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ZOOLOGICAL SECnKTAIjy OF THK MNNEAN SOCirTY SECOXD EDITION LIBF.ARY RATIONAL MUSEUM ^ PF CANADA LONDON KEGAN PAUL, TRENCH, & CO., 1 PATERNOSTER SQUARE 1882 012155 I When I first I was my intent these I intendi fticts of anima] treated of the Descent. Fin material was Ibeing comprise |have made ar ' International iivision of the 'Mental Evoli [for press withii My object i lave thought ii i-esembling a te phology, to whi lay turn when pemselves wit rhich this or tl bndeavour of ass {^The rights of tram JiU ,...^o/«.— «^«^-*rtf:t': [or the most p irimination mo: PEEFACE. -•o»- ire WuEN 1 first began to collect materials for this work it was my intention to divide the book into two parts. Of these I intended the first to be concerned only with the facts of animal intelligence, while the second was to have treated of these facts in their relation to the theory of Descent. Finding, however, as I proceeded, that the Imaterial was too considerable in amount to admit of ])eing comprised within the limits of a single volume, 1 have made arrangements with the publishers of the I* International Scientific Series ' to bring out the second iivision of the work as a separate treatise, under the title Mental Evolution.' This treatise I hope to get ready [for press within a year or two. My object in the work as a whole is twofold. First, I lave thought it desirable that there should be something •esembling a text-book of the facts of Comparative Psy ihology, to which men of science, and also metaphysicians, lay turn whenever they may have occasion to acquaint themselves with the J)articular- level of intelligence to ^hich this or that species of animal attains. Hitherto the mdeavour of assigning thes3 levels has been almost exclu- ,^^.Bively in the hands of popular writers ; and as these have, [or the most part, merely strung together, with dis- [rimination more or less inadequate, innumerable anec- %^' VI PREFACE. dotes of the display of animal intelligence, their books are valueless as works of reference. So much, indeed, is this the case, that Comparative Psychology has been vir- tually excluded from the hierarchy of the sciences. If we exct»pt the methodical researches of a few distinguished naturalists, it would appear that the phenomena of mind in animals, having constituted so much and so long the theme of nnscientific authors, are now considered well- nigli unworthy of serious treatment by scientific methods. Hut it is surely needless to point out that the phenomena which constitute the subject-matter of Comparative Psy- chology, even if we regard them merely as facts in Nature, have at least as great a claim to accurate classification as those phenomena of structure which constitute the sub- ject-matter of Comparative Anatomy. Leaving aside,, therefore, the reflection that within the last twenty years the facts of animal intelligence have suddenly acquired a new and profound importance, from the proved probability , of their genetic continuity wi+h those of human intelli- gence, it would remain true that their systematic arrange- 1 ment is a worthy object of scientific endeavour. This, then, has been my first object, which, otherwise stated, amounts merely to passing the animal kingdom in review in order to give a trustworthy account of the grade ofj psychological development which is presented by each[ group. Such is the scope of the present treatise. My second, and much more important object, is that of | considering the facts of animal intelligence in their rela- tion to the theory of Descent. With the exception ofl ]Mr. Darwin's admirable chapters on the mental powers and moral sense, and Mr. Spencer's great work on the Principles of Psychology, there has hitherto been no earnest attempt at tracing the principles which have been probably concerned in the genesis of Mind. Yet there is PREFACE. VU books leed, is en vir- If we Tuislunl )f miml 3iig the ed vvell- iiethods. 'nomeiia Lve Psy- i Nature, cation as the sub- ot a doubt that, for the present generation at all events, o subject of scientific in(|uiry can present a higher egree of interest; and therefore it is mainly with the iew of furthering this inquiry that I have undertaken work. It will thus be apparent that the present lus lolume, while complete in itself as a statement of the cts of Comparative Psychology, has for its more ultimate irpose the laying of a lirm foundation for my future eatise on Mental Evolution. But although, from what I ve just said, it will be apparent that the present trea- ie is preliminary to a more important one, I desire to iphasise this statement, lest the critics, in being now esented only with a groundwork on which the picture is eutually to be painted, should deem that the art dis- ig aside, B^ygjj -^ ^£ somewhat too commonplace a kind. If the ity y^a^'^Besent work is read without reference to its ultimate cquired Ji Jjgct of supplying facts for the subsequent deduction of nciples, it may well seem but a small improvement on the works of the anecdote-mongers. But if it is embered that my object in these pages is the mapping of animal psychology for the purposes of a subsequent thesis, I may fairly claim to receive credit for a sound ntific intention, even where the only methods at my osal may incidentally seem to minister to a mere love necdote. It remains to add a few words on the principles which ve laid down for my own guidance in the selection and ngement of facts. Considering it desirable to cast as fi a net as possible, I have fished the seas of popular ature as well as the rivers of scientific writing. The ess multitude of alleged facts which I have thus been ed to read, I have found, as may well be imagined, ave beeimgg^ygjy tedious ; and as they are for the most part re- t there isBg^j ^^ wholly unknown observers, the labour of reading r. obability a intelli- arrange- This, te stated, in review grade of by each • lis that of I [heir rela- |eption ofl il powers on the! been no I vm PREFACE. them would have bceu useless without some trustworthj»jjjj.j i .1 principles of selection. The first and most obvious pri^iciplAjj^j^j^^^ 1 that occurred to me was to regard only those facts whicilgy ^^^ stood upon the authority of observers well known as co"i»)servations n petent ; but I soon found that this principle constituteAjj^j princinle much too close a mesh. Where one of my objects was tM,, selection determine the upper limit of intelligence reached by th:fij|^.jj present and that class, order, or species of animals, I usually fouiiM j^^ uncons •' that the most remarkable instances of the display of inteM^g ^g 1 ligence were recorded by persons bearing names more fjeiitg which f' less unknown to fame. This, of course, is what we miglM.vpr and 1 1 antecedently expect, as it is obvious that the chances niuMjjj. .^^ ^j j , , always be greatly against the more intelligent individual j^j^..^„g seek' among animals happening to fall under the observation M^^ .^^^^ x J the more intelligent individuals among men. Therefore* those of oth soon found that I had to choose between neglecting all til g^ much th more important part of the evidence — and consequently Bg^ ^uided in t most cases feeling sure that I had fixed the upper lintnt of the f of intelligence too low — or supplementing the principle looking to authority alone with some other principles selection, which, while embracing the enormous class alleged facts recorded by unknown observers, might felt to meet the requirements of a reasonably criti method. I therefore adopted the following principles filter to this class of facts. First, never to accept an allej fact without the authority of some name. Second, in case of the name being unknown, and the alleged factB^^ ^^ 'xi J sufficient importance to be entertained, carefully to ccBpgjpjj^ i^- j #. sider whether, from all the circumstances of the caseBg^ j-j^ ■,. recorded, there was any considerable opportunity for i^Blosophicall observation ; this principle generally demanded that Mning throi h alleged fact, or action on the part of the animal, should let m-al affin > of a p«'irticularly marked and unmistakable kind, lookBallelism is rfl to the end which the action is said to have accompli sli^jjoad outlin ending order, the selected chology whic in some cas son of my ural groups th For it is a gdom were cl PREFACE. IZ fhird, to tabulate all important observations recorded by iknown observers, with the view of ascertaining whether ley have ever been corroborated by similar or analogous )servations made by other and independent observers. lis principle 1 have found to be of great use in guiding iy selection of instances, for where statements of fact liich present nothing intrinsically improbable are found be unconsciously confirmed by different observers, they ive as good a right to be deemed trustworthy as state- jents which stand on the single authority of a known ob- •ver, and I have found the former to be at least as abun- ^nt as the latter. Moreover, by getting into the habit always seeking for corroborative cases, I have frequently |en able to substantiate the assertions of known observers those of other observers as well or better known. So much, then, for the principles by which I have len guided in the selection of facts. As to the arrange- jnt of the facts, I have taken the animal kingdom in ?ending order, and endeavoured to give as full a sketch the selected evidence at my disposal permitted of the i^chology which is distinctive of each class, or order, i, in some cases, family, genus, or even species. The dson of my entering into greater detail with some tural groups than with others scarcely requires explana- For it is almost needless to say that if the animal igdom were classified with reference to Psychology in- |ad of with reference to Anatomy, we should have a very ferent kind of zoological tree from that which is now [en in our diagrams. There is, indeed, a general and, llosophically considered, most important parallelism ming through the whole animal kingdom between ictural affini-^.y and mental development; but this illelism is exceedingly rough, and to be traced only )road outlines, so that although it is convenient for X PEEFACE. the purpose of definite arrangement to take the anima kingdom in the order presented by zoological classificaj tion, it would be absurd to restrict an inquiry into Anima Psychology by any considerations of the apparently d\i proportionate length and minute subdivision with whicj it is necessary to treat some of the groups. AnatomicallJ an ant or a bee does not require more consideration than beetle or a fly ; but psychologically there is need for great a difference of treatment as there is in the r^j very dissimilar case of a monkey and a man. Throughout the work my aim has been to arrive definite principles rather than to chronicle mere inc| dents — an aim which will become more apparent whi the work as a whole shall have been completed. Therefoij it is that in the present volume I have endeavoured, far as the nature and circumstances of the inquiry woi permit, to suppress anecdote. Nevertheless, althoughl have nowhere introduced anecdotes for their own sakej have found it unavoidable not to devote much the large part of the present essay to their narration. Hence, wij the double purpose of limiting the introduction of ane dotes as much as possible, and of not repeating moj than I could help anecdotes already published, I havej all cases, where I could do so without detriment to main object, given the preference to facts which haj been communicated to me by friends and correspondeDj And here I may fitly take the opportunity of expressiJ my thanks and obligations to the latter, who in Lstonil ing numbers have poured in their communications durij several years from all quarters of the globe. I make tl statement because I desire to expkin to all my com pondents who may read this book, that I am not the U sensible of their kindness because its bounty has re| dered it impossible for me to send acknowledgments I PREFACE. XI idividual cases. However, I should like to add in this mnection that it does not follow, because I have only loted a small percentage of the letters which I have re- vived, that all of the remainder have been useless. On le contrary, many of these have served to convey infor- mation and suggestions which, even if not reserved for )ress quotation in my forthcoming work, have been of 36 in guiding my judgment on particular points. There- Ire I hope tliat the publication of these remarks may Irve to swell the stream of communications into a yet [rger flow. * In all cases where I have occasion to quote statements fact, which in the present treatise are necessarily Limerous, I have made a point of trying to quote trbatim,. Only where I have found that the account [van by an author or a correspondent might profitably Imit of a considerable degree of condensation have I [esented it in my own words. And here I have to express my very special obligations Mr. Darwin, who not only assisted me in the most ^nerous manner with his immense stores of information, well as with his valuable judgment on sundry points difficulty, but has also been kind enough to place my disposal all the notes and clippings on animal belligence which he has been collecting for the last forty [ars, together with the original MS. of his wonderful [apter on ' Instinct.' This chapter, on being re-cast for |e * Origin of Species,' underwent so merciless an amount compression that the original draft constitutes a rich )re of hitherto unpublished material. In my second brk I shall have occasion to draw upon this store more rgely than in the present one, and it is needless to add I ' Letters may be addressed to me directly at 18 Cornwall Terrace, Rent's Park, London, h.W. Xll PREFACE. I that in all cases where I do draw upon it I shall be careful] to state the source to which I am indebted. [The above was written when I sent this work to the publishers several months ago, and I have thought itl best to leave the concluding paragraph as it originalljj stood. But in making this explanation, I cannot alludfi to the calamity which has sinf^e occurred without paying my tribute, not alone to the memory of the greatesa genius of our age, but still more, and much more, to th| memory of a friend so inexpressibly noble, kind, anij generous, that even my immense admiration of thMfTEODucTioN naturalist was surpassed by my loving veneration for thJ man.] >PLICATION OP '. I Animals lOLLUSCA fTS . KES AND Wasps CKMITES ^•IDERS AND SCOJ m fEMAlNING ARTK riSM lATRACHIANS AN ►rk to the bought it| originallji not alludj at paying e greatest] )re, to thj kind, anij »n of th»TBODUCTION CONTENTS. -•o«- • t PAOB 1 CHAPTER I. >PLICATI0N OP THE FOREGOING PRINCIPLES TO THE LOWEST I Animals ....•••• 18 lOLLURCA CHAPTER II. • • • 25 JT8 . CHAPTER III. . 31 Iees and Wasps CHAPTER rV. . . 143 CHAPTER V. ERMITES ..... • • * . 108 CHAPTER VI. I'iDERs AND Scorpions • • . 204 • CHAPTER VII. EMAINING ARTICULATA . • • . 226 CHAPTER VIII. ISH . . . . • • « • . 241 CHAPTER IX. atrachians and Reptiles « • . 254 \ 1 1 ■! i' XIV Birds Mammals Rodents . Elephant The Cat. CONTENTS. CHAPTER X. CHAPTER XI. • • • CHAPTER XII. CHAPTER XIII. • • • CHAPTER XIV. CHAPTER XV. FoxBS, Wolves, Jackals, &c. CHAPTER XVI. The Dog, CHAPTER XVII. Monkeys, Apes, and Baboons Index PAOll 2661 32f| 42l 43] 4; 491 SFORE we be^ [roughout the lould understi tactly msan b; 5ry different t] ir own Individ contemplate kgnizance of a [e the most uli which we are other person [ate cognizance can only -i ^oughts and fe lich appear to ive a subject lalysis of mii sting in this, Istricted to th( call our ow ive immediate INTEODUCTION. SFORE we begin to consider the phenomena of mind Iroughout the animal kingdom it is desirable that we lould understand, as far as possible, what it is that we Eactly msan by mind. Now, by mind we may mean two try different things, according as we contemplate it in ir own individual selves, or in othe'r organisms. For if contemplate our own mind, we have an immediate Ignizance of a certain flow of thoughts or feelings, which [e the most ultimate things, and indeed the only things, which we are cognisant But if we contemplate mind other persons or organisms, we have no such imme- [ate cognizance of thoughts or feelings. In such cases can only infer the existence and the nature of Noughts and feelings from the activities of the organisms lich appear to exhibit them. Thus it is that we may ive a subjective analysis of mind and an objective lalysis of mind — the difference between the two, con- sting in this, that in our subjective analysis we are Istricted to the limits of a single isolated mind which call our own, and within the territory of which we ive immediate cognizance of all the processes that are )ing on, or at any rate of all the processes that fall Ithln the scope of our introspection. But in our ob- jctive analysis of other or foreign minds we have no |ch immediate cognizance; all our knowledge of their )erations is derived, as it were, through the medium of ibassadors — these ambassadors being the activities of >e organism. Hence it is evident that in our study of limal intelligence we are wholly restricted to the ob- 3tive method. Starting from what I know subjectively B 2 INTRODUCTION. of the operations of my own individual mind, and thj activities which in my own organism they prompt, proceed by analogy to infer from the observable activitiej of other organisms what are the mental operations thai underlie them. Now, in this mode of procedure what is the kind cj activities which may be regarded as indicative of mindf I certainly do not so regard the flowing of a river or thj blowing of the wind. Why? First, because the object! are too remote in kind from my own organism to admit my drawing any reasonable analogy between them anJ it ; and, secondly, because the activities which they pre] sent are of invariably the same kind under the same ci cumstances ; they afford no evidence of feeling or purpos| In other words, two conditions require to be satisfied beforj we even begin to imagine that observable activities indicative of mind : first, the activities must be displaye| by a living organism ; and secondly, they must be of kind to suggest the presence of two elements which wl recognise as the distinctive characteristics of mind such — consciousness and choice. So far, then, the case seems simple enough. Wherevt we see a living organism apparently exerting intention( choice, we might infer that it is conscious choice, anj therefore that the organism has a mind. But furthe reflection shows us that this is just what we cannot doj for although it is true that there is no mind without thj power of conscious choice, it is not true that all apparei choice is due to mind. In our own organisms, for ii stance, we find a great many adaptive movements peil formed without choice or even consciousness coming intj play at all — such, for instance, as in the beating of on hearts. And not only so, but physiological experiment! and pathological lesions prove that in our own and other organisms the mechanism of the nervous system sufficient, without the intervention of consciousness, t| produce muscular movements of a highly co-ordinate edJ apparently intentional character. Thus, for instance, if man has his back broken in such a way as to sever ti nervous connection between his brain and lower extremil INTRODUCTION. 