in Lm. Th^e eifect. o/'' goK^edit /• • or blood in bequeathing hereditary disposition and refinement have aSy ORIGIN AND DEVELOPMENT OF INSTINCTS. 196 m now to the more important case of animals, I shall give only a few examples among almost any number that I could quote. Thus, in Norway, the ponies are used without bridles, and are tramed to obey the voice ; as a consequence a race-pecuharity has been established, for Andrew Knight says "the horse breakers complain, and certainly with very good reason, that it is impossible to give them what is called a mouth; they are nevertheless exceedingly docile, and more than ordmarily obedient, when they understand tlie commands of their masters."* Again, Mr. Lawson Tait tells me that he had a cat which was taught to beg for food like a terrier, so that she developed the habit of assuming this posture— so very unusual in a cat— whenever she desired to be fed. All her kittens adopted the same habit under circumstances which precluded the possibility of imitation ; for they were oiven away to friends very early in life, and greatly surprised^theip new owners when, several weeks afterwards, they began spontaneously to beg.f In order to show that the same principles apply to animals m a state of nature, it will be enough to adduce the one instance of hereditary wildness and tameness, for this instance affords evidence of the most conclusive kind. Wild- ness or tameness simply means a certain group of ideas or disposition, having the character of an instinct, so that we may properly speak of a wild animal as " instinctively afraid " of man or other enemy, and of a tame one as instinctively the reverse. Indeed, one of the most typical and remarkable illustrations of instinct that could be given is that of the in- born dread of enemies, as exhibited, for instance, by chickens at the sight of a hawk, by horses at the smell of a wolf, by monkeys at the appearance of a snake, &c. Now, fortunately there is material for amply proving both that these instincts may be lost by disuse, and, conversely, that they may be acquired as instincts by the hereditary transmission of ancestral experience. been alluded to, and I think observation will show that the same applies to the sense of modesty. i-f ™ w • FAil. Trans., 1839, p. 369. t Inasmuch as thp action of "begging" is so unusual in the Cat, the above case of its he p -.tsvy transmission is more remarkable than the similar cases which occur i- u Dog ; see Lewes, Problems of Life and Mind. vol. i, p. JJ9, and i lake Cosmic Philosophy, vol. ii, p. 150, and mo e especiallv a case recorded by Mr. L. Hurt, in Nature (Aug. 1, 1872) of a Skye ter/iei i| < : !■ ■ m i - \ ■ M "; .-!- i i -■} 1 ! _ ; 196 MENTAL EVOLUTION IN ANIMAL8. > I I "•>m ,1 ! s U, I m; i ' la m.J^ r?l*^f* instinctive wildness natural to a species ra/biL' 1?L'^T '^ ^^"'^-^"ly rendered by the cLe o rabbits As Mr. Darwin remarks, "hardly any animal is more difficult to tame than the young of the wild rabbit raTbit'^uTl'rb % '^"" '""k ^^^ y-»« of ?he tame rabbit but I can hardly suppose that domestic rabbits have at le^astXtf;^ for tameness alone ; so we must attribule at least the greater part of the inherited change from extreme wildness to extreme tameness, to habit and'long-cont S tZaTnNTV '"' '" ^^^ ^^^ ^« ^dd«' "Captain buhvau, KN., took some young rabbits from the Falkland Islands, where this animal has been wild (i.e. feral) for several generations, and he .'s convinced that they are more Zul 'Tk^ '?'^ ''^\ ^^^ ^^^bi^« in Engla^nd The facility of breaking m the feral horses in La Plata can I think, be accounted for on the same principle of some Httle W " Ziull'Z'T''^ being^ong^nhereTinll! breed. Similarly Mr. Darwin points out in his MSS that there is a great contrast between the natural tameness of the tame duck and the natural wildness of the wild.t The still more remarkable contrasts which are presented between our domestic dogs, cats and cattle I shall consider later on : for m them it is probable that the principle of selection has belonging to him which had great difficulty in acquirinff bv tuiHon fl, accomphshment of begging, but afterwards habituairpSed it as a S^n.™! expression of desire. Mr. Hurt then adds " OnT-.f i?™'^"^®^ " as a general never ,ee„ her f«U.„, i. i„ ZV.ZAit of .it. „s'L^'£l™i'i° J" Ihe wild rabbit,' says Sir J. Sebright (On Instincts 1836 n inw;« k far the most untameable animal that I know „nH t i i i P' "^ " ^^ British Mammalia in mv possession T S^V T .i,^''''^ ''''** °'°'* °* ^^^^ nest, and endeavoured"? KeTm, buttlw'tTertcS' S dZ ^^ hide themselves, or ta^ke to fhe wSer if 'tW ^^"^'^'''*«ly endeavour to person approach whilst the youngl^jJm the ttme d.lt°^ ^ater, should any rmo#""' ""^^ - ^'^ — "- i=nttfSrr theS '\)t ORIGIN AND DEVELOPMENT OP INSTINCTS. 19^ played an important part, and at present we are confining our attention to the evidence concerning the formation of secondary instmcts, or the mere lapsing of intelligence into instinct without the aid of selection. We see, then, that the instinct of wildness may be eradi- cated by mere disuse, without any assistance from the pnnciple of selection, and further, that this effect persists, or becomes but gradually obliterated, through successive genera- tions of the animals when feral, or restored to their abori- ginal conditions of life. Conversely, it has now to be shown that instincts of wildness may be acquired by the hereditaiT transmission of novel experiences, also without the aid of selection. This is shown conclusively by the original tame- ness of ammals m islands unfrequented by man, gradually passing into an hereditary instinct of wildness as the special experiences of man's proclivities accumulate ; for although selection may here play a subordinate part, it must be a very subordinate one. Pages might be filled with facts on thia head from the writings of travellers, but to economize space 1 cannot do better than refer to Mr. Darwin's remarks, with their appended references in his chapter at the end of this volume. To these remarks, however, I may add that the development of fire-arms, together with the growth of sportin<^ interests, has given game of all kinds an instinctive know- ledge of what constitutes "safe distance," as every sportsman can testify; and that such instinctive adaptation to newly developing conditions may take place without much aid from selection is shown by the short time, or the small number of generations, which is sufficient to allow for the change— witness, for instance, the following, which I quote from the paper on "Hereditary Instinct" by the careful observer Andrew Knight:— "I have witnessed, within the period above mentioned, of nearly sixty years, a very great change m the habits of the Woodcock. In the first part of that time, when it had recently arrived in the autumn, it was very tame; it usually chuckled when disturbed, and took only a very short flight. It is now, and has been during many years, comparatively a very wild bird, which generally rises in silence, and takes a comparatively long flight, excited 1 conceive, by increased hereditary fear of man."* • Phil. Trans., 1837, p. 369. 111! ;! ^i 1 ' i ' 1 1 \[ :'■ i ■ H l^^l )'> Mi . , I f 198 MENTAL EVOLUTION IN ANIMALS. instfnctfwheZ nf /?^"'"'' "^ ^'''^^y ^" ^^' ^^^^^^ of instinct (whether of the primary or secondary class^ is Der- haps most strongly manifested in the effects of^ cross n^ ^ll 18 not indeed, easy to obtain this class of evidence In the rrl^'^^'p^fT'^'^^^.^i^y^^^^ ^^^^« i- a sfate of lire onP Tf,;.i V''^"'' ^ r^^ 'P^^^^« i« crossed with a tame one, It usually happens that the hybrid or mon-rel Droorpnv e^vid^ni" ^^r^'i Psycho?°»^- ^^d stiU m^e ?og^^^^^^^^ evidence of such blending when two different hrppiV^? domesticated animals are Lssed. havLg dTveTse heredttarv habits, or as Mr Darwin calls them, "domes c instincts^ Thus a cross-breed between a setter aid a poLter wi 1 blend Wr'S'AK^!^'^''?^ worldngpec'uliLto^ese two breeds, Lord Alford's celebrated strain of ereyhounds ao qmred much courage from a single cross witf a buU do. * and a cross with a beagle "generations blck will give to' I spaniel a tendency to hunt hares."t ^ vn„^^T' •^°'^!'^ '^^' •-" I"^ one instance I saw a verv young dog, a mixture of the Springing Spaniel aid SpTI? which dropped upon crossing the track of rSrM.e af ?ts male parent would have don^and sprangthe M in^sCe a WoodcocT i'lp ^r "^ " '^'"PJ^ '' ^^'^« afterwards found ;a:^»Ce & S7h ^^IC^^Z t'T^ rSvrm1i\ton^^^' and the experiments and o&^Z Lerlsti^l"' ""^'^ '^'"^ ^"^^ ^^* ^^^^ ^'^y ^^nierous or , On this point Mr. Darwin writes :~« These dnmPQHn in^l5. ' a r "^, "^® manner become curiously blended straight line to his master when called."! Some further remaiKs on this subject wiU be found in Mr DaSs appended essay on instinct; and here I may fit^y conekde the present chapter by quoting the foUowinc. parTaraDh which occurs in another part of WsMSS. Paragraph • Touatt on Dog, p. 311. t Blaine, Rural Sports, p. 863, quoted by Darwin. I Ongm 0/ iSpecies, p. 210. ^ u^wia. ,fi ORIGIN AND DEVELOPMENT OF INSTINCTS. 199 In Chapter VII I have given some facta showing that when races or species are crossed there is a tendency in the crossed offspring, from quite unknown causes, to revert to ancestral characters. A suspicion has crossed me that a shght tendency to primeval wildness sometimes thus appears m crossed animals. Mr. Garnett in a letter to me states that his hybrids from the musk and common duck 'evinced a singular tendency to wildness.' Waterton (' Essays on Natural History' p. 197) says that in his dick, a cross between the wild and the tame, 'their wariness was quite remarkable. Mr. Hewitt, who has bred more hybrids between pheasants and fowls than any other man, in letters to me speaks m the strongest terms of their wild, bad, and troublesome dispositions; and this was the case with some which I have seen. Captain Hutton made nearly the same remark to me in regard to the crossed offspring from a tame goat and a wild species from the western Himalaya. Lord Powis agent, without my having asked him the question remarked to me that the crossed animals from the domestic Indian J3uU and common cow ' were more wild than the thorough-bred breed ' I do not suppose that this increased wildness IS invariable; it does not seem to be the case according to Mr. Eyton, with the crossed offsprin«'"? "1 cats-being transmitted t„ fh. i„!^i? ^i ^ "^* ™°''* instructive facts with rewd to the loss of wildness by certain domesticated animals and shnT'p^Sf rf "' "^n^'^""' "y animrrhabiting p:£:zi:fsT^^'i iS^titii £s: i! :[ii BLENDED ORIGIN, OR PLASTICITY OP INSTINCT. 201 Although for the sake of clearness I have so far kept separate these two factors in the formation of instinct it has now to be shown that instincts are not necessarily confined to one or other of these two modes of origin exclusively • but on the contrary, that instincts may have, as it were, a double root—the principle of selection combining with that of lapsing intelligence to the formation of a joint result Thus heredita-y proclivities or habitual actions, which were never intelligent but, being useful, were originally fixed by natural selection, may come to furnish material for further improve- ment, or be put to improved uses, by intelligence; and con- versely, adjustments originally due to lapsed intelligence may come to be greatly improved, or put to improved uses, by natural selection. As an example of the first of these complementary cases —or that of a primary instinct modified and improved by intelligence—let us regard the case of the caterpillar wliich before changing into a crysalis, crosses a small space with a web of silk (to which the crysaHs can be firmly suspended), but which when placed in a box covered with a muslin lid perceives that this preparatory web is unnecessary, and therefore attaches its crysalis to the already woven surface supplied by the muslin;* or let us regard the case of the bird described by Knight, which observed that, having placed her nest upon a forcing house, she did not require to visit it during the day when the heat of the house was sufficient to incubate the eggs, but always returned to sit upon the e^sa at night when the temperature of the house feUf In both these cases of primary instincts modified by intellifrent adaptation to particular circumstances— and hundreds of others might be added— it is evident that if the particular circumstances were to become general, the adaptation to them becoming likewise general, would in time become instinctive by lapsed intelligence: if muslin and forcing houses were to become normal additions to the environment of the caterpillar or the bird, the former would now cease to build Its web, and the latter cease to incubate her eggs by *r,«lf/®- ^"f^ ""? u P^""®' ■^'»f?»"'%^. ■^ol. ii, p. 476. It is evident that the weaving of a web by a caterpillar adapted to the needs of its future con. dition as a frvsalis, must be due to instinct of the primary kind, inasmuch aa no individual caterpillar prior to the formation of such a struc ure can W known by expenence what it is to be a crysalis. t Loc. cit. ; m h " m / ^f- ' ' ;. . .J 1 ■ ; i ! • \ ■ \ i j..1..|] i \'l 202 flip liim,.^ I^fii .11 ! ! 1 MENTAL EVOLUTION IN ANLMALa I., . ( !l fli l\\lr .1;! i , j. i*\: '! > i-i (ps ■jh tuh' i"Jevt,S ' '.^;™'''"7 instinct w,mMbeeomo Mendea act of intelli;rence Bi,f /^f f burrowing was probably an ciples ^ *^^^ J"""'^ operation of both prin- • Tbo taott .1 ; iiis case have been told me by Dr. Eae, P.R.S. BLENDED ORIGIN, OR PLASTICITY OP INSTINCT. 203 this further development of an instinct, if the variations of the instinct are not wholly fortuitous, btit arise asTnS ' ^t adaptations of ancestral experience to the perceived requ re inents of individual experience. i^4""o- Trusting then it is sufficiently clear that the two princi- • pies which may operate either singly or torretherinfoim.nl instincts may operate together wWchevor^'of the two maf I n?n?in° 5.T' '"^ "'Y P^^ticular case. the historical priority. I may m future neglect to entertain the question of 8u4 prionty; without considering whether in this and that case seection was prior to lapsing of intelligence, or lapsTuro? n elligence was prior to selection, it wiU%e enough t^o p;;,ve that the two principles are conjoined ^ ihJlJ^T^ ^)'' '^- ^T ^° «^«^' ™uch more copiously than has been done m the above two or three illustration J not only, as was proved in the previous chapter, that fu ly may be determined by intelligence. y^imiwu Plasticity of Imtind, fL ^" fo™P!"^PwWications I have used this teiw to express the modifiabihty of instinct under the influenee of i^lZnce I sha 1 now give some chosen inslances of such ^^d Smy and then proceed to indicate the causes which most fre- quently lead to intelligence thus acting upon instinct It is of importance that I should begin by rendering the fact of he plasticity of instinct beyond'que Jion, no only becfuse alterabl^ 'ilT'^ the prevalent n'otion thit instincL ar u" alterably fixed, or rigidly opposed to intelligent alteration under changed conditions of life; but also because iuTthit principle of plasticity that largdy suppHes to na ural e tion those variations of instinct in beneficial lines, which are Huber observes: "How ductile is the instinct of bees and how readily it adapts itself to the place, the c rcum- stances. and the needs of the community " aiJ^ ^Yl "f-^i^® '^^^ ""^ ^'^ ^"^«^«ls in which instinct has at amed its highest perfection and complexity, even wSiout evidence we might be prepared to expect that instinct I everywhere ductile. Moreover the bees constitute a good i 11 !»,f ' i li : ■ 1 i 1 'hi m 1 1 ., 11 ill i 1 w 1 204 MENTAL EVOLUTION IN ANIMALS. 'ii'-i ^■i' if I ;. s?;?™V" Anil's zr""' nr''- '""="'^' ^ I i^e fivo^ Pripay kmd; yet, as we shaU see, though so wpII ™«t\?Wst- "'■ ''^'^"'"S the observation, of Huber, combs of old wal and they h^d ^Ih^^^^^^^^^ Lm"r^'/l ^i""^^ favourable season they would not have hesitated to build a new comb upon the old or but ?t being inexpedient at that period to expend the^ mo vision of stSv'of^V^'r"^ ^^.T' th%\3d°irth1 scaoiiity ot the faUen comb by another process Tbpv furmshed themselves with wax from the other combs bv wicn repairing the accidents which their masonrv had pv old wax, and forming numerous ties and braoes to unite them tbT tharwas^^t'lt" '""^. '° "?!' ™"^ ofVerhabi a" ia the.^X7.i'lrara p^dta,^"^::^^^^^^^^^ f. BLENDED ORIGIN, OR PLASTICITY OF INSTINCT. 205 "Haying placed in front of a comb which the bees were constructing a shp of glass, they seemed immediately aware that It would be very difficult to attach it tososlppeTva surface, and. instead of continuing the comb in a stSht line, they bent it at a right angle, s^ as to extend beyond the slip of glass, and ultimately fixed it to an adjlLTpart of «ie woodwork of the hive which the glass did not cover This deviation if the comb had been'a mere smple and un form mass of wax, would have evinced no small ingenuity or fno. n7 i^']f '" "^^r^ '^''' ^ «°™b consists on elch de' or face of cells ha nng between them bottoms in common and If you take a comb, and, having softened the w^x bv heat, endeavour to bend it in any pa?t at a rioht an^e vou will then comprehend the difficifltL winch our liSrardi^ tects had to encounter. The resources of their instint however, were adequate to the emergency. They made the cells on the convex side of the bent part of theTomb much iTff' ^^^ .tl^oseon the concave much ..m^/cr than uTual latte%'ut ;?•""" three or four times the diameter oS lat er But his was not all. As the bottom of the small and large cells were as usual common to both, the cells were not regular prisms, but the smaller ones considerably wider at the bottom than at the top. and conversely in tL W ones ! What conception can we form of so wonderfur a nS 1^^.?^ '"'^?'^- ^"^^' ^' Huber asks, can we com- prehend the mode in which such a crowd of iXuTe^s occupied at the same time on the edge of a comb, coidd aoS to give 1 the same curvature from on? extremity o the other or how they could arrange together to construct on one face cells so small, while on the other they imparted to them such enlarged dimensions ? And how can w^ S adeo 1 astonishment that they should have the art of makit^cd of such different sizes correspond ? " * ° Other observations of Huber show that even under ordi- nary circumstances bees are frequently in the habit of the cells winch are destined to receive drones requirinrr to be cousiderably larger than those which are destined to ?e eive neuters, and the rows of all the cells being conunuous. where j^ * Kirhy and Spence, loc. cit., pp. 485-495. I'c^3l ■t, ;' i mm 206 ti i; t , I f tl >i 1 • 'Hi ■ I ■ f'^iiii MENTAL EVOLUTION IN ANIMALS. a transition takes place from one class of cell to the otiier a complex geometrical problem arises how to unite hexagonal ceUs of a small with others of a large diameter, without Jhr^f fy^id spaces or interfering with the regularity of the comb. Without occupying space with what would necessarily be a rather lengthy exposition of the manner in which the bees solve the problem, it is enough to say that m passing from one form of cell to the other, they require to construct a great many rows of intermediate cells\vhich other wll "ft t' '"'"^ '^' °^^^"^^>^ ^«"«' b"<^ from each other ^hen the bees arrive at any stage in this process of tr:vtT;oMV"^^''''tP '' ''''' '''"^' -^ continue ?o build the whole of their comb upon this pattern. But they inva- r ably proceed from one stage to another until the transS effected. On this subject Kirby and Spence remark: Reaumcr, Bonnet, and other naturalists cite these irre^ui laiities as so many examples of imperfections. What woSld mTof'Jh their astonishment if they had been aware thlt pait of these anomalies had been calculated (? adaptive) • that there exists as it were a moveable harionyTn the mechanism by which the cells are composed ! . ^ It i! far more astonishing that they know how to qr4 the? ordinary rout.ne when circumstances require thai they should build male cells : that they should be instructed to vary the dimensions and the shape of each piece so as to return to a regular order; and that, after haviig constructed thirty or fnSiJnhfr "^ '''^^%''^\'^'^y again^ave the regular o^der ?n^, A ^^ were formed, and arrive by successfve diminu- tions at the point from which they set out Hpl again as observed in a former instance, the wonde; would be less If ,^,,.^ comb contained a certcvin number of transition mrtof 7t bu't1l'-''"''r'J^"'l^^^^^ ^^ '''' ^''^ the saZ part ot It; but this is far from being the case. The event whicn alone, at whatever period it may happen se'ms to of tr reen' t^ 1*° ""'^f "^^^- ''^'' - '^ -^polion the queen. So long as she continues to lay the e- ^^ ^^'^« does not build a web but en m1 f ^''"V''- 'P^^^^' ^^ich change of habit, howeve wis onlvl ^'"^ ^^ '''^^'^"- ^^^^ recovered its legs after m^rit'^R^'P.^'"'^' '^ "^^ «P'^^«r this case that, so far as Te n n.H..-. p •^'''"'' "^'^^"^ f^'O"^ the web-spinninc. spider wo'St^ ^ "''^'"'^ ^' concerned, the habit of hunting if 7or .1 ''^"^^-^^ ^">^ <^^"^« ^o adop to build a webJ^^;;a''t^^-3^^?/b!"-/^V'°l^' "^' ^' ^^^ m the life-time of an individual ^ ^ '''^'^''' transition that'rir;.^^^^^^^ - -y easily .nd sake of brevity, I shall rnnfino il* ^""^ ^^^6' ^^r the from the oldest most constant an^^if ^' ''''''''''' ^^^^^ most fixed of the instincts whLv' f f'^^'f ' P^'^^^^^bly the viz., the maternal ''^ vertebrated animals display, that^S^^^^Si ^:^^ '''^ P--^-^ chapter We have now te TZ^kthat:^o^^^^^ from the ancestral modes are not tr^'lV'"'' '' ^'"^^^'^'^^ caprice, bat sometimes'^' i^Ct^^^^^^^^^ . * See Anmal InteUwence from xc\^in\. r ing, m order to show briefly li.atTnf^Ju^ J T^ '^f """-^ 'J"°*« t''* fo"ow- present a "moving harrnonv" Jwvf ^ ^* "'"'''^ ^^s- cr more than bees " The characteristic' ^r^oJ^he bui ^^^0??' r'.'°° ""' ^'"^ archit. tare :-!! complete absence of an unclmngeab e SJ l^V r "T ^""''^^ " '' '^^ ^''"ost little perfect work to circumstances and to hI« , ^T *^ '"^^ "^^ir indeed ?v nVr '^'.^ '""'•''^ f°^ i^^elf on a given Sa^ nn.l "''"'T" "^ '^'^ situation, by others when they understand its"^ an'^t'S) " "''^^ "-"^^ionally aided bj Mr. Darwin in the Appendix. ' ^" ^'*- "^^'^ ^'^^'^ « briefly aUuded to :ii; •; ' 1 T" ■ M , M 1^: J ■ ^ 'I II, II' 210 MENTAL EVOLUTION IN ANIMALS. ( .' > > Mi iHl lUii show this, it will be sufficient to state the following in- stances. Thread and worsted are now habitually used by sundry species of birds in building their nests, instead of wool and horsehair, which in turn were no doubt originally substitutes for vegetable fibres and grasses ; this is specially noticeable in the case of the tailor-bird and Baltimore oriole, and Wilson believes that the latter improves in nest-building by practice— the older birds making the better nests. The com- mon house-sparrow furnishes another instance of intelligent adaptation of nest-building to circumstances ; for in tree°s it builds a domed nest (presumably, therefore, the ancestral type), but in towns avails itself by preference of sheltered holes in buildings, where it can afford to save time and trouble by constructing a loosely formed nest. A similar case is furnished by the gold-crested warbler, which builds an open cup-shaped nest where foliage is thick, but makes a more elaborate domed nest with a side entrance, where the site chosen is more exposed. Moreover, the chimney and house-swallows have taken to building in chimneys and under the roofs of houses by way of an intelligent or plastic change of instinct, and in America this change has taken place within the last three centuries or less. Indeed, accord- ing to Captain Elliott Coues, all the species of swallow on the American continent (with one possible exception) have modified the structure of their nests in accordance with the novel facilities afforded by the settlement of the country ; for he writes : — " Various species, indeed, now regularly accept the arti- ficial nesting-places man provides, whether by design or otherwise. Such is notably the case with several kinds of Wrens, with at least one kind of Owl, with one Bluebird, the Pewit Flycatcher, and especially the House-sparrow. Various other birds occasionally avail themselves of like privileges, still retaining in the main their original habits. But in no other case than that of the Swallows is the modification of habit so profound, or so nearly without exception throughout the entire family. ... All of our Swallows have been modified by human agency, excepting the Bank Swallow. .... Some of them, like the Purple Martin and the Violet-green Swallow, are still surviving their apprenticeship under the new re(/ime, which the settlement of the country ilr BLENDED ORIGIN, OK PLASTICITY OP INSTINCT. 211 has brought about. . . . Those whose acquired habits have become thoroughlj' ingrained are now pretty constant in their adherence to a single plan of architecture; but the Violet-green Swallow, for instance, at present nests in a very loose fashion, according to circumstances." * The statement made in 1870 by the distinf^uished naturalist Pouchet to the effect that within the same interval of half a century the house-swallow had materially altered its mode of nest-building at Eouen,t was subsequently shown by M. Noulet to be erroneous ;i- but this passage which I have quoted from Captain Elliott Coues is sufficient to show that facts analogous to those stated by M. Pouchet have occurred among many species of the swallow tribe. In " Animal Intelligence " I gave some cases of the remarkable intelligence which is displayed by certain birds when they remove their eggs or their young from places where they have been disturbed (pp. 288-9), and I added the remark that it is easy to see that if any particular bird is in- telligent enough, as in the cases quoted, to perform this adjustive action of conveying young— whether to feeding- grounds, as in the case of the hen, or from sources of danger, as m the case of partridges, blackbirds, and goat-suckers— inheritance and natural selection might develop the originally intelligent adjustment into an instinct common to the species. And it so happens that this has actually occurred in at least two species of birds— viz., the woodcock and wild duck, both of which have been repeatedly observed to ±ly with their young to and from their feeding-ground. Since writing the above, I have found among Mr. Darwin's MSS a letter from Mr. Haust, dated New Zealand, December 9th, 1862, and stating that the « Paradise Duck," which naturally or usually builds its nest along the rivers on the ground, has been observed by him on the east of tlie island when disturbed in their nests upon the ground, to build " new ones on the tops of high trees, afterwards bringing their younw ones down on their backs to the water," and exactly the same thing has been observed of the wild ducks of Guiana. § Now, if intelligent adjustment to peculiar circumstances is * mrds of Colorado Valley, pp. 292-4. + Comptes Eendus, Ixx, p. 492 I Ihid., Ixxi, p. 78. In the first edition of Animal Intelligence I quoted thig statement of Pouchet without knowing that it had been questioned § toee Oeol. Journ., vol. iv, p. 325. ii 11 212 MENTAL EVOLUTION IN ANIMALS. !, 1 'i\: ' I : , UDon t^TV^ °°^^ *^ "^^'^^ ^ bird transport her young her neft on n T v. ^."^ ""r^", ^ web:footed water-fowl build if the need nf^ ^''''J ^'"^^ ^^ ^^° ^^^^ "« do"bt that. continuLo. tt '^V'^^^'^^^f^* ^^^'« ^^ sufficiently long IT r^f ' ^ ^n^elhsenee which leads to it would eventu^ they f grSlty^: c^SeS e^nutbL^'Tt Ts^^'' in Jbati™°l"ZllT "it '"*"?' °f nidiflcation to that of expenWs wS f ^ ' '■'™ " "^ """^ observations and the iJastioity of the :nate,'ial inSLrC howa lyLTaS that the instinct was directed in all its fnrPP fn fi.o ^ Irood Me d'i? Fr'T? "''' ™""'"''" charaeterofth eS DTOoa. indeed, It is just because of this evidence thif r Sf '^T T'' \" *" P'^^'^"' »nnection (or"thenvise thev S in tSc with which'" "'""P'"'^ "o-inielligenrvariaS by the manner m which they adapted their ancestral instSs t TW ;»mias tor pmg.nj whioh .ri,e. f,„m jL. pa,„^, i„,u„c. b,i„g BLENDED ORIom. OR PLASTICITY OF INSTINCT. 213 " Spanish hens, as is notorious, scarcely ever si> nf «11 • K„f I have one purely bred one iust now f hoi o!! j ' ^^^ Ihree davs nffpr "Lj^viT ^- "^ u "^^*^ ^'^^ ^^ dumm es for Spanish chickeL"n the vLThpv'^^'^ '" "" 'he of all a"e9 from th,f »/,?l i, .1 ^ ""^^ *"""'" '" number, iefuLT«prfuiitrt:'rhfckr t-"°""", ¥,'^ j"=' tliat although there\ve°eBrahmf„n;i H ", ■•''""rl''''We, too, happens with every hen that'hatehSs out a brood of Zckli "3 5 domestic animals, is^pibably ana£ fs%l H ''P"'° '"''' ^°g^' '"'dothe; female animals adoptio'gthtyoun^^oTolL^s^e^^^ ^"^'^ ^"^ *^« *-* ^^ receWad'SLmTfS, wh^ I'^rnowt bf "^^"^ ^''^°""* ^^^''^ ^ ^-e jntbe^sesot^birdJin a -t'tTfltLltHE^rS^^^^^^^ fed ;faS S'sprot' Tldetrril: r;r^ ''''^^' r^'^^ -- ^-« and 1 noticed that the sparrow contim^ed tn i 1 ., ' ^''T^ ^'"^^ ^^^« ^>-''"«. nest. The behaviour ot' the Lo b T - "i^'^.'ifter thej had left the bold and its visits to the nest IZ.tr^ , ^^'^. dissimilar, the wren bemg its visits much less frcHluent " ' '''''' '^' 'P'^™^ "'^^ ^^'7 ^^y an! Pe.od offour months,Li ti £VS SS^^J^^,:^: ^^ i ■:' S .: II i ill' 1 i •■ ! ;■ : I ii: 'f^il=i 214 MENTAL EVOLUTION IN ANIMALS. iXli ■; i being prolonged ; for a pea-chick requires such care for a very much longer time than does an ordinary chick. As the separation between a hen and her chickens always appears to be due to the former driving away the latter when they are old enough to shift for themselves, I scarcely expected the hen in this case to prolong her period of maternal care, and indeed only tried the experiment because I thought that if she did so, the fact would be the best one imaginable to show in what a high degree hereditary instinct may be modified by peculiar individual experiences. The result was very sur- prising For the enormous period of eighteen months this old Brahma hen remained with her ever-growin" chicken and throughout the whole of that time she continired to pay It unremitting attention. She never laid any eg^s durinf^ this lengthened period of maternal supervision, anTif at any time she became accidentally separated from her charge, the distress of both mother and chicken was very great. Even- tually the separation seemed to take place on the side of the peacock ; but it is remarkable that although the mother and chicken eventually separated, they never afterwards forr^ot each other, as usually appears to be the case with hens and their chickens. So long as they remained together, the abnormal degree of pride which the mother showed in her wonderful chicken was most ludicrous ; but I have no space to enter into details. It may be stated, however, that both before and after the separation the mother was in the habit of frequently combing out the top-knot of her son— she standing on a seat or other eminence of suitable height, and he bending his head forward with evident satisfaction. This fact is peculiarly noteworthy, because the practice of combiner out the top-knot of their chickens is customary amoncr pea° hens. In conclusion, I may observe that the peacock reared by this Brahma hen turned out a finer bird in every way than did any of his brothers of the same brood which were reared by their own mother, but that on repeating the experiment next year with another Brahma hen and several pea-chickens the result was different, for the hen deserted her family at the time when it is natural for ordinary hens to do so, and in consequence all the pea-chickens miserably perished."'* u n} ^l^^^®,.*^ ^^e following instructive case from Jesse's Cleanings, T because it has been independently and uncon- • Nature, Oct. 28, 1875. f Vol. i, p. 98. s.r BLENDED ORIGIN, OR PLASTICITY OP INSTINCT. 215 Ml??VT^'''''^'^!?, ^"^"'^ ^^^^^ ^y » correspondent, Mrs. L. MacFarlane. of Glasgow. Indeed, the similaHty is so precise, that I think the two descriptions must refer to the same incident ; but as to this I cannot be sure, because upon my writing to Mrs. MacFarlane to enquire, she answers that she is not able to inform me. However, this point is immaterial; for my correspondent had the story at first hand from the lady to whom the birds belonged (and with whom she was intimately acquainted), so that if the case is not the same as the one narrated by Jesse, its repetition is so exact that the same description applies to both the cases. " A hen, who had reared three broods of ducks in three successive^ years, became habituated to their taking to the water, and would fly to a large stone in the middle of the pond, and quietly and contentedly watch her brood as thev swam about it Tlie fourth year she hatched her own e-4 and finding that her chickens did not take to the wateHis the ducklings had done, she flew to the stone in the pond, and called them to her with the utmost eagerness. This recollec- tion ot the habits of her former charge is not a little curious " My correspondent, Jlrs. MacFarlane, also gives me another closely similar but even more remarkable case, which was observed by her sister, Miss MackiUar, of Tarbert, Cantyre In this case a hen had also reared thrc3 successive broods of ducklings in successive years, and then hatched out a brood of nine chickens. The season being late, she was confined for some weeks till the chickens became strong enough to face the cold weather. Then, in the words of my correspondent, the first day she was let out she disappeared, and after a long search my sister found her beside a little stream which her successive broods of ducklings had been in the habit of frequenting. She had got four of her chickens into the stream which was fortunately very shallow at tlie time. The other five were standing on its margin, and she was endea- vouring by all sorts of coaxing hen-language, and by pushin "hi* 'such I.»n r^,,? ^ ™'*', ?' '"""'"'' "Sf" not able to follow thn hen about as young chickens would have done, in aceordance the np'/fT2 that this place was not too far away from Yet T 1^ ?'!r^* ^'' ^'^"^ ^^^"«g the cries of dfstresT feiS On tL .^ t ^f 'f growling noise of a younc. her bill, in the same way as hens in general comb out the • Vol. xi, p, 553, J i BLENDED ORIGIN, OR PLASTICITY OF INSTINCT. 217 feathers of their chickens. While engaged in this process, however, she used frequently to stop and look with one eve at tlie wriggling nest-full with an enquiring gaze expressive of astonishment. At otlxT times, also, her family gave her good reason to bo surprised; for she used often to tiy off the nest suddenly with a loud scream, an action which was doubtless due to the unaccustomed sensation of being nipped by the young ferrets m their search for the teats. It is further worth while to remark that the hen showed so much uneasi- ness of mind when the ferrets were taken from her to be fed that at one time I thought she was going to desert them' altogether. Alter tliis, therefore, the ferrets were always fed m the nest, and with this arrangement the hen was perfectly satisfied— apparently because she thought that she had some share in the feeding process. At any rate she used to cluck when she saw the milk coming, and surveyed the feeding with evident satisfaction. " A.ltogether I consider this a very remarkable case of the plasticity of instinct. The hen. it should be said, was a young one, and had never reared a brood of chickens A few months before she reared the young ferrets, she had been attacked and nearly killed by an old ferret which had escaped trom Its hutch. The young ferrets were taken from her several days before their eyes were open. " In conclusion, I may add that a few weeks before trying this experiment with the hen, I tried a similar one with a rabbit which had littered six days before .... Unlike the hen, however, the doe perceived the imposture at once and attacked the young ferret so savagely that she broke two ot Its legs before I could remove it. To have made the ex- periment parallel with the other, however, thp, two mammalian mothers should have littered on the same day." ^in •^' turning to the Mammalia, a friend of the Rev Mr. White, of Selborne, gave him an account of a leveret which he saw reared by a cat.* Pricliard gives an account of a cat that reared a puppy,t and from among many analogous instances that might be rendered, I shall only quote the lollowiug, as It is remarkable on account of displaying voluntary adoption by a cat of the young of animals which her other instmcts and constant practice had taught her to regard as prey • Biugley, Animal Biography, i, 269. f Nat. Hist, of Mankind, i, 102. :ll ir*' "T3 1 'i 218 MENTAL EVOLUTION IN ANIMALS. ' n Te™flerj„no t t 1m =»''vM*™»''"fee Maxwell of at the time brin"LuB a femntS '''°'' """ " <«" ""* »"« weeks P-viousl|SCtKfTSL^l?f ""'^ young rats, and at the time I £w th '^^.^''^ '"° ™» -whichwereconiinedinanemDtvs7»n „ *^ ''°™S rats the stable as a particX^goTd ^^4''^ ''' ""^ ^"^^ » • Mr. P. Dudgeon, 2^ature, vol. «, p. 77. If '.It , ! ■ f f 1 R I ^1 11 { ' ! * VARTATION OF INSTINCT IN DEFINITE LINES. 219 CHAPTER XIV. Instinct (continued). Modes in which Intelligence determines the Variation OF Instinct in Definite Lines. We have now seen that instincts may have what I term a blended origm-or, m other words, that intelfigent adiust- ment by going hand in hand with natural selection, iust greatly assist the latter principle in the work of forming instincts inasmuch as it supplies to natural selection varia- tions which are not merely fortuitous, but from the first adaptive. I shall next show what I conceive to be the chief modes m which intelligence thus operates, or co-operates with selection, in the formation of instincts ^Peraies in ^l^T-\ \^.f?^"^^'^l *«^«^s it is easy to see that the mode m which intelligence thus co-operates is by enabling an animal to perceive that, owing probably to some change in Sh-nr'T^T^-? T^?''^ ^^^P<^ ^^««^f ^° the existing^on- ditions of Its hfe by deviating in some degree from its ancestral instincts (as when the tailor-bird seeks for threads ot cotton instead of fibres of gr.ss wherewith to sew its nest) whtVhv '"'""^'^''^'^^^ S^^^"^ '''^ *^ ^'^J^^tive action ; r«i f I '^^P^t^tio" lead to an instinct de novo (as in the TJS f ^°"^y:g"^^f' ^hich has acquired the remarkable instinc. of attracting the attention of man, and leading him t.. -he nests of bees).* But with animals, as with men oi^gmal Ideas are not always forthcoming at the time they a, e wanted, and therefore it is often easier to imitate than whereby mteigence may change or deflect an instinct, is that of imitation. For although it is true that the iniiial stage ol such deflection occurs in the " original ideas," nothing • See Animal Intelligence, p. 315. i «n 'i ^!l I i n I :i • .:! II, 1 J 1 ' 1 1 lift: :m ... m i 1 l§ 1 3 i 1'' 1 ' , ; f 1 220 MENTAL EVOLUTION IN ANIMALS. i>'h> ,1 '!. > 'I ! • t i ^,1 !,i' further remains to be said of these. If they occur similarlv and simultaneously in a large number of ind^ivTduds Ts may be the case where the new adjustment is simple and obviouT nstTncT^ vr "'?? '^ ^°^^'"^^°^ *^ ^'^'^'^^ changing the SS; m ;'' °^^'' '^''' ^ ^"^ ^^^li^^d to thi^k that mutation may play an important part in this matter. I must confess, however, that in searching for evidence of one sS of animal imitating the beneficial habits of another, fhave been surprised at the rarity of its occurrence, although as I shall present y show, there is abundant eWdence of one ^nd^v^dual imitating the habits of another individua^-whethe? of Its own or of other species, and whether the action imitated IS beneficia or useless. This difference, I think is nrobablv Lta'tirV'r ' '^ '"' ''""'''r ^^^^^ '^ '"^ -"- iCe:nl imitation between species and spocies may have obtained in the past, we should now only see an instinct common to the two species, and therefore should have no evidence that it was not always common. Consequently, it is only in cases where the imitation by one specie! of ti'e habits oVanoth IS in It earher phases that we can find evidence of the fact W f 'm^ r *^' ^"^^ ''''' «f «^^h i^-^^itation that I have been able to meet with; but to them I add a number of cases of individual imitation, because this must evidS form the groundwork of imitation among species ^'''^''^^^ 1 quote the following from Mr. Darwin's MSS •- J^rom some experiments which I was making I had bean Tn J7/T^^ '' ^"'^^ ^^^^ ^^^« °^ '^' tall Mne^- bean and I daily saw innumerable hive-bees alightina as usual on the left wing-petel, and sucking at the moSth of the flower One morning, for the first time, I saw several humble-bees (which had been extraordinarily rare aTsummer w^hTb.'^''' ^\T' 1^1 ^ «"^ *^^^ i^ the act of cXng Svx and' tZ^ f- ^°ll' '^^''"^^ '^' "^^^^ '^^' «f the calyx, and thus sucking the nectar: all the flowers in the course of the day became perforated, and the hur^ble-bees in heir repeated visits to the flowers were thusTaved mucS beef tjfhonf r^- .^^' ""'^ "^"^ ^^y I ^-"d ^11 theCe. bees without exception, sucking through the holes which had been made by the humble-bles. hSw did the hive bees find out that all the flowers were bored, and how didThev 'o suddenly acquire the habit of using the holes ? I never saw though I have long attended to th? subject, or heard of W TARUTION OF INSTINCT IN DEFINITE LINES. 221 bees themselves boring holes. The minute holes made by the humble-bees were not visible from the mouth of the flower, where the hive-bees had hitherto invariably alighted nor do I beheve, from some experiments which I h^ave made of thf flower Th!\T' r^^^ ^Y"" ^^''""^^ ^^^ ^^^^^ ^hinV^W ft T,- l ^^^"ey-bean is also an exotic. I must hP Ll.f ^ ^'1'^''' f^^'' '^^ *^^ humble-bees cuttin ' the holes, and understood what they were doin- and imme- diately profited by their labour ; or that they merely imSd the humble-bees after they had cut the holes. anT when sucking at them. Yet I feel sure that if anyone who had not known this previous history had seen every single hive- bee, without a moment's hesitation, flying with the" utmost celerity and precision from the under side of one flower to Zl '"i ffV-^^ '"P^^^^ '""'^^'S the nectar, he wouW have declared that it was a beautiful cSse of instinct » Mr. Darwin in his MSS has also the following, observa- tions concerning the subject of imitation .— " ItTs difficult to determine how much dogs learn by experience and Sion I apprehend there can be little doubt that the manner of occ, tom. IV p. d39). I believe that certain doc^s in South America without education rush at the belly Sf the s a^ which they hunt, and that certain other do^s when fi^st taken out run round the heads of Peccaris. We are led to S?7M>t ^?T/^'"^^ ''' '"^^'^^ when we h ear f^om Sir J. Mitchell ('Australia,' vol. i. p. 292), that his dogs dS not learn how safely to seize the Emu by the neck, untU the close of his second expedition. On the other hand Mr Couch (Illustrations of Instinct,' p. 191) gives the case of a dS who learned, after a single battle with a Bad'er ?he spot lesson In the Falkland Islands it seems that the do^^s iaXlc^''?' P ''^ ."^^'^ '^' ^''' w^y «f -tt^^king the wild cattle (Sir J. Eoss, ' Voyage,' vol. ii, p. 246)." Again, Mr Darwin points out that many species of wild animals certainly learn to understand and to profit by the danger cries and signals employed by other species, and^his 18 a kind of imitation.* He also adduces a good deal of ■ill 1 H. : ' t :i*! n Hi Hi 'i ■■'!■ i ; i ! 222 MENTAL EVOLUTION IN ANIMALS. evidence to show that birds of different species, whether iu a state of nature or domestication, frequently imitate one another s song; and singing is certainly instinctive, for Couch says that he knew a gold-linch, which had never heard the song of its own species, nevertheless singing tliis song, though tentatively and imperfectly * YaiTell tells of a hawfinch that learnt the song of a blackbird, though afterwards it quite forgot this son^ which could not have happened with its natural musio.tt tact which shows that although imitation is able largely to modify instinct, its effects are not so deeply engrained as those which are stamped by heredity. Even the sparrow which naturally can scarcely be said to have a soncr will learn the song of a linnet,? and Bureau de la Malle gives the case of wild blackbirds in his garden learning a tune from a caged bird ;§ similarly, he taught a starling the Marseillaise, and from this bird all the other starlings in a canton to which he took it learned the air. In this way, too, many birds acquire the song of their foster-parents of other species || Lastly, a number of observations on wild birds in America imitating each other's music have lately been published bv Mr. E. E. rish.f ^ ^ It is certain, however, that some birds have a much greater aptitude than others, both for learning and retainincr the songs of different species. Thus a blackiaird [starling r\ has been known so well to imitate the crowing of a cock as to deceive the cocks themselves,** wliile Yarrell says the same thing ot a starlmg's power of imitating the cackling of a hen ft u- /°/T^ ^^^^ ^^^^^ ^^® notorious as regards the Mocking- bird {Turdus polyglottus), and also, at least when in a state appears serves to alarm the chickene, though the latter are not aborigines ot the country." And many similar instances might be given. 