8 and till rompt, activiti ions thai ies, on pinching or tickling his feet they are drawn sud- nly away from the irritation, although the man is quite conscious of the adaptive movement of his muscles; 6 lower nerve-centres of the spinal cord are competent bring about this movement of adaptive response with- t requiring to be directed by the brain. This non- ental operation of the lower nerve-centres in the pro- ction of apparently intentional movements is called flex Action, and the cases of its occurrence, even within e limits of our own organism, are literally numberless. —lerefore, in view of such non-mental nervous adjust- Z. ^^Jent, leading to movements which are only in appearance itentional, it clearly becomes a matter of great difficulty say in the case of the lower animals whether any action ich appears to indicate intelligent choice is not really ion of the reflex kind. On this whole subject of mind-like and yet not truly ntal action I shall have much to say in my subsequent atise, where I shall be concerned among other things |th tracing the probable genesis of mind from non- ntal antecedents. But here it is sufficient merely to ke this general statement of the fact, that even within experience supplied by our own organisms adaptive vements of a highly complex and therefore apparently posive character may be performed without any real ose, or even consciousness of their performance. It s becomes evident that before we can predicate the e existence of mind in the lower animals, we need e yet more definite criterion of mind than that which upplied by the adaptive actions of a living organism, soever apparently intentional such actions may be. h a criterion I have now to lay down, and I think it is that is as practically adequate as it is theoretically itimate. Objectively considered, the only distinction between msness, mp|.jyg movements due to reflex action and adaptive dmate ^D^ygjj^gjj^g ^^g ^q mental perception, consists in the stance, ^J fcaer depending on inherited mechanisms within the I sever tJmyQ^g gygtem being so constructed as to effect particular jr extremip^p^j^g movements in response to particular stimula- B 2 3 kind (1 of mind srer or thi tie objecti ) admit them am same c )r purposi fled befoii ivities ! display st be of which w )f mind Wherev ntentioni hoice, aL| ut furth annot dol ithout thl 1 appare for i nents pei oming inti ing of sperimcDi Tfn and s system ns. INTRODUCTION. tions, while the latter are independent of any such herited adjustment of special mechanisms to the eij gencies of special circumstances. Reflex actions unc the influence of their appropriate stimuli may be coil pared to the actions of a machine under the maniij lations of an operator ; when certain springs of acti are touched by certain stimuli, the whole machine! thrown into appropriate movement ; there is no room | choice, there is no room for uncertainty ; but as surely i any of these inherited mechanisms are affected by {j stimulus with reference to which it has been constructf to act, so surely will it act in precisely the same way asl always has acted. But the case with conscious menj adjustment is quite different. For, without at press going into the question concerning the relation of be and mind, or waiting to ask whether cases of menj adjustment are not really quite as mechanical in tl sense of being the necessary result or correlative of a chl of physical sequences due to a physical stimulation, it enough to point to the variable and incalculable characJ of mental adjustments as distinguished from the constaf and foreseeable character of reflex adjustments. All,! fact, that in an objective sense we can mean by a meii| adjustment is an adjustment of a kind that has not be definitely fixed by heredity as the only adjustment sible in the given circumstances of stimulation. For v;i there no alternative of adjustment, the case, in an anii at least, would be indistinguishable from one of refl action. It is, then, adaptive action by a living organism I cases where the inherited machinery of the nervous systJ does not furnish data for our prevision of what the ada| tive action must necessarily be — it is only here thati recognise the objective evidence of mind. The criteril of mind, therefore, which I propose, and to which I stl adhere throughout the present volume, is as follows:! Does the organism learn to make new adjustments, orl modify old ones, in accordance with the results of its oj individual experience ? If it does so, the fact cannot I due merely to reflex action in the sense above describj INTRODUCTION. 5 it is impossible that heredity can have provided in Ivance for innovations upon, or alterations of, its machi- kry during the lifetime of a particular individual. In my next work I shall have occasion to consider this iterion of mind more carefully, and then it will be [own that as here stated the criterion is not rigidly ex- isive, either, on the one hand, of a possibly mental jment in apparently non-mental adjustments, or, con- rsely, of a possibly non-mental element in apparently jntal adjustments. But, nevertheless, the criterion is best that is available, and, as it will be found sufficient all the purposes of the present work, its more minute ilysis had better be deferred till I shall have to treat of probable evolution of mind from non-mental an- jedents. I may, however, here explain that in my use I this criterion I shall always regard it as fixing only the [per limit of non-mental action ; I shall never regard it fixing the lower limit of mental action. For it is clear it long before mind has advanced sufficiently far in the le of development to become amenable to the test in [estion, it has probably begun to dawn as nascent sub- 3tivity. In other words, because a lowly organised imal does not learn by its own individual experience, may not therefore conclude that in performing its [tural or ancestral adaptations to appropriate stimuli isciousness, or the mind-element, is wholly absent ; we only say that this element, if present, reveals no lidence of the fact. But, on the other hand, if a lowly janised animal does learn by its own individual experi- [ce, we are in possession of the best available evidence conscious memory leading to intentional adaptation, lerefore our criterion applies to the upper limit of non- mtal action, not to the lower limit of mental. Of course to the sceptic this criterion may appear un- tisfactory, since it depends, not on direct knowledge, tt on inference. Here, however, it seems enough to [int out, as already observed, that it is the best fterion available ; and further, that scepticism of this id is logically bound to deny evidence of mind, not only the case of the lower animals, but also in that of the INTRODUCTION. higher, and even in that of men other than the sceptj himself. For all objections which could apply to the uJ of this criterion of mind in the animal kingdom wouJ apply with equal force to the evidence of any mind otbij than that of the individual objector. This is obvioi because, as I have already observed, the only evidence can have of objective mind is that which is furnished objective activities ; and as the subjective mind can nevtj become assimilated with the objective so as to learn ll direct feeling the mental processes which there accompaij the objective activities, it is clearly impossible to satisif any one who may choose to doubt the validity of inferencj that in any case other than his own mental processes evt do accompany objective activities. Thus it is that phil«| sophy can supply no demonstrative refutation of idealisi even of the most extravagant form. Common sense, hov ever, universally feels that analogy is here a safer guid to truth than the sceptical demand for impossible e\ dence; so that if the objective existence of other oj ganisms and their activities is granted — without whicj postulate comparative psychology, like all the oth( sciences, would be an unsubstantial dream — commol sense will always and without question conclude that tLJ activities of organisms other than our own, when analogou to those activities of our own which we know to be accoi panied by certain mental states, are in them accompanie by analogous mental states. The theory of animal automatism, therefore, which 1 usually attributed to Descartes (although it is not quit! clear how far this great philosopher really entertained ttl theory), can never be accepted by common sense ; and evej as a philosophical speculation it will be seen, from what ha just been said, that by no feat of logic is it possible l| make the theory apply to animals to the exclusion man. The expression of fear or affection by a dog iii volves quite as distinctive and complex a series of neurd muscular actions as does the expression of similar emotion by a lipman being; and therefore, if the evidence corresponding mental states is held to be inadequate iii the one case, it must in consistency be held similailj lem, as the n ' Of course it n INTRODUCTION. 7 ^adequate in the other. And likewise, of course, with all ther exhibitions of mental life. It is quite true, however, that since the days of Des- irtes — or rather, we might say, since the days of Joule — 16 question of animal automatism has assumed a new or lore defined aspect, seeing that it now runs straight into the ^ost profound and insoluble problem that has ever been resented to human thought — viz. the relation of body to lind in view of the doctrine of the conservation of energy, shall subsequently have occasion to consider this problem [ith the close attention that it demands ; but in the resent volume, which has to deal only with the pheno- mena of mind as such, I expressly pass the problem aside one reserved for separate treatment. Here I desire ily to make it plain that the mind of animals must be laced in the same category, with reference to this pro- lem, as the mind of man ; and that we cannot without ross inconsistency ignore or question the evidence of lind in the former, while we accept precisely the same fnd of evidence as sufficient proof of mind in the latter. And this proof, as I have endeavoured to show, is in all ises and in its last analysis the fact of a living organism lowing itself able to learn by its own individual experi- tice. Wherever we find an animal able to do this, we ive the same right to predicate mind as existing in such animal that we have to predicate it as existing in any lan being other than ourselves. For instance, a dog IS always been accustomed to eat a piece of meat when is organism requires nourishment, and when his olfactory 3rves respond to the particular stimulus occasioned by le proximity of the food. So far, it may be said, there no evidence of mind ; the whole series of events com- ised in the stimulations and muscular movements may due to reflex action alone. But now suppose that by a imber of lessons the dog has been taught not to eat the leat when he is hungry until he receives a certain verbal |gnal : then we have exactly the same kind of evidence lat the dog's actions are prompted by mind as we have lat the actions of a man are so prompted.' Now we find Of course it may be said that we have no evidence of provijtting 8 INTRODUCTION. I that the lower down we go in the animal kingdom, thJ more we observe reflex action, or non-mental adjustment) to predominate over volitional action, or mental adjust] ment. That is to say, the lower down we go in thJ animal kingdom, the less capacity do we find forchanginJ adjustive movements in correspondence with change conditions ; it becomes more and more hopeless to tem^ animals — that is, to establish associations of ideas; anq the reason of this, of course, is that ideas or mental unitj become fewer and less definite the lower we descenfj through the structure of mind. It is not my object in the present work to enter upoj any analysis of the operations of mind, as this will requirl to be done as fully as possible in my next work. Never] theless, a few words must here be said with regard to tW main divisions of mental operation, in order to defiBJ closely the meanings which I shall attach to certain temj relating to these divisions, and the use of which I canno avoid. The terms sensation, perception, emotion, and volitioj need not here be considered. I shall use them in the! ordinary psychological significations; and although shall subsequently have to analyse each of the organic mental states which they respectively denote, there m be no occasion in the present volume to enter upon tl subject. I may, however, point out one general coi sideration to which I shall throughout adhere. Takii it for granted that the external indications of menta processes which we observe in animals are trustworthy, s| that we are justified in inferring particular mental state from particular bodily actions, it follows that in con] sistency we must everywhere apply the same criteria. For instance, if we find a dog or a monkey exhibitinj marked expressions of affection, sympathy, jealousy, raga &c., few persons are sceptical enough to doubt that thj complete analogy which these expressions afibrd witl( in either case ; but this is the side issue which concerns the gener relation of body and mind, and has nothing to do with the guarantej of inferring the presence of mind in particular cases. INTRODUCTION. 9 lose which are manifested by man, sufficiently prove le existence of mental states analogous to those in man which these expressions are the outward and visible Igns. But when we find an ant or a bee apparently thibitiug by its actions these same emotions, few persons re srffici'^ntly non-sceptical not to doubt whether the itwarci and visible signs are here trustworthy as evidence analogous or corresponding inward and mental states. [he whole organisation of such a creature is so different fom that of a man that it becomes questionable how ir analogy drawn from the activities of the insect is a ife guide to the inferring of mental states — particularly view of the fact that in many respects, such as in the [reat preponderance of * instinct * over * reason,* the Isychology of an insect is demonstrably a widely different ling from that of a man. Now it is, of course, perfectly rue that the less the resemblance the less is the value of |ny analogy built upon the resemblance, and therefore lat the inference of an ant or a bee feeling sympathy or ige is not so valid as is the similar inference in the case [f a dog or a monkey. Still it is an inference, and, so ir as it goes, a valid one — being, in fact, the only in- 3rence available. That is to say, if we observe an ant or bee apparently exhibiting sympathy or rage, we must |ither conclude that some psychological state resembling Ihat of sympathy or rage is present, or else refuse to Ihink about the subject at all ; from the observable facts [here is no other inference open. Therefore, having full [egard to the progressive weakening of the analogy from luman to brute psychology as we recede through the bimal kingdom downwards from man, still, as it is the mly analogy available, I shall follow it throughout the linimal series. It may not however, be superfluous to point out Ihat if we have full regard to this progressive weaken- ing of the analogy, we must feel less and less certain [)f the real similarity of the mental states compared ; b that when we get down as low as the insects, I phink the most we can confidently assert is that the mown facts of human psychology furnish the best avail- n 10 INTKODUCTION. able pattern of the probable facts of insect psychology.! Just as the theologians tell us — and logically enough—! that if there is a Divine Mind, the best, and indeed only,! conception we can form of it is that which is formed m the analogy, however imperfect, supplied by the liumanj mind; so with * inverted anthropomorphism' we must apply a similar consideration with a similar conclusion toj the animal mind. The mental states of an insect may! be widely different from those of a man, and yet most! probably the nearest conception that we can form of theirl true nature is that which we form by assimilating themj to the pattern of the only mental states with which wel are actually acquainted. And this consideration, it isj needless to point out, has a special validity to the evo- lutionist, inasmuch as upon his theory there must be ai psychological, no less than a physiological, continuityl extending throughout the length and breadth of the] animal kingdom. In these preliminary remarks only one other pointl requires brief consideration, and this has reference to the! distinction between what in popular phraseology is calledl ' Instinct ' and ' Reason.' I shall not here enter upoL| any elaborate analysis of a distinction which is un- doubtedly valid, but shall confine my remarks to ex-| plaining the sense in which I shall everywhere use thesej terms. Few words in our language have been subject to a I greater variety of meanings than the word instinct. In! popular phraseology, descended from the Middle Ages, all the mental faculties of the animal are termed in- stinctive, in contradistinction to those of man, which I are termed rational. But unless we commit ourselves to an obvious reasoning in a circle, we must avoid assuming that all actions of animals are instinctive, and then arguing that because they are instinctive, therefore they differ from the rational actions of man. The question really lies in what is here assumed, and we can only answer it by examining in what essential respect instinct | differs from reason. INTEODUCTION. 11 Again, Addison 3ays : — I look upon instinct as upon the principle of gravitation in )odies, which is not to be explained by any known qualities lerent in the bodies themselves, nor from any laws of me- chanism, but as an immediate impression from the first Mover, jind the Divine energy acting in the creatures. This mode of * looking upon instinct ' is merely to bclude the subject from the sphere of inquiry, and so to pstain from any attempt at definition. Innumerable other opinions might be quoted from rell-known writers, booking upon instinct' in widely Ufferent ways ; but as this is not an historical work, I jhall pass on at once to the manner in which science looks upon it, or, at least, the manner in which it will jlways be looked upon throughout the present work. Without concerning ourselves with the origin of in- [tincts, and so without reference to the theory of evolution^ 76 have to consider the most conspicuous and distinctive features of instinct as it now exists. The most important )oint to observe in the first instance is that instinct (nvolves mental operations ; for this is the only point [hat serves to distinguish instinctive action from reflex, leflex action, as already explained, is non-mental neuro- luscular adaptation to appropriate stimuli; but in- jtinctive action is this and something more ; there is in It the element of mind. Such, at least, is instinctive lotion in the sense that I shall always allude to it. I |m, of course, aware that the limitation which I thus (mpose is one which is ignored, or not recognised, by lany writers even among psychologists ; but I am per- luaded that if we are to have any approach to definiteness In the terms which we employ — not to say of clear- less in our ideas concerning the things of which we speak -it is most desirable to restrict the word instinct to lental as distinguished from non-mental activity. No loubt it is often difficult, or even impossible, to decide rhether or not a given action implies the presence of the ind-element — i.e., conscious as distinguished from un- \ [onscious adaptation ; but this is altogether a separate , latter, and has nothing to do with the question of f ; 12 INTRODUCTION. ■!:; : defining instinct in a manner which shall be formallvi exclusive, on the one hand of reflex action, and on the! other of reason. As Virchow truly observes, ' it is diffi-l cult or impossible to draw the line between instinctive! and reflex action ; ' but at least the difficulty may bel narrowed down to deciding in particular cases whether! or not an action falls into this or that category of defini-l tion ; there is no reason why the difficulty should arise! on account of any ambiguity of the definitions themselves! Therefore I endeavour to draw as sharply as possible the! line which in theory should be taken to separate inJ stinctive from reflex action; and this line, as I havej already said, is constituted by the boundary of non-mental! or unconscious adjustment, with adjustment in which] there is concerned consciousness or mind. Having thus, I hope, made it clear that the difficultjj of drawing a distinction between reflex and instinctive! actions as a class is one thing, and that the difficulty ofj assigning particular actions to one or the other of ouij categories is another thing, we may next perceive that the! former difficulty is obviated by the distinction which ll have imposed, and that the latter only arises from the factl that on the objective side there is no distinction ini-| I posable. The former difficulty is obviated by the distijicJ tion which I have drawn, simply because the distinction! is itself a definite one. In particular cases of adjustivej action we may not always be able to affirm whether con{ sciousness of their performance is present or absent ; but! as I have already said, this does not aff'ect the validity of our definition ; all we can say of such cases is that if thej performance in question is attended with consciousness itj is instinctive, and if not it is reflex. And the difficulty of assigning particular actions to one! or other of these two categories arises, as I have saidj merely because on the objective side, or the side of thej nervous system, there is no distinction to be drawiil Whether or not a neural process is accompanied by a men- tal process, it is in itself the same. The advent and den velopment of consciousness, although progressively conj verting reflex action into instinctive, and instinctive into! INTRODUCTION. 13 iousness itl ktional, does this exclusively in the sphere of subjec- tivity; the nervous processes engaged are throughout the ^ame in kind, and differ only in the relative degrees of their complexity. Therefore, as the dawn of consciousness )r the rise of the mind-element is gradual and undefined, )oth in the animal kingdom and in the growing child, it ^s but necessary that in the early morning, as it were, of jonsciousness any distinction between the mental and the ion-mental should be obscure, and generally impossible to letermine. Thus, for instance, a child at birth does not }lose its eyes upon the near approach of a threatening )ody, and it only learns to do so by degrees as the result )f experience ; at first, therefore, the action of closing the ?yelids in order to protect the eyes may be said to be instinctive, iu that it involves the mind-element : ^ yet it ifterwards becomes a reflex which asserts itself even in )pposition to the will. And, conversely, sucking in a lew-born child, or a child in utero, is, in accordance with ly definition, a reflex action ; yet in later life, when con- sciousness becomes more developed and the child seeks the )reast, sucking may properly be called an instinctive iction. Therefore it is that, as in the ascending scale )f objective complexity the mind-element arises and idvances gradually, many particular cases which occupy the undefined boundary between reflex action and instinct ?:tnnot be assigned with confidence either to the one region )r to the other. We see then the point, and the only point, wherein [instinct can be consistently separated from reflex action ; 7iz., in presenting a mental constituent. Next we must |consider wherein instinct may be separated from reason. Lnd for this purpose we may best begin by considering [what we mean by reason. The term ' reason ' is used in significations almost as [various as those which are applied to ' instinct.* Some- 1 • Le., ancestral as well as individual. If the race had not always [had occasion to close the eyelids to protect the eyes, it is certain that [the young child would not so quickly learn to do so in virtue of its [own individual experience alone ; and as the action cannot be attri- jbuted to any process of conscious inference, it is not rational ; but we ■have seen that it is not originally reflex ; therefore it is instinctive 14 INTKODUCTION. limes it stands for all the distinctively human faculties^ taken collectively, and in antithesis to the mental faculties! of the brute ; while at other times it is taken to mean thej distinctively human faculties of intellect. Dr. Johnson defines it as ' the power by which man] deduces one proposition from another, and proceeds from! premises to consequences.* This definition presupposeJ language, and therefore ignores all cases of inference not! thrown into the formal shape of predication. Yet even in! man the majority of inferences drawn by the mind neveii emerge as articulate propositions ; so that although, ail we shall have occasion fully to observe in my subsequeLtj work, there is much profound philosophy in identifying! reason with speech as they were identified in the teriiif Logos, yet for purposes of careful definition so to identifj| intellect with language is clearly a mistake. More correctly, the word reason is used to signify the! power of perceiving analogies or ratios, and is in this! sense equivalent to the term ' ratiocination,' or the facultjl of deducing inferences from a perceived equivalency off relations. Such is the only use of the word that isl strictly legitimate, and it is thus that I shall use iti throughout the present treatise. This faculty, however] of balancing relations, drawing inferences, and so of fore-j casting probabilities, admits of numberless degrees ; audi as in the designation of its lower manifestations it soundsf somewhat unusual to employ the word reason, I shall iil these cases frequently substitute the word intelligence] Where we find, for instance, that an oyster profits bjl individual experience, or is able to perceive new relations! and suitably to act upon the result of its perceptions, ij think it sounds less unusual to speak of the oyster as dis- playing intelligence than as displaying reason. On this! account I shall use the former term to signify the lower! degrees of the ratiocinative faculty ; and thus in my usage! it will be opposed to such terms as instinct, reflex actionJ &c., in the same manner as the term reason is so opposed.! This is a point which, for the sake of clearness, I desire! the reader to retain in his memory. I shall always speak] of intelligence and intellect in antithesis to instinct, emo- INTRODUCTION. 15 lion, and the rest, as implying mental faculties the same \i kind as those which in ourselves we call rational. Now it is notorious that no distinct line can be di*awn letween instinct and reason. Whether we look to the [rowing child or to the ascending scale of animal life, we Ind that instinct shades into reason by imperceptible legrees, or, as Pope expresses it, that these principles are [for ever separate, yet for ever near.' Nor is this other lan the principles of evolution would lead us to expect, I shall afterwards have abundant occasion to show. [ere, however, we are only concerned with drawing what listinction we can between instinct and reason as these iculties are actually presented to our observation. And lis in a general way it is not difficult to do. We have seen that instinct involves 'mental opera- tons,' and that by this feature it is distinguished from re- lex action ; we have now to consider the features by which is distinguished from reason. These are accurately, lough not completely, conveyed by Sir Benjamin Brodie^ ^ho defines instinct as ' a principle by which animals re induced, independently of experience and reason- ig, to the performances of certain voluntary acts, which re necessary to their preservation as individuals, or the continuance of the species, or in some other fay convenient to them.'^ This definition, as I have lid, is accurate as far as it goes, but it does not state [ith sufficient generality and terseness that all instinctive 3tion is adaptive ; nor does it clearly bring out the dis- [nction between instinct and reason which is thus well )nveyed by the definition of Hartmann, who says in his Philosophy of the Unconscious,' that ' instinct is action |iken in pursuance of an end, but without conscious per- jption of what the end is.' This definition, however, is tewise defective in that it omits another of the im- 3rtant differentiae of instinct — namely, the uniformity of istinctive action as performed by different individuals of le same species. Including this feature, therefore, we [ay more accurately and completely define instinct as' lental action (whether in animals or human beings), ' Psychological Researches, p. 187. 16 INTRODUCTION. ■ ■ 1/ directed towards the accomplishing of adaptive movement] antecedent to individual experience, without necessar knowledge of the relation between the means employe] and the ends attained, but similarly performed under thj same appropriate circumstances by all the individuals the same species. Now in every one of these respectJ with the exception of containing a mental constituent an^ in being concerned in adaptive action, instinct differs froE reason. For reason, besides involving a mental coil stituent, and besides being concerned in adaptive actioE is always subsequent to individual experience, never act] but upon a definite and often laboriously acquired kno^TJ ledge of the relation between means and ends, and is ver far from being always similarly performed under the samj appropriate circumstances by all the individuals of til same species. Thus the distinction between instinct and reason both more definite and more manifold than is that betweej instinct and reflex action. Nevertheless, in particula cases there is as much difficulty in classifying certaij actions as instinctive or rational, as there is in cases wherf the question lies between instinct and reflex action. AlI the explanation of this is, as already observed, that instina passes into reason by imperceptible degrees; so thai actions in the main instinctive are very commonll tempered with what Pierre Huber calls ' a little dose judgment or reason,* and vice versa. But here, again, til difficulty which attaches to the classification of particul( actions has no reference to the validity of the distinction between the two classes of actions ; these are definite aDJ precise, whatever difficulty there may be in applying theif to particular cases. Another point of difference between instinct aiii reason may be noticed which, although not of invariablj is of very general applicability. It wi^l have bee| observed, from what has already been said, that tlj essential respect in which instinct differs from reason con sists in the amount of conscious deliberation which tl two processes respectively involve. Instinctive actions aii actions which, owing to their frequent repetition, becomj INTRODUCTION. 17 novemeny necessa: I employei under th ividuals c habitual in the course of generations that all the ividuals of the same species automatically perform the e actions under the stimulus supplied by the same propriate circumstances. National actions, on the other nd, are actions which are required to meet circumstances e respectj comparatively rare occurrence in the life-history of the cies, and which therefore can only be performed by an entional effort of adaptation. Consequently there arises |e subordinate distinction to which I allude, viz., that stinctive actions are only performed under particular [•cumstances which have been frequently experienced ring the life-history of the species; whereas rational tions are perfonned under varied circumstances, and rve to meet novel exigencies which may never before [ve occurred even in the life-history of the individual. Thus, then, upon the whole, we may lay down our reral definitions in their most complete form. Reflex action is non-mental neuro-muscular adjust- jnt, due to the inherited mechanism of the nervous stem, which is formed to respond to particular and often 3urring stimuli, by giving rise to particular movements an adaptive though not of an intentional kind. Instinct is reflex action into which there is imported le element of consciousness. The term is therefore a [neric one, comprising all those faculties of mind which concerned in conscious and adaptive action, antecedent individual experience, without necessary knowledge of le relation between means employed and ends attained, \t similarly performed under similar and frequently re- ping circumstances by all the individuals of the same 3cies. Reason or intelligence is the faculty which is concerned the intentional adaptation of means to ends. It there- re implies the conscious knowledge of the relation be- feen means employed and ends attained, and may be [ercised in adaptation to circumstances novel alike to le experience of the individual and to that of the species. ituent aiii iififers fro; 3tltal COE ive actioi^ never acti Lred know! and is ve !r the sami lals of tti 1 reason at betweeil particula ing certaij 3ases wherj ition. AbI hat instina s ; so thi commonll ttle dose J, again, til f particul| distinction iefinite aij plying theij istinct aDi invariabl| have bee| 1, that til reason con which tt 3 actions ail ion, becomj r^ 18 CHAPTER I. APPLICATION OF THE FOREGOING PRINCIPLES TO THE| LOWEST ANIMALS. iri'l' li': Protozoa, No one can have watched the movements of certa Infusoria without feeling it difficult to believe that thj little animals are not actuated by some amount of Intel] gence. Even if the manner in which they avoid coUisio be attributed entirely to repulsions set up in the curred which by their movements they create, any such mechanii] explanation certainly cannot apply to the small creati seeking one another for the purposes of prey, reproductid or, as it sometimes seems, of mere sport. There is! common and well-known rotifer whose body is of a cj shape, provided with a very active tail, which is armed] its extremity with strong forceps. I have seen a si specimen of this rotifer seize a much larger one with forceps, and attach itself by this means to the side of t| cup. The large rotifer at once became very active, swinging about with its burden until it came to a piecel weed, it took firm hold of the weed with its own forcej and iDegan the most extraordinary series of movemeLJ which were obviously directed towards ridding itself of t| encumbrance. It dashed from side to side in all directiol with a vigour and suddenness which were highly astoiiis| ing, so that it seemed as if the animalcule would eitl break its forceps or wrench its tail from its body, movements could possibly be better suited to jerk off tl offending object, for the energy with which the jerks wef given, now in one direction and now in another, were, aa have said, most surprising. But not less surprising PROTOZOA. 