4th edp!??^'""* o/7«*««c#, p. 113. See also Bechstein, Stulenvogel, t Brit Birds vol. i, p. 486. J Descent of Man, p. 370. § Anns, des Sc. Nat., 3rd series. 2 vol. Tome x, p. 118 '^ ' ' II Barnngton, Phil. Trans., 1773, p. 264 J Bulletin of the Buffalo Society of Nat. Sc. 1881, pp. 23-6. •* Loundoun's Mag. Nat. Hist., vol. iv, p. 433 «n;!/«^f^' "^ V*"-: '■ ^.- "°^' ''^'°. *" ^^^ ^'^■' ^0'" "' PP- 229-30, where it is said on the authority ot sundry observers, that starlings in a state of nature ;lwrnwJ^'^rt"'^r''^' Pf^*"^^''' °^°°^^*'' coot, oyster-catcher! golden plover, redshank, curlew, whimbrel, herring-gull, quail, and corn crake, while Professor Newton tells me that at Cambridge he ha heard tli« Btarbngs very perfectly imitating the quacking of ducks. VAEIATION OF INSTINCT IN DEFINITE LINES 223 and that very freoupuHv «il iw T ■ I ^^^ performance, in(T OnZh .f^^l^^^y ^^ instruction is forgotten in raoult- ^L f ? ' '"-^^^^i '^^^ <^^a<^ with all such birds " it k dulness to require nine mnnf-h^ of 1!? ,- ^- ^^ unusual of the powe'TvtTta^ ion ;S thrS'^ 2*™" unquestionably that of uttering articulate wor,)^ ^ X'' subject will require to be considered mo^ ft, IW' ^'"' utterinof a caw or sorpam info fv,^ y-i^^^^^o tne instinct of or the a°peaking?f SSte" ""=""»" °' ^ '^""'"^ '™« washfng'thefr fSZil'^lt'^H' 'T- ^°™S "'i"™'- "f most p?ob„bly Tt isT ta That tttTf/"^"^"™'.'"'"' '"■ imitation is proved bV the WfW ^ •"^° ^ "<=1»'''«<' by by a cat perf^^l'^Lt'tleSr^This'™'"'"'/? observed by Audouin * «nH >,ol • [ "^^ ^"^ ^^'st corroborated byseyml observers?/' ^'%^"^^^P^^^^"^^3^ the following:- observers, of whom I may mention Bureau de la Malle gives the case nf n fn. • u- i. belonged to himself, and'which fU the ti JT?f A^'Jk .•s.teir2 :.'=.=— '5£:-S • Anns, des So. Nat, torn, xxii, p. 397. -Ij 'I P WJtH •I * .if •lit ^^^K: 224 |i: : .,' !■• . .!• i MENTAL EVOLUTION IN ANIMALS. f V.1 w >K^" *? ^^^"'^ ^'^" ^ ^''^*' ^^d ^^ ^0" a mouse or rnS fT ^ ^'' ^ove-V^^ys ; he also Kcked his paws and rubbed them over his ears. Yet if a strange cat came into of?dn^? ^",'^r^ '' T"^-* ^''''^'^'^ Si^^' -"°ther case ,/. itA T^ ^^ ^ T^ '^'"^°S ^° ^^«k its paws and wash bv MrAf /^'""'"'^f "'\^^' ''^'^ ^' communicated to me .1 / ;i • 6 1^'"^': .Another precisely similar case I find recorded m Mr. Darwin's MSS as -rT,„ipr,,-..,.f^d to him bv Professor Hoffmann of Giessen. ... : , the late DrXit{ President of Magdalen College, L observed that his tt;, n\ 1 r °: — y , Y""^o'=' '- ' ^. uoservea tnat his King Charles terrier (which had been suckled and reared by a cat from the age of three days) was as afraid of rain as wal avoid it set his paw m a wet place ; that he licked his feet two or three times a day for the purpose of washing his face which process he performed "in the true ca d^Tpo iUon sitting upon his tail;" that "he used to watch a moS ole for hours together;" and had "in short all the wayf manners and dispositions of his wet-nurse."i Lastly, anot encase Ts recorded m" Nature "§ of a dog belonging to^Mr. H Jeens which having been reared by a caf from the age of one It after the well-known manner of cats, allowing it to run a distance then pouncing upon it, and so on for maSy minutes " ?Zr:f^ S'-'^- ?'-^'T ''''''^' *'^^ ^^«^ o^ a cat learn L from a dog the medicinal use of the herb Agrostis canina I think It IS probable that the following factlwhicn quote IZJpd ?'•"'' w-^^!' ''I '^''' '^ P^^t'at least tHe attributed to imitation, though here the imitation is within the limits of the same species. witxiiu "It has been stated that lambs turned out without their mothers are very liable to eat poisonous herbs ; ai7drt seams to be certain that cattle, when first introduced into a countrT a e killed by ea mg poisonous herbs which the cattirSadv naturalized there have learnt to avoid "(| ^ It seems needless to give further instances of imitation • Anns, des Sc. Nat., torn, xxii, p. 388 t ^'?'- EH- ''/■^««*'»'^, 3rd ed., vol. i, p. 102 I Miss Mitford's Life and Letters, vol. u,y. 277 § Nature, vol. viii, p. 79. ^ II See Annls, and Mag. of Nat m»* 9„,i o„- i •• Stillinpjleet'a Tracts, p. 350. I„ reef d tn T k " ''°'\^'' P" ^^^' «°d p. 40*. ' ^ -^^ '^e^^"^ ^° ^''"ibs, see Youatt on &heep, M' VARIATION OF INSTINCT IN DEFINITE LINES. 225 among animals, but it may be said in general thaf o. iJ.. faculty of imitation depends on observation if \.f i ^^ fl-i^ u ' <^o^'nection it is interesting to observe Tw' a child begins to imitate very early in life and Xf .^ vatbnfo; tSSieli^eT^tS^^^^ o^ detailed obser- as early as the fifteenthweek SSSn .5 '^''"'*^^'''^ '""^*^™«"^ begins this action before the child rThi^acS^ll/.^'P' ^^'" '^"y^"" P^^f«™« children, and may 1 think urobablv bfj!! T *°,''°'°^ naturally to young same movement a^s sotSglT^rimZ^^^ «ith thf of such protrusion in this aniLT see Dar-'n ^ °^ ""l^'^^" ^^'^ ^ ?'«*"••« Towards the end of tlie first ^ar i^ff f • ^^P^^^^^on of Emotions, p Hl.T and more quickly le't and Se cMd tXT^J^'"?' ^''^'""^ "^''^ ""-'«'•«" ance. At twelve mouths P?evS^oh«. 11^ l^^ ^° **iei'' pertbrm- imitative movements ShaKaristron' ^^^^^ ^-^P'^'^ti^g in its dreams -e.g., blowing with the mouth Tatr stll com^flTT'^ ^^ '' ^'^''^ '^-'^ke, are performed for mere amusement «« fa a^P!*^^^ "niitative movements t With reference to SSn 'in ^PPf «"'!.! t^^^ case with monkeys, desirable here again to exnreir. "^.''?""«f «° '^'tli instinct, I think it is thatthenidificationVbirdsis due 5^ fbY ''' v > ^«^"^«^ '^«'^''^'««. the structure of the nests Tn which ?hev hav«T^ \ '''^'^f ""^^^ i'^if «ting characteristic nidification of eS species of bird ?''^'f^ been reared-the have advanced in Animal InteuL2tlT ^ H^'°^ *^"^ maintained. I thought sufficient to StiveS considerations, which I I have found auiong S Slrw,Vs MSsV'f ir'l^^''''^' ' ^"'^ «i°«« then of the test experiment whk.hSrWantehtflf''^''*' f''t^'' '^' ^««"it« " to rear young birds from the ^7^ an ScJ^V'"- ."f ^i^-Periment "o «3gg m an artibcial nest or incubator unlika I i :H 'f ; 'I- 226 MENTAL EVOLUTION IN ANIMALS. Ir^l '! But the influence of this faculty in the formation of instinct proceeds further than we have yet noted. For among the more intelligent animals it is played upon for this very purpose by the animals themselves ; the parents of each successive generation intentionally educate their young in the performance of quasi-instinctive actions. Thus, for instance, old hawks purposely educate the instinctive facul- ties of their young, so as more quickly to bring these instincts into a state of perfection. For the manner in which hawks swoop upon their prey must certainly be regarded as instinc- tive ; yet La Malle observed,* and the observation was after- wards corroborated by Brehm,t that the old birds perfected the natural instincts of their young ones in teaching them "dexterity, as well as judgment of distances, by first dropping through the air dead mice and sparrows, which the young generally failed to catch, and then bringing them live birds and letting them loose."t And analogous facts are to be observed in the case of old birds teaching the young ones to fly. We have already seen that Mr. Spalding proved such teaching to be unnecessary in the sense of not being required to develop the power of flight. This is instinctive, so that the young bird, whether or not instructed by its parents, would fly. Yet the instruction must be of some use, as in some species, at any rate, it is the natural nest, and then observe whether when adult these birds will InstinctiTely build the nest characteristic of their species. Now I find among Mr. Darwin's MSS a letter to him from Mr. Weir, which seems to set any such question at rest. Writing under the date May, 1868, Mr. Weir says as the result of a large experience of birds kept by Lim in aviaries : — " The more I reflect on Mr. Wallace's theory that birds learn to make their nests because they have been themselves reared in one, the less inclined do I feel to agree with him." He gives the following fact, which seems to be con- clusive against this theory : — " It is usual with many Canary fanciers to take out the nest constructed by the parent birds, and to place a felt nest in its place, and when the young are hatched and old enough to be handled, to place a second clean nest, also of felt, in the box, removing the other, and this is done to avoid acari. But I never knew that canaries so reared failed to make a nest when the breeding time arrived. I have on the other hand marvelled to see how like a wild bird their nests are constructed. It is cus- tomary to supply them with a small set of materials, such as moss and hair ; they use the moss for the foundation, and line with the finer materials, just as a wild goldfinch would do, although, making it in a box, the hair alone would be sufficient for the purpose. I feel convinced nest building is a true instinct." • Anns, de Sc. Nat., torn, xxii, p. 406b t Maff. Nat. Hist., vol. ii, p. 403. X Descent of Man, p. 73. fci, I ' Hf VARIATION OP INSTINCT IN DEFINITE LINES. 227 laborioualy given ; * and the only use it can be is that of developing the powers of flight more rapidly than they would develop if not thus assisted. Similarly, the singing of birds is certainly instinctive; yet It IS improved by imitation and practice— the younc* birds listening to the old and profiting by their instruction^' as IS proved by the cases previously cited of birds which liad never heard the songs of their own species yet singino- their songs, but doing so " tentatively and imperfectly." "" ° ^ Again, although terriers take to hunting rabbits instinc- tively, it is usual, as I have myself observed, for their parents to teach them, or lead on their natural instincts by imitation, whereby the hereditary aptitude develops more quickly than it would if left to itself. The Duke of Argyllf give a curious case, which he "knows to be authentic," of a golden eagle in the possession of Mr. W. Pike, Glendarry, Co. Mayo, which in the spring of 1877 laid three eggs. These Mr. Pike took away, and substituted for them two goose eggs. The eagle hatched out the two eggs. One of the goslings died, and was torn up by the eagle to feed the survivor, " who, to the gi-eat tribulation of Its foster-parent, refused to touch it. . . . The eagle, however, in the course of time, taught the goose to eat flesh^ and (the goose having free exit and ingress to the eagle's cage) always called it by a sharp bark whenever flesh is given to it, when the goose hastens to the cage, and greedily swallows all the flesh, &c., which the eagle gives it." Again, there is evidence to show that the knowledge which animals display of poisonous herbs is of the nature of a mixed instincfe, due to intelligent observation, imitation, natural selection, and transmission ; for, as Mr. Darwin points out in the Appendix, "lambs turned out without their mothers are very liable to eat poisonous herbs ; and it seems to be certain that cattle, when first introduced into a country, are killed by eating poisonous herbs, which the cattle already introduced have learnt to avoid."| In this case there is indeed no evidence of the young . * ^"^: -^"^^y g^^®8 ^° account of such laborious instruction as witnessed by hirnself m the case of the golden eagle. See Animal Intelliqence, d 290 t Nature, vol. xix, p. 554. ;, . , v <> . J Youatt on, Sheep, p. 404. j and dnnt. and Mag. Hat. HUt. 2nd apt. vol. u, p. 364, &c. ' , \ \ 1.1 nil ill f 1:1 M t' I ' ' 'I i :i!) 228 MENTAL EVOLUTION IN ANIMALS. being intentionally instructed by the old, but they are in- structed by themselves, i.e., by their individual experience. And this 18, after all, the most important point, or the point to which the intentional education by parents is subsidiary. 1 shall therefore give a few more instances to show that many instincts (usually those of obviously secondary origin) are first manifested by young animals in an imperfect, or not luHy evolved condition, and afterwards become perfected in the school of individual experience. Such cases stand in marked antithesis to those of the congenitally perfect instincts already alluded to, which have been so weU investi- gated by Mr. Spalding. It is unquestionably a true instinct that leads a ferret to thrust Its long canines tiirough the medulla oblongata of its victim ; but Professor Buchanan states* that youn^r ferrets •; instead of having for their single object to put themselves into a position to inflict the death wound, engage in conflict with rats ;" yet they had the proper instinct, though not in complete working order, for they attacked properly the medulla oblongata of dead rats. Similarly I myself observed with the ferrets which I reared under a hen, that when half- grown and put to a rabbit for the first time, they clearly knew that their attack should be directed against one end of the rabbit, but were not quite certain which ; for after some time of indecision they in the first instance attacked the rump, and only after finding this of no use tried the proper place. But of more interest stiU in this connection was the behaviour of these ferrets when half-grown towards a fowl. They had been taken away from their foster-mother the hen some weeks previously, but still no doubt retained a recoUection of her. Therefore, when presented with another hen, their hereditary instincts prompted attack, while their individual associations inhibited the prompting. There was therefore a manifest conflict of feelings, which had its ex- pression in a prolonged period of indecision. And although eventually the hereditary instincts prevailed over the ass*o- ciations formed by individual experience, the prolonged hesitation proved that the latter exerted a strong modifvinrr force. ° "^ ° Mr. Darwin says in his MSS that in 1840 he saw some chickens which had been hatched without a mother, and • Anns, and Mag. Nat. Hist., vol. xviii, p. 3/8. ^ VARIATION OP INSTINCT IN DEFINITE LINES. 22D "when exactly four hours old thev ran iumnpri .\.w i scratched the ground, and cuddledTogTtt r^ ^M hen ; aU actions beautifully instinctive." After Jvint tin-! as an instance of what I have called pure i istinct 1^ no ceeds by way of comparison to say "It m 1 1 hnvl y thought that the man'ner in whicY' fowls Sk rfilW- their beaks lifting up their heads, and aUowin-. the water to rundown by Its gravity, would have been sp'^eciallHau .ht asL'dThat' tl T^ "°'. ^\^^^ ^ "- nS Sly assured that the chickens of a brood reared by themselves C'ff IL'T^^'^ 'Vr ^^!^« t« be pressed ini a Troth but If there were older chickens present, who had learnt to at^;efth^;arr ^"^^ ^^^^^^^ ^^^^^ -vements^ Ind tU^ ^\1T^' i^V^bole. then, with reference to the modes s?y tha^ ?n Sfr' ^P^J^^^l^^^o^ifying instinct, we ma^ say that m aU cases when it does so, there must first be mtelligent perception of the desirability of the modification ac'c rdiS ^r.ot "''"^^^' "^° -°^^^> ^^:^z accordingly In some cases the principle of imitation nro- bably assis s in changing the instinct by inducing other indi- viduals of the same species, and living in the same area to follow the example of their more intelhgent commnions or the hab ts of one species sngyestinff to the members of anothe; species the modification of an instinct. Lastly, nteSnce m^y^operate by the intentional tuition of yo^uufby fhei? T.T,,-^T."*'-^T-^T *^^ ^^^^ evidence of the extreme modification which instinct maybe made to undergo by the effects of individual experience, or of changed conditio^ (^^^ li?e islhat which IS afforded by the enormou^s mass of facts o wh ch we are naturally led on by some of the cases just given • I mein the tos connected with the domesticatioi of linimds Tor the effects of domestication in modifying instincts are miZ as strongly shown as are its effects in^nodi'^^^^glt"^^^^^^^^^^ as was long ago observed by Dr. E. Darwin.^ So important and extensive a class of facts, however, require toTe con- sidered by themselves. I shall therefore now proceed to do mitation or of education operating upon instinct durina the lifetime of tlie individual. ^^i-m^ tue ■a 'jiii.i: ■ 1 I ; ■ 1 230 MENTAL EVOLUTION IN ANIMALS. t 1'. ; ■", ; . f \\-' ' W ' 1 r 1 ■ '!i:^' :;!, W<< ;Ii "I i! r , I . i iitiii (■■ \ \ ■■ CHAPTER XV. Instinct (continued^ Domestication. Fkom the nature of the case it is not to be expected that wo should obtain a great variety of instances among wild animals of new instincts acquired under human observation seemg that the conditions of their life as a rule remain pretty uniform for any periods over which human observa- tion can extend. But fortunately, from a time anterior to the beginning of history, mankind, in the practice of domestica- ting animals, has been engaged on making what we may consider a gigantic experiment on this subject. Seeing that the animals chosen for this purpose have been bred and reared under human care for a series of innumerable genera- tions, and that in some cases the members of certain " breeds " are persistently selected and trained to perform certain kinds of work, we should expect, if instincts arise by secondary means in conjunction with primary, to find evidence, not only of the dwindling of natural instincts, but also ol the formation of new and special instincts. For it IS evident that artificial education and artificial selection by man are influences the same in kind, though not in degree, as those of natural education and natural selection, to the com- bined operation of which our theory ascribes the formation of instincts. We might therefore, as I have said, expect to find among our domestic animals some evidence of the formation of what we may call artificial, or in Mr. Darwin's phraseology domestic instincts. And such evidence we do find. _ Taking first the case of the impairment or loss of natural instincts, I have already alluded to the striking example supplied by the hereditary tameness of domesticated animals. More, however, now remains to be said on this point, foi it Hi DOMESTICATION. S81 will be rememberod that previously our attention wag con- fiiiod to ciistis in which this loss is to be attributed to changed experience rdone, without the aid of selection, or to primary means unassisted by secondary. In this connection I ad- duced the cases of the Rabbit and the Duck ; I shall now adduce the cases in which artificial selection has probably- assisted mere disuse in obliterating natural wildness. The most remarkable of these instances is perhaps that supplied by the Cat, inasmuch as the nearest congener of this animal— the wild cat— is the most obstinately untame- aljle of all animals. The case of the Dog, however, is in this connection scarcely less remarkable, seeing that fierceness and distrust are such constant features in the psychology of all the wild races. Probably, too, if there were such an animal now in existence as the truly wild Horse, we should find Its disposition to resemble that of the Zebra, Quagga, or Wild Ass, the latter of which, though not so untractaTle as either of the former, is nevertheless a very different animal in this respect from our proverbially patient donkey. Simi- larly, as Handcock observes, " In the wild state kine possess acuteness of sight and smell, and a spirit of fierceness in defending their young, which disappear when, by domestica- tion, we have reduced them to a condition in which the former of these qualities would be of no value, and the latter dangerous to themselves and others." This consideration led Handcock to add the shrewd remark, " Upon the whole it seems to be established as a principle that, where there is no room for the exercise of pure instinct, either by man's interposition or otherwise, it will languish, like all the natural senses."* So much, then, to prove that instinctive wildness is eradicated from all species which have been sufficiently Ion" exposed to tlie influences of domestication. I shall now give a few facts to show that the power of domestication thus to reduce or destroy the innate tendencies of w^ld animals extends to still more special lines of psychological forma- tion. Mr. Darwin saysf " All wolves, foxes, jackals, and species of the cat genus, when kept tame, are most eager to attack poultry, sheep, and pigs ; and this tendency has been found incurable in dogs which have been brought home as puppies * Zoological Journal, p. 320. f Origin of Species, p. 211. 'i| > :'■ .1 li> ,1 L m 232 ', < , MliJ ti''''i i ■ I HI I liiU iiyiik MENTAL EVOLUTION IN ANIMALS. from such countries as Tierra del Fuego and Australia, where the savages do not keep these domestic animals.* How rarely, on the other hand, do our civilized dogs, even when quite young require to be taught not to attack poultry, sheep and pigs I7o doubt they occasionally do make an attack and are then beaten; and, if not cured, are destroyed: so that habit and some degree of selection have probably con- curred m civibzmg by inheritance our dogs. On the other hand, young chickens have lost, whoUy by habit, that fear of the dog and cat which no doubt was originaUy instinctive in them ; for I am informed by Captain Button that the youna chickens of the parent stock, ^he Gallm hankwa, wheS reared m India under a hen, are at first excessively wild So It IS with young pheasants reared in England under a hfen It IS not that chickens have lost aU fear, but fear only of dogs and cats; for if the hen gives the danger-chuckle, they will run (more especiaUy young turkeys) from under her, and conceal themselves m the surrounding thickets " The MS adds, "Pigeons are not as constantly kept as poultry, and every fancier knows how difficult it is to keep hi^ favourites sate from their incorrigible enemy— the cat." As additional evidence that instincts may be lost or as Handcock says, "languish" under domestication, it is enough to pointy to the instinct of incubation having become aborted in the Spanish hen; and to the maternal instincts havin^r similarly dwindled in cattle in certain parts of Germany where for hundreds of generations it has been the custom to remove the calves from the mothers immediately after birth t The same authority says that sheep will allow strange lambs to suck them m countries where it has long been th? custom to change lambs, which is not the case with other sheep. the foKng^S.^ ^'^^"^ '"'^'''"' '''' ^^'"^^^ " given, from which I quote ahin Ihth Sir*J%TwS?f • ^f^^ '^"^ ^™" Australia, whelped on boaid ■mp, which Sir J. Sebright tned for a year to tame, but which 'if led near sheep or poultry became quite furious.' So again Captain FitzRoy saVs thaJ not one of the n,any dogs procured from the nltiyes of Tiei™ X Juego and Patagonia which were brought to England could easily be preyented from indulgence in the most indiscriminate attack on poultry, younffSes S^ p. 1-2. Also Waterton s Essay on Nat. Hist, p. 197, for extreme wildnpso J SnLt wT '* "^^' t"" 't?^> • ^"^ tlieVss';iso conSaTe tter 5om Sir James Wilson, giving Mr. Darwin an account of a tamed Dineo whic^ obstinately persisted in killing poultry and ducka wheneyer he got Ee ^ t Stuorn, Veber Race:%, &c., s. 82. DOMESTICATION. 233 -.'■-tly according to Mr. J. Shaw, "where the dog is valued solely for food, as in the Polynesian Islands and China, it is described as an extremely stupid animal,"* and White says m his "Natural Histoiy of Selborne,"t that these dogs have lost some of what we must regard as their strongest instincts, lor though they are so strictly carnivorous animals, from' having been for so many generations fed on vegetable food they have lost their instinctive taste for flesh." Thus much, then, for what we may call the negative in- fluence of domestication, or its power of destroying natural instincts. We shall now turn to the still more striking and suggestive side of the subject, viz., the positive influence of domestication m developing new instincts not natural to the species but artificially produced by accumulative instruction through successive generations, combined with selection. And here I shall confine myself to the species of domestic animal m which these effects have been most conspicuous, viz the Dog. Doubtless the reason why these effects are most con- spicuous in the case of this animal is because his utility to man has always depended mainly upon his inteUigence, so that man has here persistently directed the influences of domestication towards an artificial shaping of that intelli- gence. For It is in this connection of interest to observe that the only features in the primitive psychology of the doer which have certainly remained unaffected by contact with man, are those features which, being neither useful nor harm- lul to man, have never been either cultivated or repressed feuch IS the case, for example, with the instincts of coverin^r excrement, rolling in filth, turning round and round to make a bed, hiding food, &c.J As evidence of the positive influences of domestication on the psychology of the dog, I may first draw attention to what occurs to me as a very suggestive case. One of the most dis- ■HT *JF^^^. sentence occurs as a quotation in a letter by Mr. Shaw to Mr. Darwin, but the reference is not supplied. t Letter 57. *i, hl"^ ¥'^^?® ^"■^f *^** ^* ^^ "°* "'^ti^ i^ i« ^«t -t all an^unusua thing to find that If a master consigns his dog to the care of a friend previously unknown to the animal, the atter wil feel quite safe under the charge of one whom he has seen to be his master's friend. For the time being the allegiance of the animal is transferred, and he feels to his master? friend not as to a stranger, but as to a deputed owneT It is not I sdS JbT^^^''^''-r^'' "PP^^^« '^ ^' ^he acquired B- stmct of barking is, as it were, an ofFshoot from this acquired instinct of property, and of protecting self as propeitv bv or'Ses'' '''^"'"" '' ' "^'^^^^ '^ the%proacVo?^tranVr^ Mr. Darwin has made a strong point of other and still more special "domestic instincts " of the dog wMch are fiXSoT;.' interesting than those above mentionrd! trom the fact of their having been intentionally bred into the instincts of the sheep-dog, retriever, and pointer. • He brieflv alludes to these cases in the "Origin of Sneciec, " A. 9nqf from which therefore I shall quote. ' fprolf^r^^ ^^ -^^^ ^^''^''f^ ^'®^^« ^f I^ogs, and see what dif- ferent tendencies are inherited, many ot^ which caimoffmm being utterly useless to the aninial, hLe blen inSed f oS their one or several wild prototypes. I have talked wS m saying that occasionally a young sheep dog without anv S aiurorr'^h^ ''''' '"^ ^"^ ^°^"d^^he flock, an J that all thorough-brea dogs can be easily taught to do this- pugnacity yet they do not worry the sheep, as auv wild canine animal of the same size wmdd do. Look aoaTnVthe Eetriever which so naturally takes to brin.nn<7back\nv object to his master. The pj. W. D. Fox iSms me tS ■U ) 1 ,1 j: . !l 1 ■■ ' I i • #1 236 i ■iJj! : f MENTAL EVOLUTION IN ANIMALS. he taught in a single morning a Eetriever six months old to fetch and carry well, and in a second morning to return on the path to search for an object left purposely behind and not seen by the dog. Yet I know from experience how difficult it is to teach the habit at least to terriers. " Let us consider one other case, though so often quoted, that of the Pointer. I have myself gone out with a young dog for the first time, and his innate tendency was shown in a ludicrous manner, for he pointed fixedly not only at the scent of game, but at sheep and large white stones ; and when he found a lark's nest, we were actually compelled to carry him along; he backed the other dogs. . . . The silence of Pointers, also, is the more remarkable, as all who have studied these dogs agree in classing them as a sub-breed of Hound, which gives tongue so freely. But the tendency in the young Pointer to back other dogs, or to point without perceiving any scent of game when they ee other dogs point, is perhaps the most singular part of ias inborn pro- pensities.* " Now if we were to see one kind of wolf, in a state of nature, running round a herd of deer, and skilfully driving them whither he liked, and another species of wolf, instead of chasing its prey, standing silent and motionless on the scent for more than half an hour with the other wolves of the pack all assuming the same statue-like attitude and cautiously approaching, we should surely call these actions instinctive. The chief characteristics of instinct seem to be fulfilled in the pointer. A young dog cannot be supposed to know why he points, any more than a butterfly why it lays its eggs on a cabbage It seems to me to make no essential difference that pointing is of no use to the dog, only to man ; for the habit has been acquired through artificial selection and training for the good of man, whereas ordinary instincts are acquired through natural selection and training exclu- sively for the animal's own good. The young pointer often points without any instruction, imitation, or experience; though, no doubt, as we have also seen sometimes to be the • "With respect to the inherited tendency to back, see St. John't Wild Sport of the Highlands, 1846, p. 116 ; Colonel Hutcliinson on Bog Breaking, 1850, p. 144; and Blaine, Ency. of Rural Sports, p. 791.— Besides the tendency to point, pointers inherit a peculiar mann»r of quartering their ground." , in; "III' DOMESTICATION. 237 case with trae instincts, he often profits by these aids More- ?ro'pensitt '' ''''^"''' " '°^'°"'^«" '^^ ^^^"'^ " The most important distinction between pointincr &c and a true instmct, is that the former is less strictly inhe'rited* and vanes greatly in the degree of its inborn peSon •• this however, is just what one might have expected fo; both mental and corporeal characters are less true in domestic c^'Sions oVlV^°"/' - «tate of nature, inasmuch as the r conditions of life are less constant and man's selection and training far less uniform, and have been continued fVan ducS?^ ^ shorter period, than is the case in nature'^pro- ^ Although the familiar fact of young pointers pointin^^' instinctively does not need further corroboraLn Jshall quotf a brief passage from the paper of Mr. Andrew Kntht on bacJiing, to what extreme mcety of detail the hereditary knowledge may m some cases extend. ^«ieuitary inrlllVLri^ ^''T'' *^^^ "^''^ 3^°""S P^i^ters, of slow and indolent breeds, wil point partridges without any previous instruction or practice. I took one of them to a spoUvTere I had just seen a covey of small partridges alight in August and amongst them I threw a piece of brSad to Induce ^0'' to move from my heels, which it had very little dispos'tioS to do at any time except in search of something to e^t. On getting among the partridges, and perceiving the scent of ^i^Uf'STf^'fr ^"ddenly fixed, and its^muscles rigid and It stood trembling with anxiety for several minutes I then caused the birds to take wing, at sight of which it exhibited strong symptoms of fear an^d noneV pleasure 1 young Springing Spaniel, under the same circumstances" ruUbrtb'off^''""'^^-'^^^^ exultation, and I do not nonP nf f the young pointer would have done so too, if none ot its ancestry had ever been beaten for sprino/nc partridges improperly." f^"'©"'© From this same paper I must quote the following and more or less analogous cases :— "^ in LI >'°""S Terrier whose parents had been much employed m destroying Polecats, and a young Springing Spaniel wh^ose \l'\ • n I 'M 1 :i -i\ \':i I i 16 Phil. Tram., 1837, p. 367. ! I .i ', , 4 ';, , 1, \i\ :i' ifiiii' 238 MENTAL EVOLUTION IN ANIMALS. n f 1 ancestry through many generations had been employed in finding Woodcocks were reared together as companions, the Terrier not having been permitted to see a Polecat or any other animal of similar character, and the Spaniel having been prevented seeing a Woodcock or other kind of game. The Terrier evinced, as soon as it perceived the scent of the Polecat, very violent anger ; and as soon as it saw the Polecat attacked it with the same degree of fury as its parents would have done. The young Spaniel, on the con- trary, looked on with indifference, but it pursued the first Woodcock it ever saw with joy and exultation, of which its companion, the Temer, did not in any degree partake. . . In several instances young and wholly inexperienced dogs appeared very nearly as expert in finding Woodcocks as their experienced parents. "Woodcocks are driven in frosty weather, as is well known, to seek their food in springs and rills of un'Vozen water, and I found that my old dogs knew about as well as I did the degree of frost which would drive the woodcocks to such places ; and this knowledge proved very troublesome to me, for I could not sufficiently restrain them. I therefore left the old experienced dogs at home, and took only the wholly inexperienced young dogs ; but to my astonishment some of them, in several instances, confined themselves as closely to the unfrozen grounds as their parents would have done. When I first observed this I suspected that woodcocks might have been upon the unfrozen ground during the preceding night, but I could not discover (as I think I should have done had this been the case) any traces of their having been there ; and as I could not do so, I was led to conclude that the young dogs were guided by feelings and propensities similar to those of their parents." Elsewhere in his essay this author remarks, " It m.ay, I think, be reasonably doubted whether any dog having the habits and propensities of the Springing Spaniel would ever have been known, if the art of shooting birds on the wing had not been acquired." Lastly, with reference to those artificial instincts of the dog, which are of this highly specialized nature — amounting, in fact, to hereditary memory of a most minute kind — I may allude to a remark made by Professor Hermann, that sporting dogs appear, when first taken out to hunt, and there- DOMESTICATION, 239 fore previous to any individual experience, to anticipate the ettects ot a gun m bringing down a bird .♦ Suggestive, however, as is the formation by man of such special canine instincts as we have now considered we have m them only, as it were, smaU details of the modification which human agency has produced in the psychology of the ^^\ } I^' "^^^^^ "^^^ ^°^^ ^^"^^ ^^^^ inan has in a sense created the remarkable structure of the greyhound or the bulldog, than that he has implanted the no less remarkable instincts of the pointer or the retriever ; but we should gain a very inadequate conception of the profound influence which he has exercised in moulding the mind of this animal were we to confane our attention to such special cases as these vw7f contrast the psychology of "the friend of man" with that of any of the wild breeds, we see at once, not only that the animal has had many of its natural instincts sup- pressed and many artificial instincts imposed, but also that it has acquired as Sir J. Sebright has observed, "an instinctive love of man But the general affection, faithfulness, and docility of the dog, are too proverbial to need special exposi- tion We have merely to observe that these qualities, so unlike anythmg with which we meet in wolves, foxes, jackals, and wild dogs generally, can only be attributed to prolon^red contact with, and selection by, his human masters ; so that as the domestic dog is at present constituted these artificiaUv imposed qualities usually lead the animal to entertain higher attection and faithfulness towards man than towards its own kind It may not be superfluous in this connection again to point out that among wild animals we do not unfrequently hnd a disposition to associate with members of other species even when no actual benefit arises from the association ; and m this accidental or useless proclivity we may distinguish the germ which m the case of the dog has been cultured into what we see— amply justifying the remark of the old writer quoted by Darwin, "A dog is the only thing on this earth that luvs you more than he luvs himself." Not only affection, faithfulness, and docility, but Hkewise all other emotional qualities of the dog which are useful to man have been developed by man to the extraordinary degree which we observe. It would be superfluous to cite, • Eandbuvh der Fhysiologie, Bd. II, Theil II, pp. 282-8. s. ! B hi: tj'^ii: " "I, tin '; h'l 240 MENTAL EVOLUTION IN ANIMALS. or even to give references to cases illustrating the exalted level to which sympathy has attained. This, together with the intelligent affection from which it springs, gives rise to a love of approbation and dread of blame, which as far as they go are in no way distinguishable from the same feelings as they occur in man himself. To this subject I shall have to return when in my next work we come to treat of the genesis of Conscience. Again, as Mr. Grant Allen has pointed out, the sense of dependence which a dog shows is very instructive. "The original dog, who was a wolf or something very like it, could not have had any such artificial feeling. He was an inde- pendent, self-reliant animal. . . . But at least as early as the days of the Danish shell-mounds, perhaps thousands of years earlier, man had learned to tame the dog." There- fore, as a result of continuous education, selection, and breed- ing, althoug-i " among a few dogs, like those of Constanti- nople, the instinct may have died out by disuse when a dog is brought up from puppyhood under a master, the instinct is fully and freely developed, and the masterless condition is thenceforth for him a thwarting and disappoint- ing of all his natural feelings and affections."* Indeed, so strong are the combined effects of long-con- tinued breeding and individual education, that they may overcome the strongest of natural instincts and desires — witness a dog which will starve rather than steal, and also the recorded cases in which even the maternal instinct has been overborne by the desire of serving a master. To give only one example of this surprising fact, I shall quote from the " Shepherd's Calendar " of the poet Hogg : — A collie belonged to a man named Steele, who was in the habit of consigning sheep to her charge without super- vision. On one occasion, says Hogg, "whether Steele reriiained behind or took another road, I know not, but, on arriv .ng home late in the evening, he was astonished to hear that his faithful animal had never made her appearance with the drove. He and his son, or servant, instantly prepared to set out by different paths in search of her, but on their going out into the streets, there was she coming with the drove, not one missing, and, marvellous to relate, she was carrying a young pup in her mouth. She had been taken in travail on • Evolutionist Ahmad, p. 182, et sej. tr: DOMESTICATION. 241 the hills, and how the poor beast had- contrived to manacre her drove in her state of suffering is beyond human calcula- tion, tor her road lay through sheep the whole way. Her master's heart smote him when he saw what she had suffered and effected; but she was nothing daunted, and, havinc/ deposited her young one in a place of safety, she again set' out full speed to the hills and brought another and another till she brought her whole litter, one by one ; but the last one was dead, _ There is still one respect— and this a most suggestive one —m which artificial instincts resemble natural instincts, over and above that of obliteration by disuse or acquirement by training and selection. In order to show this it will be suffi- cient to quote the following passage from Mr. Darwin's MSS part of which has already been published in the " Variation of Animals and Plants under Domestication " (vol. i p. 43) : — ' " It is well known that when two distinct species are crossed, the instincts are curiously blended, and vary in the successive generations, just like corporeal structures To give an example: a dog kept by Jenner (Hunter's "Animal Econoniy,' p. 325), which was grandchild, or had a quarter- blood of the jackal m it, was easily startled, was inattentive to the whistle, and would steal into fields and catch mice in a peculiar manner. Now I could give numerous examples of crosses between breeds of dogs, both having artificial instincts, m which these instincts have been most curiously blended as between the Scotch and English sheep-dog, pointer and setter : the effect, moreover, of such crosses can sometimes be traced for very many generations, as in the courage acquired by Lord Orford's famous greyhounds from a single cross with the bull-dog (" Youatt on the Dog," p. 31). On the other hand, a dash of the greyhound will give a family of sheep- dogs a tendency to hunt hares, as I was assured by an intel- ligent shepherd." Our a posteriori proof of Proposition VII is now concluded, and with its proof our considerations on the origin and' development of instinct are drawing to a close. For we have now seen that instincts may arise under the influence of natural selection alone, under that of lapsing intelligence alone, or under both these influences combined. And in m II: 'i i 242 MENTAL EVOLUTION IN ANIMALS. proving that habits intelligently acquired may, like habits acquired without intelligence, bo inherited, we have also proved, as in the analogous case of primary instincts, that tnese habits m the course of generations may vary, that their variations maybe inherited, and that the favourable variations may be fixed and further intensified by natural or artificial selection. For it is only by granting all tliese statements that we can possibly explain many of the foregoing facts Uearly man could never have produced the artificial instincts ot the dog, unless he had practically recognized the facts of variability and inheritance- a recognition which is forcibly expressed in the immense difference between the market value of a pointer or setter of important pedigree and a pointer or setter whose parentage is unknown. As Thompson well says:— ;' It would be necessary to recommence the busi- ness ot training with each successive generation, if the bodily and mental changes which the animals have undergone in the continued process of domestication had not become so en- gratted as to be propagated with them. -These acquired characteristics have gathered fresh strength in each succeed- ing generation, till at length they have assumed a perrnanent stamp. And if artificial selection is of such high importance m the formation of domestic instincts, much more must natural selection be of importance in the formation of natural instincts. LOCAL AND SPECIFIC VARIETIES OP INSTINCT. 243 CHAPTER XVL Instinct (continued). Local and Specifio Varieties of Instinct. I have now shown that instincts may arise through the mtluence of natural selection, or of lapsing inteUigenc?. or of both these principles combined; and that even fuUy formed instincts are liable to change when changing circumstances require The most striking evidence on this head, or that of the mutability of fully formed instincts, is perhaps the evidence given m the last chapter, showing the influence of domestication both m obliterating the strongest of natural and m creating the most fantastic of artificial instincts But inasmuch as we have previously seen that any considerable change in the circumstances to which an instinct is appro- priate is apt to throw the machinery of that instinct out of gear, the evidence of the mutability of instinct drawn from the effects of domestication may be open to the criticism that the changes produced are of an unnatural character, or due to an impairment of the normal apparatus of instinct. I do not myself think that if this criticism were raised it would be one of any force, seeing that domestication not only has the negative effect of impairing or destroying natural instincts but also, as I have said, the positive effect of creating artifi- cial instincts Still it is desirable to supplement the evidence drawn from the facts of domestication with further evidence drawn from the field of nature; for here, at least, no criticism of the kind which I have suggested can be advanced. T pro- pose, therefore, in this chapter to consider all the facts which 1 have been able to collect, tending to show that amon^ animals m a state of nature instincts undergo tram formations which are precisely analogous to those that they undergo ■^•■ti^ -n m^ If i if. 244 MENTAL EVOLUTION IN ANIMALS. ■fi ,! \y. 1 :!111 among animals in a state of domostioation. Tlio kind of evidence on which I rely to show this is two-fold-lst tl^ and 2ud the similar occurrence of specific varieties. Zom/ Varieties of Instinct. thnf^fHf"" ^^^^^.^tof these two divisions I shall seek to show that the mutahdity of instinct finds a most marked and su- gestive expression m certain cases where wild animals of the same species living m diiferent parts of the world (and there- fore exposed to different environments), present differencesTn their instinctive endowments of a marked and cons an? k nd One class of such cases has already been given with reference to the acquisition of an instinctive fea? of man Ty those animals in a state of nature which inhabit localities frequented by man : bu as the subject appears to me an important one seeing that a definite local variety is on its way to becom! mg a new instinct-I shall now give all the best instances which I have been able to collect icscances Beginniiig with insects, Kirby and Spence state on the authority of Sturm that the dung-beetle, which rolls ud pellets or little baUs of dung, sav°es itseif the tmuble of making the pellets when it happens to live on sleep pasures; for it then "avails itself of the pellet-shaped baffs suppl es. Here we have intelligent adaptation to peculiar thelT'.