19 3 TO THE tenacity with which the smaller rotifer retained its Id ; for although one might think that it was being lost jerked to pieces, after each bout of jerking it was In to be still attached. This trial of strength, which 1st have involved an immense expenditure of energy in [portion to the size of the animals, lasted for several lutes, till eventually the small rotifer was thrown lently away. It then returned to the conflict, but did succeed a second time in establishing its hold. The liie scene was as like intelligent action on the part of [h animals as could well be imagined, so that if we were lepend upon appearances alone, this one observation lid be sufficient to induce me to attribute conscious 3rmination to these microscopical organisms. I But, without denying that conscious determination may (e be present, or involving ourselves in the impossible of proving such a negative, we may properly affiim until an animalcule shows itself to be teachable by in- fdual experience, we have no sufficient evidence derived lerivable from any number of such apparently intelli- [t movements, that conscious determination is present. }refore, I need not wait to quote the observations of sundry microscopists who detail facts more or less jilar to the above, with expressions of their belief that Iroscopical organisms display a certain degree of instinct itelligence as distinguished from mechanical, or wholly [-mental adjustment. But there are some observations [ting to the lowest of all animals, and made by a com- mt person, which are so remarkable that I shall have to be them in full. These observations are recorded by H. J. Carter, F.R.S., in the 'Annals of Natural tory,' and in his opinion prove that the beginnings of linct are to be found so low down in the scale as the lopoda. He says : — ' Even Athealium will confine If to the water of the watch-glass in which it may be [ed when away from sawdust and chips of wood among 3h it has been living ; but if the watch-glass be placed the sawdust, it will very soon make its way over the of the watch-glass and get to it.' This is certainly a remarkable observation ; for it seems c 2 20 ANIMAL INTELLIGENCE. I ;! to show that the rhizopod distinguishes the presence] the sawdust outside the watch-glass, and crawls over brim of the latter in order to get into more congerJ quarters, while it is contented with the water in the watl glass so long as there is no sawdust outside. But to J ceed: On one occasion, while investigating the nature of scj large, transparent, spore-like elliptical cells (fungal?) wl protoplasm was rotating, while it was at the same time char] with triangular grains of starch, I observed some actinophop rhizopods creeping about them, which had similarly shaj grains of starch in their interior ; and having determined j nature of these grains in both by the addition of iodiiifj cleansed the glasses, and placed under the microscope a portion of the sediment from the basin containing these cells actinophryans for further examination, when i observed oiifj the spore-like cells had become ruptured, and that a portioi its protoplasm, charged with the triangular starch-grains, slightly protruding through the crevice. It then struck i that the actinophryans had obtained their starch- grains frj this source ; and while looking at the ruptured cell, an nophrys made its appearance, and creeping round the cell] last arrived at the crevice, from wl if^li it extricated one of 1 grains of starch mentioned, and then crept off to a good tance. Presently, however, it returned to the same cell ; although there were now no more starch-gi-ains protruding, actinophrys managed again to extract one from the inteij through the crevice. All this was repeated several tin showing that the actinophrys instinctively knew that those nutritious grains, that they were contained in this cell,i that, although each time after incepting a grain it went a^ to some distance, it knew how to find its way back to the i again which furnished this nutriment. On another occasion I saw an actinophrys station itj close to a ripe spore-cell of pythium, which was situated iil a filament of Spirogyra crassa; and as the young ciliaf monadic germs issued forth, one after another, from the del cent spore-cell, the actinophrys remained by it and cau every one of them, even to the last, when it retired to anotl part of the field, as if instinctively conscious that there nothing more to be got at the old place. But by far the greatest feat of this kind that ever presen itself to me was the catching of a young acineta by an I PROTOZOA. 21 Iggish amoeba f as the former left its parent ; and this took ce as follows : — In the evening of the 2nd of June, 1858, in Bombay, while Iking through a microscope at some EuglcncR, j and indeed draws a sharp distinction between what considers their ' involuntary ' and ' voluntary ' movemeii| In this distinction, however, I do not at all concur ; although I am well acquainted with the difference tween the active and slow rhythm upon which the tinction is founded, I see no evidence whatever supposing that the difference involves any psychologid element. The active swimming is produced by stimj lation, and is no doubt calculated to lead to the escape the organism ; but this fact certainly does not carry beyond the ordinary possibilities of reflex action. M even when, as in some species is constantly the cai bouts of active swimming appear to arise spontaneoiiji or without observable stimulation, the fact is to be a| tributed to a liberation of overplus ganglionic energ or to some unobservable stimulation ; it does not justi the supposition of any psychical element being coj cerned.^ M'Crady gives an interesting account of a meduj which carries its larvsB on the inner sides of its bell shaped body. The manubrium, or mobile digestive ca\ij * For an account of the natural movements of the Medusas and t| effects of stimulation upon them, see Croonian Lecture in Phil. 2rtr\ 1876, and also Phil. Trans. 1877 and 1879. ECUINODERMATA. S8 movemeiil |tlie animal, depends, as in the other Medusae, from the imit of the concave surface of the bell, like a clapjxT tongue. Now M*Crady observed this depending organ I be moved first to one side and then to the other side the bell, in order to give suck to the larva} on the ^es of the bell — the larvae dipping their long noses into nutrient fluids which that organ of the parent's body itained. I cite this case, because if it occurred in one I the higher animals it would probably be called a case linstinct ; but as it occurs in so low an animal as a lly-fish, it is unreasonable to suppose that intelligence ever have played any part in originating the action, ^erefore we may set it down as the uncompounded suit of natural selection. Some species of medusae — notably Sarsia — seek the [ht, crowding into the path of a beam, and following it lively if moved. They derive advantage from so doing, jause certain small Crustacea on which they feed like- 36 crowd into the light. The seeking of light by these jdusse is therefore doubtless of the nature of a reflex (;ion which has been developed by natural selection in ler to bring the animals into contact with ( heir prey, [ul Bert has found that Daphnia pulex seeks the light Specially the yellow ray), and Engelmann has observed same fact with regard to certain protoplasmic organisms. tt in none of these or other such cases is there any pence of a psychical element being concerned in the )cess. Echinodeimiata, Some of the natural movements of these animals, as |o some of their movements under stimulation, are very jgestive of purpose; b^ ^ I have satisfied myself that ire is no adequate evident ■ of the animals being able to 3fit by individual experience, and therefore, in accordance th our canon, that there is no adequate evidence of their libiting truly mental phenomena. On the other hand, study of reflex action in these organisms is full of |;erest — so much so that in my next work I shall take 3m as typical organisms in this connection.^ I' See Croonian Lecture, 1881, in forthcoming issue of PMl. Trans. 24 ANIMAL INTELLIGENCE. Annelida. I, i ill Mr. Darwin has now in the press a highly interestii work on the habits of earth-worms. It appears from observations that the manner in which these animals dral down leaves, &c., into their burrows is strongly indicatii| of instinctive action, if not of intelligent purpose — seeiij that they always lay hold of the part of the leaf (ev« though an exotic one) by the traction of which the le will offer least resistance to being drawn down. But this work will so shortly be published, I shall not forest any of the facts which it has to state, nor should I yi like to venture an opinion as to how far these facts, wM considered altogether, would justify any inference to| truly mental element as existing in these animals. Of the land leeches in Ceylon, Sir E. Tennent givJ an account which likewise seems to bespeak intelligenij as occurring in annelids. He says : — In moving, the land leeches have the power of planting oJ extremity on the earth and raising the other perpendicularly! watch for their victim. Such is their vigilance and instinij that on the approach of a passer-by to a spot which they infe they may be seen amongst the grass and fallen leaves on tlj edge of a native path, poised erect, and preparing for thq attack on man and horse. On descrying their prey they vance rapidly by semicircular strides, fixing one end firmly arching the other forwards, till by successive advances they lay hold of the traveller's foot, when they disengage themselvj from the ground and ascend his dress in search of an apertu to enter. In these encounters the individuals in the rear of I party of travellers in the jungle invariably fare worst, as tl| leeches, once warned of their approach, congregate with sii gular celerity.* • Natural History of Ceylon, p. 481. 25 CHAPTER II. iskves on tH MOLLUSCA. SHALL treat of the jNIollusca before the Articulata, jcause as a group their intelligence is not so high. ideed, it is not to be expected that the class of limals wherein the * vegetative ' functions of nutri- [on and reproduction predominate so largely over the limal functions of sensation, locomotion, &c., should resent any considerable degree of intelligence. Never- leless, in the only division of the group which has inse organs and powers of locomotion highly developed -viz., the Cephalopoda — we meet with large cephalic langlia, and, it would appear, with no small develop- lent of intelligence. Taking, however, the sub-king- |om in ascending order, I shall first present all the rustworthy evidence that I have been able to collect, [ointing to the highest level of intelligence that is at- lined by the lower members. The following is quoted from Mr. Darwin's MS. : — Even the headless oyster seems to profit from experience, 3r Dicquemase ('Journal de Physique,' vol. xxviii. p. 244) [sserts that oysters taken from a depth never uncovered by the I, open their shells, lose the water within, and perish ; but lysters taken from the same place and depth, if kept in reser- FOU's, where they are occasionally left uncovered for a short lime, and are otherwise incommoded, learn to keep their shells [but, and then live for a much longer time when taken out of the water. ^ ' This fact is also stated by Bingley, Animal Biography, vol. iii. 3. 454, and is now turned to practical account in the so-called ' Oyster- schools ' of Franco. The distance from the coast to Paris being too reat for the newly dredged oysters to travel without opening their ^hells, they are first taught in the schools to bear a longer and longer exposure to the air without gaping, and when their education in this irespect is completed they are sent on their journey to the metropolis, inhere they arrive with closed shells, and in a healthy condition. 26 ANIMAL IXTELLIGEXCE. I' III Some evidence of intelligence seems to be displayed by the razor-fish. For the animals dislike salt, so thai when this is sprinkled above their bm^rows in the sand] they come to the surface and quit their habitations. Bu] if the animal is once seized when it comes to the surfad and afterwards allowed to retire into its burrow, nr] amount of salt will force it again to come to the surface.' With regard to snails, L. Agassiz writes : ' Quiconqud a eu I'occasion d'observer les amours des limapons, nel saurait mettre en doute la seduction deployee dans leJ mouvements et les allures qui preparent et accomplissenf le double embrassement de ces hermaphrodites.' ^ Again, Mr. Darwin's MS. quotes from Mr. W. White' a curious exhibition of intelligence in a snail, which doel not seem to have admitted of mal-observation. ThiJ gentleman 'fixed a land-shell mouth uppermost in chink of rock ; in a short time the snail protruded itself! to its utmost length, and, attaching its foot verticalljl above, tried to pull the shell out in a straight line. Not! succeeding, it rested for a few minutes and then stretched! out its body on the right side and pulled its utmost, butl failed. Resting again, it protruded its foot on the left! side, pulled with its full force, and freed the shell. This! exertion of force in three directions, which seems so| geometrically suitable, must have been intentional.' If it is objected that snail shells must frequently bel liable to be impeded by obstacles, and therefore that thisl display of manceuvring on the part of their occupants is tol be regarded as a reflex, I may remark that here again we I have one of those incessantly recurring cases where it is| difficult to draw the line between intelligence and non- intelligence. For, granting that the action is to a certain! extent mechanical, we must still recognise that the! animal while executing it must have remembered each ofl the two directions in which it had pulled ineffectually before it began to pull in the third direction; and it is improbable that snail shells are so frequently caught in positions from which a pull in only one direction will| ' Bingley, loc. cit., vol. iii. p. 449. « De VEsphe et de la Clmse, &c., 1869, p. 106. ' A Londoner's Walk to Edinburgh, p. 155 (1866). MOLLUSCA. 27 jlease them, that natural selection would have developed special instinct to try pulling succe? ively in three [irections at right angles to one another. The only other instance that I have met with of the )parent display of intelligence in snails is the remark- )le one which Mr. Darwin gives in his ' Descent of Man,' the authority of Mr. Lonsdale. Although the inter- retation which is assigned to the fact seems to me to go 3yond anything that we should have reason to expect of lail intelligence, I cannot ignore a fact which stands Ipon the observation of so good an authority, and shall lerefore quote it in ]\Ir. Darwin's words : — These animals appear also susceptible of some degree of per- lanent attachment : an accurate observer, Mr. Lonsdale, in- ' |)riiis me that he placed a pair of land-snails {Helix pomatia), 16 of which was weakly, into a small and ill-provided garden. terashbrt time the strong and healthy individual disap- Bared, and was traced by its track of slime over a wall into an djoining well-stocked garden. Mr. Lonsdale concluded that had deserted its sickly mate ; but after an absence of twenty- |>ur hours it returned, and apparently communicated the result its successful exploration, for both then started along the ime track, and disappeared over the wall.^ In this case the fact must be accepted, seeing that it [ands on the authority of an accurate observer, and is of definite a kind as not to admit of mistake. Conse- lently we are shut up to the alternative of supposing le return of the healthy snail to its mate a mere acci- mt, and their both going over the wall into the well- |;ocked garden another mere ax3cident, or acquiescing in 16 interpretation which Mr. Darwin assigns. Now, if [e look closely into the matter, the chances against the )uble accident in question are certainly so considerable to render the former supposition almost impossible. |n the other hand, there is evidence to prove, as I shall imediately show, that a not distantly allied animal is iquestionably able to remember a particular locality as [s home, and habitually to return to this locality after kding. Therefore, in view of this analogous and cor- Dcscent of Man, pp. 262-3. 28 ANIMAL INTELLIGENCE. ■a W roborative case, the improbability of the snail remembering for twenty-four hours the position of its mate is verjl much reduced ; while the subsequent communication, ij it took place, would only require to have been of t\\^ nature of * follow me,' which, as we shall repeatedly find] is a degree of communicative ability which many inverte-j brated animals possess. Therefore, in view of these coii| siderations, I incline to Mr. Darwin's opinion that the fact] can only be explained by supposing them due to intelliJ gence on the part of the snails. Thus considered, thesJ facts are no doubt very remarkable ; for they would appea to indicate not merely accurate mem-ory of direction and locality for twenty-four hours, but also no small degree oj something akin to ' permanent attachment,' and sympaj thetic desire that another should share in the good thing] which one has found.