-r^' • '^.' 'f^^^^' l^^ve beeS quoted as one o the plasticity of instinct; but as sheep-pastures are definite instinct. All cases of such local variation must have some determining cause, and doubtless most frequently this cau e IS intehgent adaptation to peculiar local conditions. There! fore I have chosen this case to lead off with iust because it 7^lr^^ ^"^ ^" ^"'''^ ^° '^' '' ^" the previous Again it is stated by Lor.fciere, in his history of Siam that in one part of that kingdom., which lies open to 4at' munda ions, all the ants made their settlements upon treet- no ants nests are to be seen anywhere else." And Forel states a closely similar fact with reference to a species o European ant, lasms accrhorum, which on the plains is never LOCAL AND SPECIFIC VARIETIES OP INSTINCT. 245 fouiid to build under stones, while in the Alps it frequently builds under the same stones as the Myrmica '=*i"«"''^y ana Laiitoima the hive-bees when introduced " retain their ndustrious habits only for the first two or three years. After that time they gradually cease to collect honey till thev become wholly idle."* Again. Mr. Packard, jun.. recoils some observationsf which were made by the Kev L Thonm- son whom he designates "a careful observer." of bees (Apia mellzfica) eatw^^ motlis which were entrapped in certain wrnr;T,«?iJ !f/^f ^'"'^ communicated to Mr. Darwin, he wrote, that he "had never heard of bees being in any way carnivorous, and the fact is to me incredible. Is it possible that the bees opened the bodies of the Flusia to suck the nectar contained in their bodies ? Such a degree of reason would require confirmation, and would be very wonderful'' But whatever the object of the bees may have been their actions, which are described as "suddenly dartin-'' and lurious. certainly display some marked variation of Instinct under the guidance of intelligence. Moreover, the explana- tion entertained by Messrs. Thompson and Packard-viz that the bees were partly carnivorous, is perhaps not so incredible as it appeared to Mr. Darwiu. if we remember tastesT'^' ^'^ unquestionably apt to develop carnivoroua Turning now to local variations of instinct in Birds I may first allude to the foUowing instances in the Append^ which although not adduced in this connection by Mr' Darwin, are no less apposite to it. ^ A-w"^^i^ "°^o"ous that the same species of bird has sliohtly different vocal powers in diflerent districts; and an excellent observer remarks, 'an Irish covey of partridges sprincrs with- out uttering a cal . whilst on the opposite Soasttlie" Scotch 8a>s that Irom many years' experience he is certain that in •KivhA'!!^^ ^"^'"''ff'ff' P- 188, where see for references to Dr. E. Darwin Kirby and Spenco, and later writers on this matter. -L'arwin. T American Naturalist, Jan. 1880 Tations'of ?h;Srh' «°^- n^'^P.f^l' *^*' ^^^' *"^ 663, detaihng obser- Bod!and wl'a.Sith^.^" ^' ^^^^^'burn. Messrs. Newall, F.eI, Lewi. § W. Thompson, in Wat. Hist. Ireland, vol, ii, p 65 savs he hn.R nH««. .. i this, and that it is weU known to sportsmen. ^ ' ^ oh^ovy^d ■M-l* ( .. \'' 246 MENTAL EVOLUTION IN ANIMALS. f f 1 . Vnl nl'hfof t^tlf//'"'^'"'^ -^"/^"^ ^^ *^« middle of the hented!^'* ^^ '''''' "" ^^^"' ^°^ ^« ^^^^tly in- Professor Newton informs me that the Eing-plover on ^sVafsT;:rot'""" ''/-''''''' ^^^ Suffolk'hTbltually aisplays a yeiy curious and instructive case. These birdi naturally Md on the sea-shore, depositing their ea.s in a hollow which they scoop out in the shinSe The°sea has wS W f ''''"" *'^ 'f'^''^' sand^unes in qrstion which have become covered with grass. Apparentlv the Emg-plovers have gone on breeding for numberiess 'enera! tK)ns on the site which was at one time the sea cr^^t thl distance between them and the sea having therefore ^^^^^^^^^^ increased more and more.f Hence the birds are n^rS on wide grassy surfaces instead of on shingle but the^? mstmct of laymg their eggs on stones remains fso that after having scooped out a hollow in the ground, they collect small stones from all quarters and deposit'them in the^hoUow This has the effect of rendering their nests very conspSs and tiie fact shows m a striking way how a fixed ancestoUnstinct may, while m the main persisting under changed condit ons oLaS- ^"^^^?^^le«« ?o vary in reference to these changed conditions as to constitute the beginning of a new instinct r,.,f H -S'^^'V"'^^"'.'' °^^°^^1 ^^ri^tion in the instincts of nest-bui ding, I may in this connection again refer to the tS 'TT'^'t '''^' P^^^^^^^ly ^^^tioned i^ illus! tration of the plasticity of instinct under the mou din. influence of intelligence.J I allude to the fact thaTon hf American Continent various species of birds-notably a kind of Owl, a Blue-bird, the Pewit Flycatcher, several specTes fri Yfl ^""^ ""^^'^y ^^1 *^« species of Swallow-have adapted the structure of their nests to the artificiallstina! places provided by man, in just the same way (though more gradually and on a much larger scale) as did he cSlonTof Palm-swifts m Jamaica. But with still more speciaSr- fere:t^"iSLT24'''' "^ ^"^ ^^^'^"^ ^^^^ ^^ singing in dif. X^leX^^"""' ^' ^'^' ^'"^P'^^ '^'' °^'"y «^ *^« '"^^e^ given i:: ... LOCAL AND SPECIFIC VARIETIES OP INSTINCT. 247 ence to the local variation of instinct, I may here quote a further statement from Captain Coues' work previously cited; for it shows that even on different parts of the American Continent the same species of birds exhibit these differences m their mode of nest-building. He says:—" There is no question of the fact that some of the Swallows which in the East now invariably avail themselves of the accommo dation man furnishes, in the West live still in holes in trees, rocks, or the ground ;" and he proceeds to give several special mstances.* Lastly, the fact has already been noted that House-sparrows exhibit a similar local variation of instinct wherever they come into contact with the dwellinos of man.t ° _ Passing on now to other animals, we find several instruc- tive cases of the local variation of instinct among the Mam- malia. Thus the curious habit Las been observed amon^ cattle inhabiting certain districts of sucking bones. Arch° bishop Whately made this the subject of a communication to the Dublin Natural History Society many years aero Eecently it has been observed by Mr. Donovan of cattlein mtal,t and by Mr. Le Conte, of cattle in the United States.5 Probably this habit is induced by the absence of some con- stituent of food in the grass which is supplied by the bones and therefore if the habit happened to prove beneficial to the cattle (instead of deleterious as Whately asserts), it is easy to see that cattle in a state of nature might become trans- muted from herbivorous to omnivorous, or even purely car- nivorous. Probably the ancestors of the Pig have ppssed ttirough the former of these stages. On the other hand, the Bear seems to be in process of becoming omnivorous from the contrary direction— being carnivorous in its affinities but not infrequently adopting the habit of eating grass and herbs. And in this connection I may refer to an interesting case of transition from herbivorous to carnivorous habits which was published at the Academy of Natural Science of Phila- TiT *£i^' "'i'' ?;.^^,*' ^^'^ ^^*' ^ *^'"''' *®"^^ '« confirm the statement of Mr. Edward {Zool p. 6842) that on the coast of Banffshire the house- flwallow presents a local instinct of building in caves and on proiecting rocks t When house-sparrows build in trees— wliich they occasionally do and which must be regarded as reversion to primitive instinct-" the stmcture i« Tery large more than a yard in circumfeience, and covered with a dome." (larrel's Brituh Birds, 4tli Ed., Pt. X, p. 90.) X Nature, vol, xx, p. 457. § Ibid. ■t A I if hM III 'I I •* 1. H 248 MENTAL EVOLUTION IN ANIMALS. (<) » ' delphia on February 18th, 1873, by Mr. W. K. G. Gentry. A rodent popularly known as the Chickaree (Scinus hwlsmius), IdZL ^ T^ ^^ •'l'.^^? '' °°^°^^"y herbivorous, has adopted m the neighbourhood of Mount Airy a habit common among the Mustelidw, of climbing trees for the pur- pose of catching birds and sucking their blood. Mr. Gentry suggests that this transition from herbivorous to carnivorous Habits may have arisen from the propensity shown by some Et'/.'"f ^"^ '^' ^P.^f birds-the passage from this habit to that of suckmg the blood of birds bein| but small, i^astly m this connection I may adduce a precisely analogous case of a marked local variation of instinct taking place in a species of bird. ° ^ Mr I. H. Potts, writing from Ohinitahi to " Nature" (Feb- !!!M7 f ' .?' 'T, *^^^ *^^ mountain parrot (Nestor notahhs) was then exhibiting a "progressive development of change m habits from the simple tastes of a honey-eater to the savageness of a tearer of flesh." For « the birds come in flocks, single out a sheep at random, and each ahghting on ilL^^f^/fi,*'''''^ *'f' °^* *^^ ^°°1' ^"^ makes the sheep bleed till the animal runs away from the rest of the sheep. Ihe birds then pursue it, and force it to run about tOl it becomes stupid and exhausted. If in that state it throws Itself down, and lies as much as possible on its back to keep the birds from picking the part attacked, they then pick a tresh hole in its side, and the sheep, when so set upon, in some instances dies . . Here we have an indigenous species making use of a recently imported aid for subsistence, at the cost ot a vast change in its natural habits." Since this account was written the change of habits in question has jlZl T?!^.^ 1^1 ''''°"' ^^^^^^ ^" the sheep-farmers. It appears that the birds prefer the fat parts of the£ victims and have learnt to bore into the abdominal cavity straight down upon the fat of the kidneys, thus of course kilHng the Another case of local variation of instinct is furnished by the statement of Adamson. that in the island of Sor rabbits do not burrow. This statement, however, although accepted by Dr. E. Darwin, has not, so far as I know, been either con- firmed or refuted. But with reference to variations in the instinct of burrowing, I may allude with more confidence to the case given by Mr. Darwin in the Appendix on the LOCAL AND SPECIFIC VARIETIES OF INSTINCT. 249 authority of Dr. Andrew Smith, viz., " that in the uninhabited parts of South Africa the hyaenas do not live in burrows, whilst in the inhabited and disturbed parts they do. Several mammals and birds usually inhabit burrows made by other species, but when such do not exist they excavate their own habitations." In " Animal Intelligence " I stated, under the authority of Dr. Newbury's Eeport on the Zoology of Oregon and California, that the beavers in those districts exhibit the peculiarity of never constructing dams, and seeing that the building of these structures may be regarded as one of the strongest instincts manifested by the species, I supposed the failure of the Oregon and Californian beavers in mani- festmg this instinct to constitute a remarkable case of the local variation of instinct. Professor Moseley, however, who has travelled in Oregon, now writes me that this absence of beaver dams is in his opinion due simply to the severity with which the nnimals are trapped. "What few beavers that remam are too constantly liable to interruption to be able to construct dams, or for this to be worth their while. They thus live a more or less vagrant life about the streams." It will be observed, however, that Professor Moseley speaks of " the few beavers that remain," whereas Dr. Newbury says of the same districts : — " We found the beavers in numbers of which, when applied to beavers, I had no conception." Therefore' I infer that since the time when Dr. Newbury's Pteport was published, the number of the beavers must have been greatly reduced by trapping. But if so, at the time when the Eeport was pubhshed, Professor Moseley's explanation of the absence ^ dams can scarcely have applied to the facts of the case. Hence, I am still disposed to think that we have in this case an instance of the local variation of instinct — seeing that the variation of habit was remarkable even before the introduc- tion of the disturbing elements to which Professor Moseley now alludes. Be this as it may, however, it is certain that the solitary beavers of Europe present a striking local varia- tion of instinct, not only in having lost their social habits, but also in having ceased to build either lodges or dams. The last instance of the local variation of instinct which I have to adduce is one which has already attracted a good deal of attention ; I refer to the barking of dogs.* The habit • A BomewLat analogous instance seems to be supplied by the"cat-a' ^^K i f' ' 1! 250 MENTAL EVOLUTION IN ANIMALS. i! M f : ft' ,' of barking, althougn perhaps acquired as a result of domesti- cation IS so innate and general among most of the breeds that It deserves to be regarded as an instinct. Yet Ulloa noticed that in Juan Fernandez the dogs did not attempt to bark till taught to do so by the importation of somedo-^s Irom Europe— their first attempts being strange and un- natural Linnaeus records that the dogs of South America did not bark at strangers. Hancock says that European dogs when conveyed to Guinea "in three or four generations cease to bark and only howl like the dogs natives of that coast Lastly, it is now well known that the dogs of Labrador are silent as to barking. So that the habit of bark- ing, which IS so general among domestic docs as to be of the nature of an instinct, is nevertheless seen to vary with geographical position. '' Specific Variations of Instinct. To the above instances of the local variations of instinct I shall now add a few cases of what we may caU specific variations of mstinct-that is to say, instincts which occur in a species of a character strikingly different from the instincts which occur m the rest of the genus. After what has been said on the local variations of instinct, the attesti value of tlie cases which we are about to consider must be evident. For we should expect that if the conditions which determine a local variation of instinct are constant over a sufficient lengt ■ ri time, the variation should become fixed by here- dity and so give rise to a change of instinct in the species afiected— which change ought to become observable in the contrast exhibited by the instincts of this species and those of the rest of its allies. This head of evidence becomes of special value when we remember that it is the nearest approach we can hope to obtain of anything resembling a paheontology of instincts. Instincts, unlike structures, do not occur in a fossil state, and therefore in the course of their modification they do not leave behind them any permanent record, or tangible evidence, of their transformatioHs But we obtain evidence of transformation almost as conclusive in the cases to which I now allude; for if a living species wallings" of cats; for, accordinc; to Roulin (quoted by Dr. Carpenter in LOCAL AND SPECIFIC VARIETIES OF INSTINCT. 251 inhabiting a certain restricted area exhibits a marked depar- ture irom the instincts elsewhere characteristic of its cenus we can scarcely question that the departure is indeed a departuTe~%.e., that originally the instincts were the same as those occurring in the rest of the genus, but that owincr to peculiar local conditions, local variations of instinct arose and were continued till they became hereditary, and so led to Qpartmgaway of the instincts of this species from those or its allies.* For the sake of brevity I shall here confine my instances to those which may be drawn from Birds. The following concise statement of facts relating to the strong mstinct of parasitism in the only two genera oi birds where it is known to occur, is quoted from an Editorial note m 'Land and Water" (Sep. 7, 1867). and displays very remarkable and instructive cross-relations as rec^ards the existence and absence of this instinct in the sundry species composing these two genera. " The only non-cuculine genus of birds known up to the present time, which has the habit of entrusting its e4 to the charge of strangers, is that of the cow-buntings (Mdothrus) and the parasitic habit of M. pecoris of North America has been amply described by the ornithologists cited by our correspondent. There are several other species of this genus and the same parasitic habit was observed in another of them by Mr. Darwin. The Molothri are birds belonging to the great American family of Cassicidce, which corresponds to that of SturmdcB m the Old World; and they are nearly akm to txie troopials (Agelaius). It is remarkable that not any ot the various American Cuculidce are parasitic: whereas several genera of this family inhabiting the major continent and its islands, with Austraha, are now well known to be so. * From the above remarks it will appear that t do not agree with Mr. Darwm in h>8 view, expressed in the Appendix, that cases o^spedfio variation of mstmct are difficulties in the way of his theory of the Sal development or evolution of instincts. On the contrary.^for the ^na given above, I regard such cases as corroborations of ths theory 2 source of this diflerence of opinion is, that while Mr. Darwin is Ybove all nZct"l"eTtwf ' "''r^^ f 'T''''''.^ ^^""^^ '^ *^^ formation of fn instinct, 1 feel that to expect such evidence in every case of instinct would be unreasonab e, if not inconsistent with the tlieoiy that innumerabTe !n stincts owe their present existence to the destruction through nau'ialselec. tion 01 the animals which presented them in a lesser degree oipexSi)nI Khali recur to this pomt in a future chapter. i'oiict.uon. * M 252 MENTAL EVOLUTION IN ANIMALS. ■f ■ ) ■ HI !li 't , ( 1 Pirst, there are the very numerous species of true Cuculus, with Its immediate sub-divisions, inhabitants chiefly of Southern Asia, Africa, and Australia. Secondly, the crfested cuckoos {Coccystes), exemplified by C. glandarius, which is common enough in Spain, and has been known to stray into this country. This bird deposits its eggs in the nests of mag- pies and crows. Another species (C. melanoleums), which is very common m India, selects for this purpose the nests of a particularly noisy and familiar group of birds in that part of the world often called 'dire-birds' {Malacocercus) ; and as the latter la,y a spotless blue egg, similar in colour to that of the hedge-chanter {Accentoi' mochilaris) of Europe, the e^cr of the particular cuckoo which seeks their nests is of a nearly similar spotless greenish-blue colour. Another very common Indian bird of this family is the koel {Eudynamis orientalis) the male of jiuch is coal-black, with a ruby eye. and the female beautifully speckled. A pair, in fine condition, may now be seen m one of the aviaries in the Zoological Gardens. Ihe Indian koel mvaiably deposits its egg in a crow's nest, and the egg is not unlike that of a crow in its colouring and markings. Several other species of koel inhabit the Asiatic islands, and there is one in Australia; and as the koels are not migratory birds, it follows that the parasitic habit is in- dependent of any migratory necessity. That extraordinary cuculme bird, the Australian channel-biU {Scythrops nmce- fioilandia;), is known to be parasitic, for the young have been repeatedly seen tended and fed by birds of other species ; and therefore it is a lapsus pennm on the part of Mr. Gould, in his Handbook of the Birds of Australia.' describing a speci- men ot it as having been an 'incubating female !" But the coucals {Centropus), very common and conspicuous birds in bouthern Asia, Africa, and Australia, are not parasitic • neither, we have reason to believe, are the extensive malkoha series {Fhcenicophaus and kindred genera), which inhabit the same geographical area. Among the American Cuculidce, the species of Coccyzus are nearly akin to the crested cuckoos {Loccystes) oi the major continent; and these, like the^Q,vQ,. aitic Cuculidce, produce their eggs at considerable intervals so that eggs and young of different ages are found in the same nest ; while more advanced young, that had quitted the nest, are still fed by their parents while keeping to the immediate vicinity of the nest; as may likewise be observed LOCAL AND SPECIFIC VARIETIES OF INSTINCT. 253 of the screech-owls (>SX:f hel^^^^^^^^^ .^^ "direct out of reflex action T?nw^?ifl u ^^f""''® immediately mind-element arosp anrl if a,^ t\t o , -^ ^ which the present a PossiTthX d" i^ifcK^t ST'"* T instincts— or instincts nf fi.o i^ 7 ^ ?* *^® simpler taken origin T s thi?d mnH ^^^^^.^J^^als-may have converse ^r oppo te of t^at wb-'l^^ be observed, is the lapsing of intellSce- it i« f /^ we have called the cuLnates in coS^^^^^^ «P to. or ceases to be reflex and Wnn!. • f-.x *^'^^® ^he action sce„di„« „. bet^^de SUol^Slo rS* "Lf that such a process may take place is I tbinV ^f Ji ■'■ grounds very probable, although^ fro AL t^^i^^^^^^^^ f/'^''^ It IS not possible to find proof 1,f itsTcc^e for ifif 7'' cipiently pre enf ThpJ 1 ?1 ^^^s^io^sness even if in- 'III f|; .^•'i' |i it a iii ,«'! iil '1!; ■ \ Ml- ; J. f '■ > I' 1 s'u f ' : l-y ''!;. r' ■j ; 'i ;. ■ i, ■ Mi I 1 ' :''■ 262 MENTAL EVOLUTION IN ANIMALS. ir h:i , mnH^I'^" *!!^ /^^S'^ ^""^ *^^ instinctive, this possible third mode in which rudimentary instincts may arise need not cla m fmnlr ^^^^°"^^ f^^ subject IS, as we have seen, of much importance m relation to the origin of consciousness It only remains to point out that if instincts ever do nirir'T' ''^''^r^^'^t -plication wouldTpea? must « W«\^'''''' admits, that "survival of the fittest must always be a co-operating cause." I should, however even here be inclined to go further, and to say that survTval of the fittest must m this co-operation be of more than the subordinate importance which Mr. Spencer attributes ?o it fCCl^rV^'''^ "S"^°,'^^ '^'^ «^ '^'^ Medusa seeking the light, and supposing the action to have become dimly t^s::^tL'll!^"fr"'^'°^*^"^^^^^ ^^^^^^^^ ^^-^^y to seek the light first began to manifest itself, and the indi- viduals which sought the light were therebv enabled to nro SdTonc:!'''^ 'H"'^? ^^^ not," natural sd'ecK would at once begin to develop the reflex association between luminous stmitdation and movement towards light. HerTin brSina'v^'f "^'"'^"^ "^ ^7 ''^'' ^^"«« «f ^ directly equii^ bratmg kind seems out of the question, inasmuch L apart couTdKor>T'''-^^;'^ ^ '^^^^^^^-' i« absent' there light and the obtainmg of food in the light. Only by natural selection could such a bond hav. here been established and the same considerations apply to many or most of the Quas:U instinctive actions exhibited by low animals. ^ bo much then for the view which would regard aU in- s incts as outgrowths of reflex action. But scarcely less objectionable is the other extreme view which woS rec/aS all instincts as outgrowths of intelligence. This as I have tne Duke of Argyll, who seems never to have read Mr S eXn* Bu?r' '!i' ^rtP"^-^ of instincts by Taturai selection.* But be individual opinion what it may surely it IS suftici^ntly evident, as pointed out at the commencernent of our discussion, that to assign aU instincts to an inSent ( ( EXAHIINATION OP THE THEORIES OF OTHER WRITERS. 263 on^fhil^lT^r.^*^'"'^*,^* ^.^^^°« ^ ^^lid explanation of one thing a satisfactory explanation of another ,.^f^''''i''''^'''S. then, in the light of all the foregoincr facts both the principles Avhich are concerned in the development' Ba^^r """^ P*'' ^"^ ^"^ '^'^' ^^" opinion of Mr. In the « Origin of Species " he writes (pp. 206-7^ " Tt p?n'h?T ^^^^,^^itf 1 action to become inherited-and it can be shown that this does sometimes happen-then the Sot l'' ^''^''"^ 7^^^ '"'S^'^^^y ^^« ^ habit and an Mnl..f • TT/^i '^.°'" ^^ ^°* *« h« distinguished. If Mozart, instead of playing the pianoforte at thrle years old with wonderfully little practice, had played a tune with no practice at all, he might truly be said to have done so instinc- tively.* But It would be a serious error to suppose that the greater number of instincts have been acquired by habit in one generation, and then transmitted by i^eritance to sue ceeding generations. It can be clearly shown that the most rbnf'1'1.'"?^"''?^^'^ ^^''^ ^« are acquaLted namely those of the hive-bee and of many ants, could not posS have been acquired by habit. possiDiy . " It will be universally admitted that instincts are as important as corporeal structures for the welfare of each species, under its present conditions of life. Under chanS conditions of life, it is at least possible that slight modla^ en. r^'^^'i f «^'- ^' P^^^^^^l^ '^ ^ species Tnd tfit see .n% r^^u*^^* '^'^"'1^ ^" ^^^^ ^^^^ «« little, then I can see no difficulty in natural selection preserving and continu- ally accumulating variations of instinct to aSy extent hat was profitable It is thus, I believe, that all the more com- plex and wonderful instincts have Originated. As modSl usenr b«V?'''^^ structures arise from^ and are increased by, noHoubt 'htl''' ^^T^^i'^hed or lost by disuse, so I d^o effltrnf hk f ''•'' ""'^^ '^'^'"'^'- ^^<^ I ^^elieve that the to the Pfftt T 't "^r^ r^'^ °^ subordinate importance to ihe effects of natural selection of what may be called spontaneous variations of instincts ;_that is of^ariattlns ,.'r i;r 1 1 f ' 1 i ' ■•.r ; n^ 264 MENTAL EVOLUTION IN ANIMALS. produced by the same unknown causes which produce slicrht deviation of bodily structure." proauce siigiit Again in the "Descent of Man," he repeats substantiflllv the same judgment (pp. 67-8); and among h MSsTfin^ the following passage, which I shaU quote because it serves to " iuK^^^^^ ^'^"r^^ t'^^^^ emphatic manner Altliough, as I have attempted to show there is a strik- ing and close paraUelism between habits and instincts Ind a hough habitual actions and states of min^do hecome here^ di ary, and may then, as far as I can see, most Tronerlv be called instinctive; yet it would be, I beCe the Stest ZlX ^k\'' fl ^'''' ^-Jo^ity of instincts as Sred through habit and become hereditary. I believe fW rnlf tion, of shght and profitable modifications of other instS- which modifications I look at as due to the same causes which produce variations in corporeal structure Indeed I suppose that it will hardly be doubted, when an ins^rnctiVe strengthened and perfected by habit; just in the samd manner as we may select corporeal structures ^onducin'^o fleetness of pace, but likewise improve this quality by train^ ing in each generation." lu^xiuy uy craiu- From these quotations it is evident that Mr Darwin SclfonTfo?' ?°'' ''^ ''^''^^'' intelligence and nat^S selection as operating causes in the formation of instinct but that he regarded natural selection as the more impor ant of the two Although, however, he does not exp Sslv say so I cannot doubt-in fact I know-that he fuUy Seized inVu7h:f Sr fo?^^^^^^^^ in supplying adap'tivT^dt iin uisnea Horn fortuitous variations to be seized unon hv natural selection. Viewed in this relation, natural se^^ction may be deemed a promoting cause of the apsin-r of L'^m gence in 3 mstinct, and the two principles workin' in con 'aC B^ff'l '''"'' l^r'' P-^-'than eiS iorkh " alonj. But if I were asked which of the two I deem morP important, I should say that natural selection must be Lw to slight itiall)' [ find ves to mner. strik- ; and here- ly be 3atest Hired most 3elec- ncts ; auses ied. I ctive lified I the gical a any d in been same g to :ain- ural net; tant say zed dis- by "ion !lli- on- ing ore [to ; I'' , ■, ;j s 1 !i *■ ( t ; ,r :r:( n m ■ 'h iMM Ml i i' "e- r L sx A r: r I o H . I f.TELLI C [ K '" f. C T I O N EXAMINATION OP THE THEORIES OP OTHER WRITERS. 265 tion of all the reasons whicTlTave now ^t^^^^^^ T^^T truest judgment-and this without referTncPtn Vl« *^^ proachable authority upon the subierf wS ?v • u v^"" '"''^P' held to speak. ^ ^^^^ ^^^^^ ^^ must be General Summary on Instinct. instincts) are able to .nrin^ w ^^, ""^ definition of senfpH flot? u- P "°- ^®^"® a^icl there i have renre- thaffnllvflV^ !" important additional priinmle viz circumstances leading to an ^n^lZ^J^J^^ ants, are sterile. Lewes can neVer havo W .^'■'''^*''l'. ^^^ '^'^o^g bees and his mind, for it proves his theory Slamlnl r,'^.'''^^^' '^^^'^ Presented to It is hkewise ineompatible with VncS" Lo^'^^'^m''^'' "^^^^ writes :-" The automatic actions of a hi K°^- ''"'' ^*''" »°»tance, ho ans^ver to outer relations so ciantlvexnPviJ".? f? °^ ^*« ^"^^ ''^^l^. organically remembered " (PW«S/?v o^P.^'T'^"^'^ ""'*/''7 ^'••^' '^^ i* *ere as Lewes also forgot, that^Se nS ^hfchtlf"^^' ''F{ ^*'^- ^"* ^' ^°'SetB' has not thus "constantly expLienced" - ''^^ automatic actions perfonning these actior.f betbreirhas itseff T^"" ""'^^'T'' f"'" i* begins by cell-makinl. and u-itliout its mrents ev« hLw I*""/ "^'^"'"^"^l experience of In the whole range of instiJct'^o m. ^ unZiii'lIC":-'^' '^-porU^ce. been chosen by iVIr Snenc.T .in^^ih^ u'wrtunate illustration could have ifii ill! fl^li ji 111 266 MENTAL EVOLUTION IN ANIMALS. ki. I have ilned the ttoZX t^^^^^^^^^^ ^^^'^Y' order to represent the farf- Hiof f f^^r'^^ ^^ their summits in adaptation^ or primLvLrl ^°*^^>°t and non-inteUigent together and then possess a Z''''^ ^"■^'^"^'^' ^^^ f"«e ^ further growth. I have To t ' ""?". '^P °^ P^^^'^^P^e of the two sides of the dia^ Sr''^'^'^ ""^°^ ^^^ween place at one othe^po nS/ i^'^ and secondary, to take Instinct and the brSlSl, ?v *^^ ^"^^^^ ^""^''^ry Instinct. I do this trbri„?o\ tS ^'" '^ ^''°^^''^ ' fact that when once a noni?ii-" V^'°°«.''P"°^in^ the been formed, it is most readv tn^n^ *vT ^T^'^^ '""'^^^^ has by the principle oHnteSetn^^^^^ principle is, as it were, ^bHr LtZf^'. ^^^^^^ '^'' into secondary instinct PmfV^! /^-^ ^""^^ ^^^ ^o^en remember is that whether inst n J^'^^'V? P"^^^'^°* ^^'^S to a non-intelligent mode of oS th ' ^'^ '"^ intelligent or their fuU formation come into°contnnf^ >^^^ f n-"^ '^^ ^^^^^ point; so that theTo s^'s'^f^'^^^ embodiment of aU the foreioiL f T ^^°'^"^ (^^'^S the illustrate at once the 3' "/I^^T? ^P^" *^e subject) opinion which has been so n^^on '^' ^f''^y'^ the common he sar of instinct and rein Stw'^'^.i^^ ^^P^' ^^^^^ separate, yet for ever LZT ^ '^ ^^'"^' "^^^ ^ver precLtg'cCte'rsTl^^^^^^^^^^^ ^ ^"^-^ — y of aU the Instfn^rilLrfded^^^ ^^-e I use the word tion of instinct as exSd tV ^"^^^^^^^ animals without indivX« 1 ^ ^^'^ ^°""« animals, or by to which their ins LXt^^^^^^^^^ ^^^ circumstance! a few complementary mLtrSs of H '^'''^' .^^^^ ^ g^^« stmct, and pointed out tW . t ° the imperfection of in- either from Lhange-n the eoSr^ "^'S^' ^"«e. which the ancestral in.h-nnf ''°''^' ^^^^^ ^^ the environment to the instinctTno ye"^^^^^^^^^^ ^\^^om the fact that mperfection of instinct St ^if"?'^' -^ ^^'' '^^^'^^ that K( EXAMINATION OF THE THEORIES OP OTHER WRITERS. 267 interrupted for a time anrarr rented TZT'"'''' '' case of such derangement wh^vJlh -i / ^^^'^^ gave one interruption and whir^\pT.f ^'^ ^^^ ^^^^ "^^ such regardeLs^caseof i^tnt ' ""'^ "'"' ^''^'''^ ^' with'lr^e-^eVin^^a^^^^^^^^ ^^ -t young chickens beirffihCVr^"^'^ '' «^^«. instead of runninTaw^ r^m'^ltTs't'l^^^^^ also see instincts in course of ZTT' 1 ""■ ^ ^ "^^>^ children learning to bahnpp ft J ^^^P^^^nf, among young Moreover all causes of tl^p.^ . ' ^"^ "^^'^^^ ^'^ 'P^^^^' &c! •stinct, whether TZ Mv dudt'inThr^"'^"^"^ °^ ^-" cases oi the original imw!;^ ?^ race, are so many brought us diiecarLn5 '''^- ^^ '^'^^°'^<=- ^"^ this instiScts. ^ ""^"^ ^^' 'l^^^^^^^ a« to the origin of ma/ brw,t?rh:^^i7eihef.^'^ °"°^" ^^ -^-^« That is to say I believe tW ,"! , ^"-.^'^ °' secondary, instincts may arise e'lherhv.L^"'^ ^ ''''' ^° '^"^ ^'^^^ poseless habTtsvWd lance TZ ^'T ^"^"« °^^ P^^- these habits intrSstincts withm^^^'f 5? '' '" converting concerned in the pioces^ nAt P ^^''' ^ ^'"''' ^^^"" ^^^^ becoming, by -^eS 'a^m^a^^^rri^^^^^^^^^ sCnZyrtStsVC: rr^^^^ aU as^ Splef of perfect."^ Cd tL^'^U^^' ^ ^^^^^ 1 " Practice making and, haria-^lZed from tfpS-''''"''''™ ¥'""<' »'»■»»««. and AeykopeTi7CnZJ^{]itJlt^'Z "T'T' '"'>''"« the previous and ana o -ous Zl \Zr 't"'""- ^ » t.on. were substantiated by showin- fct™tht^?T™'; manner e. displayed more o/les. brever^l.tl e^^ L"/ I ;;;.:.; 268 MENTAL EmUTION IN ANIMALS ;i I! craciee formin " »L mcUvKlual disposition and idiosvn- automati aTrfiele "SfortSrr'!'?'' *"•• ''^«^'' *■>-' amply proved by ca e in wh ch?2 L K" "'^ i"*"™'! '^' ^"^ triclcs of manner di,nI„;t,T^,? ^' '*?" obsofved of the nou-intelli^ent. or purSs7haSr.hi n''* '"'^5 inherited, of certainty; seeing tlr «?«.!/ I "'*' y^""^' '' ^ "^^"er habits ma/do so a^nd Lt even '^^fT'^'^y. «!">^n. useful plastic ; much moie tl.Pn 1 . !?"^ ^?™^^^ "^^^^^^^3 are habit be variable tU V ;w'^ ^^'^'l fortuitous sports of directions teva^^^^^^^^ ^^^ ^^^)^ ^'-^ Profitable natural selectionTs uoTss a matt.f nf ^ T^t ""^ ^^^^ ^^ be questioned by any one wh^tSl^ certainty, and m .11 not as a principle concorno^fnTi ^''^J^' '^ ^''^'^"^al selection Thus only^can '^;'*^^^^^^^^ ^ ^^g'-^^""' structures, (such as the caddis- wolVo.H^^^^^^^^^ ""'""^ ^^^ ^"^^^Is (such as that ofinXt^^nf Tor '"''^ instincts, it was first sWnH^^ ''^''^ ^'' secondary frequently perform d become 1^^^^^^^ and next that thTy areTh^ritef tm hI: '^ '^'' ^"^^^"^^^^^^^ habits in the race. The former ftf if '^ -v''^ automatic the latter was proved bvsurb .«= """Ti^'^' ^" "^^^^ o^^; ■ handwriting family anS,X? f '"' ^' *^°'^ ^^ hereditary characteristics Ve^^^^^^^^^^ in'Jf'"'''^^^'^J f ^^^'^^t^' ^^^e sense of modesty ^In anS. fh. '"' ^°°^ ^''^^'''S, and an hereditary tendency lo^ht ' ^• '^ ' ^''T^^' '' '^'^ ^^ ponies fromVwayVot ha^^g ^^m^olt^s'"'' dTh" ^-^^^ ^ dog present ng an inherited »,?n„^% . ' ^ '^■.^°8S«is'3 animals showing a^tSet" Cr\ %he\f ^^^^^^^ 1'^ enemies, such fear beinrr in=f oo I i ^®^^ particular animals'Cnotably in th! rabbit Zf T^^l" '^''^'^"''ated not likely to have had anv ™rf .™d duck, where selection is ness); an^imalsXinfoZeCclffdfl'^™'"'-^^"" man for several geSerS;ions aftefhl / r'"?" "^ °^ them, then acqui^g inZetfv "di^ead o?h?m™and'™"^ learnms what constitutes safe dist^nce^S' Se-arr. ifi ^fl^CoLlJ^ --^-^-"^ ^^-i^cts Of blend- fat inScTs L^" S tri'u^l^- -^-ted examples aps,ng intelligence alone the rW '"^"'""^ "lone, or by that instincts in aenemlnro ?"*'"«'''<>« went on to show or oti ,, ,,^3^ tCrodeTofl.i"4r^^^^^^ confinei^t: that these principles when worK' ■' ^'^ *^^^ contrary ^eate) .fluence in evol^l'lZtZV'^,. '''^'''''^'^ ^a/e can have .vhen working siSX p ' '^^"^ f ^^^^^ ^^ them hereditary proclivities or hatotupHn'' "M^" «"« hand, though never intelliapn/ T ^^ °"^ ^^^^ch, bein^^ usefnl selection, may coSf fu ' ^f' 'f ^ """>^ ^^^^ by \ata a ^ent or be '"putTo Jt er^terbv ?n. f- ^^^^^ i-Prove' versely, adjustments originallv dl J^r^'"j«'"''' ' ^ndf con- come to be greatly impiCd or «». ? ^?T^ intelligence may selection For, taking the Sr.''^1'^^ ««««' by natural seen, intelligent actions may b™?H T' ^^' ^« ^« h'-^ve as secondary instincts, and ^if S!^l\^°f, ^^^^^^^ automatic their variations iixed in ben^ciaTS ^^^" ^^ry and h«ve how much more scope may bp 1 ? ^-^ "^^"^^^ selection this further develop^LTof an instL'f' "/'f ^^ selection in this instinct are not wholly fortu2t> ^^' ™^tions of adaptations of ancestral experLnrp . ^ """'" ^' intelligent ^ents of individual experience rl'?' ^'''^^^^^ ^«q^">«- mustm suchacasebewSrf'nf? '^-l' ""^^"^^^ selection than It does when working S t th?T^ ^?'^^ ^^^^"^age instincts, where it is qimt^Kn J , ■ formation of primnrv instead of with va4 K^^^^^^ vai?SZ gence. are from the first a^Xl itT'^r'^ ^7 inteUi- principle of lapsing intemSp n,' A^ """^ ^^^« ^^early, the , greater advantL when thu??n"'*^''^^^^^ng at a much tion, than it i? ZheVwZTJ^^^^^^^^ always tend to favour tL be t If ± Tir" ^^"' '"'" ^"^^ and by concentrating the power of hpf f !'«'"^ adjustments, tend^ .. more speedily to^^^Sef S^roL^.t^^^^^^^^ -^f^}^7^;^:;SV^^^ Origin, natural selection or lapsing ^^Sl^^^tX:^'^^^ mi t 1:! 1i ' ■■■!■ IMAGE EVALUATION TEST TARGET {MT-3) V- {./ A .ff v.. 1.0 I.I 11.25 1^ 116 1^ ■^ 140 US ■■■■ 1.4 6" 2.5 [22 M 1.6 ^^ 'y.^ >» rS '^ ' i^Ifji "^^ -♦.'■^ v ^ Sciaices Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 \ ,'^'^T^^v^'.'""^^"*"^ *° '^' individuals whch manifest them ; for it is of the essence of the theory of natural selection to suppose that the interests of the [ndi- vidual are, in the process of selection, subordinated to those of the species. It is, for example, manifestly to the dS rnHplr-'^'^'^^^-r^-^^.^^P^*^^^^^^^ ''' kind, inasmuch asS, own death is speedily mduced by the act; but seeing that the act IS essen lal to the continuance of the species, we perce ve whT.rlT^ selection must here have developed an Snc? which virtuaUy amounts to that of suicide. And the same remark applies to all siniilar cases, such as that alluded to in Animal Intelligence" of soldier ants and termites sacrificino tliemselves for the benefit of the community-i.e., the species i : M INSTINCTS APPARENTLY DETRIMENTAL TO THE SPECIES. 277 But of course the case is entirely alterpH wliom -«,« another, It would annihilate my theory " TnH it t S- s:is: ^""^ '^""■^ -"" «%p.;loih': °ctro? Of a^ w;is4f rsrs:Th:tr tt: r::^ one case, either of an instinct which ™detrim!r?n? f„ ,7 Tlu beneflfof '\r "' ™^. ^'"'"^ ■>- -^'1'° fee" 10 tne benefit ot other species. For, on the ohp hnnri if here is any one such case of an indispitable Ld ^^^^^^ clearly have to modify our whole theory in orSr to meet it while, on the other hand, if there is no such case thXt of obvious SeTtlf ' ""''^'^^^ i' ^"^^^1 instinctrbing of of Txclus ve nS tn^nJJ.'' ""^"'^ "^""^^^^^ ^^«°^' ^°d never VI exclusive use to other species, must be takpn aa fi^^ strongest possible evidence of the theory that ascribes aU mstincts to the causes which we have assigned ^oo/ T^ ^' "^^^ '^^ ^* °^<^^ *^^a<^ there is only one apmrenfc wl'^^r 'f ^^!?"*^ ^'^ °^^ ^P^'^ies having exclusive refer' nee bei^eficLuf thi '"°''"' ^^^'^"^^^ ^^-^ -^ casrof St: to7tL spe^^^^^^^ "%7^ frn?^^ '^^^ '^^^^^ ^1«^ beneficial cLcerned Th. f <^he latter cases we are not, of course, concerned The former is the case of aphides vieldina im m^ZT^'w '""'"'r^ ""'' already b'een consS Ij Mr.Darwm. His explanation is that, "as the excretion i^ extremely viscid, it is no doubt a convenience to the apSs ^naLXXZl^fef' '''-"' '^^" '^^ '''' '' ^^« -"!« oi the rattl.. t, ' '■ ''ii' m;i iiii i! n ' H 278 MENTAL EVOLUTION IN ANIMALS. to have it removed; therefore probably they do not excrete solely for the good of the ants."^ Coining now to the other branch of the subject, after due ll^Z "" \^^l ^^^y}^^^ ot' two or three instincts which could possibly be cited as presenting the appearance of bein- detrimental to the species which manifest them. I shall therefore consider these cases separately «,,T.Lf'*'ifl''"^/''T?^-~~^^^ ^^""^^ ^f'the evidence on this subject will be found m my other work.f It will there be seen that two or three independent witnesses-including a friend of Dr. Allen Thomson ou whose accuracy he says he tw'S '"' *''^""""^ *° ^^"^ ^^^^^ °f the popular saying that when a scorpion is surrounded by fire, or otherwise exposed to undue heat it will commit'suicide by stingin' Itself to death. It will be seen, however, by referring to h? correspondence in question, that the alleged facts are disputed by other observers, and also, as I have already indicated that they were not observed by Dr. Thomson himself. _ The effect of republishing this correspondence and of pointing out the desirability of obtaining further evidence upon he matter has been to induce tv?o verrcompeten? naturahsts to make some observations upon the subject. One of these naturahsts is Professor Lankester, who published his observations m the " Journal of the Linnean Society " (1882) and the other is Professor Lloyd Morgan, who published hi<,' agree that the scorpions never commit suicide, and as Mr Morgan exposed f ht animals to a variety of dreadful tortures with a umtormly negative result, I think the question may . . ^ .f "'"'''^^.'■^^ ^ ^^^^^'^- Moreover Mr. G. Bidie, who started the previous correspondence in "Nature," has recently addressed another letter to that Journal^ in which he makes the not improbaDle suggestion that, as in his experiments he applied heat by condensing the rays of the sun with a lens upon a small point of the scorpion's back, the animal in stinging Itself " may have merely been trying to get rid of an imaginary enemy." / o o«i' xau oi an 2. ^^c^/s/i/^n^^-Aroj/^A/^fowc— The determination shown by many kimis of insects to fly towards and through a flame 18 unquestionably due to instinct, and as such mi|ht be ad- • Onjr,, of Species, p. 208. + Animal Intelligence, pp. 222-5. t July 12, JS83. " ' ff INSTINCTS APPARENTLY DETRIMENTAL TO THE SPECIES. 279 duced as evidence of an instinct detrimental alike to the individual and to the species. But before this conclusion could be reached several possibilities reauire to be attended ta In the first place, flame in Nature is an exceedingly rare phenomenon, so that we comld scarcely expect that any instinct should have been developed for the express purpose of Its avoidance. Therefore, if the general economy of ni m '"i . ofita genial influence. As little hv liffTo ^t, on the land the qa,r^ooV f ^ ^'^^^ *^® ^^^^^ encroached they do to this day » "^^"^'^^^« ^«^d remain, as in fact BentCl::TClZZr!^r^^ '^^'^'^''^ ^^ -other these migrations'nlm^M^^^^ Museum, Claristiauia.* His^dew i, flTo? ' ^^^ ^""'^""'^^^^ production is excessive imiuJn/ '%^^^^^? years when re- hunger, as well as bv "f?r . "^^5 f individuals are led by by ?hi;™ c tJ overfloTJS 's^^ r.'- P— J home, and^preid out^' fve J an arr^ f-^^^'' ^^"^'^"^ larger than obtains in an vothp? off r ^^- '' ^^^^^iderably circumstances." As breed n. Ly '^''''l ""'^^^ ''"^^^^ wandering, in cases where L two or t^ '''' throughout the the production of youn. has been pI/"" ^^^ceeding years are incessantly pushed t'nwnrri.fl excessive, « the masses the migration^beCmes an Tver^^^^^^^^^ {he fells; and remote portions of the coun?rv ." i?^ 9f the lower and far penetrate further in search Jftlr.-''^'^'^""^^ ^^'^^^^^ habits (and which are cambl« .f ' .'"'^^^^^ *° ^^^^i' subsistence) uitS thev «£ i ^^S^g them a permanent in some other manner " '^^^^'^ ^^ ^^' ''^ or destroyed as w';faa\\f LSS^^^ - the subject, think we may most Sel"i ^^ ^^ ^^^vvs, I The most imporTant pdnt^of dfffp''^"^'^ "'' *" ^^^ latt;r. and Mr. ColLt has ^rXence foT'' ^f ^^^en Mr. Crotch while Mr. Crotch states thItTh. • T'"'^''''' ^^ ^^^t. For wards without reference to tt "."^rations are made west- Mr. Collett is emphat"?n fay Lg tha't " thJ w ^.-^^^ry. place m the direction of thevluLlnd ttt '-^^""f take out from the plateauxianrStLn-T^H'' '""^ ^T'^ IS an end of Mr Crotch'cTi?!^. 5 1, ^^ this is so, there to explain would be wht tlI\^''^ *^' ^^^>^ ^^^^^^ty left they still conSe on their nn^ f ^'"^"^^^^^ ''^'^ the sea, multitudes by drowning ThPn '°"''f ^^P'"^^ ^^ thei; not far to seek For X^V 3 • ' ^""f T *° this, however, ia in their wanderings thev ooT. ''^ ^'^'^' ^"^ '""'^ that when iw». -Soc. Ji,i,r., vol. xiii, p. 327, e« ^^2. MIGRATION. 285 lemming furnishes aiy diStv to t,h» ?i? ""^"'."'"' "^ *''« over and above that whLh faVmiS^^d tX ,7°'""^^ more important case of migration in^Z.!. i ^ .? '"^er and tion of which I shaU now proceed ^ ' ^ '^' '=°''^"««'- Migration. migration are to bfE in th« ^'f ?' *^ '"^"^^ of is l-nfflcient to refer to °^Cm:i^?Pn^*™',?'^ I ^i-k it concerning the migraLs Tc abfflTsf 4°' ^r^"^ pillars (238-40^ thono-h ^c v.«„ T A^^," ^^"^-^-2)* and Cater- following re^iabW^^^^^^^^ ^ ^^^ ^^^ the « Colonies and India." ' ""^ ^ ^^^^^ ^^'o^ the would' l7d5?ke ryrX'trnT^^^'T^' .^-^ -^-P^^^-^ to the "Eangitikei lSvoL^e»W^nl^?^'^^^^^^^ local railway a few days aC In thl ^i.^^^ ,P^^^^ «^ ^h? kina. New Zealald S alv of ^^'^!;^^^^^?^ «f Tura- thousands strong was marohi^« ! ^^^^'P'^^f.^^' hundreds of new field of oats'wTnXtig cre'alon^^Th'^^^^^- ! the creeping vermin x^t^v^ «t v^ T i. ^«- thousands of engine, aSd^sudd™" tle^traTn ?:! {o'a'd"^'' °' *^ examination it was fiund tteLThee ° of the „''°P- v°5 become so ffreasv that ti^^,, i f "^"*^^^^ ^' tiie engine had vancing-thrcTuld not Jp'th? rdls'^'Tir'" ^'H ^^ eng ne-driver nrocured mSJiLj . _, ■ 8"""^ =«id the the%rain madeTS starf te ,>n " S\""= '^"^' ™4 stoppage caterpilla^ in thlsaL' C T\ *'",?«™S *« engme and overran the carri'agi „sMe andtt-'" °™' "'^ -nTi^oSr^" MiiraS -^.^ -r orrnro::?™to"i]e%rn7r-n '^^^^^^^^ south to north The column wh,v{^ f"^^ ^^"^^"^ ^">^ reet broad, „ew low ^Zl^fd ^.t^ t^^'^ III 'J ' I ^ I' ': ii. 1 J: 1 1) 1 , I i ■ 1 286 MENTAL EVOLUTION IN ANIMALS. '11 'Uli The caterpillar of this species is not gregarious. Professor Bonelli also describes a migration similar in all respects including locality, except th^t it lasted longer— the insects covering the flowers at night and proceeding on the iourney by day. -^ Immense swarms of migratory Dragon-flies have been at times observed, the most remarkable case being one that occurred in May, 1839, and which seems to have extended over a great part of Europe. The insects flew at a height of 100 to 150 feet, and seemed to follow the direction of the rivers.* Many species of Fish are known to migrate regularly for purposes of spawning, such as the herring, sahnon, &c., and also to find water ; f while among Eeptiles the most remark- able instance seems to be that which is furnished by the Turtles which visit Ascension Island to deposit their eggs. How the animals can find this comparatively small speck 'of land in the midst of a vast ocean is very unaccountable. I have recently written to Professor Moseley upon the subject, and in reply he says, "No man without proper modern means of finding latitude and longitude could reach either Tristan or Ascension; and it is especially difficult for animals whose eyes cannot bp raised above the sea-level, and to whom, therefore, the islands are visible for a comparatively small radius only. Merchant skippers have several times been unable to find Bermuda, and on return baffled have reported the island gone down." But, as Professor Moseley adds, " It is Just possible that the animals do not retire far from the land after all, but hang about unobserved," I think It is undesirable to enter into any discussion where the facts are still of an uncertain character. Among Mammals, from whales to mice, we meet with many inigratory species, but it is among Birds that the propensity is most prevalent. Indeed, a very competent authority on all matters pertaining to ornitholo^ry has said in the new " Encyclopaedia Britannica : " " Every bird of the northern hemisphere is to a greater or less degree migratory in some part of its range. Such a conclusion brings us to a BtiU more general inference—viz., that Migration, instead of * For a full account see Weissenbome, Loundoun't Mag. Nat. Ristt N.S., vol. iii. ' t See Animal Intelliffince, 218-50. MIGRATION. 287 of the indicated the animals in which the W,w •''™"8 ™^ Migration at the beafnn^n! ^ f^ * ?^^^^^ ^ remarks on .»f^^.e.thate,^atSSs tt^{l„:! rdSt^^HoTntS"''-^' '^ '''-^^^ P^^^^^^^^ species in ie J^^ tT:^::^-^^^^^^^-^ of kno^ng the diin In S i^St •"^' ^""^ ^ ^^"^ ana.,i2"™"^y^-^r^^^^^^^ n,a, ^ ani.a,saSr„-2--^^;^^^^^^^^^ crigfn^te.tS'^'A'i'' ^TSs'^ht ^""""1^ "'^ ancestors Of miaratorvflnimJio, ^f^^^ ^« *ha<^ the or want of Zf^lyT^^ZZT''^^ ^"^^^' ^^ ^^^^ we may weU believe that fhl L ^^?'^^'^' ' "^^^ in time become an instinctxve mssion " asT,^?^'^ ''"^'^i^"^ ^^"^^ cated sheep in Spain In Z'..? /v.^'^^'? ^^^^ ^^^^^sti- be used, and iftZ course of '"1 ^''^'' '^' ™Ss would the land over which thevTw in f\^ successive generations to become slowirsubmeT.ed the it''' fT\" J°""^^>^« ^«^'« unaltered, and thus ^81^,1/^! f. ""^ ^'^^* ^^^^^ "^^^^^^ • Professor Newton, P. E S Ar^ '- -, »u the main facts of migration as regaSa biras? ' ''^ ^''^ * S^"*^ '•««*^' "« • i 11 in > m 'I :^ it 'l I \ ' I 288 MENTAL EVOLUTION IN ANIMALS. >.l t pendently arrived at by Mr. Wallace. It is only now that Mr. Darwin's views upon this subject are published, although they were committed to writing as they appear in the Appendix between twenty and thirty years ago. Mr. Wallace however enunciated substantially the same views in a letter to "Nature" in 1874 (Oct. 8),* from which I shall quote w extenso, not only for the purpose of showing the coincidence to which I have alluded, but also because I think that the additional element which Mr. Wallace mentions— i.e., the separation of breeding and subsistence areas — ^is a most im- portant one. " Let us suppose that in any species of migratory bird, breeding can as a rule be only safely accomplished in a given area ; and further, that during a great part of the rest of the year sufficient food cannot be obtained in that area. It will follow that these birds which do not leave the breeding area at the proper season will suffer, and ultimately become extinct ; which will also be the fate of those which do not leave the feeding area at the proper time. Now if we sup- pose that the two areas were (for some remote ancestor of the existing species) coincident, but by geological and climatic changes gradually diverged from each other, we can easily understand how the habit of incipient and partial migration at the proper season would at last become hereditary, and so fixed as to be what we term an instinct. It will probably be found that every gradation still exists in various parts of the world, from a complete coincidence to a complete separa- tion of the breeding and subsistence areas ; and when the natural history of a sufficient number of species in all parts of the world is thoroughly worked out, we may find every link between species which never leave a restricted area in which they breed and live the whole year round, to those other cases in which the two areas are absolutely separated. The actual causes that determine the exact time, year by year, at which certain species migrate, will of course be diffi- cult to ascertain. I would suggest, however, that they will be found to depend on those climatic changes which most affect the particular species. The change oi colour, or the fall of certain leaves; the change to the pupa state of certain insects; prevalent winds or rains; or even the • Captain Hutton also foreshadowed these views in 1872 1 lee Trais, New Zealand Inst., p. 235. MIGRATION. 289 i ;' W tt"rj!.encT"^"^^ ^' ^^^ -^^ -^ water, .ay all have sicai;^^Lt7etr^ besides being intrin- enquiries made by Mr Darwfn wV I V°^ '"^PP'^'^ ^^°»i the is a general relatLslip betwe ' opf ^^^^«^r^ ^^^^<^ ^^^^re is independent reason LcSudeh'T ''^'"1' ^^^^^ ^^ere assu'r^;iil^fi^^ tS^ tMs theory .Lestwo important of direction, and second that a nn l"""^' ^ "^''^ ""'^^"'^ ««"«« the particular directZ to t . 'a •""'^f '" knowledge of certain that the younTc^^^^^^ for It is its parents) canno^t be guire^nS.^ \"S^^"^ '^''' means, and it is asserted hi fi. ^"''^Jo^^^ey by any other of many other ;;.V'^^£^^^^ theVung separately, the first is no more than ! 'L ''/'.'TP^^^^'^ accountable though the factTol t! 'V^^l^^t of fact, un- accurate sense of dlect t Satrv bin /' ^^ '^^^'. ^ ^-^ possess, and it is probablv k« ? ^ i"*^? unquestionably "homing" faculty which is shown 'k ^'^^ '' '^'^ ''''^^^^^ animals, and also, as mJ DamlnTnl. ^ "^^7 domesticated I could iill ppges wi7h iftLTwS Vr' ^^ '""""^ ™^^- all parts of the world describini^ 5 ^'? '"'"^^^^ ^^^^^^ cases of the display of thTsfocfltvb'v 7 ^''' remarkable i J tms laculty by dogs, cats, horses,^ Je^wSl^h^if^SLVrje"^ ?:i^""? ^ *^e onl, fact I W work entitled T/^e ^aturaliJinR^ZVn I ' *^'°,''y" M""- "^^-dis in his fcn-er i^haradj-iu. rnar^JaZf—Ve:"^!'- ?'*,*^^ °^%nitory golden tudes (b^^t without ever alightingCtLTonnn ''^!^*^' [^ countless multi- seen passing over the islands on the^r ^^f,"'""'?*'^ «o"th, while they are never fact that the two journevs are token h.?^ J*'"™*'^ °°'^^- ^ow, if i^s I encountered by thl abovf theory ^'Lt^asMTn "T'' ' ^^^^^^^^ -°"Jd bj ^J^thern joui^ey. althou^gh Z 2S SSeHe^iSo^Xrhrerp: t See Temminck, Man. d'Orn o^ 2 ,•,•; t ^ j f tiert« t« i^«;.o^e. On the other WlLl' ^T?^"' -P" ^'"^' "^"^ Seebohm •those who have had no instruction do nT""^' *^** '" ^^^'^'^^^ «f swallows f « «een to be led by those whose aae and « '"•^™*"' ^""^ *be young birl mnvTf °';fc".'^"'^ *^dds that L Xood aXZ"', ^^"^ ^^^"^ knowledge pany the old birds in their migration '•?* is ?n^^''^f ^'^t*^" ^^^te to accom- • . . . they perish the victims of thJ^' '° *^^* *bey reach matunly f I W: *^^-/-'^ble to folW the r ;;r S:^??:' ^°? '' *^« '-'^^ S^ t I We one instonee of . eat returS^ ^^ Sf^sZL't^Oon ^ I ., m 'If M i I :'ii i 290 MENTAL EVOLUTION IN ANIMALS. ' JJ i I' • p' . tv #1 • asses, cows, sheep, goats, and pigs ; but as so many similai cases are already on record, I ieel it is needless to add to the number. The remarkable fact is that the animals are able to find their way back over immense distances, even though the outgoing journey has been made at night, or in a closed box ; so that it is truly upon some sense of direction, and not merely upon a memory of landmarks, that they must rely. Moreover, it is certain that in many cases, if not as a general rule, the animals on their return journey do not traverse the exact route which they had taken in the out- going journey, but take the " bee-line ";♦ so that, for instance, it the out-going journey has been made over two sides of a triangle, the return journey will most probably be made over the third side. One instance, the account of which I have received from a correspondent in Australia, is of suffi- cient interest in this connection to quote. " A pair of horses were sent many hundred miles round the Australian coast by ship ; as they did not like their new quarters, they started back by land ; but after returning 230 miles they were pulled up by a peninsula on the coast, where they were eventually recovered. They did not attempt to retrace their steps to clear this difficulty ."t Huddersfield, a distance of two hundred miles. A still more remartable case, however, was published by Mr. J. B. Andrews in Nature several years ago (vol. viii, p. 6). The Archduchess Marie Regnier passed the winter of 1871-2 at the Hotel Victoria, in Mentone, and while there took a fancy to a spaniel belonging to the landlord, M. Milandri. In the spring of 1872 she brought the dog with her by rail to Vienna. Not long afterwards it reappeared at the hotel in Mentone, having thus run a distance of nearly a thousand miles. On arriving it died of fatigue and was buried in the hotel gardens, where a monument now commemorates the performance. Mr. A. W. Howitt writing to Nature from Victoria at about the same time (vol. viii, p. 322) gives a number of cases of horses and cattle finding their way home over greater or less distances, and I specially allude to his communication because he says that in some of the cases the return journey was made after a considerable lapse of time — months and even years. * This is an American term which I employ because in itself showing the observed regularity of the fact as regards bees— it being the custom to find wild hives of honey by catching several bees, and letting them go again from different places. The insects under these circumstances make straight for their hive, so that by obsen'ing the point where several "bee-linea" intersect, the honey seekers are able to find the hive. 1 1 may here also quote an observation by Mr. Darwin to the same effect :— • •' I sent a riding-horse by railway from Kent via Yarmouth, to Freshwater Bay, in the Isle of Wight. On the first day that I rode eastward, my horse, when I turned to go home, was very unwilling to return towards his stable, and he eeveral times turned round. This led me to make repeated trials, and every MIOKATIOlf. 291 pose of the hypo7esi'"at„:eTbyT^:u:"tr', *V^- that the return journev is dnp fn t ^ ^^"ace* to the effect perceived durin« the out "n^nc, • ^ ^^^"^oj'y of the odours serving as land marks Tltw ''T"'^' <^^^«e odours thus only two hypothZs ope? !> t -^ '^'"'^' *' ""' '^"'" "'" First, it ha's%eertho'^'gh pLw/^^^^^^^^ "^^1 ^^^ ^^^^«- endowta with a special sense enablLthLr'^' "'"^ ^' magnetic currents of fh^ To fi ^"^^iing them to perceive the by a compasfTere is no n'h'"^ f '° ^"^^^ ^^^"^«^1^«« ^s to this hyUes^but as" f Xl /SSf ? ^"^^'"^^ we may disregard it rur v"0"y aestitute of evidence, animals are able to keen an un'."n^ "'^''' ^^P°'^^^^« ^« '^^^ and curves taken in the 01?^^-''°"' ''^''^^' ^^^^e turns general imp^ssU^^^STeS^'^r' T ^^^^^^ ^ substantiated by the faof fW ^Vr ^^'^ hypothesis ia savage man is certain! vpL*^'/' •¥'• ^^^^^» observes, and a friend of Tv own ^^^^^^ with some such faculty who has spent' Z;7eaMl7foff ^T^' ^^^^^^ America, informs me that etpn n -r '?' ^"^ P^'^^"^^ of accustomed to sLh ^i^'mtve LbTs o^^^^^^ "'^" ^?.«" faculty in a decree of nPrfppHn« • • 1 ' H^»p: ^HpMi^'^i ^^KmSei •' If 294 MENTAL EVOLUTION IN ANIMALS. eludes that the sense of direction cannot depend upon any process of dead-reckoning. At the suggestion of Mr. Darwin he also tried the effect of attaching a magnetized needle to the thorax of a bee ; but the bee having succeeded in getting nd of the encumbrance, he did not repeat the experiment. Now, although the observations with the rotating box are no doiibt very interesting, they do not appear to me to sustain the definite conclusion that the sense of direction is not due to a process of dead-reckoning. It is of course impossible to suppose that the bees could retain a register of all the turns to which they were submitted in the sling, and, there- fore, if it were certain that they found their way home by means of their sense of direction, I should agree with M. Fabre in concluding, once for all, against the theory of dead-reckoning. But there is no evidence to show that the bees which found their way home did so by means of their sense of direction. It is quite possible that they found their way home simply from their knowledge of land-marks ; for the distance to which they were taken was only three kilo- metres, and it is known that the hive-bee will go tbr^p ^-iraes that distance in its ordinary foraging excursions.* Moreover, the fact that only a comparatively small number of the bees succeeded in returning (about 22 per cent.), is suggestive of the explanation that these were the only ones which, durin), °T'''°^ """/ ^^^ (Cambridge) and other tov^Tis, apparently ata low whither to proceed, and attracted by the light of the street lamps.'^ t isee Journ. Linn. Soc, 1883. ^ i ii M^l I I 1.1 1 ! 1 -■■.<■■•!• VI ■! I Uh i 'I: 206 MENTAL EVOLUTION IN ANIMALS. be pursued. It is, without question, an astonishing fact that a young cuckoo should be prompted to leave its foster-parents at a particular season of the year, and without any truide to showthe course previously taken by its own parents; but this IS a fact which must be met by any theory of instinct which aims at being complete, Now upon our own theory it can only be met by taking it to ue due to inherited memory. I confess to me it seems incredible that many hundred miles of landscape scenery should constitute an object of inherited memory,* to say nothing of long stretches of ocean ; but the case is not quite so hopeless as to require so extreme; a hypothesis. • Wheu we say that upon our theory the youncr cuckoo must be supposed to find its way on its first journey by inherited memory, we need not necessarily affirm that this IS the memory o2 a landscape. As I have said in the pre- vious paragraphs, we do not yet know what it is that guides the course of migratory birds in general; but whatever this ""^^i, ''i?* ^^^ scarcely be the appearance of the country over which they pass, seeing not only that the distances are so great and that two hundred or three hundred miles of ocean may separate one piece of country over which they travel irom a:iother, but also that the journeys may be taken by night. Of what, then, is the inherited memory on which the young cuckoo (if not also other migratory birds) depends ? We -can only answer, Of the same (whatever thi:- may be) as that upon which the old birds depend. When we certainly know what this is, we shall first be able to ascertain whether It IS incompatible with the theory of evolution to suppose that It can be an object of hereditary memory. Thus, for the sake of example, let us suppose that the old birds in their outgoing journey guide their way by flying towards the south wind (as has been suggested to me by Mr. William Black, who believes that swallows always start against the south wind) ; heredity would in this case have an easy task in associating the warm moist breath of this wind with a desire to fly against it. Of course I only adduce tliis suggestion in order to show how simple the mere question of heredity might become, if once we knew the means whereby migratory birds m general find their way. The only difference between the faculty of homing and the instinct of migration, so far as l«p!^^'''! ^^^"^ "^^l ^'■'.* ^^'^"ced by Canon Kingsley (Nature, Jan. 18, lSfa7), and has since been independently suggested by several writers. INSTINCTS OF NEUTER INSECTS. 297 the matter of way-finding is concerned, seems to me to be this — that in the case of the young cuckoo, and perhaps also in that of certain other migratory birds, the animals know their way instinctively, or without even one lesson. But if we could ascertain upon what it is that the faculty of homing depends (which, be it observed, is not an instinct, seeing that its occurrence is the exception and not the rule, even in the species which exhibit it), we might very probably get a clue to explain the manner in which heredity has been able to work up this faculty into the instinct of migration. No doubt this discussion is most unsatisfactoiy, and the reason is that we are so much in the dark about the facts. All, therefore, that I have attempted to do is to show that, in the present state of our information, the migratory instinct cannot fairly be quoted as a difficulty in the way of our theory of the formation of instincts in general. And, in order to give emphasis to this statement, I may allude to' the general facts already mentioned— viz., that the migratory instinct is both variable and graduated, that it is occasionally exhibited by domesticated animals, and that the sense of direction on which it depends is a very general one among animals, if not also in savage man ; for all these facts tend to show that whatever the causation of the migratory instinct may be, it has probably been proceeding upon the lines of evolution in general. f! ,) >■ , ;[j It Instincts of Neuter Insects, Mr. Darwin has pointed out a serious difficulty lying against his theory of the origin of instincts by natural selection" aiid one which, as he justly remarks, it is surprising that no one should have previously advanced against the well-known doctrine of inherited habit, as taught by Lamarck. The difficulty is that among various species of social insects, such as bees and ants, there occur " neuter," or asexual individuals, which manifest entirely different instincts from the other or sexual individuals, and, as the neuters cannot breed, it is difficult to understand how their peculiar and distinctive instincts can be formed by natural selection, which, as we have seen, requires for its operation the transmission of mental faculties by heredity. The difficulty is increased by the fact that among the termites and many species of anta II, ;-^ 298 MENTAL EVOLUTION IN ANIMALS. Whfch Jfr '-^'^ r^"' °^ """<^^^« °«^"^" i« *^« S^^e nest. .^ n=f w ""ii^^^ ^^'^ °°^ ^«°<^^e^ ^oth in structure and in instincts. The only possible way in which this difficulty can be met is the way m which it has been met by Mr. Darwin VIZ. by supposing "that selection may be applied to the th^nL'' 'V^? if dividual." " Such f Jith may^Uplaced in nZrZtl °^«^^^'\*^^on .^hat a breed of cattle always yielding ?ormprS.'''^''f f/"^'"^^ l'"S ^°^°^ ^^"Id, it is probable, he lormed by carefully watching which individual bulls and cows, when matched, produced oxen with the longest horns- and yet no one ox would ever have propagated its kind :» and similarly, of course, with regard"^ to the instincts of neuters Otherwise stated, we may regard the nest or hive as Itself an orgamsm of which the sexual insects and the several castes of neuters constitute the organs ; and we mav then suppose natural relation to operate upon this organism «,^nnnZ > ; somewhat in the same way as we habitually suppose It to operate upon the "social organisms" or com- munities of mankind. No doubt, when ca?efully considered the analogy between a hive and an organism, or even between a mve and a social community, is not a close analogy so far as the modus operandi of natural selection is concerned • for in individuals, while m the other case there is no such great contrast between different classes of a human community as that which obtains among the different castes of an insect community. The root of the question really consists Tn whether or not it is possible to suppose that natural selection may operate upon specific types as distinguished from indivi- dual members of species. During his life-time I had the advantage of discussing this question with Mr. Darwin and I ascertained from him that it had greatly occupied his thoughts while writing the "Origin of Species;" but that hnding it to be a question of so much intricacy, he deemed it unadvisable to enter upon its exposition. It would occupv too much space were I to attempt such an exposition here, ^hl.i. 7-!^^'''^'i? V^^ subject only because I desire to show that It IS really this general question which is involved in the case of the special difficulty with which we are now concerned. On some future occasion I intend to argue this general question, and then I shall hope to mitigate the force oi this special difficulty. I may, however, point to one fact INSTINCTS OF THE SPHEX. 299 which Mr. Darwm has observed, and which is of much importance a,s indicating that the different castes of neuters have arisen by degrees, and therefore presumably under the influence of natural selection. This fact is that, when care! lully searched for, neuters presenting more or less weU marked gradations of structure between one caste and another may be occasionaUy found in the same nest* On the whole therefore, I conclude, with regard to this particular case of difficulty, that it is not so formidable as to exclude the explanation furnished by the hypothesis of natural selection supposing that we have already accepted this hypothesis as explanatory of other and less difficult cases. Instincts of the Sphex. Several species of this division of the Hymenoptera dis- play what I think may be justly deemed the most remarkable instincts m the world. These consist in stinging spiders insects, and caterpillars in their chief nerve-centres, in con- sequence of which the victims are not killed outright, but rendered motionless; they are then conveyed to a burrow previously formed by the Sphex, and, continuing to live in their paralyzed condition for several weeks, are at last avail- able as food for the larvae when these are hatched. Of course the extraordinary fact which stands to be explained is that ot the precise anatomical, not to say also physiological know- ledge which appears to be displayed by the insect in stin-ina only the nerve-centres of its prey. The following, so fa'^r as is at present known, are the main features of this verv sur- prising case. ^ The same species of Sphex always preys upon the same species of victim. When the victim is a spider^he instS ot Its assailant dictates that a single sting shall be given in the large ganglion where, in the case of the spider, most of the central nervous matter is aggregated. When the victim IS a beetle, the Sphex which preys upon it—there are ei-ht species which prey upon two genera— first throws the insect upon Its back, then embraces it and plunges the sting through the membranes between the first and the second pairs of lee? • tfie stmg thus strikes the main nerve-centre, which is unusually agglomerated in beetles of this genus. When the prey is a • See Origin of Species, 231-2. 1 1 I; # { v .HI -I 'il V\\\ 300 MENTAL EVOLUTION OF ANIMALS. cricket, the insect is thrown, as in the previous case, upon its back, and while holding it down with her mandibles firmly fastened upon the last segment of its abdomen, her feet on the sides holding down the body of the cricket-the anterior feet holding down the long posterior legs of the prey, and the hind feet holding back the mandibles, so as to prevent these trom biting, and at the same time making tense the mem- branous junction of the head with the body-the Sphex darts her stmg successively into three nerve-centres ; first into the one below the neck which she has stretched back for the pur- pose, next into the one behind the prothorax, and lastly into the one lower down. A cricket thus paralyzed will live for six weeks or more. When the prey is a caterpiUar, a series ot six to nine stmgs are given, one between each of the seo-- mentsof the body beginning from the anterior end: the dibles*^ partially crushed by a bite with the man- Now so far as the spider and the beetle are concerned I do not see much difficulty presented by the facts to our theory of the formation of instincts. Tor as both the larcre nerve-centres of the Spider and the sting of the Sphex occSr upon the median line of their respective possessors, if the stinging of the ganglion were in the first instance accidentally favoured by this coincidence— which appears to me not im- probable, seeing that the nerve-centre is thus the most likely place for the stmg to strike,— it is evident that natural selec- tion would have had excellent material on which to work for tlie purpose of developing such an instinct as we now observe Again m the case of the beetle, M. Fabre expressly notices that the only vulnerable point in the hard casing of the animal is in the articulation where the Sphex th?usts her sting; so that there is nothing very remarkable in natural selection having developed an instinct to sting at the only ^ossible ""^ ^^^ ^""^^ "^^^"^ '^'°^'°° '^ mechanically But the case is certainly very different with the cricket and the caterpillar; for here— or at least in the latter case— we encounter the extraordinary and unavoidable fact of an insect, without any accidental guiding or mechanically * All the above facts are taken from the works of M. J H Fabre &rthem. ''^''"'' ''^' ^""^ ''''^' ^^^ ^^^ *^« ^^' to observe ij INSTINCTS OF THE SPHEX. 801 imposed necessity, instinctively choosing a number of minute points in the uniformly soft body of its prey, with an appa- rently very precise knowledge that it is only at these par- ticular points that the peculiar paralyzing influence of its sting can be exercised. After duly considering this case I must candidly say that I feel it to be the mJst perplexing which has yet been brought to light, and the one which il most ditticult of explanation upon the principles of the fore- ^i°'''f J i,®''^^- ^^ /^' however, most desirable that the facts should be more thoroughly investigated, for it might then appear that some clue would be given as to the origin and development of this instinct. So far as our information at present extends I can only suggest that this origin must have been of a purely secondary kind, although its subsequent development may probably have been assisted by natural selection In other words, so far as we have any means of judging 1 can see no alternative but to conclude that these wasp-like animals owe their present instincts to the hioh intelligence of their ancestors, who found from experience the ettects of stinging caterpillars between the segments of their bodies, and consequently practised the art of so stino-ins them till It became an instinct. v^'It'^^t^^® ^^^^ y^^"* °^ ^'^ li^® I had some conversation with Mr. Darwin upon this matter, and, after deliberatino- upon It for some time, he eventually came to the conclusion which I have just stated— as will be at once apparent from the following letter which he wrote to me, and which will serve m a few words to indicate what appears, I think, to be the naost probable steps by which these singular instincts were acquired. "I have been thinking about Pompilius and its allies — Wease take the trouble to read on perforation of the corolla by Bees, p. 425 of my « Cross-fertilization," to end of chapter i^ees show so much intelligence in their acts, that it seems not improbable to me that the progenitors of Pompilius ori.' . f]'r -^i mil 306 MENTAL EVOLUTION IN ANIMALS. of shamming dead occurs in most if not all the classea o! the animal kingdom. The suliject therefore demands from us serious attention, because on the one hand, as previously remarked, it is obvious that the idea of death and of its conscious simulation would involve abstraction of a higher order than we could readily ascribe to any animal, and on the other hand it is not very easy otherwise to explain the facts. I shall first of all quote what Couch says upon the sub- ject, as he is the first author, so far as I am aware, who did not at once take it for granted that animals consciously feign death, and. who also supplied a reasonable hypothesis to account for the facts. He says : — " But a more probable explanation is, that the suddenness of the encounter, at a time when the creature thought of no such thing, had the effect of stupefying his senses, so that an effort of escape was out of his power, and the appearance of death was not the fictitious contrivance of cunning, but the consequence of terror. And that this explanation is the true one appears, among other proofs, from the conduct of a bolder and more ferocious animal, the Wolf, under similar circum- stances. If taken in a pitfall it is said that it is so subdued by surprise, that a man may safely descend and bind and lead it away or knock it on the head ; and it is also said that when it has wandered into a country to which it is a stranger it loses much of its courage and may be assailed almost with impunity."* " A similar action to that of the Fox has been observed in a little animal to which it is not common to ascribe more than an ordinary degree of cunning or confidence in its own resources. In a bookcase of wainscot, impervious to light, certain articles were kept more agreeable to the taste of mice than books, and, at midday, when the doors were suddenly opened, a mouse was seen on one of the shelves ; and so rivetted was the little creature to the spot that it showed all the signs of death, not even moving a limb when taken into the hand. On another occasion, on opening a parlour-door, in broad daylight, a mouse was seen fixed and motionless in the middle of the room ; and, on advancing towards it, its appear- ance in no way differed from that of a dead animal, excepting that it had not fallen over on its side. Neither of these • Mag. Nat. Hist., l^few Ser., voL ii, p. 121. FEIGNING DEATH. assea ol (Is from eviously d of its I higher d on the luiu the the sub- who (lid ;ly feign hesis to Idenness ht of no that an ranee of but the the true a bolder circum- subdued )ind and 3aid that stranger ost with observed ibe more 1 its own to light, taste of 3uddenly ; and so lowed all ken into •-door, in !ss in the s appear- ixcepting of these 307 creatures made an effort to escape, and were taken „n nf leisure; nor had they received anVhurt oT h'jury L L* Boon displayed every mark of being alive and wdZ' ^ It would be as easy to catch a Weasel asleen as off ,>- bemg „h«t, Puss, deceived by its app^fe ' WeLn^ss lail had of It round the body had prevented any ?arl er eflbrt at injury ; but the Weasel can ha?Sy be sunnosed t^ h J K™' «ng a deception all the ^Me^T^f fnte^ ^^^.^ This hypothesis would require to be substinh'nfprl w special experiments before it would merit urn^^^^^^^^^^^^ ance. These experiments would consist in allowin 'an aniS" mmediatery that it is observed shamming dead to len" Hs liberty, and to watch it without the animal knowing th'itt being observed. If it were then to continue for any con side able time motionless, the fact would tend to prove Couoh'^ Tesence of dan Jr S ?n ' '"^'P^'^"^ the passiveness in the inesence or aanger clue to conscious purpose. I once thnimhf- that I had myself the opportunity of trying this experS for having caught a wild scjuinel in a cloth I oterveSt the animal immediately became motionless. TurniiJL out upon the ground and concealing myself from its view I waiteda • Illustrations of Instinct, p. 125. H 1^ I* Hi I M^ i: W' 808 MENTAL EVOLUTION IN ANIMALS. ' ( wild animal on being captured may be sufficient to causa actual death, and the researches of Professor Preyer on the hypnotism of animals (conducted long after Coucli's book was published and having no special reference to the present question), showed that fright is a strong predisposing cause of " Kataplexy," or mesmeric sleep in animals. This allusion to Professor Preyer's researches leads me next to remark that he ascribes the shamming dead of insects to the exclusive influence of kataplexy. Having observed the potency of this influence in producing analogous condi- tions in the neuro-muscular systems of higher animals— even as far down the series as the cray-fish, Avhich were made to stand upon their heads whiie in the hypnotic state — it was perfectly logical in him to attribute the shamming dead of insects to the same cause. And his reasoning might have been greatly strengthened had he been aware of the import- ant facts which had been observed by Mr. Darwin, and which are now given in the Appendix. These facts, it will be noted, are, that there is no species of spider or insect of which it can be said that the attitude assumed when sham- ming death at all closely resembles the one which the animal assumes when really dead ; that in many cases this attitude is very dissimilar ; and therefore that all " shamming dead " amounts to in tliese animals is an instinct to remain motion- less, and thus inconspicuous, in the presence of enemies. And it is easy to see that this instinct may have been de- veloped by natural selection without ever having been of an intelligent nature — those individuals which were least in- clined to run away from enemies being preserved rather than those which rendered themselves conspicuous by move- ment. That is to say, it is easy to see how the instinct may have become developed by primary means ; for if it were of more advantage to an animal when in danger to become motionless, and therefore inconspicuous or unattractive to enemies, than it would be to ocek safety in fliglit, of course it is obvious that in such cases natural selection would always have operated in the direction of producing quiescence, no less than in other cases it would have operated in the direction of producing activity. Now, 1 think it is not at all improbable that " kataplexy " may have been of much assistance in originating, and possibly also in developing, this instinct. FEIGNINO DEATH. 809 continued alonftL^!^. 1? *°"°" ''""'<' "n™' 'ikely b« state occur with irrpnt qii/1^-.»,„ i^iuuiuy, so as to make the to 18 removed • *""'^ "^ ^'''""'"S "i""'"- pec«.i^ties?f 'ol^rtiofofS™ ,f"^ Prinoiples of Cotl : VobabteS" bS *' of'^hth^iLrt^r V '"™' ^^^ *^^^^^^ instinct TW ? selection has constructed this particular themselves to be pierrediitKiranJl^^^^^^^ ^'"'^' "^'" «"ff«' smallest signs of terror" JddB^lZt^f^? P"*'"' '''"'°"* discovering the kind of stupor occasioned by terror "th. 1 *""? """'f' ''' "^^"^ ^^Pposel, " a when the object of terror i7remov^ BnfT"' ""f^* °2*^/'' ^''^ ^ ^««°'er does not pass off immediatelv Tnnn fi,- !•* ™^.^'*' °^ ^'^^^^ ^^^ "stupor" long as the katap ectic sSte liin }^ ""'t*!^" °^ ,**^° «*™"1»« ' it '^sts as on its back. ^ ^ '*''^' '° '^^^'^''^ '^"^«' 8«^'li M the owl when held 310 MENTAL EVOLUTION IN ANIMALS. m lilr I ni: of doubt, and even if the phenomena of kataplexy were not available for natural selection to seize upon for the purpose in question, there can be no doubt that other materials might have been so ; for, a priori, there seems to be at least not more difficulty in developing an instinct to remain motionless under certain circumstances, than in developing one to run away ; and as a matter of fact, all animals which are protectively coloured have, either as cause or consequence, developed their instincts in the former directiou. Therefore we must suppose that an animal which was not sufficiently locomotive to find safety in flight, would be most closely attended to by natural selection in the direction of encourag- ing quiescence— and this whether or not natural selection were provided with kataplectic susceptibilities on which to operate ; kataplexy alone could not form the. instinct. So far, then, the subject is sufficiently clear. But now, we have obviously some important distinctions to draw. Foi the shamming dead of a highly intelligent animal like a fox is a widely difierent matter, psychologically considered, from the shamming dead of insects ; so that an explanation v/hich might be held fully adequate to account for the latter might not be so to account for the former. Thus while I have no hesitation in regarding the fact in insects as due to a non- •p intelligent instinct developed by natural selection in the way just explained, I cannot see how this could well be the case in vertebrated animals. A fox would never have so good a chance of escape from an enemy by remaining motionless as ic would by the use of its legs, which it requires a fox-hound to overtake. Moreover the shamming dead is here far from invariable, and so is not, as in the case of insects, instinctive. Therefore, although I did not fully agree with Preyer in assigning the universal (instinctive) quiescence of certain insects when alarmed to the unassisted influence of kata- plexy, I think that the occasional (accidental) display of quiescence by wild vertebrated animals under similar circum- stances tends much more unequivocally in favour of his view. For here the action is not universal, or even usual ; and when it does take place it must, as a rule, be rather detrimental to the animal than otherwise — seeing that the whole economy of the animal is here adapted to rapid movement. Therefore 1 think that in the case of Birds and Mammals the hypothesis of Couch already quoted is the most reasonable — especially FEIGNING DEATH. 311 if we supplement it with our knowledge concernin*^ the recently discovered facts of kataplexy.* ° On the other hand, not to shirk a difficulty, I have some re- markable evidence which tends to show that certain monkeys sham dead with the deliberate purpose, not of escaping from enemies, but of deceiving intended victims. Here, of course there can be no terror and no kataplexy, so that if we accept the evidence of the fact we must seek for some other expla- nation. ^ Thompson gives in his « Passions of Animals " (pp. 455- 7), the case of a captive monkey which was tied to a long upright pole of bamboo in the jungles of Tillicherry. The ring at the end of its chain fitting loosely to the slippery pole, the animal was able to ascend and descend the latter at pleasure. He was in the habit of sitting on the top of the pole, and the crows taking advantage of his elevated position, used to steal his food which was placed every morning and evening at the foot of the pole. " To this he had vainly expressed his dislike by chattering, and other indications of his displeasure equally ineffectual; but they continued their periodical depredations. Finding that he was perfectly un- heeded, he adopted a plan of retribution as effectual as it was ingenious. One morning when his oormenters had been par- ticularly troublesome, he appeared as if seriously indisposed • he closed his eyes, dropped his head and exhibited various other symptoms of severe suffering. No sooner were his ordinary rations placed at the foot of the bamboo, than the crows watching their opportunity, descended in great num- bers, and according to their usual custom, began to demolish his provisions. The monkey began now to descend the pole by slow degrees as if the effort were painful to him, and as if so overcome by indisposition that his remaining strength was scarcely equal to such an exertion. When he reached the ground he rolled about for some time, seeming in great a«ony until he fou-d himself close to the vessel einployed to Con- tain his foot, ,-hich the crows had by this time well nigh devoured. There was still, however, some remaining, which a sohtary bird, emboldened by the apparent indisposition of the monkey, advanced to seize. The wily creature was at this time lying in a state of apparent insensibility at the • The winking of the wolf's eye, mentioned by Captain Lyon, would be quite compatible with a certain phase of the hypnotic state. ii J- i 5 ;N 5'v 312 MENTAL EVOLUTION IN ANIMALS. .f 1 ' ' foot of the pole and close by the pan. The moment the crow stretched out his head, and ere it could secure a mouthful of the mterdicted food, the watchful avenger seized the depre- dator by the neck with the rapidity of thought and secured it from doing further mischief. He now began to chatter and grm with every expression of gratified triumph, while the crows flew round, cawing, as if deprecating the chastisement about to be inflicted on their captive companion. The monkey continued for a while to chatter and grin in triumph ; he then deliberately placed the crow between his knees and' began to pluck it with the most humorous gravity. When he had completely stripped it, except of the large feathers in the pinions and tail, he flung it into the air as high as his strength would permit, and after flapping its wings for a few seconds, it fell to the ground with a stunning shock. The other crows, which had been fortunate enough to escape a similar castigation, now surrounded it and immediately pecked It to death. The animal then ascended its pole, and the next time his food was brought, not a single crow approached it." I have quoted this case although it sounds well nigh in- j credible, not merely because Thompson is a good authority, /^ but because in all its essential details it has been uncoi.- sciously corroborated by the observations of a friend of my own, VIZ., the late Dr. W. Bryden, C.B. This gentleman, without being cognizant of the above anecdote, told me that he had himself repeatedly witnessed a tame monkey (I forget the species) in India lying on its back perfectly motionless for long periods of time, till the crows in the neighbourhood, supposing him to be dead, approached within grasping dis- tance, when he used to make a sudden spring at one of them, and proceed slowly to pluck it alive, apparently for the mere love of gratifying his passion of cruelty— although, however, he used to suck the juicy ends of the larger feathers. As I can quite rely on Dr. Bryden's veracity and cannot imagine how in such a case there can have been any room for malobserva- tion, I am inclined to lend a credence to the above anecdote which I should otherwise have regarded with distrust. Now if, as I can scarcely doubt from Dr. Bryden's account, some monkeys display the remarkable trick of really and of set purpose shamming death, the only possible explanation of the fact is that, having observed crows to congregate round motionless carcasses, they infer that by remaining motion- FEIGNING DEATH. 313 less they may induce these animals to come within grasping distance. No doubt this displays an astonishing amount o1 deliberative inference ; but it is to be observed that the fact, if It is a fact, does not imply any abstract idea of death ; it implies only the idea of imitating a previously observed quiescence with the purpose of bringing about the same result — approach of birds— which that quiescence had pre- viously been observed to produce. Seeing that monkeys are highly imitative as well as highly observant animals, this interpretation is not so antecedently incredible as at first sight it no doubt appears. But now it follows that if monkeys are able consciously and with deliberate intent to remain motionless for the purpose of gaining a particular object, other and almost as intelligent animals may do the same. Thus, notwithstanding the proba- bility previously pointed out that the shamming dead of wolves and foxes may be due to kataplexy, there here arises a possibility of its being due to intelligent purpose. As bearing on this possibility, I will quote two cases which appear to have been sufficiently well observed. The first is one which has been recently published by Brigade Surgeon G. Bidie in "Nature" (vol. xviii, p. 244). He says : — " Some years ago, while living in Western Mysore, I occupied a house surrounded by several acres of fine pasture land. The superior grass in this preserve was a great tempta- tion to the village cattle, and whenever the gates were open trespass was common. My servants did their best to drive off intruders, but one day they came to me rather troubled, stating that a Brahmin-bull which they had beaten had fallen down dead. It may be remarked that these bulls are sacred and privileged animals— being allowed to roam at large and eat whatever they may fancy in the open shops of the bazaar-men. On hearing that the trespasser was dead, I immediately went to view the body, and there sure enough it was lying exactly as if life were extinct. Being rather vexed about the occurrence in case of getting into trouble with the natives, I did not stay to make any minute examination, but at once returned to the house with the view of reporting the afifair to the district authorities. I had only just gone for a short time when a man, with joy in his face, came running to tell me that the bull was on his legs again and quietly / L If-! 1 . i um ' i i r ■ : ' 314 MENTAL EVOLUTION IN ANIMALS. 