* The case to which I have just alluded as proving beyond all doubt that some Gasteropoda are able to retaiij a very precise and accurate memory of locality, is that oj the common limpet. Mr. J. Clarke Hawkshaw publishes in the Journal ol the Linnsean Society the following account of the habit| in question : — The holes in the chalk in which the limpets are often to bej found are, I believe, excavated in a great measure by raspini from the lingual teeth, though I doubt whether the object is tcl form a cavity to shelter in, though the cavities, when formedl may be of use for that purpose. It must be of the greatest imf portance to a limpet that, in order that it may insure a firml adherence to the rock, its shell should fit the rock accurately! when the shell does fit the rock accurately, a small amount o| muscular contraction of the animal would cause the shell to ad here so firmly to a smooth surface as to he practically iml moveable without fracture. As the shells cannot be adapted! daily to difierent forms of surface, the limpets generally retumj to the same place of attachment. I am sure this is the easel with many ; for I found shells perfectly adjusted to the uneven! surfaces of flints, the growth of the shells being in some parts! * The facts, however, in order to sustain such conclusions, of course! require corroboration, and it is therefore to be regretted that Mr. Lons[ dale did not experimentally repeat the conditions. MOLLUSCA. 29 jlistorted and indented to suit inequalities in the surface of the lints. . . . I noticed signs that limpets prefer a hard, smooth surface to pit in the chalk. On one surface of a large block, over all ^ides of which limpets were regularly and plentifully distri- Duted, there were two flat fragments of a fossil shell about inches by 4 inches, each embedded in the chalk. The chalk ill round these fragments was free from limpets ; but on the kmooth surface of the pieces of shell they were packed as closely IS they could be. I noticed another case, which almost amounts, to my mind, to a proof that they prefer a smooth surface to a lole. A limpet had formed a clearing on one of the sea-waed- [jovered blocks before referred to. In the midst of this clearing kvas a pedestal of flint rather more than one inch in diameter, standing up above the surface of the chalk ; it projected so iiuch that a tap from my hammer broke it ofi". On the top of ^he smooth fractured surface of this flint the occupant of the clearing had taken up its abode. The shell was closely adapted to the uneven surface, which it would only fit in one position. Che cleared surface was in a hollow with several small natural cavities, where the limpet could have found a pit ready made to Shelter in ; yet it preferred, after each excursion, to climb up to the top of the flint, the most exposed point in all its domain.^ It appears certain from these observations, which to some extent were anticipated b}"" those of IMr. F. C. Lukis,^ that limpets, after every browsing excursion, return to me particular spot or home ; and the precise memory of lirection and locality implied by this fact seems to justify IS in regarding these actions of the animal as of a nature mquestionably intelligent. Coming now to the cephalopoda, there is no doubt [that if a larger sphere of opportunity permitted, adequate [observation of these animals would prove them to be much the most intelligent members of the sub-kingdom. I Unfortunately, however, this sphere of opportunity has hitherto been very limited. The following meagre ac- count is all that I have been able to gather concerning the psychology of these interesting animals. According to Schneider,^ the Cephalopoda show un- • Journal Linn. Soc. vpl. xiv. p. 406 et seq. 2 Mag. Nat. Hi«t. 18.31, vol. iv. p. 346. • Thieresche Wille, § 78. 30 ANIMAL INTELLIGENCE. '':il mistakable evidence of consciousness and intelligence! This observer had an opportunity of watching them for long time in the zoological station at Naples ; and hi says that they appeared to recognise their keeper aftej they had for some time received their food from hinj Hollmann narrates that an octopus, which had had struggle with a lobster, followed the latter into an adjacenj tank, to which it had been removed for safety, and therl destroyed it. In order to do this the octopus had tj climb up a vertical partition above the surface of ttj water and descend the other side.^ According tJ Schneider, the Cephalopoda have an abstract idea oi water, seeking to return to it when removed, even thougH they do not see it. But this probably arises from thj sense of discomfort due to exposure of their skin to tha air ; and if we can call it an ' idea,' it is doubtless shareij by all other aquatic Mollusca when exposed to air. ' Leben der CepTialopodeny s. 21. :!■'. ■:. 31 CHAPTER III. ANTS. ^ITHIN the last ten or twelve years our information on le habits and intelligence of these insects has been so ^nsiderably extended, that in here rendering a condensed )itome of our knowledge in this most interesting branch comparative psychology, it will be found that the lapter is constituted principally of a statement of observa- )ns and experiments which have been conducted during the lort period named. The observers to whom we are mainly [debtedfor this large increase of our knowledge are Messrs. lies, Belt, Miiller, Moggridge, Lincecum, MacCook, and tr John Lubbock. From the fact that these naturalists j)nducted their observations in different parts of the )rld and on widely different species of ants, it is not ^rprising that their results should present many points difference ; for this only shows, as we might have ex- acted, that different species of ants differ considerably in ibits and intelligence. Therefore, in now drawing all lese numerous observations to a focus, I shall endeavour show clearly their points of difference as well as their )ints of agreement ; and in order that the facts to be |)iisidered may be arranged in some kind of order, I shall 3al with them under the following heads : — Powers of jiecial sense ; Sense of direction ; Powers of memory ; lotions ; Powers of communication ; Habits general in lindry species ; Habits peculiar to certain species ; General [telligence of various species. Powers of Special Sense, Taking first the sense of sight, Sir John Lubbock made |iiumber of experiments on the influence of light coloured passing through various tints of stained glass, with the 32 ANIMAL INTELLIGENCE. M ■ ! following results. The ants which he observed greati dislike the presence of light within their nests, hurr}irj about in search of the darkest corners when light is af mitted. The experiments showed that the dislike is muJ greater in the case of some colours than in that of other] Thus under a slip of red glass there were congregated one occasion 890 ants, under green 544, under yellow 49| and under violet only 5. To our eyes the violet is as opaqi] as the red, more so than the green, and much more than the yellow. Yet, as the numbers show, the ants U scarcely any tendency to congregate under it : there wej nearly as many under the same area of the uncovers portion of the nest as under that shaded by the viol] glass. It is curious that the coloured glasses appear to a) on the ants in a graduated series, which corresponds wiJ the order of their influence on a photographic plate. Ej periments were therefore made to test whether it mig| not be the actinic rays that were so particularly distastefj to the ants ; but with negative results. Placing violj glass above red produces the same effect as red gla alone. Obviously, therefore, the ants avoid the violj glass because they dislike the rays which it transmit! and do not prefer the other colours because they like u rays which they transmit. Sodium, barium, strontiun and lithium flames were also tried, but not with so mucj effect as the coloured glass. It has just been observed that the relative dislike whi(| Sir John Lubbock's ants showed to lights of different colon seems to be determined by the position of the colour i the spectrum — there being a regular gradation of intolj ranee shown from the red to the violet end. As these anl dislike light, the question suggests itself that the reasd of their graduated intolerance to light of different coloid may be due to their eyes not being so much affected the rays of low as by those of high refrangibility. In tli connection it would be interesting to ascertain whetli] ants of the genus Atta show a similarly graduated intolf ranee to the light in different parts of the spectrum ; ii both Moggridge and MacCook record of this genus thatf not only does not shun the light, but seeks it — coming i ANTS — SPECIAL SENSES. 33 glass sides of their artificial nests to enjoy the light of imp. Possibly, therefore, the scale of preference to its of different colours would be found in this genus to Ithe reverse of that which Sir John Lubbock has found the case of the British species. As regards hearing, Sir John Lubbock found that [nds of various kinds do not produce any efifect upon insects. Tuning-forks and violin notes, shouting, jistling, &c., were all equally inefficient in producing the fhtest influence upon the animals; and experiments ih sensitive flames, microphone, telephone, &c., failed to |ld any evidence of ants emitting sounds inaudible to lan ears. Lastly, as regards the sense of smell. Sir John Lubbock Ind that on bringing a camel's-hair brush steeped in [ious strong scents near where ants were passing, '• some it on without taking any notice, but others stopped, evidently perceiving the smell, turned back. Soon, rever, they retm-ned, and passed the scented pencil. ter doing this two or three times, they generally took further notice of the scent. This experiment left no ibt on my mind." In other cases the ants were observed wave about and throw back their antennae when the ^nted pencil was brought near. That ants track one another by scent was long ago sntioned by Huber, and also that they depend on this ise for their power of finding supplies which have been jviously found by other ants. Huber proved their [war of tracking a path previously pursued by their [ends, by drawing his finger across the trail, so oblite- ting the scent at that point, and observing that when the Its arrived at that point they became confused and ran [out in various directions till they again came upon the lil on the other side of the interrupted space, when they [oceeded on their way as before. The more numerous p systematic experiments of Sir John Lubbock have Illy corroborated Huber's observations, so far as these Unts are concerned. Thus, to give only one or two of lese experiments ; in the accompanying woodcut (Fig. 1) is the nest, B a board, n f g slips of paper, h and m D 84 ANIMAL rNTJiXLIGENCE. B similar slides of glass, on one of which, A, there was placj pupse, while the other, m, was left empty. Sir John Lu bock watched two particular (marked) ai| proceeding from A to h and back a£ carrying the pupae on A to the nest Whenever an ant came out of A upon Bl transposed the slips/ and ^r. Therefore] the angle below n there was a choice sented to the ant of taking the unscenti pathway leading to the full glass A, or scented pathway leading to the empty gli m. The two marked ants, knowing th^ ^ ' — } ' — "" way, always took the right turn at t ^^^' ^' angle ; but the stranger ants, being guid only by scent, for the most part took the wrong turn the angle, so going to the empty glass m. For out of 1| stranger ants only 21 went to h, while the remaining \\ went to m. Still the fact that all the stranger ants not follow the erroneous scent-trail to m, may be taken | indicate that they are also assisted in finding treasure the sense of sight, though in a lesser degree. Therefc^ Sir John Lubbock concludes that in finding treasure * tl are guided in some cases by sight, while in others tl track one another by scent.' As further evidence showing how much more ants pend upon scent than upon sight in finding their way, following experiment may be quoted. In the accompanj ing woodcut (Fig. 2) the line marked 1, 2, 3 represeii] the edge of a paper bridge leading to the nest ; A tl| top of a pencil which is standing perpendicularly uj a board, represented by the general black surface; the top of the same pencil when moved a distance a few inches fi-om its first position A. On the td of this pencil were placed some pupas. Sir John Lull bock, after contriving this arrangement, marked an an and put it upon the pupae on the top of the pencu After she had made two journeys carrying pupae fi:om tlf pencil to the nest (the tracks she pursued being repre| sented by the two thick white lines), while she was in tli nest he moved the pencil to its position at B. The thij ANTS — SPECIAL SENSES. 85 jite line represents the course then pursued by the ant its endeavours to find the pencil, which was shifted only I few inches from A to B. That is, * the ants on their urney to the shifted object travelled very ofton back- ..U^ Fig. 2. Irds and forwards and round the spot where the coveted lect first stood. Then they would retrace their steps rards the nest, wander hither and thither from side to |e between the nest and the point A, and only after ry repeated efforts around the original site of the larvae Lch, as it were, accidentally the object desired at B.' [erefore the ants were clearly not guided by the sight the pencil. The same thing is well shown by another form of 3eriment. ' Some food was placed at the point a (Figs, md 4) on a board measuring 20 inches by 12 Jnches, Dij -Li... •.'^.AKY iS[ATiOis^/.i. Museum 36 ANIMAL INTELLIGENCE. and so arranged that the ants in going straight from it I the nest would reach the board at the point 6, and aftj passing under the pap tunnel c, would proce between five pairs wooden bricks, each inches in length and inches in height. WU they got to know thJ way they went qiii| straight along the line Fig. 3. to a. The board was thj twisted as shown in Fig, 4. * The bricks and tunnel bei| arranged exactly in tl same direction as' fore, but the boa having been moved,tJ line d e was now oif side them. The chana however, did not at discompose the and but instead of goii( as before, through tunnel ^and betwe the rows of bricks I a, they walked exacJ Fig. 4. H;, '■: along the old path to e.* Keeping the board steady, moving the brick patb to the left-hand corner! the board where the fol was next placed (Fig. had the effect of makil the ant first go to the position of the food at I whence it veered to a nj position, which we call X. The bricks food were then moved I Fig. 6. wards the right-hand corner of the board — i.e, over a tance of 8 inches (Fig. 6). The ant now first went t«| ANTS — SENSE OF DIRECTION. 37 Fig. 6. is made to contradict their [en to ic, and not finding the food at either place, get to )rk to look for it at random, and was only successful ter twenty-five minutes' indering. And, as evidence how ich more depend*.' ^e ley place upon scent in \ding their way than |>on any other of their unities, it is desirable to iote yet one further ex- [riment, which is of great terest as showing that len their sense of smell ise of direction, they follow the former, notwithstanding, we shall presently see, the wonderful accuracy of the [formation which is supplied to them by the latter. * If, len F, niger were carrying off larvae placed in a cup on a 3ce of board, I turned the board round so that the side lich had been turned towards the nest was away from it, ^d vice veracif the ants always returned over the same ick on the board, and, in consequence, directly away )m home. If I moved my board to the other side of my tificial nest, the result was the same. Evidently they plowed the road, not the direction.' There can be little doubt that ants have a sense of [ste, as they are so well able to distinguish sugary sub- mces ; and it is unquestionable that in their antennae ^ey possess highly elaborated organs of touch. Sense of Direction, As evidence of the accuracy and importance of the bse of direction in the Hymenoptera, we must here Iduce Sir John Lubbock's highly interesting experiments ants — leaving his experiments in this connection on Bes and wasps to be considered in the next chapter, fe first accustomed some ants (Lasius niger) to go to id fro to food over a wooden bridge. When they had )t quite accustomed to the way, he watched when an ant IS upon a bridge which could be rotated, and while she 38 ANIMAL INTELLIGENCE. was passing along it, he turned it round, so that end 6 \tJ at c, and c at 6. * In most cases the ant immediatel turned round also ; but even if she went on to b or c, the case might be, as soon as she came to the end of ti bridge she turned round.' Next, between the nest an the food he placed a hat-box twelve inches in diametJ and seven inches high, cutting two small holes, so thi the ants in passing from the nest to the food had to paj in at one hole and out at the other. The box was fixtf upon a central pivot, so as to admit of being rotated easil without much friction or disturbance. When the ants ' well learnt their way, the box was turned half round i soon as an ant had entered it, 'but in every case ti ant turned too, thus retaining her direction.* Lastlil Sir John took a disk of white paper,^ which he place| in the stead of the hat-box between the nesiand tli food. When an ant was on the disk making towari] the food, he gently drew the disk to the other side of ti food, so that the ant was conveyed by the moving surfacl in the same direction as that in which she was going, m beyond the point to which she intended to go. Undl these circumstances ' the ant did not turn round, but weij on ' to the further edge of the disk, when she seemed good deal surprised at finding where she was.' These experiments seem to show that the mysteriod * sense of direction,' and consequent faculty of ' homing! are in ants, at all events, due to a process of registerin| and, where desirable, immediately counteracting anychang of direction, even when such change is gently made by I wholly closed chamber in which the animal is moving, aiii not by any muscular movements of the animal itself. AdI the fact that drawing the moving surface along in tli| same direction of advance as that which the insect pursuing does not affect the movements of the latteil seems conclusively to show that the power of registratioi has reference only to lateral movements of the travellinj surface ; it has no reference to variations in the velocity of advance along the line in which the animal is pro greasing.^ ' While this MS. is passing through the press Sir John Lubbock hai ANTS —MEMORY. Powers of Memory, 89 Little need here be said to prove that ants display }ine powers of memory ; for many of the observations and )eriments already detailed constitute a sufficient demon- oration of the statement that they do. Thus, for instance, le general fact that whenever an ant finds her way to a ^ore of food or larvae, she will return to it again and again a more or less direct line from her nest, constitutes iple proof that the ant remembers the way to the store. is of considerable interest, however, to note that the iture of this insect-memory appears to be, as far as it 368, precisely identical with that of memory in general. lus, a new fact becomes impressed upon their memory repetition, and the impression is liable to become Faced by lapse of time. More evidence on both these itures of insect-memory will be adduced when we come treat of the intelligence of bees ; but meanwhile it is lough to refer to the fact that in his experiments on jits, Sir John Lubbock found it necessary to teach the Isects by a repetition of several lessons their way to [easure, if that way was long or unusual. With regard to the duration of memory, it does not jpear that any experiments have been made ; but the (llowing observation by Mr. Belt on this point in the case the leaf-cutting ant may here be stated. In June 1859 found his garden invaded by these ants, and following their paths he found their nest about a hundred yards ad another paper before the Linnaean Society, which contains some Iportant additional matter concerning the sense of direction in Its. It seems that in the experiment above described, the hat-box Is not provided with a cover or lid, i.e. was not a • closed chamber,' |d that Sir John now finds the ants to take their bearings from the pection in which they observe the light to fall upon them. For in experiment with the uncovered hat-box, if the source of light andle) is moved round together with the rotating table which sup- Irts the box, the ants continue their way without making compen- klDg changes in their direction of advance. The same thing happens Ithe hat-box is covered, so as to make of it a dark chamber. Direction 1 light being the source of their information that their ground is being pved, we can understand why they do not know that it is being pved when it is moved in the direction of their advance, as in the eriment with the paper slip. 40 ANIMAL INTELLIGENCE. distant. He poured down their burrows a pint of commo brown carbolic acid, mixed with four buckets of wateij The marauding parties were at once drawn off from ttj garden to meet the danger at home, and the whole formij carium was disorganised, the ants running up and do^ again in the utmost perplexity. Next day he found thed busily employed bringing up the ant-food from the oil burrows, and carrying it to newly formed ones a few ys distant. These, however, turned out to be only intende as temporary repositories ; for in a few days both the o| and the new burrows were entirely deserted, so that supposed all the ants to have died. Subsequently, hoiJ ever, he found that they had migrated to a new site, aboi two hundred yards from the old one, and there establisha themselves in a new nest. Twelve months later the aol again invaded his garden, and again he treated them tol strong dose of carbolic acid. The ants, as on the previoj occasion, were at once withdrawn from the garden, aij two days afterwards he found * all the survivors at worki one track that led directly to the old nest of the year befoij where they were busily employed in making fresh exc( vations. Many were bringing along pieces of ant-fo from the nest most recently deluged with carbolic acid I that which had been similarly deluged a year before, from which all the carbolic acid had long ago disappeaid ' Others carried the undeveloped white pupse and lar\j It was a wholesale and entire migration;' and the next the nest down which he had last poured the carboUc was entirely deserted. Mr. Belt adds : * I afterwards foB that when much disturbed, and many of the ants destroy^ the survivors migrate to a new locality. I do not doi( that some of the leading minds in this formicarium re lected the nest of the year before, and directed migration to it.' Now, I do not insist that the facts necessarily pointl this conclusion ; for it may have been that the leaders] the migration simply stumbled upon the old and vac nest by accident, and finding it already prepared as a nd forthwith proceeded to transfer the food and pupsB tol Still, as the two nests were separated from one another! Bcies, is knowi ANTS — MEMORY. 41 |o considerable a distance, this hypothesis does not jem probable, and the only other one open to us is that Ihe ants remembered the site of their former home for a period of twelve months. And this conclusion is rendered 3SS improbable from a statement of Karl Vogt in his iThierstaaten,' to the effect that for several successive jears ants from a certain nest used to go through certain ihabited streets to a chemist's shop 600 metres distant, order to obtain access to a vessel filled with syrup. As cannot be supposed that this vessel was found in suc- 3ssive working seasons by as many successive accidents,. can only be concluded that the ants remembered the rup store from season to season. I shall now pass on to consider a class of highly re- larkable facts, perhaps the most remarkable of the many jmarkable facts connected with ant psychology. ^ It has been known since the observations of Huber lat all the ants of the same nest or community recognise |ne another as friends, while an ant introduced from lother nest, even though it be an ant of the same jcies, is known at once to be a foreigner, and is usually laltreated or put to death. Huber found that when he Bmoved an ant from a nest and kept it away from its )mpanions for a period of four months it was still recog- jised as a friend, and caressed by its previous fellow- jitizens after the manner in which ants show friendship, iz., by stroking antennae. Sir John Lubbock, after re- [eating and fully confirming these observations, extended lem as follows. He first tried keeping the separated ant ray from the nest for a still longer period than four lonths, and found that even after a separation of more lan a year the animal was recognised as before. He re- [eated this experiment a number of times, and always |ith the same invariable difi'erence between the recep- ^on accorded to a foreigner and a native — no matter, Ipparently, how long the native had been absent. Considering the enormous number of ants that go to lake a nest, it seems astonishing enough that they should >e all personally known to one another, and still more- stonishing that they should be able to recognise members 42 ANIMAL INTELLIGENCE. I of their community after so prolonged an absence. ThinU ing that the facts could only be explained, either by the ants in the same nest having a peculiar smell, or bj all the members of the same community having a par] ticular pass-word or gesture-sign, Sir John Lubboclil with the view of testing this theory, separated some antj from a nest v hile still in the condition of pupae, and when they emerged from that state as perfect insectJ transferred them back to the nest from which they haj been taken aS pupae. Of course in this case the ants iij the nest could never have seen those which had beej removed, for a larval ant is as unlike the mature insect a grub is unlike a beetle ; neither can it be supposed thaj a larva, hatched out away from the nest, should retail when a perfect insect, any smell belonging to its parenl nest — more especially as it had been hatched out bj ants in another nest ; * nor, lastly, is it reasonable ti imagine that the animal, while still a larval grub, can havj been taught any gesture-signal used as a pass-word by thj matured animals. Yet, although all these possible hypo theses seem to be thus fully excluded by the conditioul of the experiment, the result showed unequivocally thaj the ants recognised their transformed larvae as native-bon members of their community. Lastly, Sir John Lubbock tried the experiment going still further back in the life-history of the anl before separating them from the nest. For in Septembd he divided a nest into two halves, each having a queeil At this season there were neither larvae nor eggs. Ttl following April both the queens began to lay eggs, and August — i,e, nearly a year after the original partitioniu of the nest — he took some of the ants newly hatched frod the pupae in one division, and placed them in the othJ division, and vice versa. In all cases these ants were re| ceived by the members of the other half of the dividei nest as friends, although if a stranger were introduced intl -either half it was invariably killed. Yet the ants whicj • It is to be noted that although ants will attack stranger arj introduced from other nests, they will carefully tend stranger lanj similarly introduced. ANTS — MEMORY. 43 [ere thus so certainly recognised by their kindred ants friends had never, even in the state of an egg, been resent in that division of the nest before. On this highly ^markable fact Sir John Lubbock says : — Theae observations seem to me conclusive as far as they go, id they are very surprising. In my experiments of last year, lough the results were similar, still the ants experimented jith had been brought up in the nest, and wei-e only removed Br they had become pupse. It might thereford be argued ^at the ants, having nursed them as larvse, recognised them len they came to maturity ; and though this would certainly in the highest degree improbable, it could not be said to be ipossible. In the present case, however, the old ants had ab- llutely never seen the young ones until the moment when, Ime days after arriving at maturity, they were introduced into |e nest ; and yet in all ten cases they were undoubtedly recog- ;d as belonging to the community. It seems to me, therefore, to be established by these experi- ents that the recognition of ants is not personal and indi- lual ; that their harmony is not due to the fact that each [t is individually acquainted with every other member of the imunity. At the same time, the fact that they recognise their friends |en when intoxicated, and that they know the young born in leir own nest even when they have been brought out of the jrysalis by strangers, seems to indicate that the recognition is |t effected by means of any sign or pass- word. We must, therefore, conclude with reference to this Ibject that the mode whereby recognition is undoubtedly fected is as yet wholly unintelligible ; and I have broduced these facts under the heading of memory only [cause this heading is not more inappropriate than any ler that could be devised for their reception. It ought here to be added also that the power of lus recognising members of their community is not con- |ed by the limits of blood-relationship, for in an experi- mt made by Forel it was shown that Amazon ants 3ognised their own slaves almost instantaneously after absence of four months. Under this heading I may also adduce the evidence as J enormous masses, or, as we might say, a whole nation ants recognising each other as belonging to the same 44 ANIMAL INTELLIGENCE. nationality. New nests often spring up as oflfshoots froj the older ones, and thus a nation of towns graduallj spreads to an immense circumference around the originJ centre. Forel describes a colony of F, exsecta whici comprised more than two hundred nests, and covered space of nearly two hundred square metres. *A11 ill members of such a colony, even those from the further) most nest, recognise each other and admit no stranger.' Similarly, MacCook describes an *ant town' in til Alleghany Mountains of North America (' Trans, AmeJ Entom. Soc.,' Nov. 1877) which was inhabited by ^. exsi\ toidea. It consists of 1,600 to 1,700 nests, which rise cones to a height of from two to five feet. The groui] below is riddled in every direction with subterraneai passages of communication. The inhabitants are all on tli most friendly terms, so that if any one nest is injured] is repaired by their united forces. It remains to be added in connection with this subjeJ that the recognition is not automatically invariable, bJ when * ants are removed from a nest in the pupa statj tended by strangers, and then restored, some at least ( their relatives are certainly puzzled, and in many casf| doubt their claims to consanguinity. I say some, becau while strangers under the circumstances would have bed immediately attacked, these ants were in every amicably received by the majority of the colony, and it sometimes several hours before they came across one \flj did not recognise them.' It may also be added that Lasiua flavus behavj towards strangers quite differently and much more h pitably than is the case with L, niger. The strangj shows no alarm, but, on the contrary, will volunt enter the strange nest, and she is there received wi kindness ; although from the attention she excites, the numerous communications which take place betwecl her and her new friends, Sir John was * satisfied that m knew she was not one of themselves. . . . Very differentj the behaviour of L, niger under similar circumstances, tried the same experiment with them. There was communications with the antennae, there was no cleanin ANTS — EMOTIONS. 45 Ut every ant which the stranger approached flew at her ike a Uttle tigress. I tried this experiment four times ; lach stranger was killed and borne off to the nest.' ETYiotions, The pugnacity, valoi\r, and rapacity of ants are too rell and generally known to require the narration of )ecial instances of their display. With regard to the mderer emotions, however, there is a difference of opi- [ion among observers. Before the researches of Sir John Lubbock it was the prevalent view that these insects dis- [lay marked signs of affection towards one another, both ly caressing movements of their antennae, and by showing )licitude for friends in distress. Sir John, however, has 3und that the species of ants on which he has experi- lented are apparently deficient both in feelings of |ffection and of sympathy — or, at least, that such feelings re in these species much less strongly developed than 16 sterner passions. He tried burying some specimens of Lasms niger leneath an ant-road ; but none of the ants traversing the md made any attempt to release their imprisoned com- lanions. He tried the same experiment with the same isult on various other species. Even when the friends in lifficulty are actually in sight, it by no means follows lat their companions will assist them. Of this, he says, |e could give almost any number of instances. Thus, men ants are entangled in honey, their companions (evote themselves to the honey, and entirely neglect leir friends in distress ; and when partly drowned, their Kends take no notice. When chloroformed or intoxicated leir own companions either do not heed them, or else Iseem somewhat puzzled at finding their intoxicated )llow-creatures in such a condition, take them up, and irry them about for a time in a somewhat aimless manner.' [urther experiments, however, on a larger scale, went to low that chloroformed ants were treated as dead, i.e. Amoved to the edge of the parade-board and dropped i^er into the smTOunding moat of water ; while intoxicated 46 ANIMAL INTELLIGENCE. ■f" ants were generally carried into the nest, if they were antj belonging to that community ; if not, they were thro^ overboard. This care shown towards intoxicated friend appears to indicate a dim sense of sympathy towardj afflicted individuals; but that this emotion or instind does not in the case of these species extend to healttj individuals in distress seems to be proved, not only by tli] experiments of burying already described, but also by ttj following : — On Sept. 2, therefore, I put two ants from one of my nesu of F.fuaca into a bottle, the end of which was tied up via muslin as described, and laid it down close to the nest. In | second bottle I put two auts from another nest of the sas species. The ants which were at liberty took no notice of til bottle containing their imprisoned friends. The strangers in tlj other bottle, on the contrary, excited them considerably, whole day one, two, or more ants stood sentry, as it were, ovej the bottle. In the evening no less than twelve were collect round it, a larger number than usually came out of the nests any one time. The whole of the next two days, in the san way, there were more or less ants round the bottle containij the strangers; while, as far as we could see, no notice whatevij was taken of the friends. On the 9th the ants had eati through the muslin, and effected an entrance. We did nol chance to be on the spot at the moment ; but as I found U ants lying dead, one in the bottle and one just outside, I tl there can be no doubt that the strangers were put to deatlj The friends throughout were quite neglected. Sept. 21. — I then repeated the experiment, putting tl ants from another nest in a bottle as beforp. The same sceiil was repeated. The friends were neglected. On the otha hand, some of the ants were always watching over the bottlj containing the strangers, and biting at the muslin which pn tected them. The next morning at 6 a.m. I found five ani thus occupied. One had caught hold of the leg of one of tlj strangers, which had unwarily been allowed to protrude throua the meshes of the muslin. They worked and watched, thong not, as far as I could see, with any system, till 7.30 in tlij evening, when they effected an entrance, and immediately a tacked the strangers. Sept. 24. — I repeated the same experiment with the san nest. Again the ants came and sat over the bottle containiij the strangers, while no notice was taken of the friends. ANTS— SYMPATHY. 