1 .'I !h I! Ml 1 grazing. Suffice it to say that the brute had acquired the trick of feigning death which practically rendered its expul- sion impossible, when it found itself in a desirable situation which it did not wish to quit. The ruse was practised fre- quently with the object of enjoying my excellent grass, and although for a time amusing, it at length became troublesome, and resolving to get rid of it the sooner, I one day, when he had fallen down, sent to the kitchen for a supply of hot cinders, which we placed on his rump. At first he did not seem to mind this much, but as the application waxed hot, he gradually raised his head, took a steady look at the site of the cinders, and finally getting on his legs went off at a racing pace and cleared the fence like a deer. This was the last occasion on which we were favoured with a visit from Cur friend." Now here we have a case of apparent simulation of death I frequently repeated with an intelligent purpose, and as the / narrator is a medical man, we mvst suppose that the simula- tion was well done. Nevertheless, the idea which the animal had may only have been that of remaining inert, and trusting to his weight in preventing his removal. The case, however, is unquestionably a remarkable one, and the inter- pretation which I have suggested becomes perhaps less pro- bable in view of the other case to which I have alluded, and which I shall now proceed to give. This case is published in the late Mr. Morgan's book on the Beaver (p. 269), and he says it " was communicated to the author by Mr. Coral C. White of Aurora, New York, who carried out the fox. His veracity is unimpeachable." " A fox one night entered the hen-house of a farmer, and after destroying a large number of fowls, gorged himself to such repletion that he could not pass out through the small aperture by which he had entered. The proprietor found him in the morning sprawled out upon the floor, apparently dead from surfeit ; and taking him up by the legs carried him out unsuspectingly, and for some distance to the side of his house, where he dropped him upon the grass. No sooner did Eeynard find himself free than he sprang to his feet and made his escape. He seemed to know that it was only as a dead fox that he would be allowed to leave the scene of his spoliations ; and yet to devise this plan of escape required no ordinary effort of intelligence," &G. i :l FEIGNING DEATH. 315 If the facts are here correctly recorded (and in aU the points upon which I am about to dweU they agree closely with some of the cases given by Couch), one would scarcely suppose that the mere approach of a man in openina the door of the hen-house could have caused either the kind or degree of alarm which is known to produce kataplexy ; while It IS somewhat doubtful whether the stimulus occasioned by dropping the fox upon the grass would have been sufficient suddenly to dispel the kataplectic state. Therefore, in such a case as this it seems to me that the probability rather inclines to the shamming dead having been due to an intelligent pur- pose, even although we may not suppose the animal to have had any idea either of death as such, or of its conscious simulation. Thus the case with respect to the higher animals --It we have due regard to all the evidence which has now been presented— seems to me one of no small difficulty The truth simply is that there is a lack of sufficient observation by experimental means, to determine whether wolves and more especially foxes, simulate death-i.g., remain motion- less in certain circumstances of danger with the conscious purpose ol iurthering their escape ; or, perhaps almost as probably, whether the motionless condition of these animals under such circumstances is due to the occurrence of the hypnotic state. With regard to these animals, therefore, as with regard to the Brahmin-buU, I have thought it best not to express a definite opinion either way; but rather to pre- sent all the evidence on both sides with the view of stimu- lating experimental enquiry of the kind that I have sug- gested by any one who may have the opportunity of con- ducting It.* Such an enquiry having been conducted by Mr. Darwin in the case of insects and spiders has closed the question as far as they are concerned, by leaving no room to suppose that their beha-iour is due to conscious purpose. The evidence with regard to the higher Mammalia, on the other hand, points to a different conclusion, for the full establishment of which further and corroborative evidence is doubtless necessary. Be it observed, however, that in these cases the difficulty .f-^nH ll^"";^' ^\^J^'^- ''**^^ ^^^i"g '•^'^•i ^^^ aboTe and so having under- 8tx>od the nature of the question, had laid down his fox upon the grts with extreme gentleness and immediately concealed himself, he might greatly have furthered the solution of the (iuestibn. " S**^""/ "ave ^^aml 1 'I „ jlJu ■:i- ■ I ^ u 316 MENTAL EVOLUTION IN ANIMALS. has no reference to any question of instinct — for, unlike the case of insects, the habit is much too exceptional to be regarded as instinctive — but to determining whether the facts are due to intelligent purpose or to some purely physio- logical effects of fear. In the more remarkable of the above- quoted cases, no doubt, the latter hypothesis is not available; but it may be so in some of the others, and even where this hypothesis is not available, it becomes most desirable to understand the class of ideas which indur- '\ faimtil to behave in a manner so closely simulating de. * 'ere, how- ever, I am only concerned with showing that i v difficulty of arriving at such an understanding has nothing to do with the present theory as to the formation of instinct. I '. !!li •u jJii t ■ Feigning Injury, In the " Contemporary Eeview " (July 1875) the Diike of Argyll, in an article on " Animal Instinct," argues that the female duck could hardly have consciously learnt to imitate the movements of a wounded bird ; and that the young merg- ansers, which squat on the mud when alarmed and are thus made inconspicuous while the old ones fly away, are in the same case. Mr. Darwin, in some MS notes on this article, observes that he agrees with the Duke in not ascribing the deceptive movements of the female duck, &c., to conscious imitation of wounded birds ; but thinks that a female bird which, from solicitude for her nestlings, would endeavour to fight a threatening quadruped as a hen does a dog, might, by alternately attacking and retreating, inadvertently draw the enemy away from the nest. Natural selection, acting on this primitive habit, might then develop the running away from the nest as an instinct ; and if, as is probable, carni- vorous quadrupeds would be more likely to follow birds apparently unable to fly than birds apparently well, the action of drooping the wing, &c., might have been slowly developed. The instinct of squatting shown by young birds, which are thus rendered inconspicuous, was no doubt acquired in the same way and for the same reason as the instinct of shamming dead in insects. The instinct, however, in the case of young birds may have originally been acquired by older animals (due in the first instance to being partlj FEIGNING INJURY. 317 inlike the lal to be ether the \y physio- ihe above- available; vhere this 3irable to f'aimtil to 'ere, how- fficulty of ) with the bhe Duke s that the ;o imitate ing merg- 1 are thus ire in the is article, ribing the conscious male bird eavour to og, might, itly draw acting on ing away )le, carni- iow birds well, the en slowly ds, which jquired in iistinct of sr, in the q[uired by Qg partl;^ paralyzed by fright), and then, in ancordance with the general principles of heredity, being inherited at an earlier age by the progeny. It will thus be seen that Mr. Darwin was disposed to attribute the instinct, both of the mother and young to an exclusively primary origin ; but I confess that the case does appear to my mmd one of difficulty, and I am rather inclined to think that the instinct of the mother in the case of the duck, peeweet, partridge, and all birds which present it, must have originally been assisted by intelligence. It must be admitted, from what we know of hens, that the maternal feelings may be so strong as to lead to a readi- ness to incur danger or death rather than that the brood should do so. Tlierefore, when in the presence of a four- footed enemy the mother bird begins alternately attack- ing and retreating in the manner alluded to by Mr. Darwin, if she were intelligent enough to observe that on retreating without taking wing she was followed up, there can be no doubt that she might with intentional purpose thus lure away the enemy from her young. If so, those parents which had sense enough to adopt this device would no doubt be able to rear a greater number of broods than could the less observant parents ; and the young broods of such intelligent parents would inherit a tendency to adopt this device when they themselves became mothers. Thus the originally intel- ligent device would slowly become organized into an instinct, and so be now performed with mechanical promptitude by every individual partridge, plover, and duck. The greatest dithculty 13 to account for the drooping of the wing, and this, I think, can only be done by regarding it, with Mr. Darwin^ as of an unblended primar- origin. The case, however is unquestionably very remarkaule. Such are the only instincts which have occurred to me as hkely to present any special difficulty to the foregoing theory of the origin and development of instincts in general. Mr. Darwm m his chapter on Instinct in the " Origin of Species " has fully discussed several other instincts in this connection (viz., the parasitic instinct of the cuckoo, the cell-makincr instinct of bees, and the slave-making instinct of ants); but as these do not present any real difficulty, I shall not wait to go over the ground already so thoroughly traversed by 21 318 MENTAL EVOLUTION IN ANIMALS. CHAPTER XIX. Eeason. i ' Ml ! ' 11 I SHALL begin this chapter by quoting from " Animal Intel- ligence my definition of the word " Reason," in order that my use of the word may be clearly understood. ^ "Reason is the faculty which is concerned in the inten- tional adaptation of means to ends. It therefore implies the conscious knowledge of the relation between means employed and ends attained, and may be exercised in adaptation to circumstances novel alike to the experience of the individual and to that of the species." In other words, " it implies the power of perceiving analogies or ratios, and is in this sense equivalent to the term 'ratiocination,' or the faculty of dexiucing inferences from a perceived equivalency of relations This latter is the only use of the word that is strictly legiti- mate, and it IS thus that I shall use it throughout the present treatise. This faculty, however, of balancing relations draw- ing inferences, and so of forecasting probabilities, admits of numberless degrees." The object of the present chapter will be that of tracin^r the probable genesis of this faculty, and, in order to crive clearness to the discussion, I desire it to be remembered that I reserve the terms Reason and Ratiocination to designate the faculty above defined. I shall use the term Inference to designate the less highly developed mental antecedents out ot which, as I shall show, I conceive Reason to have been evolved. No doubt every act of reason is also an act of in- ference, but we shall find that it is absolutely necessary to have some word to signify indifferently the lowest and the highest stages of that whole class of mental processes which culminates m symbolic calculation. The word Inference is fit m REASON. 319 the best that I can find, and therefore it will bo understood that in my usage, while all acts of reason are likewise acts of inference, all acts of inference need not be acts of reason. Thus much as to terminology being premised, I may pass to the subject of the present chapter. I have already, in earlier chapters, endeavoured to show how it is probable that consciousness arises out of reflex action (or that the mind- element becomes attached to nervous processes of adjustment), when the latter arrives at such a degree of complexity, or has reference to external circumstances having such a degree of inconstancy, that the nerve-centre becomes a seat of com- parative turmoil among molecular forces. Whenever this stage is reached, and a nerve-centre begins to become con- scious of its own working, we pass, according to my classifi- cation, from the domain of reflex action into that of instinct —instinct being, in my terminology, reflex action into which there is imported the element of consciousness. But now, as during the course of evolution the lower forms of life are required progressively to adjust their actions to circum- stances of growing complexity and inconstancy, or to occasions of growing infrequency, it follows that the organized instincts with which they are endowed must at some point begin to become inadequate; a greater flexibility in the power of adjustive response is needed, and if any such flexibility is possible under the conditions of ganglionic action, those individuals which best attain to it will survive, and so the improvement will become general to the species. Now we know tha,t such an increase of flexibility is possible under the conditions of ganglionic action, and this increase of flexibility on its subjective side we know as the faculty of reason. It is here needful to consider in what this faculty consists. While treating of the genesis of Perception I pointed out that the faculty admits of numberless degrees of elaboration. These we found to depend largely, or even chiefly, upon the degree of complexity presented by the objects or relations perceived. Now when a perception reaches a certain degree of elaboration, so that it is able to take cognizance of the relation between relations, it begins to pass into reason, or ratiocination. Contrariwise, in its highest stages of develop- ment, ratiocination is merely a highly complex process of perception— ie., a perception of the equivalency of perceived ^■'1 f' I mMU^ i. < I t ^^ ! f'i t. " /r? i* 320 MENTAL EVOLUTION IN ANIMALS. ratios which are themselves more or loss elaborated percepts formed out of simpler percepts, or percepts lying nearer to the immediate data of sensation. Thus, universally ratiocination may be considered as the higher development of perception ; for at no point can we draw the line and say that the two are distinct. In other words, a perception is always in its essen- tial nature what logicians term a conchision, whether it has reference to tlie simplest memory of a past sensation or to the highest product of abstract thought. For when the highest product of abstract thought is analyzed, the ultimate elements must always be found to consist in material given directly by the senses ; and every stage in the symbolic construction of ideas in which the process of abstraction consists, depends upon acts of perception taking place in the lower stages. True it is that these acts of perception here have reference to the symbols of ideas, which may themselves be far removed from the simple and immediate memories of past sensations ; but as we can nowhere draw the line between perception of the one order and perception of the other, we ought to reco"- nize that in the case of this faculty there is nowhere any difference in kind, although everywhere a difference in degree : or, otherwise stated, intellectual processes which culminate iii symbolic reasoning are everywhere processes of cognition, and of these processes the term perception is a generic name. ' But having thus shown that in my opinion there is no real break between cognition of the lowest and of the highest order, I must next show at what places I think it is conve- nient, for the sake of historical description, to mark off what I may term conventional stages in the development of cog- nition. This I have already done for the lower stages of such development in my chapter on Perception, where it was shown that the first stage consists in merely perceiving an ev<-,ernal object as an external object, the next stage in rQco ' » « - n BEASON. 331 to make the important addition that it must be strictly limited to the objective aspect, as distinguished both from the subjective and ejective aspects of the phenomena. In other words, if vre have regard only to the physical aspect of the phenomena {i.e., the physiology of ganglionic processes as expressed in the adjustive movements of organisms), this statement of the case is unexceptionable. But if we pass from physiology to psychology, the statement ceases to be adequate ; for both in the region of subjective and of ejective psychology it would fail to express the important distinction between two very different acts of mind — viz., one in which there is no knowledge of the relation between means em- ployed and ends attained, and one in which there is such knowledge.* But, passing over this point, we arrive at a lucid state- ment of the view that "when the correspondence has advanced to those environing objects and acts which present groups of attributes and relations of considerable complexity, and which occur with comparative infrequency — when, consequently, the repetition of experiences has been insufficient to make the sensory changes produced by such groups cohere perfectly with the adaptive motor changes — when such motor changes and the impressions that accompany them simply become nascent: then, by implication, there result ideas of such motor changes and impressions, or, as already explained, memories of the motor changes before performed under like circumstances, and of the concomitant impressions." Still there is not yet any manifestation of rationality. But now, " when the confusion of a complex impression with some allied one causes a confusion among the nascent motor exci- tations, there is entailed a certain hesitation, and .... ultimately some one set of motor excitations will prevail over the rest." The strongest set will eventually pass into action, and as this set will usually have reference to the circumstances which have recurred most frequently in experience, "the action will, on the average of cases, be the one best adapted to the circumstances. But an action thus produced is nothing * It will be observed that if we adopt Mr. Spencer's definition of Instinct, the breach on the mental side is still further widened— the distinction between Instinct and Eeason being then equivalent to the distin(;tion between nervous actions having no mental counterparts at all, and nervous SbCtiona which on their subjective side are inteationall^r adaptive. 833 MENTAL EVOLUTION IN ANIMALS. ' «\ IlKh II else than a rational one This, however, is just the process which we saw must arise whenever, from increas- ing complexity and decreasing frequency, the automatic adjust- ment of inner to outer relations becomes uncertain and hesitating. Hence it is clear that the actions we call instinc- tive pass gradually into the actions we call rational." Now in an earlier part of this treatise I have stated my belief that consciousness arises when a nerve-centre is sub- jected to a comparative turmoil of molecular forces, which finds its physiological expression in delay of response, or, as Mr. Spencer says, in " hesitation," But I do not believe that in all such cases Eeason, as distinguished from Consciousness, must arise. Therefore I should say that, although there cannot be Eeason without such ganglionic friction, there may be such ganglionic friction without Eeason. There may, for example, be a large, and even a distressing amount of such friction produced in the case of a conflict of instincts ; there may in such cases be prolonged delay ending in " the strongest group of antagonistic tendencies at length passing into action ;" and yet no act of reason need arise. In what respect, then, do I diffier from Mr. Spencer touch- ing the genesis of Eeason ? I differ from him, firstly, in not deeming an act of reason as such a constant or invariable index of ganglionic disturbance greater than that which may arise under other circumstances of psychical activity (and therefore in not deeming that reason must necessarily arise out 7 of such disturbance); and, secondly, in not deeming that Eeas(*n can only arise out of Instinct. Taking these two points of difference separately, it will be enough to say of the first that it has reference only to the earliest origin of Eeason, or to acts of reason of the simplest kind ; in the case of more elaborate processes of reasoning I have no doubt that the ganglionic disturbance must be great, and that without such disturbance these more elaborate processes would not be possible. But this, of course, is a widely different matter from concluding that wherever gan- glionic disturbance reaches a certain degree of complexity, leading to a consequent delay of response, there Eeason (as distinguished from vividness of consciousness) must neces- sarily arise. On the contrary, I hold that in the lower stages of what I have defined as Eeason (and, a fortiori, in all the stages of what I have defined as Inference), there may not be 'the SEASON. 333 more, and there may not be even so much ganglionic dis- turbance or consequent delay of response, as there may be where no act of rationality is concerned — as, e.g., in a conflict of instincts. Turning now to my second point of difference with Mr. Spencer, I can see no adequate ground for concluding with him that Eeason can only arise out of Instinct. On the contrary, holding, as I have explained, that Eeason has its antecedents in the habitual inferences of sensuous perception, that Instinct (as distinguished from Reflex Action) likewise has its antecedents in sensuous perception, and that neither Reason nor Instinct can advance beyond this first origin without an always corresponding advance in the powers of perception ; holding these views, I am forced to conclude that Perception is the common stem out of which Instinct and Reason arise as independent branches. In so far as Percep- tion involves Inference, Instinct involves Perception, and Reason involves Inference, there arises, of course, a genetic connection between Instinct and Reason ; but this connection is clearly not of the kind which Mr. Spencer indicates : it is organic, and not historic. This important divergence in my views from those of Mr. Spencer I take to be due to his manner of regarding the relations that subsist between nervous changes which are accompanied by Consciousness, and nervous changes which are not so accompanied. Thus the divergence between our views on this matter began so far back as in our respective analyses of Memory, where I observed, " I cannot agree that if psychical changes (as distinguished from physiological changes) are completely automatic, they are on this account to be precluded from being regarded as mnemonic. . . . . In so far as they involve the presence of conscious recognition, as distinguished from reflex action, so far, I think, no line of demarcation should be drawn between them and any less perfect memories."* Again, the divergence was manifested when I came to treat of Perception, and I there gave my reasons for regarding it as " very questionable whether the only factors which lead to the differentiating of psychical processes from reflex nervous processes are (as Mr. Spencer alleges) complexity of operation combined with infrequency of occur- rence."t And the divergence in question became still more • See p. 130. t See p. 140. 22 ^ ' 1 1 1 . A ■S' ' ■ i' t t 1 '■■{ I if . ' : I ' t i 1 ' tl 1 •■ H p'i 334 MENTAL EVOLUTION IN ANIMALS. pronounced when I arrived at my analysis of Instinct ; for by identifying Instinct with compound reflex action, we found it to be evident that Mr. Spencer wholly disregards what I take to be the essentially distinguishing feature of Instinct, viz., the presence of Perception .is distinguished from Sensa- tion. Thus, lastly, when we now come to the province of Eeason, the same divergence recurs. Whether for the special purpose in hand I accept Mi'. Spencer's definition of Instinct as coripound reflex action, or adhere to my own definition of it as reflex action into which there is imported the element of consciousness, I alike find it impossible to agree with him that Eeason necessarily and only arises out of Instinct. For, taking first Mr. Spencer's definition of Instinct, I cannot agree that Reason necessarily and only arises out of compound reflex action, because I see it to be a fact that in the higher organisms we meet with numerous cases of enormously compound reflex actions which present no indi- cations of rationality. And some of these oases, it may be parenthetically observed, can nevfsr at any period of their developmental history have been rational, and afterward^: have become automatic by frequency of repetition. Such, for example, cannot have been the case with the compound reflex actions which are concerned in parturition, nor with those more obscure reflex actions which now bafhe our rationality to comprehend — I mean the changes set up by an impreg- nated ovum in the walls of the uterus. These are instances of immensely compound reflex actions which must alway^3 have occurred with great rarity in the life-h story of indi- viduals, and can never at any time have been either the causa or the effect of rationality. Again, taking my own definition of Instinct, I cannot agree that Reason necessarily and only arises out of reflex action into which there is imported the element of conscious- ness. For this element is merely the element of Perception, and I do not know of any evidence to justify the conclusion that Perception can only arise out of the growing complexity and infrequency of reflex actions. As I said in my chapter on Perception, " the truth is that, so far as definite knowledge entitles us to say anything, the only constant physiological difference between a nervous process accompanied by con- sciousness and a nervous process not so accompanied, is that of time. In very many cases no doubt this difference may SEASON. 335 be caused by the intricacy or the novelty of the nervous pro- cess which is aeconipauied by consciousness;"* but seeing that in ourselves, as just observed, highly intricate and very infre- quent nervous processes may take place mechanically, I do not think we are justified in concluding that complexity and in frequency of ganglionic action are the nnly factors in deter- mining the rise of consciousness. But even supposing, for the sake of argument, that they are, still it would not follow that the only road to Eeason lies through Instinct. Percep- tion being the element common both to Instinct and to Eeason, it may very well happen (and ind -ed I think actually does happen) that Eeason arises directly out of tho!,,a automatic inferences which, as we have seen, are given in Perception, and which, as we have also seen, furnish the con- ditions to the origin of Instinct. From this statement, however, I hope it will be manifest that I do not dispute that Eeason may, and probably does in many cases arise out of Instinct, in ihat the perceptive basis of Instinct is so apt to yield material for the higher percep- tions of Eeason. I merely object to the doctrine that Eeason can arise in no other way. And, as further showing the untruth of this doctrine, I may in conclusion point to the numberless instances given in my chapters on Instinct of the reciprocal action between Instinct and Eeason — the develop- ment of the former sometimes leading to the higher develop- ment of the latter and sometimes, as in all cases of the formation of Instinct by lapsing intelligence, the development of the latter leading to the higher development of the former. Such reciprocal action could not take place were it true that Instinct is always and necessarily the precursor of Eeason. I must not take leave of this discussion on Eeason with- out briefly alluding to the very prevalent vlew-*-with which of course I do not agree — that the faculty in question is the special prerogative of Man. As the most enlightened and best informed writer who of late years has espoused this doctrine is Mr. Mivart, I shall take him as its exponent, and in examining his arguments on the subject I shall consider argument? which can be that I am examining the best adduced in support of the view in question. Mr. Darwin, in his " Descent of Man," gives the foUow- • See p. 140. >.■'!' lb ' 838 MENTAL EVOLUTION IN ANIMALS. ing account of tho exhibition of Keason on the part of a Crab:—" Mr. Gardner, whilst watchini,' a shore crab (f/slasi- mus) making its burrow, threw some shells towards the hole. One rolled in, and three other shells remained within a f(iW inches of the mouth. In about five minutes the crab brought out the shell which had fallen in, and carried it away to the distance of a foot ; it then saw the three other shells lying near, and evidently thinking that they might likewise roll iii^ carried them to the spot where it had laid the first. It Avould, I think, be difficult to distinguish this act from one performed by man by the aid of reason."* Mr. Mivart, after quoting the above, calls the concluding sentence an "astonishing remark."! I shall, therefore, pro- ceed to consider the very prevalent opinion to which such a commentary introduces us, and which consists, as I have said, in regarding the faculty of Eeason as the special prerogative of Man. I must begin by again observing that the faculty of Reason, in the sense of a " knowledge of the relation between means employed and ends attained, .... admits of numberless degrees ; " and I hold it to be a mistake, greater than any other that has been committed in psychological science, to suppose that there is any difference of kind whether this faculty is exercised with reference to the highest abstractions of introspective thought, or to the lowest pro- ducts of sensuous perception ; whether the ideas involved are general or special, complex or simple, wherever there is a process of inference from them which results in establishing a proportional conclusion among them, there we have some- thing more than the mere association of ideas; and this something is Eeason. If I were to see a large stone falling through the roof of my conservatory, and on climbing to the wall above saw three or four other stones just upon the edge, I should infer that the stones which fell previously stood In a similar relation to my conservatory, and therefore that it would be desirable to remove the others from their threaten- ing position. This would not be an act of association, but an act of reason (though a simple one), and it is psychologically identical with the act which was performed by the crab. Further, according to J. S. Mill, " all inference is from paiticulars to particulars: General propositions are merely • Desuenl of Man, p. 270. f Lessons from Nature, p. 213. REASON. 337 registers of such inferences already made, and short formiilre for making more." Now although this doctrine is not universally accepted by logicians— Whately, for instance, having maintained the exact converse, and many minor writers more or less agreeing with him,— I feel compelled to fall in with it on purely logical grounds, or without reference to ariy considerations drawn from the theory of evolution. For it appears to mo that Mill is completely successful in showing that only by this doctrine can the syllogism be shown to have any functions or any value. " It must be granted that in every syllogism, considered as an argument to prove the conclusion, there is a pditio princ'qni. When we say, All men are mortal; Socrates is a man; therefore Socrates is mortal ; it is unanswerably urged by the adver- saries of the syllogistic theory that the proposition, Socrates is mortal, is presupposed in the more general assumption. All men are mortal." Therefore, " no reasoning from generals to particulars can, as such, prove anything : since from a general proposition we cannot infer any particulars, but those which the principle itself assumes as known." This is not a suit- able place in which to discuss such a question of logic at length, and therefore I shall merely refer to Mill's exposition of it* But as I can see no escape from tlie view which he enforces that the major premiss of a syllogism is merely a generalized memorandum of past particular experiences, and therefore that all reasoning is, in the last resort, an infer- ence from particulars to particulars ; I think that this con- clusion (arrived at without reference to the theory of evolution) is available to argue that there is no difference in kind between the act of reason performed by the crab and any act of reason performed by a man. It must be remembered that I am not now discussing the larger question as to whether there is any distinction in kind between the whole mental organization of an animal and the whole mental organization of a man. This larger question I shall fully discuss in my subsequent work. Here I am only endeavouring to show that so far as the particular faculty of mmd is concerned which falls under my definition of reason, there is no such distinction. A process of conscious infer- ence, considered merely as a process of conscious inference, 'I • n * Logic, vol. i, Cliap. IlL :;I1 l! i.. t* 338 MENTAL EVOLUTION IN ANIMALS. ;'. !' iil . \k itii is the same in kind wherever it occurs and whatever degree of elaboration it presents. But here I must meet an assertion which is often made, and which has been presented by Mr. Mivart with his accustomed adherence to logical form, and therefore with much apparent cogency. He says : — " Two faculties are distinct in kind if we may possess the one in perfection without thereby implying that we possess the other ; and still more so if the two faculties tend to increase in an inverse ratio, the perfection of the one being accompanied by a degradation of the other. Yet this is just the distinction between the instinctive and rational parts of man's nature. His instinctive actions are, as all admit, not rational ones ; his rational actions are not instinctive. Even more than this, we may say the more instinctive a man's actions the Zess are they rational, and vice, versd ; and this amounts to a demonstration that reason has not, and by no possibility could have been, developed from instinct. In man we have this inverse ratio between sensation and perception, and in brutes it is just where the absence of reason is most generally admitted {e.g., in insects) that we have the very summit and / perfection of instinct made known to us by the ant and the bee. . . . Sir William Hamilton long ago called atten- tion to this inverse relation ; but when two faculties tend to increase in an inverse ratio, it becomes unquestionable that the difference between them is one of kind."* Now I meet this argument by denying the alleged fact on which it reposes. It is simply not true that there is any con- stant inverse ratio of the kind stated. It is no doubt true in a general way (as the principles of evolution would lead us to anticipate), that as animals advance in the scale of mental development their powers of intelligent adjustment are apt to become added in larger measure to their less elaborate powers of instinctive adjustment; but that there is no inverse proportion between the tv;o must be evident to any one who has directed his attention to the mental endowments of animals. Thus, so far is it from being the case that " the absence of reason is most generally admitted" among the ants and bees, that all the observers with whose writings I am acquainted are unanimous in their opinion that there are no animals among the Invertebrata which can be said to • Lessonn from Nature, pp. 230-1. /«) \\i' li REASON. tltJU equal the ants and bees in respect of drawing intelligent inferences. Furthermore, looking to the animal kingdom as a whole, I should say that while there is no very constant relationship between the powers of instinct and those of intelligent inference, such relationship as tliere is points rather to the view that the complexity of mental organization which finds expression in a high development of the instinc- tive faculties, is favourable to the development of the more intelligent faculties* And that there should be such a general correspondence is no more than the theory of evolu- tion might lead us to expect ; for the progressive complica- tion of instincts tends to diminish, as Mr. Spencer observes, their purely automatic character. But, on the other hand, that this correspondence should be general and not constant might also be anticipated, seeing that instincts may arise either without the precedence of intelligence, or by means of the lapsing of intelligence. In the next place, as regards Man, I do not think that Mr. Mivart's argument is any more satisfactorily established by fact. It is no doubt true that " the more instinctive are a man's actions the less are they rational, and vice versd;" but this, again, is no more than we should expect, on the hypo- thesis of human instincts being due to hereditary experience, while processes of conscious inference are chiefly due to indi- vidual experience. It thus happens that the instinctive actions preponderate over the intelligent actions during infancy, and that the scale begins to turn during childhood. But in all this there is nothing to show that the two are distinct in kind ; and in subsequent life their generic identity is shown by the fact that the principle of lapsing intelligence may cause, even in the experience of the individual, actions which are at first consciously adaptive or rational to become by repetition automatic or instinctive. To what misconception, then, are we to ascribe the very prevalent doctrine that Eeason is the special prerogative of Man? I think the misconception arises from an erroneous meaning which is attached to the word Reason. Mr. Mivart, for instance, habitually follows the traditional usage and invests the word with the meaning that belongs to self-conscious Thought. Thus he expressly says that in denying Eeason to * Cf. Pouchet, "L' Instinct chez les Insedes," in Eev. des Deux Monties Feb. 1670, p. U'JO. 1 1. : 'M 1 •! ' i I' I II 'I 340 MENTAL EVOLUTION IN ANIMALS. 11 brutes all he maintains is that " they have not the power of forming judgments;"* that is, in his own definition of a judgment, the power of reflective or self-conscious Thought. In my subsequent work I shall have much to say upon the psychology of Judgment ; but here it is enough to observe that I hold the power of reflective thought, which the forma- tion of a judgment implies, to constitute no essential part of a process of reason as such, although when present it unques- tionably afibrds that process much new material with which to be concerned. As I have said, I regard reasoning to be a process of consciously inferring, and therefore conclude that it should make no difference to our classification of the rational faculty whether the subject matter on which it may happen to be exercised has reference to the sphere of feeling or to that of thought. And, as Mr. Mivart allows that animals perform " practical inferences," I further conclude that my difference with the school which he represents has reference, so far, only to a matter of terminology. There is, without question, some enormous distinction between the psychology of man and that of the lower animals, and hereafter I shall have to consider at much length what this distinction is. Here I am only concerned with showing that it does not consist in animals having no vestige of the faculty of Eeason in the sense above defined. And, in order to show this, I feel, as I have already remarked, that it would be superfluous to render specific instances of the display of animal reason ; for they have already been given in such abundance in my former work. ft ' m\ " Is not the earth With various living creatures, and the air Eeplenished? .... know'st thou not Their language and their ways ? They also know And reason not contemptibly." — Milton, i I |i • Lessons from Nature, p. 217. I .. tr EMOTIONS. 341 i CHAPTER XX. ■| •'1 Animal Emotions, and Summary of Intellectual Faculties. It will be observed on turning to the diagram that I attribute to animals the following emotions, which I name in the probable order of their historical development: — Surprise, Fear, Sexual and Parental Affection, Social Feelings, Pug- nacity, Industry, Curiosity, Jealousy, Anger, Play, Atfection, Sympathy, Emulation, Pride, Resentment, Esthetic Love of Ornament, Terror, Grief, Hate, Cruelty, Benevolence, Revenge, Rage, Shame, Remorse, Deceit, Ludicrous. This list, which leaves many of the human emotions without men- tion, exhausts all the emotions of which I have found any ^evidence in the psychology of animals. Before presenting this evidence in detail, perhaps it will not be thought superfluous again to insist that in attributing this and that emotion to such and such an animal, we can depend only upon inference drawn from actions, and that this inference necessarily becomes of less and less validity as we pass through the animal kingdom to organisms less and less like our own ; so that, for instance, " when we get as low down as the insects, I think the most we can confidently assert is, that the known facts of human psychology furnish the best available pattern of the probable facts of insect psychology."* Still, as the known facts of human psychology do furnish the best available pattern, we must here, while treating of the emotional faculties, follow the same method which we have hitherto followed while treating of the intel- lectual faculties — viz., while having full regard to the pro- gressive weakening of the analogy from human to brute psychology as we recede through the animal kingdom down- wards from man, nevertheless using the analogy so far as it goes as the only instrument of analysis that we possess. * Animal Intelligence, pp. 9-10, where Bee for a more full discussion of this point. ' ' 342 MENTAL EVOLUTION IN .VNIMALS. f m Mi I shall now proceed, as briefly as possible, to render the evidence which hps induced me to ascribe each of the above- named emotions to animals, and remembering that I have in each case written the emotion upon the diagram at the level • of mental evolution where I have found the earliest evidence of its occurrence, it follows that in the majority of cases the emotion is present in the higher levels of mental evolution in a more highly-developed form. It will be observed that in the diagram I represent the Emotions as a class to take their origin from the, growing structure of mind at the same level as that at which the faculty of Perception takes its origin. I do this because I think that as soon as an animal or a young child is able to perceive its sensations, it must be able to perceive pleasures and pains ; hence, when the antecedents of a painful percep- tion recur in consciousness, the animal or child must anticipate the recurrence of that perception — must suffer an ideal representation of the pains, and such suffering is Fear. And that, as a matter of fact, Fear of this low or vague order is manifested at about ':he second or third week of infancy, is the general opinion of those who have most carefully observed the development of infant psychology.* To specify the class in the animal kingdom where a true emotion of Fear first arises is clearly a more difficult matter, and indued it is impossible to do so in the absence of any definite know- ledge as to the class in which Perception first arises. But while, as previously ( x^lained, I am not able to say whether or not the Coelenterata, and still less the Echinodermata, are able to perceive their sensations, I think the evidence becomes very strong in the case of insect Larvae and Worms. And that both the one and the other manifest striking symptoms of alarm m the presence of danger may be easily shown. For instance, a few months ago I had an opportunity of observing the habits of the processional caterpillar mentioned in " Animal Intelligence."t Wishing to ascertain whether I could artifi- • See Preyer, loc. cit. t Pp. 238-40. It will be seen on referring to this passage that D« Villiers' account difPers materially from that of Mr. Davis. For he says that, on removing one of the chain of caterpillars, the whole chain stopped imme- diately with one consent, like a single organism. Mr. Davis on the other hand said that the information was communicated from caterpillar to cater- pillar at the rate of somewliat less than a second per caterpillar. On repeat- ing this observation a great number of times, I could obtain no corroboration at all of De Villiers' statement, while I found that of Mr. Davis to be correct EMOTIONS. 