47 The next morning again, when I got up, I found five ants )und the bottle containing the stmngers, none near the friends. LS in the former case, one of the ants had seized a stranger by le leg, and was trying to drag her through the muslin. All lay the ants clustered round the bottle, and bit perseveringly^ lough not systematically, at the muslin. The same thing hap- Bned all the following day. On repeating these experiments with another species (viz., \orTnica rufeacens) the ants took no notice of either bottle, id showed no sign either of affection or hatred. One is almost ^mpted to surmise that the spirit of these ants is broken by ivery \i.e. by the habit of keeping slaves]. But the experi- [ents on F. fusca seem to show that in these curious insects iiti'ed is a stronger passion than affection. We must not, however, too readily assent to this ^neral conclusion, that ants as a whole are deficient in [e tenderer emotions ; for although the case is doubtless with the species which Sir John examined, it appears be certainly otherwise with other species, as we shall lesently see. But first it may be well to point out that |en the hard-hearted species with which Sir John had ta seem not altogether devoid of sympathy with sick or itilated friends, although they appear to be so towards |althy fiiends in distress. Thus the care shown to toxicated friends seems to indicate, if not, as already served, a dim sense of sympathy, at least an instinct to jserve the life of an ailing citizen for the future benefit the community. Sir John also quotes some observa- |ns of Latreille showing that ants display sympathy with itilated companions ; and, lastly, mentions an instance [ich he has himself observed of the same thing. A spe- len of F, fuaca congenitally destitute of antennae was icked and injured by an ant of another species. When |>arated by Sir John, another ant of her own species 16 by. ' She examined the poor sufferer carefully, then Iked her up tenderly, and carried her away into the pt. It would have been difl&cult for any one wha messed this scene to have denied to this ant the pos- jsion of humane feelings.' Moggridge is also of opinion It the habit of throwing sick and apparently dead ants 48 ANIMAL INTELLIGENCE. 1 I into the water, is ' in part to be rid of them, and partlvj perhaps, with a view to effecting a possible cure ; for have seen one ant carry another down the twig whict formed their path to the surface of the water, and, afteil dipping it in for a minute, carry it laboriously up againj and lay it in the sun to dry and recover.* But that some species of ants display marked signi of what we may call sympathy even towards healthy coinJ panions in distress, is proved by the following observation of Mr. Belt. He writes :^ — One day, watching a small column of these ants (t'J Uciton humata), I placed a little stone on one of them to m cure it. The next that approached, as soon as it discovered it| fiituation, ran backwards in an agitated manner, and soon coo municated the intelligence to the others. They rushed to tiij rescue ; some bit at the stone and tried to move it, others seiz the prisoner by the legs and tugged with such force that thought the legs would be pulled off, but they persevered unti they got the captive free. I next covered one up with a pie of clay, leaving only the ends of its antennae projecting. It vii soon discovered by its fellows, which set to work immediatelj and by biting off pieces of the clay soon liberated it. Anothfl time I found a very few of them passing along at intervals, confined one of these under a piece of clay at a little distaDJ from the line, with his head projecting. Several ants passed i| but at last one discovered it and tried to pull it out, but cou not. It immediately set off at a great rate, and I thought | had deserted its comrade, but it had only gone for assistanM for in a short time about a dozen ants came hurrying up, eij dontly fully informed of the circumstances of the case, for thtj made directly for their imprisoned comrade and soon set hij free. I do not see how this action could be instinctive. It n sympathetic help, such as man only among the higher mai malia shows. The excitement and ardour with which thj carried on their unflagging exertions for the rescue of tha comrade could not have been greater if they had been humij beings. This observation seems unequivocal as proving felloj feeling and sympathy, so far as we can trace any analoj between the emotions of the higher animals and those] ' Thfi Naturalist in Nicaragua, 1874, p. 26. ANTS— COMMUNK'A TION. 49 ^sects. That insects with such highly organised social ibits, and depending so greatly on the principles of co- )eration, should manifest emotions or instincts of an inci- Iciitly altruistic character, is no more than we should itecedently expect on the general principle of survival the fittest. Our only surprise should be that these notions, or instincts, should appear to be so feebly de- koped in some species of ants, and, as we shall subse- lently see, also of bees. But it may be worth while in [is connection to point out that the valuable observation Mr. Belt above quoted refers to the species of ant which, we shall subsequently find, presents the most highly ranised instincts of co-operation that are to be met with long ants, and therefore the greatest dependence of the ^Ifare of the individual on that of the community. And (e same remark is applicable to our native species, F. san- tinea, which the Rev. \^^ W. F. White has repeatedly 3n rescuing buried companions very much in the manner [scribed by Mr. Belt ; and he does not appear to be ac- lainted with Mr. Belt's observations. He figures one se in which he saw three ants co-operating to dig out )uried comrade Powers of Gomniunication. Huber, Kirby and Spence, Dugardin, Burmeister, [anklin, and other observers have all expressed them- Ives as more or less strongly of the opinion that members Ithe same community of ants, and other social Hymen- tera, are able to communicate information to one )ther by some system of language or signs. The facts, mver, on which their opinion rests have not been stated th that degree of caution and detail which the accept- ce of the conclusion requires. Thus, Kirby and Spence ^e only one instance of supposed communication between ts,2 and even this one is inconclusive, as the facts de- ibed admit of being explained by supposing that the ts simply tracked one another by scent ; while Huber > See Leisure Hour, 1880, p. 390. ' Introduotmn to Entomoloy ij , vol. ii. p. 524. E 60 ANIMAL liNTKLLIGENCE. merely deals in general statements as to * contact a ancennoe,' without narrating any particulars of his observa tions. Therefore, until within the last few years then was really no sufficient evidence to sustain the generJ opinion that ants are able to communicate with oj another ; but the observations which I shall now data must be regarded as fully substantiating that generJ opinion by facts as abundant and conclusive as the moj critical among us can desire. I shall first narrate in own words the more important of Sir John Lubbocl;| experiments in this connection : — I took three tapes, each about 2 feet 6 inches long, ad aiTanged them parallel to one another and about 6 inctj apart. An end of each I attached to one of the nests {F. nigci and at the other end I placed a glass. In the glass at the ei| of one tape I placed a considerable number (300 to 600) i larv86. In the second I put two or three larvae only, in third none at all. The object of the last was to see whet many ants would come to the glasses under such circumstancj by mere accident, and I may at once say that scarcely did so. I then took two ants, and placed one of them to 1 glass with many larvae, the other to that with two or thn Each of them took a larva and carried it to the nest, retui for another, and so on. After each journey I put anotll larva in the glass with only two or three larvae, to replace tlj which had been removed. Now, if several ants came under t above circumstances as a mere matter of accident, or accoi panying one another by chance, or if they simply saw the Ian which were being brought, and consequently concluded tlj they might themselves find a larva in the same place, then I numbers going to the two glasses ought to be approximatf equal. In each case the number of journeys made by the would be nearly the same ; consequently, if it was a matter! scent, the two glasses would be in the same position. It woif be impossible for an ant, seeing another in the act of bring, a larva, to judge for itself whether there were few or maf left behind. On the other hand, if the strangers were brou^ then it would be curious to see whether more were broii to the glass with many larvae than to that which only contaii two or three. I should also mention that every stranger imprisoned until the end of the experiment. The results of these experiments were that duiil ANTS — COMMUNICATION. 51 b- hours the ants which Imd nccess to a glass containing Imerous larvae brought 257 friends to their assistance ; lile during an interval 5^ hours longer those which litt'd the glass with only two or three larvre brought only friends ; and, as already mentioned, no single ant came Ithe glass which contained no larvae. Now, as all the isses were exposed to similar conditions, and as the ^ds to the first two must, in the first instance at all mts, have been equally scented by the passage of ants fr them, these results look very conclusive as proving le power of definite communication, not only that /SB are to be found, but even where the largest store is )e met with. To this interesting account Sir John Lubbock adds, — I One case of apparent communication struck me very much. id had an ant (F. niger) under observation one day, during [ch she was occupied in carrying off larvae to her nest. At it I imprisoned her in a small bottle ; in the morning I let I out at 6.15, when she immediately resumed her occupation, ring to go to London, I imprisoned her again at 9 o'clock, bn I returned at 4.40 I put her again to the larva). She lined them carefully, and went home without taking one. Ithis time no other ants were out of the nest. In less than inute she came out again with eight friends, and the little made straight for the heap of larvoe. When they had gone -thirds of the way I again imprisoned the marked ant; others hesitated a few minutes, and then with curious quick- returned home. At 5.15 I put her again to the larvae. I again went home without a larva^ hut after only a few jnds' stay in the nest, came out with no less than thii-teen ids. They all went towards the larvae, but when they had ibout two-thirds of the way, although the marked ant had [he previous day passed over the ground about 150 times, ] though she had just gone straight from the larvae to the she seemed to have forgotten her way, and considered ; [after she had wandered about for half an hour, I put her to larvae. Now, in this case, the twenty-one ants must have brought out by my marked one, for they came exactly I her, and there were no other ants out. Moreover, it would that they must have been told, because (which is very Dus in itself) she did not in either case bring a larva, and E 2 62 ANIMAL INTELLIGENCE. consequently it cannot have been the mere sight of a lai] which had induced them to follow her. Further experiments proved, as we might have ei pected, that although an ant is able to communicate [ her friends in the nest that she has found treasure sod where outside, she is not able to describe to them its pJ cise locality. Thus, having exposed larvae and placed | ant upon them as before. Sir John watched every time : came out of the nest with friends to assist her, but instt| of allowing her to pilot the way, he took her up carried her to the larvae, allowing her to return witlj larva upon her own feet. Under these circumstances friends, dlthough evidently coming out with the intent} of finding some treasure, were never able to find it ; i wandered about in various directions for a while, and tlf returned to the nest. Thus, during two hours brought out in her successive journeys altogether nol than 120 ants, of which number only 5 in their unguiJ wanderings happened to find the sought-for treasif This result seems to prove, as we might have expectj that the communication is of the nature of some amounting to no more than a * follow me.' Other ej ments confirmed this result, and also brought out fact that ' some species act much more in association t!j others — Formica fusca, for instance, much less tj Lasiua niger,^ Thus Sir John Lubbock placed some hoi| before a marked specimen of the former species ; although she visited and revisited the honey during! entire day, she brought out no friends to share it; although in her journeys to and from the nest she happej to pass and repass many other individuals, they took] notice of each other. The obvious objection to these experiments, thai ant observing a friend bringing home food or a pi might infer, without being told, that by accompany the friend on the return journey she 'might participate the good things,' has been partly met by the fact alrej stated, viz., that there is so very marked a differenc the result if, on experimenting on two ants, one had ao to a large treasure and the other only to a small one. ANTS — COMMUNICATION. 53 put this matter beyond question, Sir John Lubbock [ied the experiment of pinning down a dead fly, so that le ant which found it was unable, with all her tugging, move it towards the nest. At length she went back the nest for assistance, and returned accompanied by ^ven friends. So great was her excitement, however, lat she outran these friends, * who seemed to have \me out reluctantly, as if they had been asleep, and were ily half awake ; ' and they failed to find the fly, slowly leandering about for twenty minutes. After again tug- lug for a time at the fly, the first ant returned a second le to the nest for assistance, and in less than a minute Ime out with eight friends. They were even less energetic Ian the first party, and having lost sight of their guide in le same manner as happened before, they all returned to ie nest. Meanwhile several of the first party, which had the while been meandering about, found the fly, and ^oceeded to dismember it, carrying the trophy to the pst, and calling out more friends in the ordinary way. lis experiment was repeated several times and on difFer- kt species, always with the same result. Now, as Sir mn remarks, ' the two cases (i.e. those in which the ant [ought out friends to her assistance even when she had booty to show) surely indicate a distinct power of com- mication. ... It is impossible to doubt that the friends ere brought out by the first an^ ; and as she returned ipty-handed to the nest, the others cannot have been luced to follow her by merely observing her proceedings. conclude, therefore, that they possess the power of re- lesting their friends to come and help them.' In order to ascertain whether the signs which com- micating ants make to one another are made by means sound, Sir John Lubbock placed near a nest of Lasius ivus six small upright pillars of wood about 1 J inch high, Id on one of these he put a drop of honey. ' I then put jree ants to the honey, and when each had sufficiently , I imprisoned her, and put another ; thus always keep- three ants at the honey, but not allowing them to go Une. If, then, they could summon their friends by md, there ought soon to be many ants at the honey.* 54 ANIMAL INTELLIGENCE. The result showed that the ants were not able thus to to one another from a distance. As additional proof of the general fact that at events some ants have the power of communicating infoi mation to one another, it will be enough here to quote i exceedingly interesting observation of the distinguislJ geologist Hague. The quotations are taken froi his letters written to Mr. Darwin, and published Nature : * — On the mantelshelf of our sitting-room my wife has habit of keeping fresh flowers. A vase stands at each end, near the middle a small tumbler, usually filled with violeij Some time ago 1 noticed a pile of very small red ants on the m above the left-hand vase, passing upward and downward tween the mantelshelf and a small hole near the ceiling, atl point where a picture nail had been driven. The ants, wM first observed, were not very numerous, but gradually increasj in number, until on some days the little creatures formed almost unbroken procession, issuing from the hole at the descending the wall, climbing the vase directly below the m, satisfying their desire for water or perfume, and then returnin The other vase and tumbler were not visited at that time. As I was just then recovering from a long illness it b pened that I was confined to the house, and spent my days in \ room where the operations of these insects attracted my atteJ tion. Their presence caused me some annoyance, but I knexvj no effective means of getting rid of them. For several days I succession I frequently brushed the ants in great numbers froj the wall down to the floor ; but as they were not killed the : suit was that they soon formed a colony in the wall at the k of ihe mantel, ascending thence to the shelf, so that before lot] the vase was attacked from above and below. One day I observed a number of ants, perhaps thirty forty, on the shelf at the foot of the vase. Thinking to them, I struck them lightly with the end of my finger, killiij some and disabling the rest. The effect of this was immediaj and unexpected. As soon as those ants which were approacl ing arrived near to where their fellows lay dead and sufferiij they turned and fled with all possible haste. In half an m the wall above the mantelshelf was cleared of ants. During the space of an hour or two the colony from belcj » Vol. vii. pp. 443-1. ANTS— COMMUNICATION. 