343 cially imitate the stimulus which the head of one caterpillar supplied to the tail of the next in the series (and which serves to let the latter known that the series is not inter- rupted), I removed the last member of the series. As always happens when this is done, the next member stopped, then the next, and the next, and so on, till the whole series were at a halt. If I had now replaced the last member with its head touching the tail of the penultimate member, the latter would again have begun to move, then the next, and the next, and so on, till the whole series would again have been in motion. Instead of doing this, however, I took a camel-hair brush and gently brushed the tail of the then last member. Imme- diately this member again began to move, and so set the whole train again upon the march. But in order that the march should continue, it was necessary that I should con- tinue brushing the tail of the last member. Now I found that if I brushed in the least degree too hard, so as not suffi- ciently well to imitate the stimulus supplied by the hairy head of a caterpillar, the animal became alarmed and threw itself upon its side in the form of a coil. I therefore tried the experiment of puzzling the animal, by first brushing its tail gently for a considerable time— so that it should have no reason to doubt, as it were, that I was a caterpillar— and then beginning by degrees to brush it more and more strongly. I could°then see that a point came at which the animal was puzzled, so that it hesitated whether to go on or to_ throw itself upon its side. It appeared to me that at this point the animal began to become alarmed ; for the brushing was still exceedingly gentle, so that if the animal were actuated only by a pure reflex mechanism, I should not have expected so infinitesimally small a difference in the amount of stimula- tion to produce so great a difference in the nature of the response. in all particulars. I am likewise able to confirm all the other points in his account of the remarkable habits of these larvro. I may add that as soon as a member of a moving chain is removed, the next member m advance not only stops, but begins to wag its head in a peculiar manner from side to side. This perhaps may serve as a signal to the next member to stop; but, however this may be, as soon as the next one does stop, it also begins to wag its head in the same manner, and so on till aU the caterpillars in advance of the interruption are standing still and wagging their heads. And they aU continue without interruption thus to wag their heads untd the procession again begins to move. I have never seen this pecuhar movement perfomed except under these circumstances. m ■j '■ ■ itsi I i ! I 344 MENTAL EVOLUTION IN ANIMALS. Agam as regards Worms, Mr. Darwin has shown in hia work on the Earth-worm that this animal is of a " timid " disposition, darting into its burrow "like a rabbit" when alarmed Probably other kinds of worms, which are better provided with organs of special sense and consequently have more intelligence, may have more emotion. With reference to young children, Preyer is of the opinion that the earliest emotion is one of surprise or astonishment upon perceiving any change, or strikingly novel feature, in the environment. In deference to his opinion, therefore, I have placed Surprise upon the same level of emotional develop- ment as Fear ; but of course in both cases this level is so low that it is but the germs of such emotions that are here supposed to be present. This earliest stage of emotional development (18) I have made to correspond with " Emotions preservative of Self." The next stage (19) I make to coincide with the origin of " Emotions preservative of Species ; " and of these the first to appear are the Sexual. In the animal kingdom— or rather let us say in the psychological scale— these emotions are first unequivocally exhibited by the Mollusca,* which on this account, as well as for the reasons given while treatint? of the association of ideas, I have made to fill the corre- sponding level on the other side of the diagram. The next level (20) is occupied by Parental Affection, Social Feelings, Pugnacity, Emotions conducing to Sexual Selection, Industry, and Curiosity. The level, therefore, corresponds with the origin of the branch marked Social Emotions in the central psychological tree, and with the earliest Ptecognition of Offspring on the side of the intellectual faculties. The animals which first satisfy all these conditions are the Insects and Spiders.t For here, even if we exclude the Hymenoptera, we have evidence of parental affection in the care which spiders, earwigs, and sundry other insects take of their eggs and broods.f Again, numberless species of insects are highfy social in their habits ; others are highly pugnacious ; some are conspicuously industrious ;t most flying insects (as we have already seen in Chapter XVIII) display curiosity ; and, according to Mr. Darwin's elaborate enquiries, it is also in • See Animal Intelligence, p. 26. t For remarkable instances of this see ibid., p. 205 and n 229 X Ibid., pp. 22t)-8. '^' ' ruM EMOTIONS. 845 this class that we find the earliest evidence of sexual selec- tion. Coming now to level 21, 1 have assigned to it the first appearance of the emotions of Jealousy, Anger, and Play, which unquestionably occur in Fish.* On level 23 I have placed the dawn of Affection other than sexual, in view of the evidence of the emotional attachment of a python which was exhibited towards those who had kept it as a pet.t On level 24 I have placed the dawn of Sympathy, seeing that this emotion appears to be unquestionably, though very fitfully, displayed by the Hymenoptera,t which for other reasons I have felt obliged to assign to this comparatively high stage of psychological development. On the next level (25) I have given Emulation, Pride, Resentment, ^Esthetic Love of Ornament, and Terror as dis- tinguished from Fear. All these emotions, so far as I have been able to ascertain, first occur in Birds ; and in this class some of the emotions which I have already named as occurring in lower classes, are much more highly developed. § Next we arrive at Grief, Hate, Cruelty, and Benevolence, as first displayed in some of the more intelligent of the Mam- malia. Grief is shown by pining, even to death, upon the removal of a favourite master or companion ; Hate by per- sisting resentment ; Cruelty by a cat's treatment of a mouse ;|| and Benevolence by the following instances which I have met with since the publication of " Animal Intelligence." Writing of a domestic cat, Mr. Oswald Fitch says that it " was observed to take out some fish-bones from the house to the garden, and, being followed, was seen to have placed them in front of a miserably thin and evidently hungry stranger cat, who was devouring them ; not satisfied with that, our cat returned, procured a fresh supply, and repeated its charitable offer, which was apparently as gratefully accepted. This act of benevolence over, our cat returned to its customary dining- place, the scullery, and ate its own dinner off the remainder * See Animal Intelligence, pp. 212-47. t Ibid., pp. 261-2. j Ibid., pp. 48-9 and p. 156. § Ibid., pp. 270-82. Birds are the lowest animals wliicli I have myself Been, or have heard of others havin"; seen, to die of fright. II For instances of all these facts in Mammals other than Elephants, Dogs or Monkeys, see Animal Intelligence, m ;1 S| m m If 346 MENTAL EVOLUTION IN ANIMALS. of the bones,"* An almost precisely similar case has been independently communicated to me by Dr. Allen Thomson, r.E.S. The only difference was that Dr. Thomson's cat drew the attention of the cook to the famishing stranger outside by pulling her dress and leading her to the place. When the cook supplied the hungry cat with some food, the other one paraded round and round while the meal was being discussed, purring loudly. One further instance of the display of bene- volent feeling by a cat will suffice. Mr. H. A. Macpherson writes me that in 1876 he had an old male cat and a kitten aged a few months. The cat, who had long been a favourite, was jealous of the kitten and " showed considerable aversion to it." One day che floor of a room in the, basement of the house was partly taken up in order to repair some pipes. The day after the boards had been replaced, the cat " entered the kitchen (he lived almost wholly on the drawing-room floor above), rubbed against the cook and mewed without ceasing until he had engaged her attention. He then, by running to and fro, drew her to the room in which the work had taken place. The servant was puzzled until she heard a faint mew from beneath her feet. On the boards being lifted the kitten emerged safe and sound, though half-starved. The cat watched the procc3dings with the greatest interest until the kitten was released ; but on ascertaining that it was safe he at once left the rooir;, without evincing any pleasure at its return. Nor did he subsequently become really friendly with it." On the next level I have placed Eevenge as distinguished from Eesentment, and Eage, as distinguished from Anger. In " Animal Intelligence " I give some cases of apparent vindictiveness occurring in birds ;t but as the exact nature of the emotions in these cases appears to me someM'^hat doubtful, I here disregard them, and place Eevenge on the psycholo- gical level which is occupied by the Elephant and Monkeys, in which animals this passion is very conspicuous.| The same remarks apply to Eage, as distinguished irom the less violent display of hostile feeling which is suitably expressed by the term Anger. Lastly, at level 28 we arrive at the highest products of emotional development which are manifested in animal psychology, and therefore at the highest of those products • Nature, April 19, 1883, p. 580. X Animal Intelligence, pp. i587-8 and 478. t Pp. 277-8. EMOTIONS. 347 with which the present treatise is concerned. These are Shame, Eemorse, Deceit, and the Emotion of the Ludicrous. For instances of the display of these emotions by Uogs and Apes, I need merely again refer to " Animal Intelligence."* In this brief sketch of the emotional faculties as they occur in the animal kingdom, my aim has been to give a generic rather than a specific representation. I have there- fore omitted all details of the emotional character of this and that particular animal, as well as the narration of particular instances of the display of emotions. Such details and par- ticular instances will be found in sufficient abundance in my previous work, and it seems undesirable, for the larger purpose now in hand, either to repeat what I have said before, or to burden the discussion with additional facts serving only to corroborate the general assignment of levels which I have now given. Before concluding the present chapter, and with it the present work, I shall give a similar outline sketch of the assignment of levels on the other and corresponding side of the diagram, which serves to show the probable history of mental evolution so far as the faculties of intellect are con- cerned. This, of course, has already been done throughout the course of all the preceding pages ; but I think it desirable to terminate our analysis of the psychology of animals, by briefly stating in a serial form the reasons which have induced me to assign the various classes of animals to the levels of psychological development in which I have respectively placed them. It is only needful to premise that in consider- ing this side of the diagram I shall not at present wait to treat of the column which has to do with the psycho- genesis of the child, for this will require to be treated ah initio in my work on Mental Evolution in Man. I may further observe that the sundry psychological faculties which I have written on one of the vertical columns are intended as so many indices of mental evolution, and not as exhausting all the distinctions between one level of such evolution and another. Indeed, looking to the fact that our classification of faculties is conventional rather than natural, we cannot expect that any diagrammatic representation of the order in which they have been developed should admit of being made very * Pp. 438-45, and 471-78 j also 484-98. : !■ :^i ■vlW ,!, ! ,] !', ?r, I I'l -^ 343 MENTAL EVOLUTION IN ANIMALS. precise ; for in some existing animals certain faculties are more highly developed than they are in other existing animals, which nevertheless wit), i ';^.xrd to their general psychology occupy a higher levi'i nf menttil evolution. There- fore the faculties which I have nam",t:I in the vertical column have been chosen only because they serve as convenient indices to mark the general upward progress of mental evolu- tion in the animal kingdom, I have already sufficiently expressed my doubt as to the levels at which all animals below the Artirul'i.. ti ild be placed, and I have explained that this doubt arises from the difficulty, or rather the impossibility of ascertaining at what grade of psychological evolution consciousness first occurs. The positions, therefore, which I have assigned to the Ccelen- terata and Echinodermata are confessedly arbitrary, and have been determined only because I have not been able to observe that these animals give any unmistakable evidence of percep- tion as distinguished from sensation. This remark applies especially to the Ccelenterata, which in my opinion present no semblance of evidence that any of their responsive move- ments are of a perceptive, or even of a conscious nature. My judgment with respect to the Echinodermata is less confident, for although I am sure that I am right in placing them on a higher level of sensuous capability than the Ccelenterata, I am not at all sure that I ought not to have placed them one stage higher (i.e., on 18 instead of 17), so as to have brought them within the first rise of perception. For the " acrobatic " and " righting " movements which are per- formed by these animals, and which I have described elsewhere, are, to say the least, strongly suggestive of true powers of perception. It is, therefore, on the principle of preferring to err on the side of safety that I have placed the Echinoder- mata on level 17 and not on level 18. That I am justified in attributing to these animals faint powers of memory (as distinguished from the association of ideas) may, I think, be shown by thr; fact that when a star-fish is crawling along the perpendicular wall of a tank at the level of the surface of the water, it every now and then throws back its rays to feel for other surfaces of attachment, and if it does not succeed in finding such a surface, it again applies its rays to crawling along the side of the tank in the same direction as before, in order that it may again and again repeat the manoeuvre in KM0TI0N3. 349 long different lof^alities. Now, as this manoeuvre requires a time to execute, I think the fact that after it lias beeu executed the animal continues its advance in the same direc- tion as that in which it was crawling before the manoeuvre began, constitutes tolerable evidence in favour of an abidin" impression upon the nerve-centres concerned, and one which assuredly is not due to any organically imposed conditions, seeing that on no two occasions is the manoeuvre performed in exactly the same way, or even at the same intervals of time. On the next level I have placed Larvaj of Insects and Annelida. My reason for doing so is that both these classes of organisms unquestionably exhibit instincts of the primary kind,* the origin of which is also assigned to this level. In both cases, however, we meet with certain facts which may justly lead us to question whether in these animals intelli- gence of a higher order may not be present;! but liere again I think it is better to err on the safer side. It is in the MoUusca that we first undoubtedly meet with a demonstrable power of learning by individual experience,^ and therefore I have placed this class of animals upon the next level, which is occupied by the first appearance of the power of association by contiguity. Of course, if the account given by Mr. Lonsdale to Mr. Darwin of the pair of land- snails§ were ever to be corroborated by further observations, the Gasteropoda would require to be separated from the' other Mollusca and placed on a higher level in the diagram, as I have done in the case of the Cephalopoda. Next we come to Insects and Spiders on a level with the first Eecognition of Offspring and the rise of Secondary Instincts. The evidence that both these faculties occur in both these divisions of the Articulata is unquestionable and this even when the Hymenoptera are removed for separate psychological classification.!! Fish and Bntrachia are assigned to the next level which corresponds wi a the rise of Association by Similarity, which I think we are justified in first ascribing to these animals.! On level 22 I have written the higher Crustacea. I • See Animal Intelligence, 234-40, and 24. t Ibid., and Mr. Darwin's work on Worms. X Ibid., pp. 25-y. § Ibid., p. 27. (I Ibid., pp. 207-222, and 226-31. H Ibid., pp. 250-1, and 255. m\ m 350 MENTAL EVOLUTION IN ANIMALS. ! '•'!('■ FIs li 1 1 '' I I' have done so because this is the stn^e where, from inde- pendent considerations already explained, I have assigned the dawn of Reason (as distinguished from Inference), and the lowest animal psychologically considered in which I have found any evidence of this faculty is tlie crab.* , Next we come to level 23 where I have placed the Reptiles and Cephalopoda. My reason for so doing is tiiat this is the level where I have represented psychological development to have advanced sufficiently far to admit of the recognition of persons, and this degree of advance has undoubtedly been attained by the Reptiles and the Ccphalo- poda.t It will be observed that I have bracketed this and the two preceding levels togetber. My reason for doing so is that the animals and the faculties named upon these levels in some degree overlap. Thus the Batrachia are able to recognize per.sons,t and it is possible that Fisli may be able to reason,§ while, on the other hand, the Reptiles and Cepha- lopoda are not in their general psychology so far above the Batrachia and Fish as would be implied without the bracket ; yet I should not be justified in placing them all upon the same level, because I have no such definite evidence that Batrachia and Fish are able to reason as I have in the case of Crustacea, Cephalopoda, and Reptiles. On the whole, therefore, I think that the fairest mode of expressing these various cross relations is the one v.'hich I have adopted. It is not to be expected that our essentially artificial mode of distinguishing between psychological faculties should so far agree with nature, that when applied to the animal kingdom our classification of faculties should always be found exactly to fit with our classification of organisms, so that every branch in our psychological tree should precisely correspond with some branch in our zoological tree. Some amount of overlapping must be expected, and in thus comparing the one classification with the other my only surprise has been how, in a general way, the two so closely coincide. On level 24 I have placed the Hymenoptera, together with the distinction which I think most sharply marks off this stage of mental evolution, i.e., the power of communicating ideas — a power which ants and bees undoubtedly possess.|l • See Animal Intelligence, p. 233. t Ibid., pp. 259, 2G0-1, and 30. II Ibid., pp. 49-57, and 156-60. X Ihid., p. 255. § Ibid., pp. 250-1. EMOTIONS. 351 Next we arrive at Birds with the psychological distinc- tion of recognizing pictorial representations, understanding words, and dreaming.* If any of these faculties occur in any of the lower vertebrata, I have not found evidence of the fact. To the next level I have assigned the Eodents and Carni- vora, with the exception of the dog. The most marked psychological distinction which I take to mark this level is the understanding of mechanisms. For, although I have found one instance of such understanding to occur in Birds.t and although it likewise unquestionably occurs in Eumi- nants.t in neither case does the understanding appear to extend further than to the simplest order of mechanisms, and therefore is only comparable in kind with the much greater aptitude in this respect which is shown by rats,§ foxes,|} cat3,ir and the wolverine.** \M • Animal Intelb'genee, pp. 311-12. t Ihi^-, p. 816. J Ihid., pp. 388-9. § Ihid., p. 361. II Ibid., pp. 428-31. f ibid., pp. 420-22. •* Ibid., pp. 848-50. — Sir James Paget has told me of a parrot which by attentive study learned how to open a lock j but although such cases may occasionally occur in birds, they are so comparatively rare that I have thought it best to place the faculty of appreciating simple mechanical appliances on the next level, for it is here only that we may first be sure that the actions are not due to mere association. A cat which jumps at a thumb-latch, and while holding on to the curved handle beneath with one fore-leg, depresses the thumb-piece with the other and pushes the door-posts with the hind-leg, clearly shows that she has an intelligent appreciation of the facts that the latch fastens the door, that when it is depressed the door will be liberated, and that when then pushed the door will open. And if it can still be sup- posed that all this knowledge can be obtained by simple association, tl?ere is the yet more remarkable case of the monkey described in Animal Intelli- gence, which by patient investigation discovered for himself, and without ever having observed any one perform a similar action, the mechanical principle of the screw, not to say also of the lever. It is remarkable, as I observed in Animal Intelligence, that this faculty of appreciating simple mechanical appliances does not seem always to stand in any very precise or quantitative relation to the general mental develop- ment of the species which exhibit it. Thus the dog is, as to his general in- telligence, unquestionably superior to the cat, and yet his ability Li the particular we are considering is certainly not so high ; while bovine animals and horses seem to show more cleverness in this respect than in any other. Probably the explanation of this apparent disproportion in the development of the psychical faculties is to be found in the corporeal members which minister to them ; the monkey, which shows the highest power of appreciating mechanical appliances, is the animal which is best endowed with the organs of tactual examination ; the fore-paws of a cat are better instruments in this respect than those of the dog j while the trunk of the elephant, the lips of the horse, and horns of ruminants give them in the same respects an advantage over most other mammals of a comparable grade of iotelligence. t I ■' f 352 MENTAL EVOLUTION IN ANIMALS. Next we arrive at Monkeys and the Elephant, which, with the exception of the Anthropoid Apes, are the only animals that, so far as I have been able to ascertain, make use of tools* Lastly on level 28 we arrive at the highest development of the psychical powers which are to be met with in existing animals, and to this level I have assigned the Anthropoid Apes and Dogs. The meaning of the term "Indefinite Morality," which I give as distinctive of this grade of mental evolution, I shall explain in my next work, when I shall have to discuss the question touching the probable genesis of the moral sense. It is, I think, undesirable to divide this discussion, and therefore I prefer to postpone the considerr.tion of this which I take to be the earliest phase in the development of the faculty of Conscience. And for the same reason I shall postpone my analysis of the lower stages of Abstraction and Volition, both of which are crossed by the level which we have now reached, where our enquiry into the Mental Evolution of Animals comes to an end. • Animal Intelligence, pp. 408-9 and 480-94. THE END. A POSTHUMOUS ESSAY ON INSTINCT, BY CHARLES DAKWIJSr, M.A., LL.D., F.RS. APPENDIX. iffii„ ■I }r^ ;*!< ; . 1 ■■ V f I r-' ■ ■ ■■ if i I V 1 likM APPENDIX. [The full text of a part of Mr. Darwin's chapter on Instinct written for the " Origin of Species," but afterwards suppressed for the sake of condensation.] itii Migration. — The migration of young birds across broad tracts of the sea, and the migration of young salmon from fresh into salt water, and the return of both to their birth- places, have often been justly advanced as surprising in- stincts. With respect to the two main points which concern us, we have, firstly, in different breeds of birds a perfect series from those which occasionally or regularly shift their quarters within the same country to those which periodically pass to far distant countries, traversing, often by night, the open sea over spaces of from 240 to 300 miles, as from the north-eastern shores of Britain to Southern Scandinavia. Secondly, in regard to the variability of the migratory instinct, the very same species often migrates in one country and is stationary in another ; or different individuals of the same species in the same country are migratory or stationary, and these can sometimes be distinguished from one another by slight differences.* Dr. Andrew Smith has often re- marked to nie how inveterate is the instinct of migration in some quadrupeds of S. Africa, notwithstanding the persecu- tion to which they are in consequence subjected: in N". America- however, persecution has driven the Bufi'alo within * Mr. Gruld has observed tliis fact in Malta, and in Tasmania in the Bouthern hemisphere. Eeehstein {^Stuhenvogel, 1840, s. 293) says that in Germany the migratory and non-mignitory Thrushes can be distingmshed by the yellow tinge of the eoles of their feet. The Quail is migratory m S. Africa, but stationary in Robin Island, only two leagues from the con- tinent {Le Vaillani's Travels, vol. i, p. 105) : Dr. Andrew Smith confirms this. In Ireland the Quail has lately taken to remain in numbers to breed there (W. Thompson, Nat. Eist. of Ireland, vide " Hirda," vol. ii, p. 70). t^il ' I' iri 356 MENTAL EVOLUTION IN ANIMALS. Jill » M' a late period* to cross in its migrations the Eocky Moun- tains ; and those " great highways, continuous for a hundred '/miles, always several inches, sometimes several feet in ^ depth," worn by migrating buffaloes on the eastern plains, are never found westward of the Eocky Mountains. In the United States, swallows and other birds have largely ex- tended, within quite a late period, the range of their migra- tions.t _ The migratory instinct in Birds is occasionally lost ; as m the case of the Woodcock, some of which have totally, without any assignable cause, taken to breed and become stationary in Scotland.^ In Madeira the first arrival of the Woodcock is known,§ and it is not there migratory ; nor is our common Swift, though belonging to a group of birds almost emblematical of migration. A Brent Goose, which had been wounded, lived for nineteen years in confinement ; and for about the first twelve years, every spring at the migratory period it became uneasy, and would, like other confined individuals of the species, wander as far northwards as possible ; but after this period " it ceased to exhibit any particular feeling at this season."|| So that we have seen the migratory impulse at last worn out. In the migration of animals, the instinct which impels them to proceed in a certain direction ought, I think, to be distinguished from the unknown means by which they can tell one direction from another, and by which, after starting, they are enabled to keep their course in a dark night over the open sea ; and likewise from the means— whether some ^ instinctive association with changing temperature, or with want of food, &c.— which leads them to start at the proper period. In this, and other cases, the several parts of the • Col. Fremont, Report of Exploring Expedition, 1845, p. 144. + See Dr. Biicbnian's excellent memoir on tliis subject in SiUiman's F/iiiosoph. Jourii., vol. 30, p. 81. t Mr. W. Tliompson has given an excellent and full account of this ^liole subject (see Nat. Hist, of Ireland, " Birds," vol. ii, pp. 247-57), where he discusses the cause. There seems reason to believe (p. 254) that tli- mi^'ratory and nor -migratory individuals can be distinguished. For Scotlaua see St. John s W.. i Sports of the Highlands, 1846, p. 220. § Dr. Heiueken in Zoological Journal, vol. v, p. 75. See also Mr E V Haicourt's r/cetch of Madeira, 1851, p. 120. II W, Thompson, loc. cit., vol. iii, p. 63. In Dr. Bachman's paper iust refeiTftd to (^jisijs of Canada geese in confinement periodically 'rying to escape northward are giveu. * APPENDIX. 357 problem have often been confused together under the word instiuct.* With respect to the period of starting, it cannot of course be memory in the young cuckoos' start for the first time two months after their parents have departed : yet it deserves notice that animals somehow acquire a surprisingly accurate idea of time. A. d'Orbigny shows that a lame hawk in S. America knew the period of three weeks, and used at this interval to visit monasteries when food was dis- tributed to the poor. Difficult though it may be to conceive how animals either intelb'i^ently or instinctively come to know a given period, yet we shall immediately see that in some cases our domestic animals have acquired an annual recurring impulse to travel, extremely like, if not identical with, a true migratory instinct, and which can hardly be due to mere memory. It is a true instinct which leads the Brent Goose to try to escape northwards ; but how the bird distinguishes north and south we know not. Nor do we know how a bird M'^hich starts in the night, as many do, to traverse the ocean, keeps its course as if provided with a compass. But we should be very cautious in attributing to migratory animals any capacity in this respect which we do not ourselves possess ;t though certainly in them carried to a wonderful perfection. To give one instance, the experienced navigator WrangelJ expatiates with astonishment on the " unerring instinct " of the natives of N. Siberia, by which they guided him through an intricate labyrinth of hummocks of ice with incessant changes of direction ; while Wrangel " was watching the different turns compass in hand and trying to reason the true route, the nati.v. had always a perfect knowledge of it instinctively." Moreover, the power in migratory animals of keeping their course is not unerring, as may be inferred from • See E. p. Thompson on the Passions of Animalt, 1851, p. 9; and Alison's remarks on this head in the Cyclopadia of Anatomy and Physiology, article " Instinct," p. 23. t [I cannot refrain from ."rawing attention to the superiority of scientific metliod and phik)sopliical caution here displayed as contrasted with Frof-jssor HsBckel's views on tlie same subject, which in piesenee of this difHculty at once conclude in favour of som ■ r. .vs'terious additional sense (see p. 95). — Q-. J. R.] X W^rangeVs Trawls, Ent;. trans., p. 146. See also Sir G-. Grey's I^xpe- dition to Australia, \oi. i.i, p. 72, for interesting account of the powers of the Australians in thj SFUio respect. The old French missionaries used to believe that the N. Anierioan Indians were actually guided by instinct in finding thtuc way. 16 3^8 MENTAL EVOLUTION IN ANIMALS. the numbers of lost swallows often met with by ships in the Atlantic : the migratory salmon, also, often fails in returning to its own river, " many Tweed salmon being found in the Forth." But how a small and tender bird coming from Africa or Spain, after traversing the sea, finds the very same hedge-row in the middle of England, where it made its nest last season, is truly marvellous.* Let us now turn to our domesticated animals. Many cases are on record of animals finding their way home in a mysterious manner, and it is asserted that Highland sheep have actually swum o^er the Frith of Forth to their home a hundred miles distant ;t when bred for three or four genera- tions in the lowlands, they retain their restless disposition. I know of no reason to doubt the minute account given by Hogg of a family of sheep which bad a hereditary 'propensity to return at the breeding season to a place ten miles off', whence the first of the lot had been brought ; and, after their lambs were old enough, they returned by themselves to the place where they usually lived : so troublesome was this in- herited propensity, associated with the pe-iod of parturition, that the owner was compelled to sell the lot.f Still more interesting is the account given by several authors of certain sheep in Spain, which from ancient times have annually migrated during May from one part of the country to another distant four hundred miles : all the autliors§ agree that " as soon as April comes the sheep express, by curious uneasy motions, a strong desire to return to their summer habita- i f • The number of birds which by chauce visit the Azores (Consul C. Hunt, in Journ. Qeograph. Soc, vol. xv, Pt. 2, p. 282), so distimt from Europe, is probably in part due to lost directions during migration : W. Thompson {Nat. Hist, of Ireland, " Birds," vol. ii, p. 172) shows that N. American birds, which occasionally wander to Ireland, generally arrive at tlie period when they are migrating in N. America. In regard to Salmon, see Scope's Days of Salmon Fishing, p. 47. + Gardener's Chronicle, 185^ p. 798 : other cases are given by Youatt on Sheep, p. 377. X Quoted by Touatt in Veterinary Journal, vol. t, p. 282. § Bourgoanne's Travels in Spain (Eng. trans.), 1789, vol. i, pp. 38-54. In Mills' Treatise on Cattle, 177 », p. 342, there is an extract of a letter from a gentleman in Spain from which I have made extract. Youatt on the Sheep, p. 153, gives references to three other publications with similar accounts. I may add that von Tschudi {Sketches of Nature in the Alps, Eng. trans., 1856, p. 160) states that annually in the spring the cattle are greatly excited, when they hear the great bell which is carried with them ; W(>11 knowing that this ia the signal for their " approaching migration " to the higher Alps. APPENDIX. 359 in the : from tions." " The unquietude," says^nother author, " which they manifest might in case of need serve as an almanack." " The shepherds must then exert all their vigilance to prevent them escaping," " for it is a known truth that they would go to the very pface where they had been born." Many cases have occurred of three or four sheep having started and performed the journey by themselves, though generally these wanderers are destroyed by the wolves. It is very doubtful whether these migratory sheep are aborigines of the country ; and it is certain that within a comparatively recent period their migrations have been widely extended : this being the case, I think there can hardly be a doubt that this " natural instinct," as one author calls it, to migrate at one particular season in one direction has been acquired during domestication, based no doubt on that passionate desire to return to their birth- place which, as we have seen, is common to many breeds of sheep. The whole case seems to me strictly parallel to the migrations of wild animals. Let us now consider how the more remarkable migrations could possibly have originated. Take the case of a bird being driven each year, by cold or want of food, slowly to travel northward, as is the case with some birds ; and in time we may well believe that this compulsory travelling would become an instinctive passion, as with the sheep in Sr ^in. Now during the long course of ages, let valleys become con- verted into estuaries, and then into wider and wider arms of the sea ; and still I can well believe that the impulse which leads the pinioned goose to scramble northward would lead our bird over the trackless waters ; and that, by the aid of the unknown power by which mmy animals (and savage men) can retain a true course, it would safely cross the sea now covering the submerged path of its ancient land journey.* • I do not suppose that the line of migration of birds always marks the line of formerly continuous land. It is possible that a bird accidentally blown to a distant land or island, after staying some time and breedmg there, might be induced by its innate instinct to lly away, and agam to return there in the breeding season. But I know of no facts to coimtenance the idea ; and I have been much struck in the case of oceanic islands, lyu ,3 at no ex- cessive distance from the mainland, but which from reasons to be given in a future chapter I do not believe have ever been joined to the mainland, with the fact that thev seem most rarely to have any migratory birds. Mr. E V. Hnrcourt who has written on the birds of Madeira, i.-iornis rae that there are none 'in that island; bo. I am informed by Air. Caiow Hunt, it is m th* » 1 if /.. •'• )' 11 ji M" if i 1M i ;^ : i i . 1i 360 MENTAL EVOLUTION IN ANIMALS. [I will give one case of migration which seemed to me at first to offer especial difficulty. It is asserted that in the extreme north of America, Elk and Eeindeer annually cross, as if they could smell the herbage at the distance of a hundred miles, a tract of absolute desert, to visit certain islands where there is a better (but still scanty) supply of food. How could their migration have been iirst established ? If the climate formerly had been a little more favourat le, the desert a hundred miles in width might then have been clothed with vegetation sufficient to have just tempted the quadrupeds over it, and so to have found out the more fertile northern islet. But the intense Glacial preceded our present climate, and therefore the idea of a former better climate seemed quite untenable; but if those American geologists are right who believe, from the range of recent shells, that subsequently to the Glacial period there was one slightly warmer than the present period, then perhaps we have a key to the migration across the desert of the Elk and lieindeer.*] Instinctive Fear. — I have already discussed the hereditary tameness of our domestic animals ; from what follows I have no doubt that the fear of man has always iirst to be acquired in a state of nature, and that under domestication it is merely lost. In all iij3 few archipelagoes and islands inhabited by man, of which I have been able to find an early account, the native animals were entirely void of fear of man : I have ascertained this in six cases in the most distant-parts of the world, and with birds and mammals of the most different kinds.f At the Galapagos Islands I pushed a hawk off a Azores, though he thinks that perhaps the Quail, which migrates from island to island, may leave the Archipelago. [In pencil it is added " Canaries none."— G. J. R.] In the Falkland Islands, bo far as I can find, no land-bird io migratory. From enquiries which I have made, I find there is no migratory bird in Mauritius or Bourbon. Colenso asserts {Tasmanian Journal, vol. ii, p. 227) that a cuckoo, C. lucidus, is migratoiy, remaining only three or four months in New Zealand ; but New Zealand is so large an island that it may very easily migrate to the south and remain there quite unknown to the natives of the north. Faroe, situated about 180 miles from the north of Scotland, have several migratory birds (Graber, Tagebuch, 1830, s. 205) j Iceland seems to be the strongest exception to the general rule, but it lies only miles from the line of 100 fathoms. [The last ten words are added in pencil with the blanks left for subsequent filling in. — G. J. R.] * [The paragraph which I have enclosed in square brackets is faintly rtruck out in pencil. — G. J. R.]. t I have given in my Journal of Researches (1845), p. 378, details on th» Falkland and Galapagos. Mr. Cada Mosto (Kerr's Collection of Votfagea^ i ! APPENDIX. 361 tree with the muzzle of my gun, and the little birds drank water out of a vessel which I held in my hand. But I have in my "Journal" given details on this subject, and I will here only remark that the tameness is not general, but special towards man ; for at the Falklands the geese build on the outlying islands on account of the foxes. These wolf-like foxes were here aa fearless of man as were the birds, and the sailors in Byron's voyage, mistaking their curiosity for fierce- ness, ran into the water to avoid them. In all old civilized countries the wariness and fear of even young foxes and wolves are well known.* At the Galapagos Islands the great land lizards {Amllyrhynchus) were extremely tame, so that I could pull them by the tail ; whereas in other parts of the world large lizards are wary enough. The aquatic lizard of the same genus lives on the coast, is adapted to swim and dive perfectly, and feeds on submerged algse: no doubt it must be exposed to danger from the sharks, and consequently, though quite tame on the land, I could not drive them into the water, and when I threw them in they always swam directly back to the shore. See what a contrast with all amphibious animals in Europe, which when disturbed by the most dangerous animal, man, instinctively and instantly take to the water. The tameness of the birds at the Falklands is particularly interesting, because most of the very same species, more espe- cially the larger birds, are excessively wild in Tierra del Fuego, where for generations they have been persecuted by the savages. Both at these islands and at the Galapagos it is particularly noteworthy, as I have shown in my " Journal" by the comparison of the several accounts up to the time when we visited these islands, that the birds are gradually getting less and less tame ; and it is surprising, considering the degree of persecution which they have occasionally suf- ▼ol. ii, p. 246) says that at the C. de Verde Islands the pigeons were so tame ae readily to be caught. These, then, are the only large groups of islands, with the exception of the oceanic (of which I can find no early account) which were uninhabited when discovered. Thos. Herbert in 1626 in his Travels (p. 349) describes the tameness of the birds at Maiiritius, and Du Bois in 1669-72 enters into details on this head with respect to all the birds at Bourbon. Capt. Moresby lent me a M3 account of his survey of St. Pierre and Providence Islands, north of Madagascar, in which he describes the extreme tameness of the pigeons. Capt. Cannichael has described th* tame- ness of the birds at Tristan d'Acunha. • lie Roy, Lettres i'hiloso^h., p. 86. hi m iH'L .. 362 MENTAL EVOLUTION IN ANIMALS fered during the last one or two centuries, that they havn not become wilder; it shows that the fear of man is not soon acquired. In old inhabited countries, where the animals have acquired much general and instinctive suspicion and fear, they seem very soon to learn from each other, and perhaps even from other species, caution directed towards any par- ticular object. It is notorious that rats and mire cannot long be caught by the same sort of trap,* however tempting the bait may be; yet, as it is raiv that one which has actually been caught escapes, the others must have learnt the danger from seeing their companions suffer. Even the most terrffic object, if never causing danger, and if not insiiTictively dreaded, is immediately viewed with indifference, as we see ia our railway trains. What bird is so difficult to approach as the heron, and how many generations would it not require to make herons fearless of man ? Yet Mr. Thompson saysf that these birds, after a few days' experience, would fearlessly allow a train to pass within half gun-shot distance.| Although It cannot be doubted that the fear of man in old inhabited countries is partly acquired, yet it also certainly is instinc- tive ; for nesting birds are generally terrified at the first sight of man, and certainly far more so than most of the old birds at the Falklands and Galapagos Archipelago after years of persecution. We have in England excellent evidence of the fear of man being acquired and inherited in proportion to the danger incurred ; for, as was long ago remarked by the Hon. Daines Barnugton,§ all our large birds, young and old, are extremely wild. Yet there can be no relation between size and fear; * E. P. Thompson, Passions of Animals, p. 29. t JSTat. Hist, of Ireland, " Birds," vol. ii, p. 133. t [I may here refer to the corroboration which this staVement has recently received in a correspondence between Dr. Rau and JV/r Goodsir {^(^ture, July 3rd, 12th, and 19th, 1883). The former says that the wild duck, teal, &c., which frequent certain districts through which 'he Pacific Kailway has been carried in Canada, became quite fearless of the bmins the tirst tew days after traffic was opened, and the latter gives similar testimony concerning the 'w-ild fowl of Australia, adding, « The constant roar of a great passing traffic, as well as the unceasing turmoil and unearthly noises of a large railway station withm a stone's throw of their haunfs, is now quite unnoticed by these usually most watchful and wary of all birds, [i.e., wild ducks.] But for fear of trespassing on your space, I could give many 'more xliu^ifcrations of the truth of Dr. Rae'a remarks."— Q- JET § Phil. Trans., 1773, p. 264. hi APPENDIX. 363 for on unfrequented islands, when first visited, the large birds were as tame as the small. How exceedingly wary is our magpie ; yet it fears not horses or cows, and sometimes alights on their backs, just like the doves at the Galapagos did in 1G84 on Cowley. In Norway, where the magpie is not persecuted, it picks up food "close about the doors, sometimes walking inside the houses."* The hooded crow (C. comix), again, is one of our wildest birds ; yet in Egypti is perfectly tarn Every single young magpie and crow cannot have beeu i ightened in P^ngland, and yet all are fearful of man in the extreme: on the other hand, in the Falkland and Galapagos Islands many old birds, and their parents before them, must have been frightened and seen others killed ; yet they have not acquired a salutary dread of the mc^t destructive animal, man.t Animals feigning, as it is said. Death— an unknown state to each living creature — seemed to me a remarkable instinct. I agree with those authors § who think that there has been much exaggeration on this subject: I do not doubt that fainting (I have had a Eobin faint in my hands) and the paralyzing effects of excessive fear have sometimes been mis- taken for the simulation of death.|| Insects are most notori- • Mr. C. Hewitson in Magazine of Zoology and Botany, vol. ii, p. 311. t Gcotfry St. Hilaire, Amis, des Mus., tome ix, p. 471. X [I have already pointed out the refined degree to which snch instinctive dread of man is developed when it is able accurately to discriminate what constitutes safe distance from fire-arms. Since writing the. passage to which I allude (see p. 11*7), I have met with the following observation in the letters recently published by Dr. Kae in Nature, which is of interest as showing how rapidly such refinement of discrimination is attained:—" I may perhaps be permitted to give one of many instances known to me of the quickness of birds in acquiring a knowledge of danger. Golden plover, when coming from their breeding-places in high latitudes, visit the islands north of Scotland in large numbers, and keep together in great packs. At first they are easily approached, but after a very few shots being fired at them, they become not only much more shy, but seem to measure with great accuracy the distance at which they are sate from harm."— G-. J. R.] § Couch, Illustrations of Instinct, p. 201. II The most curious case of apparently true simulation of death is that given by Wrangel {Travels in Siberia, p. 312, Eng. trans.) of the geese which migrate to the Tundras to moult, and are then quite incapable of flight. He savs they feigned death so well "with their legs and necks stretched out quite stiff, that I passed them by, thinking they were dead." But the natives were not thus taken ifl. This simulation would not save them from foxes or wolves, &c., which I presume inhabit the Tundras : would it save them from hawks P The case seema a strange one. A lizard in Patagonia {Journal of Researches, p. 97), which lives on the sand near the coast, and is speckled like it, when frightened feigned death with outstretched legs, depressed body. %. ^> ^. \>. IMAGE EVALUATION TEST TARGET (MT-3) fe fe ^/ :/ "^ 1.0 I.I ISO '"■■= 2.5 III ^ 1^ 12.0 IL25 ■ u 1= i.6 'a Photographic Sciences Corporation 23 WEST MAIN STREET WEB$T£R,N.Y. 14580 (7*6) 372-4303 L17 .v '^ tv ^A. ^\ ^- ^*^ R> <^ .^■^' ) ^ f/j 364 I ■ mik k MENTAL EVOLUTION IN ANIMALS. ous m this respect. We have amongst them a most perfect Sir'^T.'i^''' ^^% TT ^"""« (^' I h^ve observed iA l^urculio and Chrysomela), from species which feign only for a second and sometimes imperfectly, still moving their antenn^(aswith some Histers), and which wiU not fei-n a second time however much irritated, to other species which according to De Geer, may be cruelly roasted at a slow fire.' without the slightest movement^to others, again, which will long remain motionless as much as twenty-three minutes, as I nnd with Chrysomela spartii. Some individuals of the same species of Ptinus assumed a different position from that of others Now it will not be disputed that the manner and dura- tion of the feint is useful to each species, according to the kind of danger which it has to escape ; therefore ther? is no more real difficulty m its acquirement, through natural selection, of this hereditary attitude than of any other. Nevertheless It struck me as a strange coincidence that the insects should thus have come to exactly simulate the state which they took when dead. Hence I carefully noted the simulated positions of seventeen different kinds of insects (including an lulus bpider, and Oniscus) belonging to the most distinct genera" both poor and first-rate shammers; afterwards I procured naturally dead specimens of some of these insects, others I killed with camphor by an easy slow death; the result was tfiatmno one mstance was the attitude exactly the same and m several instances the attitude of the feigners and of the really dead were as unlike as they possibly could be. Nidificahon and HaUtation.~WQ come now to more complex instincts. The nests of Birds have been carefully attended to, at least m Europe and the United States ; so that we have a good and rare opportunity of seeing whether TT.l^.^^l ^?"^^^on i^ an important instinct, and we shall find that this is the case. We shall further find that favour- able opportunities and intelligence sometimes slightly modify the constructive instinct In the nests of birds, also, we have an unusually perfect series, from those which build none, but lay on the bare ground, to others which make a most imperfect and simple nest, to others more perfect, and Sna^'lTh ' ^ ^"^^n ^'^\^' it buried itself quickly in the sand. If lllr^r^ *^'^° V™?]^ insignificant animal, and if she hid closed her 48 death? ^''^''^.'f^T^^ ^^ "°* P«"^^P« h^^« «aid that she was feigning APPENDIX. 365 st perfect served in 1 only for ng their )t feign a es which, slow fire, hich will utes, as I the same 1 that of nd dura- the kind no more selection, jrtheless, s should 'hey took positions n lulus- ; genera, procured others I suit was le same, 3 and of . be. to more larefully ates; so whether we shall favour- modify ilso, we h build make a 3ct, and sand. If i her ..yea I feigning to Ento- BO on, till we arrive at marvellous structures, rivalling the weavers' art. Even in so singular a nest as that of the Hirundo ICoU loeaha esculenta), eaten by the Chinese, we can, I think, trace the stages by which the necessary instinct has been acquired. The nest is composed of a brittle white translucent substance very like pure gum arabic, or even glass, lined with adherent feather-down. The nest of an allied species in the British Museum consists of irregularly reticulated fibres, some as fine as * of the same substance ; in another species bits of sea-weed are agglutinated together with a similar substance. This dry mucilaginous matter soon absorbs water and softens : examined under the microscope it exhibits no structure, except traces of lamination, and very generally pear-shaped bubbles of various sizes ; these, indeed, are very conspicuous in small dry fragments, and some bits looked almost like vesicular lava. A small pure piece put into flame crackles, swells, does not readily burn, and smells strongly of animal matter. The genus Collocalia, according to Mr. G. E. Gray, to whom I am much obliged for allowing rae to examine all the specimens in the British MuseunT, ranks in the same sub-family with our common Swift. The latter bird generally seizes on the nest of a sparrow, but Mr. Macgillivray has carefully described two nests in which the confusedly fitted materials were agglutinated together by extremely thin shreds of a substance which crackles but does not readily burn when put into a flame. In N. Americaf another species of Swift causes its nest to adhere against the vertical wall of a chimney, and builds it of small sticks placed parallel and agglutinated together • [In the MS a blank is here intentionally left for the subsequent fiUine in or an appropriate word. — G. J. R,] ° /e'^%^"^^**^''* >nMran«« see Macgillivray, British Birds, vol. iii, 1840 p. 625. For C. pelaxgius, see Mr. Peabody's excellent paper on the Birds of Massachussetts in the Boston Journal of Nat. Hist., vol. iii, p. 187. M E Robert (Com/)^e« Rendus, quoted in Anns, and Mag. of Nat. HUt., \ol viii ^^^^> V-^'^^) fo'ind that the nests of the Hirundo riparia, made in the gravelly banks of the Volga, had their upper surfaces plastered with a yellow animal substance, which he imagined to be fishes' spawn. Could he have mistaken the species, for there is no reason to suppose our bank-martin has any such habit? This would be a very remarkable variation of instinct, if it could be proved; and the more remarkable that this bird belongs t^ a dif- ferent sub-family from the Swifts and Collocalia. Yet I am inclined to believe it, for it has been affinned with apparent truth that the House-martin moistens the mud, with which it builds its nest, with adhesive saliva. 24 363 MENTAL EVOLUTION IN ANIMALS. with cakes of a brittle mucilage which, like that of the esculent swallow, swells and softens in water ; in flame it crackles, swells, does not readily burn, and emits a strong animal odour : it differs only in being yellowish-brown, in not having so many large air-bubbles, in being more plainly laminated, and in having even a striated appearance, caused by innumerable elliptical excessively minute points, which I believe to be drawn-out minute air-bubbles. Most authors believe that the nest of the esculent swallow is formed of either a Fucus or of the roe of a fish ; others, I believe, have suspected that it is formed of a secretion from the salivary glands of the bird. The latter view I cannot doubt, from the preceding observations, is the correct one. The inland habits of the Swifts and the manner in which the substance behaves in flame almost disposes of the supposition of Fucus. Nor can I believe, after having examined the dried roe of fishes, that we should find no trace of cellular matter in the nests, had they been thus formed. How could our Swifts, the habits of which are so well known, obtain roe without being detected ? Mr. Macgillivray has shown that the salivary crypts of the Swifts are largely developed, and he believes that the substance with which the materials of its nest are fitted together, is secreted by their glands. I cannot donbt that this is the origin of the similar and more copious substance in the nest of the North American Swift, and in those of the Collocalia escuhnta. We can thus understand its vesicular and laminated structure, and the curious reti- culated structure of the Philippian Island species. The only change required in the instinct of these several birds is that less and less foreign materials should be used. Hence I con- clude that the Chinese make soup of dried saliva.* In looking for a perfect series in the less common forma of birds' nests, we should never forget that all existing birds must be almost infinitely few compared with those which have existed since footprints were impressed on the beach of the New Eed Sandstone formation of North America. If it be admitted that the nest of each bird, wherever placed and however constructed, be good for that species * [It is almost needless to observe that we must remember the date at which this was written ; but it may be remarked that as early as 1817 it was pointed out by Home {Phil. Trans., p. 332) that the proventriculus of Collo- calia is a peculiar glandular structure probably suited to secrete the subatanca of which the nest consists. — Q-. J. R.] APPENDIX. 367 strong under its own conditions of life ; and if the nesting-instinct varies ever so little, when a bird is placed under new con- ditions, and the variations can be inherited, of which there can be little doubt— then natural selection in the course of ages might modify and perfect almost to any degree the nest of a bird in comparison with that of its progenitors in lon» past ages. Let me take one of the most extraordinary cases on record, and see how selection may possibly have acted • I refer to Mr. Gould's observation* on the Australian Me^a- podidse. The Talegalla lathami scrapes together a great pyramid, from two to four cart-loads in amount, of decayin^y vegetable matter ; and in the middle it deposit its eggs. The eggs are hatched by the fermenting mass, the heat of which was estimated at 90° F., and the young birds scratch their way out of the mound. The accumulation propensity is so strong that a single unmated cock confined in Sydney annually collected an immense mass of vegetable matter. The Leipoa ocellata makes a pile forty-five feet in circumference and four feet in height, of leaves thickly covered with sand, and in the same way leaves its - 'j^gs to be hatched by the heat of fermentation. The Megapodius tumulus in the northern parts of Australia makes even a much larger mound but apparently including less vegetable matter; and other species in the Mflayan Archipelago are said to place their eg^s in holes in the ground, where they are hatched by the heat of the sun alone. It is not so surprising that these birds should have lost the instinct of incubation, when the proper tem- perature is supplied either from fermentation or the sun as that they should have been led to pile up beforehand a great heap of vegetable matter in order that it might ferment • for, however the fact may be explained, it ig known that other birds wHl leave their eggs when the heat is sufficient for incubation, as in the case of the Fly-catcher which built Its nest in Mr. Knight's hot-house.f Even the snake takes advantage of a hot-bed in which to lay its eggs ; and what concerns us more, is that a common hen, according to Pro- fessor Fischer, "made use of the artificial heat of a hot-bed to hatch her eggs." J Again Eeaumur, as well as Bonnet, * Birds of Australia, and Introduction to the Birds of Australia 1848 p. 82. ' * + YarreVs British Birds, vol. i, p. 166. ^: Alison, article "Instinct" in Todd', Cyclop, of Anat. and Physiol.^ ' 1 I lii II i 368 MENTAL EVOLUTION IN ANIMALS. observed* that ants ceased their laborious task of daily n moving their eggs to and from the surface according to the / heat of the sun, when they had built their nest between the two cases of a bee-hive, where a proper and equable tempe- rature was provided. Now let us suppose that the conditions of life favoured the extension of a bird of this Family, whose eggs were hatched by the solar rays alone, into a cooler, damper, and more wooded country : then those individuals which chanced to have the accumulative propensity so far modified as to prefer more leaves and less sand, would be favoured in their exten- sion ; for they would accumulate more vegetable matter, and its fermentation would compensate for the loss of solar heat, and thus more young birds would be hatched which might as' readily inherit the peculiar accumulative propensity of their parents as our breeds of dogs inherit a tendency to retrieve, another to point, and another to dash round its prey. And this process of natural selection might be continued, till the eggs came to be hatched exclusively by the heat of fermen- tation ; the bird, of course, being as ignorant of the cause of the heat as of that of its own body. In the case of corporeal structures, when two closely allied species, one for instance semi-aquatic and the other terrestrial, are modified for their different manners of life, their main and general agreement of structure is due, according to our theory, to descent from common parents ; and their slight differences to subsequent modification through natural selection. So when we hear that the thrush of South America (T. Falklandicus), like our European species, lines her nest in the same peculiar way with mud, though, from being sur- rounded by wholly different plants and animals, she must be placed under somewhat different conditions; or when we hear that in Nortn America the males of the kitty wrens,t like the male of our species, have the strange and anomalous habit of making "cock-nests," not lined with feathers, in which to shelter themselves ; — when we hear of such cases, and they are sufficiently numerous in all classes of animals, we must attribute the similarity of the instinct to inheritance from common progenitors, and the dissimilarity, either to * Kirby and Spence, Introd. to Entomol., vol. ii, p. 519. t Peabody in Boaton Journ. Nat. Hist., vol. iii, p. 144. For our British species see Macgillivray, Brit. Birds, vol. iii, p. 23. APPENDIX, 369 Beected and profitable modification, or to acquired and inherited habit In the same manner, as the northern and southern thrushes have largely inherited their instinctive modihcation from a common parent, so no doubt the thrush and blackbird have likewise inherited much from their common progenitor, but with somewhat more considerable modifications of instinct in one or both species, from that of tneir ancient and unknown ancestor. nn Z^kT"^ now consider the variability of the nesting-imtinct. The cases no doubt, would hare been far more numerous, had the subiect been attended Sta7e, 1L°°"S"'' with the same care as in Great Britin and the Sd States. From the general uniformity of the nests of each species, we cleaHv chosln onT."?'"^ t^^'l^' ^"l^ ^' '''' '"^^^^I' "««d aSdtfe situation chosen on a high or low branch, on a bank or on level ground, whether nstnS°TheT;?"°^'T'-T T* ^''' to chance, or to int'elligen'ce but i instinct The Sj/lvia sylmcola, for instance, can be distinguished from two c o ely allied wrens more readily by its nest being lined with feathers Zn by almost any other character. ('• Yarrell's British Birds ") ^ ««f« T''*^ ""^ compulsion often leads birds to change' the situation of their nests: numerous instances could be given in various parts of the world of birds breeding in trees, but in treeless countries on the ground or Tmon^st fnt; fW.w^ r''*"*^ in "Boston Journ. Nat. Hist.." vol iv, p 249) P Sn ll?- wl^"^' '''' ^" '' \* °*^ Labrador. '< in consequoce of th? perse- M Couoh1«?i7^rf "'''^^^r' °°^^^>Win trees." instead of in the Ss. Mr. Couch ("Illustrations of Instinct," p. 218) states that three or four -ThTwhVT^' of the sparrow (F. dolesuL) having be ndesLyed' themsSel 1°"^'."' '^ by mutual agreement, quitted the%lace and seUled themselves amongst some trees at a distance-a situation whi-h thoueh Sred here° wb ""'T^' "l^^'^ *^^^ ""'' ^^^^^ '^'>-«t«- had ev;r beSe bnilTl ^r!' ^ ""^ u'^''' nests became objects of curiosity." The sparrow hn i?r„„-q l^\^ ""^^1'' °° ^'^^ branches, in ivy, under rooks' nests, in th^ hie martin ^..r'"^"^"''''-"'^ °^*^° «^'^^« °" '^^ °*'«t made'by th^ fZff "^ n , ^- °^» *^''' ^'*"'* ^^"^^y according to the place " (Mon- tegue. "Ornitho. Dict.,"p.482). The Heron (Macgillivray, "Brit. Birds"' vol IV, p. 446: W. Thompson, "Nat. Hist. Ireland," vol i p 146) builda in trees, on precipitous sea-clifPs, and amongst heath on the ground In the voM??Blo1n"/'^''''l''r.°'''"* (Peabod/in " Boston Journal Nat. ffisJ.'' vol. Ill, p. 209) likewise builds in tall or low trees, or on the ground • and s^oSmLSr^r'^'^^' "°"^^^^- ^ -'"--^^- - ^-"-. -ci Tnrl!?'n?««'^°'!/*^'^*'J"^^P'.^y= ^^ ^"^^ «««° *''at the Taylor-bird in Ind^a uses artificial thread instead of weaving it. A wild Gold-finch and th°en ^T'""''''^ ■^u'''^^' 7^' h P" ^2) first took wool, then cotton, wm often h1?M°' ^,J^^''\'5»« Pl^ed near its nest. The common Robin will often build under sheds, four cases having been observed in one season at one place (W. Thompson. "Nat. Hist. Irellnd." vol. i, p. 14) In Walea oilfntof ?nll7^ builds against perpendicular clilfs%i?-al/SvS !.rl«!^ if ^"8^=^"^ against houses; and this must have prodigiously in- creased Its range and numbers. In Arctic America in 1^2b Hirundoluni. frons (Richardson. " Fauna Boreali-Amercani,"p. 331) for the first fme bu" It against houses ; and the nests, instead of being clustered and each "avin^ a tubular entrance, were built under the eaves iS a single line and Sthout th2 'i I it r ■; ,r II ffli^t V ' I' (i [., r ^1 ! 370 MENTAL EVOLUTION IN ANIMALS. tubular entrnnre, or with a more ledge. The date of a si.nilar change In the habits of H.fulva it also known. In all changes, whether from persecution or convenience, intelligence must come into plaj in some degree. The Kittj-wren (T. vulgaris), which builds in various situations, usually makes its nest to match witli surrounding objects (Macgillivray, vol. iii, p. 21) ; but this perhaps is instinct. Yet wlien wehear from White (Letter 14) that a Willow-wren (and I have known similar case;, having been disturbed by being watched, concealed the orifice of her nest, we might argue that the case was one of intelligence. Neither the Kitty-wren nor Water-ouzel (" Mag. of Zool.," vol. ii, 1838, p. 429) invariably build domes to their nests, when placed in sheltered situations. Jesse describes a Jackdaw which built its nest on an inclined surface in a turret, and reared up a perpendicular stack of sticks ten feet in height— a labour of seventeen days : families of this bird, I may add (White's "Sel- borne," Letter 21), have been known regularly to build in rabbit-burrows. Numerous analogous facts could be given. The Water-hen (O. cMoropus) is ■aid occasionally to cover her eggs when she leaves her nest, but in one pro- tccted place W. Tliompson (" Nat. Hist. Ireland," vol. ii, p. 328) says that tiiis was never done. Water-hens and Swans, which build in or near tlie water, will instinctively raise their nest as soon as they perceive the water begin to rise (Couch " Illustrations of Instinct," p. 223-6). But the follow- ing seems a more curious case :— Mr Yarrell showed me a sketch of the nest of a Black Australian Swan, which hud been built directly under the drip of tiie eaves of a building ; and, to avoid this, male and female conjointly added semicircular « to the nest, until it extended close to the wall, within the line of drip ; and then they pushed the eggs into the newly added portion, so as to be quite dry. The Magpie {Corvus pica) under ordinary circumstances builds a remarkable, but very uniform nest ; in Norway they build in churches, or spouts under the eaves of houses, as well as in trees. In a treeless part of Scotland, a pair built for several vcars in a gooseberry bush, which they barricaded all round in an extraordinary manner with briars and thorns, so that " it would have cost a fox some days' labour to have got in." On the other hand, in a part of Ireland, where a reward had been offered for each egg and the magpies had been much persecuted, a pair , built at the bottom of a low thick hedge, " without any large collection of materials likely to attract notice." In Cornwall, Mr. Couch says he hat seen near each other, two nests, one in a hedge not a yard from the ground and " unusually fenced in with a thick structure of thorns ;" the other " on the top of a very slender and solitary elm— the expectation clearly being that no creature would venture to climb so fragile a column." I have been struck by the slenderness of the trees sometimes chosen by the magpie ; but. intA*;'« Annals and Mne of Nat History '• vol. vi„, 1842, p. 281) bus been described, which was bound by a piece of whipcord passing once round a branch of a pine tree and then firmly inter^voven with the materials of the nest : the n'^st of the chaffinch with lichen ; but Mr. Hewitson (" British Oology," p. 7) has described one m which bits of paper were used for lichen. The iVirush (TwS budds in bushes, but sometimes, when bushes abound, in holes of 3 or under sheds; and two cases are known of its having built JtualhSn the ground in long grass and under turnip-leaves (W. Thompson "S H st Bev W h "i- '' ^- J'' = ^'''''\" Il^"«tration8 of .nstir^t!"'p. 219). The ?r- VV.D. Fox informs me that an "eccentric pair of blackbirds " (T. merula) for three consecutive years built in ivv against a wall and ri^'/j."'^?''"" "'f,*-^'*^ ^^"'^ l>ors..hair, thoughts was nSg to tempt them to use this material : the eggs also were not suotted Tb« neZ ^„r"«»* "''f-- has described (in "Mewitson's British Oo ogy ")^tL nests of two Redstarts, of which one alone was lined with a nrofif<,inn nf white feathers. The Golden-crested Wren (Mr. ShrvJlJl'-Lir Trans " vol xy,p 14) usually builds an open nest attached to the under side of '* flr-branch, but sometimes oa the branch, and Mr. Sheppard has seen one pendulous with a hole on one side." Of the woudpvfnl nif «* !i t r Weaver-bird (PloceusPMippensis, " Proc W C" Julytr isl^?) abtu? one or two in every fifty have an upper chamber, in which tL male's nest grooved by ne widening of the stem of the nest^ith a pent ho^se aSdd InnH J ^'" ^°"^^'<1'' by adding two general remarks on this head by two good observers (Sheppard in "Linn. Trans "vol xv n id, L^ Tai„ t n quoted by Yarrell. "^^ritish Birds," vol.? p. 444) ' -^TWe aJe Iw^^^^^^^^^^ nesr'''"irL°vTr'"^ -^^^^r. *^1^"^^-' for^hrbunc^rgS nests. It 18 evident, says Mr. Blackwall, " that birds of the same snecies possess the constructive powers in very different degrees of perfection for the of othl!'"'"'"^^"'^'' ^'^ '"^^^^^ '^ ^ -anne^reatly^uperior to those r.y. j!.Tr °^ th^^oes above given, such as the Totanus either making a nest orbuildmg on the bare ground, or tl-.at of the Water-ouzel maki^f Jr not making a dome to its nest, ought, perhaps, to be calledTdrblelnstincJ fw t?:irrs'zv f s *''.^ t' ^?^"""f ^^^ «^ ^ doubitstinc wS 1 Jiave met w th, is that of the St/lna cisticola given by Dr. P. Savi f" Anns des Sc Nat., ' tome ii, p, 126). This bird in Pisa annually makes two neZ-" he autumnal nest is formed by lea.es being sewn together wShspiS^web; »nd the down of plants, and is placed in marshes ; the vernal nest is ullced m tufts of grass m corn-fields, and the leaves are not sewn togetS; but tS i a. m if f 372 MENTAL EVOLUTION IN ANIMALS. ■ides are thiolcer and very diflbrent materials are used. In such cases, as wm formerly remarked with respect to corporeal structures, a great and apparently abrupt change might be elTected in the instinct of a bird by one form alone of the nest being retained. In some cases, when the same species ranges into a different climate, tha nest differs ; the Artamus sordidus in Tasmania builds a larger, more com- pact, and neater nest, than in Australia (Gould's "Birds of Australia"). The Sterna minuta, according to Audubon (" Anns, of Nat. Hist,," vol. ii, 1839, p. 462), in the southern and middle U. States merely scoops a slight hollow in the sand ; " but on the coast of Labrador it makes a very snug nest, formed of dry moss, well matted together and nearly as large as that of the Turdus migratorius." Those individuals of Icterus BaUjmore (Peabody in "Boston Journ. of I«lat. Hist.," vol. iii, p. 97) "which build in the south make their nests of light moss, which allows the air to pass through, and complete it without lining ; while in the cool climate of New England they make their nests of soft substances closely woven with a warm lining." Habitations of Mammals. — On this head I shall make but few remarks, having said so much on the nests of Birds. The buildings erected by the Beaver have long been cele- brated ; but we see one step by which its wonderful instincts might have been perfected, in the simpler house of an allied animal, the Musk Eat (Fiber zibethims) which, however, Hearne* says is something like that of the Beaver. The solitary Beavers of Europe do not practise, or have lost the greater part of their constructive instincts. Certain species of Eats now uniformly inhabit the roofs of houses,t but other species keep to hollow trees — a change analogous to that in swallows. Dr. Andrew Smith informs me tliat in the unin- habited parts of S. Africa the hya3nas do not live in burrows, whilst in the inhabited and disturbed parts they do.| Several mammals and birds usually inhabit burrows made by other species, but when such do not exist, they excavate their own habitations. § In the genus Osmia, one of the Bee family, the several species not only offer the most remarkable differences, as described by Mr. F. Smith] | in their instincts ; but the indi- viduals of the same species vary to an unusual degree in this respect ; thus illustrating the rule, which certainly seems to • Jlearne^s Travels, p. 380. Hearne has given the best description (pp. 227-236) ever published of the habits of the Beaver. t Rev. L. Jenyns in lAnn. Trans., vol. xvi, p. 166. j A case sometimes quoted of Hares having made burrows in an exposed situation {Anns, of Nat. Hist., vol. v, p. 362), seems to me to require verifica* tion : were not the old rabbit-burrows used ? § Zoology of the Voyage of the Beagle, " Mammalia," p. 90. II Catalogue of British Hymenoptera, 1855, p. 158. APPENDIX. 373 hold in corporeal structures, namely, that the parts which differ most in allied species, are apt also to vary most in the same species. Another Bee, the Megachile maritima, as I am informed by Mr. Smith, near the sea makes its burrows in the sand-banks, whilst in wooded districts it bores holes in posts* I have now discussed several of the most extraordinary classes of instincts ; but I have still a few miscellaneous remarks which seem to me worth making. First for a few cases of variation which have struck me : a spider which had been crippled and could not spin its web, changed its habits from compulsion into hunting — which is the regular habit of one large group of spiders.f Some insects have two very different instincfts under different circumstances, or at different times of life ; and one of the two miglit through natural selec- tion be retained, and so cause an apparently abrupt difference in instinct in relation to the insects' nearest allies : thus the larva of a beetle (the Ciomis scraphularice), when bred on the scrophularia, exudes a viscid substance, which makes a trans- parent bladder, within which it undergoes its metamorphosis ; but the larva when naturally bred, or transported by man, on to a verbascum, becomes a burrower, and und(!rgoes its meta- morphosis within a leaf J In the caterpillars of certain moths there are two great classes, those which burrow in the paren- chyma of leaves, and those which roll up leaves with consum- mate skill : some few caterpillars in their early age are burrowers, and then become leaf -rollers ; and this change was justly considered so great, that it was only lately discovered that the caterpillars belonged to the same species. § The Angoumois moth usually has two broods: the first are hatched in the spring from eggs laid in the autumn on grains of corn stored in granaries, and then immediately take flight to the fields and lay their eggs on the standing corn, instead of on the naked grains stored all round them : the moths of the second brood (produced from the eggs laid on the standing corn) are hatched in the granaries, and then do not leave the granaries, but deposit their eggs on the grains around them ; and from these eggs proceed the vernal brood which have the * [Here follows a section on the instincts of Parasitism, Slave-making, and Cell-making, which is published in the Origin of Species. — Q-. J. R.J t Quoted on authority of Sir J. Banks in Journal Linn. Soo. X p. Huber in Mem. Soc. Phi/s. de Oenhve, tome x, p. 33. § Westwood, in Qai-denera' Chronicle, 1852, p. 261. wms 374 MENTAL EVOLUTION IN ANIMALS. different instinct of laying on the standing corn.* Some hunt- ing spiders, when they have eggs and young, give up hunting and spin a web wherewith to catcli prey: this is the case with a Sulticus, which lays its eggs within snail-shells, and at that time spins a large vertical web.f The pupie of a species of Formica are sometvmesX uncovered, or not enclosed within cocoons ; this certainly is a highly remarkable variation ; the same thing is said to occur with the con^mon I'ulex. Lord Brougham§ gives us a remarkable case of instinct, namely, tho chicken within the shell pecking a hole and then " chipping with its bill-scale till it has cut off a segment from the shell It always moves from right to left, and it always cuts off the segment from the big end." But the instinct is not quite so mvariable, for I was assured at the Eccalobeion (May, 1840) that cases have occurred of chickens having commenced so cbse to the broad end, that they could not escape from the hole thus made, and had consequently to commence chipping again so as to remove another and larger rim of sliell : more- over occasionally they have begun at the narrow end of the shell. The fact of the occasional regurgitation of its food by the Kangarooll ought, perhaps, to be considered as due to an mtermediate or variable modification of structure, rather than of instinct; but it is worth notice. It is notorious that the same species of Bird has slightly different vocal powers in different districts; and an excellent observer remarks that " an Irish covey of Partridges springs without uttering a call, whilst on the opposite coast the Scotch covey shrieks with all its might when sprung."1f Bechstein says that from many years' experience he is certain that in the nightingale a tendency to sing in the middle of the night or in the day runs in families and is strictly inherited.** It is remarkable that many birds have the capacity of piping long and difficult tunes, and others, as the Magpie, of imitating • Bonnet, quoted by Kirby and Spence, Entomologtf, vol. ii, p. 480. t DugSs in Anns, des Sci. Nat., 2nd series, tome vi, p. 196. X F. Smith in Trans. Ent. Soc, vol. iii, N.S., Pt. iii, p. 97} and De Geer, quoted by Kirby and Spence, Entomology, vol. iii, p. 227. § Dissertation on Natural Theology, vol. i, p. 117. II W. C. Martin in Mag. of Nat. Hist., N.S., vol. ii, p. 323. f W. Thompson, in Nat. Hist. Ireland, vol. ii, p. 65, says that he has observed this, and that it is well known to sportsmen. ** Stuben-vogel, 1840, s. 323. See on different powers of Bingini? in different places, a. 206 and 265. iiL i APPENDIX. 375 all sorts of sounds, and yet that in a state of nature they nevor display these powers.* As there is often much difficulty in imagining how an instinct could first have arisen, it may be worth while to give a few, out of many cases, of occasional and curious habits, which cannot be considered as regular instincts, but which might, according to our views, give rise to such. Thus, several cases are on recordf of insects which naturally have very different habits having been hatched within the bodies of men — a most rcimurkable fact considering the temperature to which they have been exposed, and which may explain the origin of the instinct of the Gad-ily or (Estrus. We can see how the closest association might be developed in Swallows, for LamarckJ saw a dozen of these birds aiding a pair, whose nest had been taken, so effectually that it was completed on the second day ; and from the facts given by Macgillivray§ it is impossible to doubt that the ancient accounts are true of the Martins sometimes associo' 1 '\g and entombing alive sparrows which have taken possession of one of their nests. It is well known that the Hive-bees which have been neglected " get a habit of pillaging from their more industrious neighbours," and are then called corsairs ; and Huber gives a far more remarkable case of some Hive-bees which took almost entire possession of the nest of a Humble- bee, and for three weeks the latter went on collecting honey and then regorged it at the solicitation, without any violence, of the Humble-bee.|| "We are thus reminded of those Gulls (Lcstris) which exclusively live by pursuing other gulls and compelling them to disgorge their food.lf In the Hive-bee actions are occasionally performed which • Blackwall's Researches in Zoology, 1834, p. 158. Cuvier long ago remarked that all the passeres have apparently a siiuilar structure in their vocal organs; and yet only a few, and these the males, sing; showing that fitting structure does not always give rise to corresponding habits. [Concern- ing birds which imitate sounds when in captivity not doing so in a state of nature, see p. 222, where there is evidence of certain wild birds imitating the sounds of other species. — G. J. R.] t Rev. L. Jenyns, Observations in Nat. Hist., 1846, p. 280. J Quoted by Geoffry St. Hilaire in Anns, des Mus., tome ix, p. 471. § British Birds, vol. iii, p. 591. II Kirby and Spence, Entomology, voL ii, p. 207. The case given by Huber is at p. 119. ^ There is reason to suspect (Macgillivray, British E' w, vol. v, p. 500) that some of the species can only digest lood which has been partially digested by other birds. 'I :ii ),l 376 MENTAL EVOLUTION IN ANIMALS. we must ranlf amongst the most wonderful of instincts ; and yet these instincts must often have beta dormant durincr many generations: 1 refer to the death of the queen, wheS several worker-larvae are necessarily destroyed, and beincr placed m large cells and reared on royal food, are thuS rendered fertile : so again when a hive has its queen, the males are all infallibly killed by the workers in autvmn : but , A»-r.f ""^ ^"^®"' "°* ^ «"igle drone is ever de- stroyed. Perliaps a rr.y of light is thrown bv our theory on these mysterious but well ascertained facts,"by considering that the analogy of other members of the Bee family would lead us to believe that the Hive-bee is descended from other iiees which i-gularly had many females inhabiting the same nest during the whole season, and which never destroyed their own males ; ^o that not to destroy the males and to give the normal food to additional larva, perhaps is only a reversion to an ancestral instinct, and, as in the case of corporeal structures reverting, is apt to occur after many generations.f -^ I will now refer to a few cases of special difficulty on our theory— most of them parallel to those which I adduced when discussing in Chapter VIII corporeal structures Thus we occasionally meet with the same peculiar instinct in animals widely remote in the scale of nature, and which conse- quently cannot have derived the peculiarity from community of descent The Molothrus (a bird something like a starlin/) ot N. and S. America has precisely the same habits with the Uickoo ; but parasitism is so common throughout nature that this coincidence is not veiy surprising. The parallelism in instinct between the White Ants, belonging f,o the Neurop- tera and ants belonging to the Hymenoptera, is a far more wonderlul fact; but the parallelism seems to be very far from close. Perhaps as remarkable a case as any on record of the same instinct having been independently acquired in two animals very remote from each other in relationship, is that ot a I^europterous and a Dipterous larva digging a conical * Kirby and Spence, Dntomologif, vol. ii, pp. 510-13. TrillitJ- r^'T'"^ 1^? ^T"°" ^^^ '^^''^ ^""^ «o "^'^"y drones as to require iiUing, see ^m,««Z Intelhgenoe p. 166, .vbere I suggest chat imong the ancestors of the Hive-bee the males may have been of use as ..ovkers. ^But possibly the drones may even now be of use as nurses to the lar-se. for I am told ^ an exponenced. bee-keeper that he believes this to b< the case.-- li^, >i.. APPENDIX. 377 pit-fall in loose sand, lying motionless at the bottom, and if the prey is about to escape, casting jets of sand all round.* It has been asserted that animals are endowed with instincts, not for their own individual good, or for that of their own social bodies, but for the good of other species, though leading to their own destruction : it has been said that fishes migrate that birds and other animals may prey on them : f this is impossible on our theory of natural selection- of self-profitable modification of instinct. But I have met with no facts in support of this belief worthy of considera- tion. Mistakes of instinct, as we shall presently see, may in some cases do injury to a species and profit another; one species may be compelled, or even apparently induced by persuasion, to yield up its food or secretion to another species; but that any animal has been specially endowed with an instinct leading to its own destruction or harm, I cannot believe without better evidence than has hitherto been adduced. An instinct performed only once during the life of an animal appears at first sight a great difficulty on our theory ; but if indispensable to the animal's existence, there is no valid reason why it should not have been acquired through natural selection, like corporeal structures used only on one occasion, like the hard tip to the chicken's beak, or like the temporary jaws of the pupa of the Caddis-fly or Phryganea, which are exclusively used for cutting open the silken doors of its curious case, and which are then thrown off for ever.$ Nevertheless it is impossible not to feel unbounded astonish- ment, when one reads of such cases as that of a caterpillar first suspending itself by its tail to a little hillock of silk attached to some object, and then undergoing its meta- morphosis; then after a time splitting open one side and exposing the pupa, destitute of limbs or organs of sense and lying loose within the loiver part of the old bag-like split skin of the caterpillar : this skin serves as a ladder which the pupa ascends by seizing on portions between the creases of its abdominal segments. and then searching with its tail. which is provided with little hooks, thus attaches itself, and * Kirby and Spence, Entomology, vol. i, pp. 429-435. t Linns)U3 in Amoenitates AcademiccB, vol. ii ; and Prof. Alison on Instinct" in Todd's Cycl. of A not. and Physiol., p. 15. X Kirby and Spence, Entomology, vol. iii, p. 287. 378 MENTAL EVOLUTION IN ANIMALS. I "1 I'll i afterwards disengages and casts off the skin which had served It tor a ladder* I am tempted to give one other analogous case, that of the caterpillar of a Butterfly (TheMa), vfhich teeds withm the pomegranate, but when fuU fed gnaws its way out (thus making the exit of the butterfly possible before Its wings are fully expanded), and then attaches with silk threads the point to the branch oi the tree, that it may not tall before the metamorphosis is complete. Hence, as in so many other cases, the larva works on this occasion for the safety of the pupa and of the mature insect. Our astonish- ment at this manoeuvre is lessened in a very sli<»ht de^n-ee when we hear that several caterpillars attach mo°re or less perfectly with silken threads leaves to the stems for their own safety; and that another cat-rpillar, before chan stances ; but the workers themselves act as if they suffered m their instinct from the imperfect state of their cmeen for they fed these male larv^ with royal jelly and treat ?hem as they would a real queen."* ButVat Is C e su?pr si^ the workers of Humble-bees habitually endeavour to seL'e and devour the eggs of their own queens; and the utmost V Se»t cr?r i "«^-««ly adequate to prevenfthi violence t Can this strange instinctive habit be of anv lZZlt:n^"r''L ^'"^ the innumerable and admirable instincts al directed to rear and multiply youn- can we mtS"''^ ''""'^r^ ^P^^«^' ^^^* thistLge' aberrant ?ue bound, ^^''^'p'^Ti "'■' ^''^ '^' population within due bounds ? Can the instinct which leads the female spder savagely to attack and devour the male after pSg with himj be of service to the species ? The Leas? of her husband no doubt nourishes her; and without some better explanation can be given, we are 'thus reduced to tl^e grossest utilitarianism, compatible, it must be confessed wth the theory of natural selection. I fear that to the foreCln. cases a long catalogue could be added ^"^e^o^"*, Conchcsion.—We have in this chapter chiefly considered the instincts of animals under the point of view whether it' s possible that they could have been acquired through he means indicated on our theory, or whether,\ven if the simple? ones could have been thus acquired, others are so complex and wonderful that they must have been specially endXd and thus overthrow the theory. Bearing in mind the facts given on the acquirement, through the sefection o? self!oril LT>Sh?^7'.™°^'^''^^"" of instinct, or through training ZJt^M- ''^'^ '? 'r ' '^P^^ ^^Sree by imitatioli, of here! ditary actions and dispositions in our domesticated animals • I'nstinotrnr''^'^'"' ^'^^J'"' '' ^^^^"g 1^«« ti«^«) to the nstincts ot animals in a state of nature : bearing in mind t at n a state of nature instincts do certainlv vary in some slight degree : bearing in mind how very geneivali; L fiS allied but distinct animals a gradation iS the more complex nstincts, which show that it is at least possible that a complex instinct might have been acquired by 'successive steps [and then, will """'" \ P- '^^K.^ ^°"? ^''* °f ''^^^^ i"«^^t8 ^'hich either in their larval or mature condition will devour each other is given ii:; IE m 384 MENTAL EVOLUTION IN ANIMALS. In P-i- which moreover generally indicate, according to our theory, the actual steps by which the instinct has been acquired, in as much as we suppose allied instincts to have branched off at different stages of descent from a common ancestor, and therefore to have retained, more or less unaltered, the instincts of the several lineal ancestral forms of any one species : bepring all this in mind, together with the certainty that instincts are as important to an animal as their generally correlated structures, and that in the struggle for life under changing conditions, slight modifications of instinct could hardly fail occasionally to be profitable to individuals, I can see no overwhelming difficulty on our theory. Even in the most marvellous instinct known, that of the cells of the Hive-bee, we have seen how a simple instinctive action may lead to results which fill the 'mind with astonishment. Moreover it seems to me that the very general fact of the gradation of complexity of instincts within the limits of the same group of animals ; and likewise the fact of two allied species, placed in two distant parts of the world and sur- rounded by wholly different conditions of life, still having very much in common in their instincts, supports our theory of descent ; for they are explained by it : whereas if we look at each instinct as specially endowed, we can only say that it is so. The imperfections and mistakes of instinct on our theory cease to be surprising : indeed it would be wonderful that far more numerous and flagrant cases could not be detected, if it were not that a species which has failed to become modified and so far perfected in its instincts that it could continue struggling with the co-inhabitants of the same region, would simply add one more to the myriads which have become extinct. It may not be logical, but to my imagination, it is far more satisfactory to look at the young cuckoo ejecting its foster- brothers, ants making slaves, the larvse of the Ichneumidfe feeding within the live bodies of their prey, cats playing with mice, otters and cormorants with living fish, not as instincts specially given by the Creator, but as very small parts of one general law leading to the advancement of all organic bodies — Multiply, Vary, let the strongest Live and the weakest Die. 1, ' I INDEX TO MENTAL EVOLUTION IN ANIMALS. Abercrombie, Dr., a case of apoplexy described by, 38 Abstraction, 145, 152-3, 352. Actinia. See Anemone, .^iian, on instincts of capon, 171. .^istbetic emotions in animals, 311, 345. Affection in animals, 345. Aleipidce, eyes of, 85-6. Alford, Lord, hounds of, 198. 241. Alison, Professor, on sense of modesty as instinctive, 193. Allen^ Grant, on sense of temperature, 97; on sense of colour, 100; on ratedd'oV240 ' ^^^~"' o^s^^^e of dependence shown by domesti- Amoeba, power of discrimination in, 55. Amphibia senses of sight, hearing, smell, taste, and touch in, 90- memorv m, 124 ; grade of mental evolution of, 349-50. Amphioxus, destitute of auditory organs, 90, Anatomy, relation of comparatiTe, to comparatire psychology 5 Andrews, J. B., on homing faculty of a dog, 290. Anemone sea-, observation upon discrimination of, 48-9 j sense of smcU in 88 ; mistaken by a bee for a flower, 168. Anger, in animals, 341, 345. ^n«ej,^a, consciousness in, 77; special sensation of, 56, 86; emotions of. 344 ; grade of mental evolution of, 344. Anthropoid apes.. See Ape. Ants brain of ,46 J memory in, 146; individual yariations of instincts of 183 ; local variations of instincts of, 244-5 ; pets of, 185 ; receiving secretion from aphides, 277-8; sense of direction in, 295; glave- niHking instincts of, 317 ; grade of mental evolution of, 350 Ape, delusions of a sun-struck, 150 ; intelligence of an anthropoid, 328. Apes, anthropoid, using tools, 352 ; grp,de of mental evolution of. 352 Aphides, yielding their secretion to ants, 277-8. Arachnida, special sensation in, 56. See Spider and Scorpion. Argyll, Duke of, on an eagle teaching a goose to eat flesh, 227'; on origin of instincts, 262 ; on instinct of feigning injury, 316 Articulata, special senses of, 56, 84-8 ; memory in, 123 ; imagination in. 145-6 {instinct of in feigning death, 303, et seq.; emotions of. 344 1 grade of mental evolution of, 349. Association of Ideas. See Ideas. Ataxy, analogous to lunacy, 44. Audouiii, on puppies learning to imitate cats, 223. :iii' 386 MENTAL EVOLUTION IN ANIMALS. Auerhaoli, on rlilomma-time in perception, 134-6. Aurelia anvita, nervouB system of, 69. 6. Bain, Professor Alexander, on associated movements, 41, 43 ; «" a"9^'*; tiou of i.leas, l:iO ; on perception, 125 ; on ideas as faint revivals of perceptions, 142-3 ; on evolution of mstmct, 256. Baines, Mrs. M. A., on a puppy learning to imitate a cat, .J24. Banks.Sir J., on modified instincts of a spider, 209. „« i,„„f f,„™ Barking, inst net of, round a carriage, 182 186 , instinct of an offshoot from acquired instinct of protecting master's property, 23a ; not practised by does in certain parts of the world, 250. Bnrrington. on birds acquiring songs of their foster parents. 222. Bastian, D^., on sense of direction, 292-3 ; on mtelligenco of orang-outang, 328. Bat, sensibilitv of blinded, 94. . . ... . * u,„;„ a a Bateman, Dr." Frederick, on relation of intelligence to mass of brain, 44. . Btites, on memory of Hymenoptera, 123. Batrachia. See Amphibia. , .. - ♦•„„ mo Baxt. on reaction-time as increased by complexity of perception, 133. Bear, becoming omnivorous, 247. n • t- „* *„ -„o<,«„ Jn Beaver, local variation of instinct in, 249 j relation of instinct to reason m, 329 l:;s^trr" ^nltii.' inSS 0T166-8, 174-5. 179, 203-9 ; boring hole, in SL, 220-1; local variations of instincts of. 245 ; sense of direc- tion in, 290, 293-4; cell-making instinct of, 317; grade of mental evolution of, 350. Beetles, memory in, 123; instincts of dung, 241. Begging, hereditary transmisbion of, in dog and cat, 1 Ja-t>. Belt, on memory of Hymenoptera, 123. Bembex, instincts of, 166, 191-2. oak a Benevolence, in animals, 341, 345 ; in cats, 345-0. Bennet, on birds dreaming. 149. Beran, the Bev. J., on mistaken instincts of bees and wasps, 167. Bidie. G.. on alleged instinct of scorpion to commit suicide. 2/8 ; on a DUU feigning death, 313-14. Bineley. on crabs feigning death, 305. Birds, special senses of, 57 ; sight, 91 ; touch, 92 ; colour-sense, 99-100 ; dreaming, 149; instincts of young, , -- - , . i. of 168 trivial and useless instincts of. 176; attachments between different .pecies of, 185. and with other animals 183-5 ; varl^tlon8 in nest-building of. 209-12; variations in incubating mstmcta ot, 212 17; mtinctive' singing of, 222; imitating songs of other birds. 222-3; teaching their youlg, 226-7; local variatK)ns of/°f;°° J 245-7 specific variations of instinct in, 251-5; flying towards hght, 279 mig^rn of. 286-9, 2.5-7; feigning death. 303-5 ; feigning injury. 316-17 ; emotions of. 345 ; grade of mental evolution of, 351. Biscacha, instinct of, 190. Black. William, on migration of swallows, ^4b. Blackbird, conveying young. 211. Blackie, Professor, on colour-sense, 100. hearing. 91-2; smell, taste, and memory, 124 ; perception. 131 ; 161-5. 170-1; mistaken instincts li INDEX. 387 Blaine, on Lord Alford's hounds, 198 ; on inherited tendency to bark in Bporting dog», 23fi. Blue-bird, local variation of instinct of, 210, 246. Blyth, on a fox feigning death, 3U4. Bod, on carnivorous habits of wasp, 245. Bond, on variation in nest of nut-hatch, 182. Bonelli, Professor, on a migration of butterflies, 288, Brain, relation of intelligence to moss of, 44-6. Brehm, on old birds educating young, 226. Brent, on instincts of crossed canaries, 199. Brewster, Sir D., on unconscious inference in perception, 321. Brodie, Sir B., on infants remembering taste of particular milk, 115 j on inheritance of instinct as due to cerebral organization, 264. Brunelli, on stridulation of grasshopper, 86. Bryden, Dr. W., on a monkey feigning death, 312-13. Buccola, Dr. Ot., on length of the reaction-time in perception among the uneducated and idiotic, 138. Buchanan, Professor, on imperfect instincts of young ferrets, 228. Biichner, on individual dispositions shown by ants, 183. Bull, wildness of cross between Indian and common cow, 199; Brahmin feigning death, 313-14. Burdach, on imagination in animals, 151. Burrowing, instinct of, 248-9. Burton, P. M., on mistaken instinct of a moth, 167. Butterflies, littorul, continuing to frequent an area whence the sea has retired, 246 ; migration of, 285-6. 11 1 0. Caddice-fly, instincts of the, 191. Calderwood, Professor, on the relation of intelligence to the mass of the brain, 44. Callin, Or., on sense of direction in man, 293. Cameleon, sense of colour in the, 98. Canary, diversity of individual iiisposition of the, 182 ; instincts of crossed breeds of the, 199 ; instinctive nidification of the, 226. Capon, instincts of the, 171. Carpenter, Dr. W. B., on discrimination shown by protoplasmic organisms ; on acquired habits, 181 ; on cats not howling in S. America, 250 ; on a case of couching for cataract, 322 ; on inheritance of handwriting, 194. Carter, H. J., on sensation in Rhizopoda, 80. Castration, changes produced by, on instinct, 171-2. Cat, idiosyncracies of the, as regards mousing, 182 ; associating with hares, &c., 184 ; hereditary disposition to beg in a family of the, 195 ; rearing progeny of other animals, 217-18 ; loss of instinctive wildness of the, under domestication, 231 ; not howling iu S. America, 249-50 ; sense of direction in the, 289 ; cruelty and benevolence in the, 345-6 j under- standing of mechanism by the, 351. Caterpillar, instincts of the processional, 342-3. Caterpillars, migrations of, 285. Cattle, learning to avoid poisonous herbs, 224, 227; instincts of wild under domestication, 231 ; dwindling of natural instincts of in Ger- many, 232 ; sucking bones, 247 ; sense of direction in, 290. Causation, appreciated by animals, 155-8. 888 MENTAL EVOLUTION IN ANIMALS. Cephalopoda, intoUigonce of reloted to organs of touoli, 67 1 oyei of, 88 i enri> of, 89 i factilo organi of, 89 ; colour-nenso in, 98; iDrn.ory in, \2'1 \ imagination in, 145 ; grade of uientul oroluiion of, 349-00. Cerebrum, funotion» of the, 34-46. Chalicodoma, instincts of, 16H. Cliuracter, individiiiil. Sve Disposition. Chelmon roslratus, 89. Chesuldcn, on a case of couching for cataraet, 322-8. Chickens. See Binls. Choice, as criterion of mind, 17-20; physiological ospcct of, 47-56. Clifford, Professor, on ejects, 16. Cobb, Miss, on inheritance of handwriting, 194, Cwlenterata, consciousness in, 76, 348 ; special sense of, 83-4 ; emotions of, 342 ; grade of mental evolution of, 348. Collett, R., on niigration of the lemming, 283-6. Colour-sense, 98-104. Comparative Psychology in relation to comparutiTC anatomy, 6 ; objects of, as a science, 6-7. Comte, on B^etitihism in animals, 154. Conceptualism, 145. Conductility, 68. Conscience, evolution of, 352. Consciousness as the distinctive character of mind, 17 ; evolution of, 70-77 j definition of impossible, 72; degrees of, 72; time relations of, 73; possibly developed to supply conditions of feeling pleasure and pain. 111. Conte, Le, on cattle sucking bones, 247. Couch, on mistaken instinct of a bee, 167-8 ; on variations in the instinct of incubation, 182; on a dog learning how to attack a badger, 221; on a goldfinch sinjiing instinctively, 222 ; on birds learning and forgetting the snngs of other birds, 223 ; ou the instinct of feigning death, 303-8, 315. Coues, Captain Elliot, on local variations of instinct in birds, 210, 246-7. Crab, olfactory organs of, 87-8; experiments in psychology of the Hermit, 122-3 ; migration of the Land, 146, 285 ; feigning death, 305 ; reason in the, 336, 350. Crayfish, kataplexy of the, 308. Crc.r, aquatic habits of the, 253, Cripps, on an elepliant feigning death, 305. Crocodile, alleged dreaming iii the, 149; divers dispositions in families of the, 188. Crossing, effects of, in blending instincts, 198-9. Crotch, on migration of the lemming, 282-5. Cruelty in animals, 541, 345. Crustacea, special senses of, 84, 87 ; colour-sense of 98-9 : lemory of, 122 imagination of, 145-6; grade of mental evolution oi, ^ii<-aO. Cuckoo, mistaken instincts of the, 168; parasitic and no'.-par. s^itic habits or the, 251-2 ; parallelism of instincts of the, with r '.ostJ of Moiothrut, 273-4; migration of the young, 289. Cuculion», 188-90 ; on instincts of biscacha, 189-90; on inheritance of liandwriting, 194 j on wildness and tanienesti in rabbits, horses, and ducks, 196, and in wild animals, 197 ; on effects of t rossiiig ujwn instincts, 198-9 ; on intelligent imitation by animals, 220-2 ; on protrusion of lips by orang-outang, 225 •, on sheep and cattle learning to avoid poisonous herbs, 227 j on oblitemtion of wild instincts under domestication, 231-2 ; on acquisition of domestio instincts, 236-9 ; on bees eating moths, 245 ; on local variations of instinct in birds, 245-fi ; on the hyccna not burrowing in South Africa, 249; on speciJic variations of instinct as dilHcultios against the theory of natural selection, 251 ; on parasitic habits of Molothrua, 251 ; on ndoptivo structures developed by natural selection, 253-4; on evolution of instinct, 261-6 ; on similar instincts of unallied animals, 273 ; on dis- similar instincts of allied animals, 274 ; on trivial and useless instincts, 274-6 ; on instincts apparently detrimental, 276-82 ; on migration of lemming, 282 ; on theory of migration, 287-97 ; on sense of direction, 29u-3 ; on instincts of neuter insects, 297-9 ; on instincts of sphex, 299 and 303 ; on beos boring corollas of flowers, 220-1, 301-2 ; on instinct of feigning death, 308 j on instinct of feigning injury, 316-17 ; on reason in a crab, 336 ; on emotions of earthworms, 344 ; on sexual •election, 344-5. [For all references to matter now published in the Posthumous Essay on Instinct, see Index to the Essay. The following are references to all the quotations from, and allusions to, the unpublished MSS of Mr. Darwin which occur in the pages of the present work.] On changes produced in instinct by abnormal individual expe- rience, 115 ; on instinctive fear and ferocity in young animals as directed against particular enemies or kinds of prey, 165 ; on mistaken instincts of ants, 168 ; on instinct of a kitten modified by individual experience, 17:i ; on analogies between instincts in species and acquired habits in individuals, 179-80; on diversity of disposition in birds, 182 ; on hereditary tricks of manner displayed by a child, 185 6, and by a terrier, 186 ; on peculiar dispositions and habits transmitted in croco- diles, ducks, horses, and pigeons, 188- 9 j on autohiatic actions displayed by idiots and by an idiotic dog, 193 ; on instinctive wildness and tame- ness respectively displayed by the progeny of wild and tame hor-es, rabbits, and ducks, 196 ; on effects upon instinct of crossing, 199 ; on intelligent modification of instinct in bees, 207 ; on wild ducks building in trees, 211 ; on hive-bees sucking through holes made in corollas by humble-bees, 220-1 ; on dogs learning modes of attack by experience and imitation, 221 ; on birds of une species learning danger cries of birds of another, 221-2 ; on a dog learning by imitation the habits of a cat, and lambs and cattle learning to avoid poisonous herbs, 224 ; on canaries isared in a felt nest afterwards constructing a normal nest, 226 ; on the non-instinctive character of the drinking movements of chickens, 228-9 ; on the incorrigibly wild instincts of sundry wild animals when : -i! 390 MENTAL EVOLUTION IN ANIMALS. ftif domesticated, 232 ; on the stupidity of Chinese dogs, 233 ; on the arti^ ficially bred instincts of sheep-dogs, pointers, and retrievers, 235-7 ; on the effects upon artilicially bred instincts of crossing, 241 ; on structures adapted to obsolete uses, 253-4 ; on the causes of the evolution of instinct, 264 ; on insects flying into flame, 278-80 ; on the instinct of feigaing injury as exhibited by the duck, partridge, &c., 316-17. Darwin, T)r. E., on mistaken instinct of Musca carnaria, 167; on a cat imitating a dog, 224; on eft'euts of domestication on instincts, 229; on bees ceasing to collect honey in California, 245 ; on rabbits not bur- rowing in Sor, 248. Darwin, Francis, oa. bees boring holes in corollas of flowers, 302. Daphnea pulex, colour-sense oi", 98. Davis, on instincts of the processional caterpillar, 342-3, Davy, Sir U., on a'.i eagle teaching young to fly, 2ii7. Death, feigning of, by animals, 303-16. Death-watch, feigning death, 309. Deceit, in animals, 341, 347. Delusions, in animals, 149-60. Diagram, explanation of the, 63 9. Dilemma-time in perception, 134-5. DioncBd, discrimination sliown by, 50-1. Diiecticn, sense of, 259-94. . Discrimination, in relation to choice, 47-62 ; shown by vegetable tissues, 49- 51 ; by protoplasmic organisms, 51. Disposition, individual, of men and animals, 182. Dog, sense of smell in the, 93 ; sense of musical pitch in the, 94 ; imagina- tion in the, 146 and 148-9 ; homesickness and pining of the, as proof of imagination, 151-2 ; appreciation of cause by the, 155-8 ; instinct of collie barking round a carriage, 182 ; attachment of the to other animals, 184; inherited antipathy of a, to butchers, 187 ; useless instincts of the, 176, 190 ; instinct of, in turning round to make a bed, 193 ; hereditary transmission of begsing in breeds of the, 195-6 ; effects of crossing upon insiincts of the, 198; learning by imitation, 221, 223-4; teaching young, 227 ; influence of domestication upon psycholofjy of the, 231-42 ; barking of the, 249-55; sense of direction in the, 289-90; inabihty of the, to appreciate mechanism, 351 ; grade of mental evolution of the, 352. Domestication, effects of, upon instinct, :;30-42. Donders, Professor, on reaction-times in perception, 132, 135. Donovan, on cattle sucking bones, 247. Dragon-flies, migrations of, 286. Dreaming, in animals, 148-9. Drosera, discrimination sliown by tentacles of, 49-50. Duck, sense of touch in the, 92 ; instincts of the young, 171, 196 ; a breed of showing fear of water, 188 ; natural wildness and tameness of the, 196; instincts of the, modified by crossing, 199 ; conveying young, 211 ; build- ing on trees, 211 ; instinct of the, in feigning injury, 316. Dudgeon, P., on a cat rearing rats, 218. , , j- ao Dujardin, on relation of intelligence of ants to size of peduncular bodies, 4b. Duncan, on spiders feigning death, 309. Duncan, Professor P. M., on instinct of Odynerus, 191-2. I j lAlai««^BE«ifcifei I 'i E. Eagle, variation in nest-buildiiig of the, 182 ; teaching young to fly, 227 ; teach- ing a goose to eat flesh, 227. INDEX. 391 Ear. See Hearing. Enrtliworma. See Worms. Earwig, memory in, 123 ; parental affection of, 344. Echinudermata, nervous system of, 28-30 ; consciousness in, 76, 348 j special senses of, 56, 84 ; memory in, 122, 348-9; emotions of, 342 j grade of mental evolution of, 348-9. Education of young aninaals by their parents, 226-9. Edward, on local variation of instinct in the swallow, 247. Eject, 16. Elam, on somnambulism in nnimals, 149. Elephant, intelligence of the, related to the trunk, 57 ; memory in the, 124; dreaming in ihe, 149; instinct of the, in goring wounded companions, 176 ; feigning death, 305 ; emotions of the, 346 ; using tools, 352. Emotions, physiological aspect of, 53 ; which occur in animals, 341 ; origin of, 342 ; distinctive, of different animals, 34:. -7. Emulation, 341, 345. . «. i. j t. Engelmann, on protoplasmic and unicellular organisms being affected by light, 80; on one infusorium chasing another, 81; on colour sense of Enfflena viridis, 98. Englena viHdis, as affected by light, 80 ; colour sense of, 98. Equation, personal, 135-7. E\olution, Organic, taken for granted, 7 ; Mental, a necessary corollary, 8; human, excluded from present work, 8-10; of nerves by use, 30-33; of discriminative and executive powers, 47-62; of mental faculties as shown in the diagram, 63-9 ; of consciousness, 70-7 ; of sense of tem- perature, 97-8; of visual sense, 97-8; of colour-sense, 98-103; of organs of special sense, iP3-4 ; of pleasures and pains, 105-11 ; of memory, 111-17 ; of association of ideas, 117-24 ; of perception, 127- 9; of imagination, 144-54 ; of fetishism, 154-8 ; of instinct, 177- 255 ; of reason, 318-35 ; of conscience, 352. Ewart, Professor, on Echinodermata, 84 ; on colour-sense of Octojpus, 99. Excitability, 68. Excrement, instinct of burying, 176. Exner, Professor, on physiology of perception, 132-7, Eye. See Sight. Eyton, on instincts of crossed Geese, 199. F. Fabre, J., on instincts of Bembex, 166, and of Sphex, 179, 299-303 ; on sense of direction in bees, 293-4. Fear in animals, 341 ; in young children and low animals, 342-3. Feeling. See Sensation. Feelings, logic of, 325. Feigning death, 303-16 ; injury, 316-17. Fenn, Dr. C. M., on imagination in a wolf, 147. Ferrets, reared by alien, 216-17 ; imperfect instincts ot young, 228; analogy between instincts of, and those of Sphex, 303. Terrier, on functions of the cerebrum, 35. Fish, sense of sight in, 89 ; blind, 89 ; luminous, 89 ; sense of hearing in, 90; of smell, taste, and touch, 90; cf colour, 98-9; memory in, 123-4; imagination in, 153, 286 ; feigning death, 303 ; emotions of, 345 ; grade of mental evolution of. 349-50. Fish, E. E., on birds iniilating each other's songs, 222 ■i If 392 MENTAL EVOLUTION IN ANIMALS. Fiake, on hereditary transmission of begging in dogs, 165 ; on the subordinate part played by natural selection in the development of instinct, 256. Fitch, Oswald, on benevolence shown by a cat. 345-6. FitzEoy, Capt., on instincts of wild dogs under domestication, 232. Fleming, on delusions shown by rabid dogs, 149-50. Flesh-fly, mistaken instinct of the, 167. Flounder, sense of colour in the, 98. Ford, W., on sense of direction in man, 291, 292. Forel, on variations of instinct and individual dispo ntion in ants, 183, 209, 244-5. Fowl. See Hen. Fox, the, feigning death, 304, 314-15 ; understanding of mechanism by the, 351. Fox, the Eev. W. D., on inherited tendency to beg in a terrier, 186 ; on in- stincts of a retriever, 236. Fredericq, on colour-sense of Cephalopoda, 98-9. Fritsch, on functions of the cerebrum, 35. Frog, colour-sense in tl.e, 98 ; changed instincts of the tree, 254. Furnarius, imperfect instincts of the, 281. ( I a Oalen, on instinct of a kid, 115. Gallus bankim, wildness of chickens reared from wild stock of, 232. Galton, Francis, on hereditary genius, 194. Ganglia, structure and functions of, 26-33 ; Mr. Spencer's theory of genesis of, 32. Gardener, J. S., on moths flying into a waterfall, 280. Gardner, on intelligence of a crab, 336. Garnett, on instincts of crossed ducks, 199. Gasteropoda, eyes of, 88 j memory in, 121. See Mollusca. Generalization, 145. Gentry, W. K. G., on carnivorous habits of herbivorous rodent, 248. Gladstone, W. E., on colour-sense, 100. Goatsucker, conveying young, 211. Gold-crested warbler, nidification of the, 210. Goltz, on functions of the cerebrum, 35. Goose, eye of the Solen, 91 ; instincts of crossed, 199 ; learning to eat flesh, 227 ; instinct of upland, 253 j Siberian, feigning death, 303-4 j attftch- ment of a, to a dog, 184-5. Goring, instinct of, 176, 379. Gosse, on gregarious habits in nidification, 253 Gould, on instincts of terrestrial geese, 253. Grebe, acjuatic instincts of the, 253. Grief, in animals, 341, 345. Grouse, instincts of North American, 201. Guanacoe, instincts of the, 190. Guer, on somnambulism in animals, 149. Ouyne, on migration of the lemming, 282-6. H. Hffickel, Professor, on sense-organs, 81, S.^'-e ; on supposed unknown sense pobsessed by Fish, 90; on supposed unknown senses possessed 1 1 INDEX. 393 ibordinate ,256. 183, 209, m by the, 8 J on in- 2. of genesis I eat flpsh, 4; altftcli- unkno^^Ti by MammalB, 95; on evolution of sense-organs, 98 104; on colour- sense, 100. . ... ..■ 1QQ Hall G. Stanley, on hypnotism lengthening reaction-time m perception, IdS. HaniUton, Sir W., on pleasures and pains, 105 ; on inverse relation between instinct and reason, 338. Hancock, on dogs not barking in Guinea, 250. Handcock, on obliteration of natural instincts under domestication, 231. Handwriting, inheritance of, 194. Hate, in animals, 341, 345. Haust, on ducks building in trees, 211. Hawfinch, learning the song of a blackbird, 222. Hawk, eye of, 91 ; old, teaching young to capture prey, 226 ; changed m- stincts of Swallow-tailed, 254. „ ^ • ,, „ oo n Hearing, sense of, in Medusae, 82; in Articulata, 86-7; m MoUusca, 88-9; in Fish, 90; in Amphibia and Reptiles, 90; in Birds, 91-2; in Mam- mals, 93-4; reaction-time of, 132. Selix pomatia, memory in, 122. , u e Helmholtz, Professor, on reaction-time as increased by complexity of percep- tion, 133. « , , J i.!. Hen, instinct of cackling in the, 176, 289 ; wildness of the. when crossed with a pheasant, 199 ; conveying young, 211 ; experiments and observations on the incubating and natural instincts of the, 213-17 ; drinkjng move- ments of tlie, not instinctive, 229 ; loss of incubating instinct of the Spanish, 212. Hennabe, on the byrax dreaming, 149. , . x- « Heredity, in relation to reflex action, 17-18 ; influence of, on formation of nervous structures, 33 ; in association of ideas, 43 ; in reference to sensa- tion, 95-104 ; to pleasures and pains, 105-11 ; to memory and associa- tion of ideas, 111-24 ; to perception, 130-41 ; to instinct, 180, 185-92, 200-3 231-42 ; of handwriting and psychological character, 194-5 ; of begging in dogs and cats, 195-6 ; of wildness and tameness, 195-7 ; of artificial paces in horses, 188 ; with reference to migration, 289, 296-7. Hering, on muscle strengthening by use, 112. . , . , , , , Herman, on reaction-times of different senses, 132 ; on inherited knowledge shown by sporting dogs, 239. Eeteropoda, eyes of, H8. e T,r j ca Hertwig, Professors O. and R., on nervous system of Medus(^, bV. Hewetson, on variation in the nest of the nuthatch, 182. Hewett, on wildness of hybrids between fowls and pheasants, 199. Hill, Richard, on gregarious habits in nidifieation, 253. Hitzig, on functions of the cerebrum, 35. Hofucker, on inheritance of handwriting, 194. HoH'mann, Professor, on a puppy learning to imitate a cat, 224. Hogg, on instincts of a sheep-dog, 240-1. Hollman, on memory in Cephalopoda, 122. Homing-faculty of aiumals, 95, 153-4. Home-sickness'in animals, proof of imagination, 151-2. Honig-Schnied, on reaction-time for taste, 133. Hon ibill, nidifieation of the, 255. Horse, memory in the, 124; inheritance by the, of artificial paces, 188; useless instincts of the, 190 ; natural tameness of the leral, 196 ; sense of direction in the, 289-91. Houdin, Robert, remembering his art of iuggling with balls, 36; on rapidity of perception acquired by training, 138. House-fly, mistaken instinct of the, 167. 394 MENTAL EVOLUTION IN ANIMALS. House-sparrow, nidification of the, 210. Houzeau, on stridulation, 8fi ; on birds dreaming, 149 ; on mistaken in* stinctB, 167 ; on inability of infants to localize pain, 326. Howitt, A. W., on homing faculty of horses and cattle, 290. Uuber, on instincts of bees, 168, 203-9. Huber, P., on instincts of a caterpillar, 179. Huggins, Dr., on sense of musical pitch in a dog, 94; on inherited antipathy of a dog to butchers, 187. Humboldt, on individual disposition in monkeys, 188. Humming-bird hawk-moth, mistaken instinct of the, 167. Hunger, sense of, 95. Hunter, John, on tricks of manner being inherited, 185. Hurdis, on migration of the golden plover, 286. Hutchinson, Colonel, on inherited tendency to bark in sporting dogs, 236. Hutton, Captain, on wildness of the hybrid between the tame and wild goat, 199 ; on wildness of chickens reared from wild Oallus bankiva, 2'o2 j on migration, 288. Huxley, Professor T. H., on evolution of sense-organs, 104. JIt/drotoa, nerve-tissues in, 24. Hyaena, not burrowing in South Africa, 244. Mylobates agilis, its sense of musical pitch, 93. Hymenoptera. See Ants and Bees. Hypnotism, reaction-time under influence of, 138 ; of animals, 308-11. Hyrax, dreaming in the, 149. 14 , It f-ri t I li Ichneumon, instincts of the, 166. Ideas, association of, 37-8, 111-24; definition of, 118; composite, ana- logous to muscular coordinations, 42-4. Idiots, size of brain of, in relntion to intelligence, 45; personal equation of, 138 ; tricks of manner shown by, 181 ; automatic actions of, 193 ; imita- tive actions of, 225. Industry, 341. Imagination, 142-58 ; analysis of, 142-4 ; stages and evolution of, 144-5 ; stages of, as occurring in different animals, 1 45-54. Imitation, effects of, on formation of instinct, 220-9; by hive-bees of humble bees, 220-1 ; by dogs of other dogs, 221 ; by dogs of cats, 223- 4; by birds of one another's songs, and of articulate speech, 222-3 ; by monkeys, children, savages, and idiots, 225 ; by young birds in nidifica- tion sugLjestod by Mr. Wallace, 225-6 ; of parents by young of sundry animals, 226-9. Incubation, instinct of, 177. Infant, ccnscioix-ness in the, 77 ; preferring sweet tastes, and remembering taste of milk, 114-16; earliest power of associating ideas, 120-1, and mental images, 152 ; when spoon-fed forgetting to suck, 170, 180 ; learn- ing to balance the head, &c., 175-6 ; imitative movements of the, 225 ; inability of the, to localize pain, 326 ; emotions of fear and surprise in the, 342. Inference. See Reason. Infusoria. See Protozoa, Injury, feigning of, by animals, 316-17. Ii, sects, eye? of, 84-5; colour-sense of, 99; imagination of, 145-6; instincts of, 1(35-8, 179, 201-2, 203-9, 220-1, Z'^i, 277-81, 285-6, 290, 293-5, 297 -3u9 i emoiious of, 34Ju INDEX. 395 Instinct, pTiysiological aspect of, 52; as hereditary memory, 115-17, 131 ; definition of, 159; involves a mental element, 1(!0; perfection of, 160-7 ; in voung birds and mammals, 161-5 ; in inseots. 165-8, 179, 201-2, 203-9, 220-1, 277-81, 285-6, 290-5, 297, -303-8; of Hying, 165; imperfection of, 167-76; as affected by interruption of normal con- vei'se with environment, 169-72, by castration, 171-2, by insanity, 173-4; trivial and useless, 176; origin and development of, 177-99; primary, 180-92 ; secondary, 192-9 ; ell'ects of crossing upon, 198-9 ; blended origin or plasticity of, 200-218; of nidification, 210-12; of incubation, 177, 212-13 ; maternal, 212-18 ; as moulded by imita- tion, 219-25, by education, 226-9, and by domestication, 230-42; of singing in birds, 222-3 ; of attacking rabbits in forrets, 228 ; of drinking in fowls, 229 ; local and specific varieties of, 2'13-55 ; not fossilized, 250, 254-5 ; evidence of transformation yielded by specific varieties of, 250-5 ; views of other writers on evolution of, 256-72 ; general sum- mary on and diagram of development of, 265-72 ; cases of special diffi- culty in display of, 273-317 ; similar in unallied animals, 273-4 ; dis- similar in allied animals, 274; trivial and useless, 274-6; apparently detrimental, 276-85 ; alleged, of scorpion in committing suicide, 278 ; of flying throngh flame, 278-80 ; of hen cackling, pheasant crowing, shrew- mouse screauiing, &c., 280-1 ; of migration injurious. 281-5; of lemming, 282-5 ; of migration, 285-97 ; of neuter insects, 265, 207-9; of sphex, 299-303; of feigning death, 303-16; of feigning injury, 316-17; in , relation to reason, 338-9. J. Jackson, C. J., on instinct of the Californian woodpecker, 255, Jackson, Dr. J. Hughlings, on pre-perception, 139. Jealousy, 341, 315. Jeens, C. H., on a puppy learning to imitate a cat, 224. Jelly-fishes. See MeduscB. Jerdon, on birds dreaming, 149. Jesse, on changed instincts of a hen, 215; on snakes feigning death, 305. E. Kataplexy. See Hypnotism. Kidd, W!, on diversity of disposition in larks and canaries, 182. Kingsley, Canon, on migration of birds, 296. Kirby, on modified instincts of larva', 180. Kirby and Spence, on larvae remembering tlie taste of particular leaves, 115; on instincts of insects, lb6, 167, 179-80, 201, 201-8, 244, 245. Kittens, instincts of, 164-5, 172. Knight, Andrew, on liereditary transmission of acquired mental endowments in animals, 195, 197, 198, 237, 238 ; on intelligence of a bird, 201, and of bees, 208. Knox, D E., on a variation in nest-building of the golden eagle, 182. Kries, on dilemma-time in perception, 134-5. Kuszmaul, Prolessor, on infants preferring sweet tastes, 116. i If ; tr; 396 MENTAL EVOLUTION IN ANIMALS. lamarck, his theory of evolution of nerves by use, 33. LamellibrancMata, eyes of, 88. Landrail, feigning death, 304-5. Language, as mental symbolism, 153. Lankester, Professor, on alleged instinct of scorpion to commit suicide, 278. Lapsing of intelligence, 178-80. Lapwing, habit of, in flying down to sportsman when fired at, 189 ; associating with rooks and starlings, 185 ; instinct of, in feigning death, 317. Lasius aeerborum. local variation of instinct of, 244-5. Leech, Dr., on modified instincts of a spider, 209. Lemming, migratory instincts of the, 169, 282-5. Lepidoptera, sense of hearing in, 86. See Butterfly. Le Roy, on imau'ination of animals, 146-7. Leuret, on intelligence of an orang outang, 328. Leveret, roared by a cat, 217. Lewes, Q-. H., case of sleeping waiter described by, 36; on sensationp as groups of components, 41 ; his definition of Sensation, 78 ; on pre- peneption, 139 ; on instincts of ducklings, 171 ; on hereditary irans- mission of begging in dogs, 195; ignores natural selection in development of instinct, 256. Lewis, on carnivorous habits of wasp, 245. Limpet, memory in the, 121. Lindsay, Dr. Lauder, on dreaming and delusions in animals, 148-9. Linnceus, on dogs not borking in S. America, 250. Lodge, Colonel, on sense of direction in man, 293. Logic of feelings and signs, 325. "^ Lonbiere, on local variations of instinct in ants, 244. Lonsdale, on memory in a snail, 122. Lord, J. K., on instinct of the CaUfornian woodpecker, 255. Lubbock, Sir John, on deafness of ants, 86 ; on sense of smell in ants, 87 1 on colour-sense of Daphnea pulex and Mymenoptera, 98-9 ; on memory of bees, 123 ; on sense of direction in Hymenoptera, 293-5. Lucretius, on dreaming in dogs, 148. Ludicrous, emotion of, in animals, 341, 347. Lunacy, analogous to ataxy, 44. Lyon, Captain, on a wolf feigning death, 304. fi ' f ^i;; '.' "'^i L ,r 1 1 M. MacFarlane, Mrs. L., on changed instincts of fowls, 215. Muckillar, Miss, on changed instincts of a hen, 215. Macpherson, H. A., on benevoh nee shown by a cat, 346. Macroglossa siellatarum, mistaken instinct of, 167. Magnus, Aibertus, on instincts of the capon, 171. Matrnus, Dr., on colour-sense, 100. Malle, Dureau de la, on inheritance by horses of artiQcial paces, 188 ; on birds imitating the songb of other birds, 222 ; on a terrier imitatins; a cat, 2:<3-4 ; on old birds educating ^ oung, 226 ; on instinct of burying ■upurfluous food, 233. INDEX. 397 Mammals, speoial Bonses of, 57; sight, 92; hearing, 93-4; taste and touch, 94; colour, 99 ; memory of, 124; perception of young, 131 ; imagina- tion of, 146-54; inetinctB of young, 164-5; mistaken instincts of, 169; trivial and useless instincts of, 176; attachment between dif- ferent species of, and with other animals, 184-5 ; imitation in, 223-5; teaching their young, 227; local variations of instinct in, 247-50;' migrations of, 286 ; homing faculty of, 289-91 ; feigning death, 304^5 ; emotions of, 345-7. Man, mental evolution of, questioned by some evolutionists, 8-10; subjective and ejeotive evidence of mind in, 15, et seq. ; relation of size of brain of, to intelligence, 46 ; substitution of mau. Psychology, relation of Comparative to Comparative Anatomy, 5 j di.^tinctlon between, and Philosophy, 11. R. Babbit, imagination in the, 147-8} instinctive antipathy of t>io yp"ng *« ferrets, 161-5 ; imperfect instinct of the, with regard to wnasels, 16y , natural wildness and tameness of the, 19f5 ; not burrowing m Sor, ;J48. Rae, Dr. J., on instinct of ducks, 196 j on instinct of grouse, 201. Bage, in animals, 346. Ratel, habit of the, in turning somersaults, 189, 270. Bats, understanding of mechanisms by, 351. Battle-snake, tail of the, 277. Eazor-fish, memory in the, 122. Eeaction-time, in perception, 132-5. j. .• Beason, physiological aspect of, 63 ; supplementing muscular co-ordmntion by machinery, 59 ; definition of, 318 ; evolution of, 319-35 ; relution ot, to perception, 819-26; grades of, 318-25; in animal kingdom 325-9 ; Mr Spencer's views on development of, 330-5; Mr. Mivart s views upon, 335-40 ; Mr. Mills' views upon, 336-7 ; in relation to mstinct, 330—40. Reaumur, on larvae remembering the taste of particular leaves, instincts of bees, 166 ; on instincts of the capon, 171-2. Becognition of oH'spring, 349. BecoUection, 120. Boflection, 145. . „„ „„ Reflex action, explanation of, and theory of its evolution, 26-33 ; arising from habit, 38; rise of consciousness from, 74-5; distinction between, and sensation, 78-9 ; in reference to memory and association of ideas, 111-24 ; to perception, 139-41 ; to instinct, 159-60. Eegret, in animals, 347. Bhea, mistaken instinct of the, 168. < Bemorse, in animals, 341. ^ , -„ .,. u E«ngger, on changed instincts of a wild cat in confinement, 172; on attach- ment of a monkey to a dog, 184. „ , , j ^ i, „* on Reptiles, sense of sight in, 90; hearing, smeU, taste, and touch of, 90; colour sense of, 98; memory in, tf4; perception m, 131 ; imagination in, 149, 153-4 ; migrations of, 286 ; feigning death, 305 ; emotions ot, 345 ; grade of mental evolution of, 350. Resentment, 341, 345. Retriever. See Dog. Eevenge, in animals, 341, 346. Ehizopoda, powers of special aenie in, 80. Eibot, on memory, 111-13. ... , oar Ring-plovers, continuing to build where sea has retired, 246. Bomanes a. J., observations on MeduscB, 31-2; on sea-anemones, 48, 8.} ; on Echinodermata, 84, 342, 348-9; on sense of hearing in Lepi- doptera and Birds, 86, 92; on sense of smell in crabs, 87-8; on sense of musical pilch in » dog, 94; on colour-sense of Ootojius, y8-9j on 115 : on INDEX, e, lf)0. distinction I young to isels, 16i)j Sor, ;J48. 401 earliest age at which an infant is able to assorinfo ideas, 120-1. on inability of hermit-cmb to associate simple ideas, ._J 3: on time-rela. tions m perception 136-7; on sense of mysterious in, and appreciation ffwriftZft *'''' l^^'f' °- »"«*'"''"^e antipathy of youn/r*bbits to ferrets, 164-5 ; on handwriting, 19lj on incubatory instincts. 213-11. on animals dying of terror. 307-8 ; on instincts and emotions of the pro' cessional caterpillar, 342-3 ' Rooks, associating with starlings, 185. Rosa, Baptista, on instincts of the capon, 171. Ross, Sir J., on dogs learning how to attack wild cattle, 221. Koulm, on cats not howling in South America, 250. Routh, Dr., OP a puppy learning to imitate a cat, 224. Koy Le. on imagination of wild animals, 146-7 ; on mental character! of a dog of wild parentage, 198; on the migration of birds, 289. ■ordination reliition of, •m, 325-9 ; irt's views o instinct, I, 115 ; on 33 ; arising n between, u of ideas, on attach- 3h of, 90; magination motions of, es, 48, 83 s » in Lepi- i ; on sense r, y8-9j on S. slimo^'^^i™' p^'jf ™y' °° intelligence of an orang-outang, 328. Satiety, sense of, 95. Savag sense of direction in, 289, 291 5 tendency to imitation shown by, Schafer, Professor E. A., on nervous system of Aurelia aurita, 69. Schneider, on sense of vision in Serpults, 86. Scorpion, alleged instinct of the, to commit suicide, 278 Sebright. Sir J. ou natural wildness and tameness of rabbits and ducVs, 196; on instincts of an Australian puppy, 232; on love of man as in stmctive in domestic dogs, 239. Seebohm, on migration of birds, 289. Scinut hudsoniua, change of instincts in, 248. Seneca, on dreaming in dogs, 148. Sensation, as compound 40-1 ; physiological aspect of, 51-2; defined, 78, survey of, in animal kingdom, 8J-95 ; of temperature. 95-8; of colour actiraf 159-6? perception, 125-6 ; as stimulus to reflex ^'"'of riol?98-l(J4°^ ^'"'^''' '^'"'' ""'^ '"*"**^' ^^ • "^ ^^•"P^rature, 96 -8 , Serpent. See Reptiles. Serpulce, sense of vision in, 86. Setter. See Dog. Sexual affection and selection, 341, 344. Shame, in animals, 341, 347. Shaw, J on stupidity of dogs in China and Polynesian Ts-lands 033 Sheep, learnmg to avoid poisonous herbs, 224, 227; changed instincts of under domestication, 232; killed by parrots, 248; sense^f direction S, Sheep-dog. See Dog. Shrew-mouse of South Africa, injurious instinct of the, 169 and 280. Shuttleworth M,s8 C, on mistaken instinct of bees and wasps, 167. Sight sense of, in Protista 81; in Medusa, 81-2; in EchiuodJrn.ata, 84; of simple and compound eyes, 84-5; of Worms, 85-6; of Fish, 89 ^ of tZ^^fV^^^'^''^''^ ^^-^ ', °^ ^'''^'' 91 ' °^ Mamm'als, 92 ; lactic u- time ot, 133; m young animals, 161-4, Sigismund, on infants remembering the taste of milk, 114, 402 MENTAL EVOLUTION IN ANIMALS. mi Signs, logic of, 326. - . „« Skate, olfactory q;'«ans of the, PO. Skylark, folRning death, 304.. . qoq a Smith, Adam, on a ca»o of couching for cataract, 3-3-4. Smith. Dr. Andrew, on hycena. not burrowing m South Africa, 249. Smith, F., on instinct of beeB, 208. ,:.„»;„„ oao Smith, Col. H., on instincts of wild dogs under domestication, 282. Smith, W. a., on carnivorous habits of wasps, 2io. Snail, memory in the, 122. ... j lu nnK Snak;, homing faculty of the, 153-4, f«>8"'"K ^'"^^.V^J- . ^^s ants and Smell sense of in Protista, 81 5 in sea-anemones 83 , ^"J,''''^^^^^ crabs, 87-8 ; in MoUusca, 80 j in Fish, Amphibia, and Reptiles, W , m Birds', 92 ; in Mammals, 92-3. Snipe, sense of touch in the, 92. Social feelings, in animals, 341, 344. IpSlit^DoS^on'&sUncts of young birds and mammals. 161-6. 170-1. Spallanz'ani, on sensibiUty of blinded bats, 94. Spaniel. See Dog. Speech, acquirement of, by Tolition, 41-.^. ^P^^I:o:ZSL:^!^^-2. on consolidation of states ^P"of ;on cTousne,B,42-3, on evolution of consciousness 74-6, on plea^ sures and pains, 105-7, on perception, 125 , on memory, 129 30. on «re-Dertept^on, 139 , on perceptive faculties arising from reflex, 140, on Fdeas as Snt Revivals o/^percVions, U2-3 ; -J«*'l'"r on e'E^n 154-5 • on race characteristics in psychology of man, 194, on evolution of instinct, 256-62 ; on instincts of bees. 265. Sphex. instincts of the, 179, 299-303. Sphinx-moth, «»i«t'*''eni"f^i°'''°irM damnation in the. 146, modified 303. See Arachnida. Sprat, Surinam, eye of the, 90. Squirrel, a, dying of terror, 307. Star-fish. See Echinodermata. Starlings, associating with rooks, 185. Starling, imitating songs of other birds, iZ^-6. St John, on inherited tendency to bark l" ^P"''^.'"^ 'I"?''' f 6- S ore S on variation in nest-building of the missel- thrush, 182 Kd, Dr J. W., on change of instincts produced by «istration, 171-2. Stuorn! on dwindling of maternal instincts of cattle. 232. Sturm, on instincts of the dung-beetle, -244. ' tion, 321-2. Surinam Sprat, eye of the, 90. IwaC: pSstfdty and local variation of instincts of the. 210, 246-7 , migra- tion of the, 296. Swallows, nidification of, 210-11. 1. lew S wSon, on mistaken instinct of the Australian parrot, 167. Swanderdam, on instincts of beee, 166. INDEX. 403 (Swift, eye of the, 91. Sympathy, 341, 846. See Swallow. Bparrow, nidiflcation of the, 210 ; ehani{o. Mammals, migrations of, 355-6, 358 9 j instinctive fear shown by, 361 j habitations of, 372-3. INDEX. 409 king their ; of bees, Is, 376-7 ; only once small and of Abya- to excre- ipparently ; of cock se scream- 82-3. Martin, nidification of the, 364, 369, 370. Martins, cooperation shown by, 375. Martin, W. C., on regurgitation of food by the Kangaroo, 374. MegapodidcB, nidification of, 367-8. Mice, wariness of, 362. Migration, 355-60; of young birds, 355; of quail, 355 ; of buffalo, 3f5 6; theory of, 359; of elk and reindeer, 360; of lemming, squirrel, and ermine, 380 ; of insects, 380 ; of pigeons, antelopes, and bisons, 381. Molothrus, instincts of, 876. Montague, on nidification of sparrows, 369. Moresby, Capt., on tameness of birds at Providence Islands, 361. Mosto, Oada, on tameness of C. de Verde Island pigeons, 3U1. Musk-rat, habitation of, 372. led within N. Nidification, 364-72; of swallows, 365-6; of MegapodidcB,ZQ1-S; tions in instinct of, 3(i9-73 ; double instinct oi, 371-72. ' Tf ightiugale, variations in singing of the, 374. Taria- , 377, 378, Osmia, variation in instincts of, 372-3. Ostrich, scaitcring her eggs, 382. P. Partridge, variation in instincts of the, 373. Peabody, on nidification of Cypelus pelasgius, 365 ; of kitty-wrens, 368 ; of herons, 369 ; of Totanus macularius, 371 ; of Icterus baltimore, H2i. Pheasant, maternal instincts of the hen, 379 ; crowing instincts of cock, 381. Pigeon, fearlessness of the, at C. de Verde Islands, 361, and at Galapagos, 363 ; instincts of the Abyssinian, 379 ; migration of the Passenger, 381 ; instinct of the, in attacking wounded companions, 360. Ptinus, feigning death, 364. Pulet, variations of pupa of, 374. Quail, migration of the, 355. Q. d 370, of a in gulls, ; powprg by, 361$ Eae, Dr. J., on fearlessneBB shown by birds of railway trains, 362 ; and of firearms, 363. Kat, musk, habitation of the, 372. Bat, wariness of the, 362. Eeaumur, on instincts of ants, 3fi8. E«dstarts, nidification of a pair of, 371. Reindeer, migrations of the, 360. 410 MENTAL EVOLUTION IN ANIMALS. Reinwardts, on animals dying in the Solfortar« of Java, 380, Rieliardson, on nidification of American swallows, 369-80. Roberts, M. E., ou nidification of Mirundo riparia, 365. Robin, fainting from fright, 363 ; nidification of the, 369. s. Salmon, migrations of the, 355, 35S. Savi, Dr. P., on the double instinct o " ' lon shown by Sylvia eisticola, 371. Scope, on migration of salmon, 358. Scrope, W., on deer expelling wounded companions from herd, 381. Sheep, homing faculty of Highland, 358; migratory instinct of Spanish, 358-9. Sheppard, on the nidification of a golden-crested wren, 371. Shrew-mouse, instinct of a, in screaming when approached, 382. Smith, Dr. Andrew, on migrations of quail, 355} on hyttnas not burrowing in S. Africa, 372. Smith, F., on variations in instincts of bees, 372-3. Snake, incubating eggs in a hot-bed, 367. Sparrow, nidification of th^, 369. Spence, on migration of insects, 380. Spider, feigning death, 364 ; changed instincts of a, 373 ; double instincts of the hunting, 374 ; maternal instincts of the, mistaken, 382 j instinct of the female to devour male, 383. Sterna minuta, variations in nest-building instincts of, 372. St. Hilaire, Geoffry, on tameness of hooded crows in Egypt, 363. St. John, on non-migratory habits of woodcock, 356. Sullivan, Captain, on a duck defending a goose from a hawk, 381. Swallows, migration of, 358 ; nidification of, 365-6, 369-80 ; cooperation of, 375. Swans, nidification of, 370. Swift, non-migratory habits of the, 356 ; nidification of the, 365-6. Sylvia eisticola, double instinct of nidification shown by, 371. ir ' '