55 jntinued to ascend until reaching the lower bevelled edge of le shelf, at which point the more timid individuals, although [nable to see the vase, somehow became aware of trouble, and imed about without further investigation, while the more iring advanced hesitatingly just to the upper edge of the lelf, when, extending their antennae and stretching their necks, ley seemed to peep cautiously over the edge until beholding leir suffering companions, when they too turned and followed le others, expressing by their behaviour great excitement and jiTor. An hour or two later, the path or trail leading from le lower colony to the vase was almost entirely free from ants. I killed one or two ants on their path, striking chem with iy finger, but leaving no visible trace. The effect of this was lat as soon as an ant ascending towards the shelf reached the )t where one had been killed, it gave signs immediately of it disturbance, and returned directly at the highest possible sed. A curious and invariable feature of their behaviour was [lat when such an ant, returning in fright, met another ap- Daching, the two would always communicate, but each would irsue its own way, the second ant continuing its journey to ^e spot where the fir;jt had turned about, and then following pt example. For some days after this there were no ants visible on the ill, either above or below the shelf. Then a few ants from the lower colony began to reappear, lit instead of visiting the vase which had been the scene of the ister, they avoided it altogether, and following the lower 3nt edge of the shelf to the tumbler sta^iding near the middle, ule their attack upon that. I repeated the same experiment ^re with precisely the same result. Killing or maiming a few the ants and leaving their bodies about the base of the tum- fcr, the others on approaching, and even before arriving at the |)per surface of the shelf where their mutilated companions ere visible, gave signs of intense emotion, some running away jmediately, and others advancing to where they could sm-vey je field and then hastening away precipitately. Occasionally an ant would advance towards the tumbler ^til it found itself among the dead and dying ; then it seemed I lose all self-possession, running hither and thither, making Ida circuits about the scene of the trouble, stopping at times Id elevating the antennaj with a movement suggestive of tinging them in despair, and finally taking flight. After this lother interval of several days passed, during which no ants ■ \i{.' 56 ANIMAL INTELLIGENCE. I appeared. Now, three months later, the lower colony has been! entirely abandoned. Occasionally, however, especially wheJ fresh and fragrant violets have been placed on the shelf, a fewl ' prospectors ' descend from the upper nail-hole, rarely, almostl never, approaching the vase from which they were first drivecl away, but seeking to satisfy their desire at the tv;mbler. Tcj turn back these stragglers and keep them out of sight for number of iays, sometimes for a fortnight, it is sufficient tcj kill one or two ants on the trail which they follow descendinj the wall. This I have recently done as high up as I can reaclij three or four feet above the mantel. The moment this spot reached, an ant turns abruptly and makes for home, and in little while there is not an ant visible on the wall. In a subsequent volume of * Nature ' (viii. p. 244J JNIr. Darwin publishes another letter which he received froif Mr. Hague upon the same subject. It seems that Mr. Mog gridge suggested to Mr. Darwin that, as he and others haj observed ants to be repelled by the mere scent of a fingcf drawn across their path, the observation of Mr. Hagii might really resolve itself into a dislike on the part of ttj aDts to cross a line over which a finger had been drawif and have nothing to do with intelligent terror inspired the sight of their slaughtered companions. The followiEJ is Mr. Hague's reply to Mr. Darwin's request for furtli( experiments to test this point : — Acting on Mr. M 's suggestion, I first tried making simpl finger-marks on their path (the mantel is of marble), and fouiil just the results which he describes in his note as observed ll himself at Mentone, that is, no marked symptoms of fear, biiti dislike to the spot, and an effort to avoid it by going around iJ or by turning back and only crossing it again after an intervJ of time. I then killed several ants on the path, using a smootj stone or piece of ivory, instead of my finger, to crush them, this case the ants approaching all turned back as before, with much greater exhibition of fear than when the simpJ finger-mark was made. This I did repeatedly. The final suit was the same as obtained last winter. They persisted! coming for a week or two, during which I continued to them, and then they disappeared, and we have seen none sina It would appear from this that while the taint of the hand i sufiicient to turn them back, the killing of their fellows withj stone or other material produces the efloct described in my ANTS— SWAEMING. 57 lote. This was made clear to me at that time, from the be- laviour of the ants the first day I killed any, for on that occa- sion some of them approaching the vase from below, on reaching [he upper edge of the mantel, peeped over, and drew back on keeing what had happened about the vase, then turned away a [ittle, and after a moment tried again at another and another point along the edge, with the same result in the end. More- over, those that found themselves among the dead and dying rent from one writhing ant to another in great haste and ex- citement, exhibiting the signs of fright which I described. I hardly hope that any will return again, but if they do, Ind give me an opportunity, I shall endeavour to act further on [r. M 's suggestion. With this quotation I shall conclude the present division [f the chapter ; for, looking to all the other observations reviously mentioned, there can be no question concern- ig the general fact that ants have the power of commu- licating with one another. And under subsequent head- igs abundant additional evidence on this point will be )und implicated with the other facts detailed. Habits General in Sundry Species. Swarming. — The precise facts with regara to the farming of ants are not yet certainly established. As 3gards some of the facts, however, there is no doubt. [he winged males and females first quit the nest in enor- lous numbers, and choose some fine afternoon in July August for their wedding flight. The entrances to le nest are widened by the workers and increased in lumber, and there is a great commotion on the sur- ice of the nest. The swarm takes place as a thick loud of all the male and female insects, rising together a considerable height. The flight continues for 3veral hours, usually circling round some tree or )wer, and it is during the flight that fertilisation is [ffected. After it is effected, the swarm returns to le ground, when the males perish, either from falling prey, in their shelterless condition, to birds or spiders, f, on account of not being able to feed themselves, from tarvation. ' The workers, or neuter ants, of their own 58 ANIMAL INTELLIGENCE. I colony have lost all interest in them from the moment oi their return, and trouble themselves no more about them,! for they we.U know that the males have now fulfilled theuf vocation.' The great majority of the fertilised femalej share the same fate as the males. But a small proportio( find concealment in holes, which they either dig for thenij selves, or happen to find ready made, and there found i new colony. The first thing they do is to pull off theij now useless wings, by scratching and twisting them, onJ after the other, with the clawed ends of their feet. Thej then lay their eggs, and become the queens of nei| colonies. Forel says that no fertilised female ever returns to bej original home ; but that the workers keep back a certaiij number of females which are fertilised before the swarmii takes place ; in this case the workers pull off the wing] of the fertilised females. The majority of observers, how] ever, maintain that some of the females composing tli| swarm return to their native home to become motherj where they had been children. Probably both statement! are correct. A writer in the * Grroniger Deekblad ' foi| June 16, 1877, observes that, looking to the injuriou effects of in-breeding, the facts as related by Forel are les] probable than those related by other observers, and that, ] they actually occur, the females fertilised before flight arJ probably kept by the ants as a sort of ' reserve corps tl which the workers resort only in case of need, and if thei fail to secure any returning queens.' Nursing. — The eggs will not develop into larvae m\ less nursed. The nursing is effected by licking tlif| surface of the eggs, which under the influence of tbij process increase in size, or grow. In about a fortnightj during which time the workers carry the eggs from highej to lower levels of the nest, and vice versa, according to tttl circumstances of heat, moisture, &c., the larvae are hatchei out, and require no less careful nursing than the egm The workers feed them by placing mouths together and rej gurgitating food stored up in the crop or proventricului into the intestinal tract of the young. The latter she/ their hunger by ' stretching out their little brown heads! ANTS — NURSING AND EDUCATIOIS. 59 ims to he; t a certai 5 swarmiiij the wingi •vers, how posing tilt e motheii statements fkblad' foi injurioi rel are le« md that, flight ai( corps t( nd if thei larvae m- eking till ce of tliii fortnight, •om highei ling to tilt re hatche the eggs ler and re entricukj tter she iwn heads' Great care is also taken by the workers in cleaning the larvae, as well as in carrying them up and down the ihambers of the nest for warmth or shelter. When fully grown the larvae spin cocoons, and are then upae, or the * ants' eggs ' of bird-fanciers. These require food, but still need incessant attention with reference ,0 warmth, moisture, and cleanliness. When the time ives for their emergence as perfect insects, the workers ssist them to get out of their larval cases by biting hrough the walls of the latter. It is noticeable that in oing this the workers do not keep to any exact time, ut free them sometimes earlier and sometimes later, in ceordance with their rate of development. ' The little nimal when freed from its chrysalis is still covered with thin skin, like a little shirt, which has to be pulled off. hen we see how neatly and gently this is done, and ow the young creature is then washed, brushed, and d, we are involuntarily reminded of the nursing of uman babies. The empty cases, or cocoons, are carried utside the nest, and may be seen heaped together there r a long time. Some species carry them far away from e nest, or turn them into building materials for the welHng.' ' Education, — ^The young ant does not appear to come to the world with a full instinctive knowledge of all its ties as a member of a social community. It is led about e nest, and ' trained to a knowledge of domestic duties, pecially in the case of the larvae.' Later on the young ts are taught to distinguish between friends and foes. f^hen an ants' nest is attacked by foreign ants, the young es never join in the light, but confine themselves to moving the pupae ; and that the knowledge of hereditary emies is not wholly instinctive in ants is proved by the Hewing experiment, which we owe to Forel. He put ung ants belonging to three different species into a glass se with pupae of six other species — all the species being turally hostile to one another. The young ants did t quarrel, but worked together to tend the pupae. When e latter hatched out, an artificial colony was formed of ' Biichner, Geisteslehcn der Thiere, pp. 66-7- «0 ANIMAL INTELLIGENCE. a number of naturally hostile species all living together! after the manner of the ' happy families ' of the showmen. Habit of keeping Aphides. — It is well known that! various species of ants keep aphides, as men keep milch cows, to supply a nutritious secretion. Huber first ob«| served this fact, and noticed that the ants collected thel eggs of the aphides and treated them exactly as thejl treated their own, guarding and tending them with thel utmost care. When these eggs hatch out the aphides are! usually kept and fed by the ants, to whom they yield al sweet ho- 3y-like fluid, which they eject from the abdomenl upon being stroked on this region by the antennae of thel ants. Mr. Darwin, who has watched the latter process observes with regard to it, — I removed all the ants from a groupof about a dozen aphidesj on a dock plant, and prevented their attendance during severall hours. After this interval, I felt sure that the aphides wouldl want to excrete. I watched them for some time through aj lens, but not one excreted ; I then tickled them with a hair iEl the same manner, as well as I could, as the ants do with theiij antennae ; but not one excreted. Afterwards I allowed an antl to visit them, and it immediately seemed, by its eager way o| running about, to be well aware what a rich flock it had dis-j covered ; it then began to play with its antennae on the abdoj men, first of one aphis and then of another ; and each, as sooil as it felt the antennae, immediately lifted up its abdomen ani excreted a limpid drop of sweet juice, which was eagerly de-j voured by the ant. Even quite young aphides behaved in manner, showing that the action was instinctive, and not tlie| result of experience. The facts also show that the jdelding of the secretioij to the ants is, as it were, a voluntary act on the part of m aphides, or, perhaps more correctly, that the instinct ti| yield it has been developed in such a relation to the re quirements of the ants, that the peculiar stimulation sup plied by the antennae of the latter is necessary to start m act of secretion ; for in the absence of this particular stimuj lationthe aphides will never excrete until compelled todl so by the superabundance of the accumulating secretioij The question, therefore, directly arises how, on evolutions i I '( ANTS — KEEPING AI»HIDES 61 principles, such a class of fiicts is to be met ; for it is cer- tainly difficult to understand the manner in which this instinct, so beneficial to the ants, can have arisen in the j aphides, to which it does not appear, at first sight, to offer any advantages. Mr. Darwin meets the difficulty thus : Although there is no evidence that any animal performs an action for the exclusive good of another species, yet I each tries to take advantage of the instincts of others ;' and *as the secretion is extremely viscid, it is no doubt a convenience to the aphides to have it removed ; therefore probably they do not excrete solely for the good of the hints.'* Some ants which keep aphides l^uild covered ways, or I tunnels, to the trees or shrubs where the aphides live. Forel saw a tunnel of this kind which was taken up a wall land down again on the other side, in order to secure a Isafe covered way from the nest to the aphides. Occasion- lally such covered ways, or tubes, are continued so as to lenclose the stems of the plants on which the aphides live. [The latter are thus imprisoned by the walls of the tube, [which, however, expand where they take on this additional function of stabling the aphides, so that these insects are really confined in tolerably large chambers. The doors of these chambers are too small to allow the aphides to escape, fhile large enough for the ants to pass in and out. Forel saw such a prison or stable shaped like a cocoon, and ibout a centimetre long, which was hanging on the branch )f a tree, and contained aphides carefully tended by the ints. Huber records similar observations. Sir John Lubbock has made an interesting addition to )ur knowledge respecting this habit as practised by a 3ertain species of ant {Lasius fiavus), which departs in a ^ery remarkable manner from the habit as practised by )ther species. He says : * The ants took the greatest care )f these eggs, carrying them off to the lower chambers nth the utmost haste when the nest was disturbed.' But the most interesting of Sir John Lubbock's observations In this connection is new, and reveals an astonishing Origin of Species, 6th ed. pp. 207-8. 62 ANIMAL INTELLIGENCE. amount of method shown by the ants in farming their j aphides. He says : — m 41 When my eggs hatched I naturally thought that the aphides belonged to one of the species usually found on the roots of I plants in the nests of Lasius Jlavus. To my surprise, however, the young creatures made the best of their way out of the nest, | and, indeed, were sometimes brought out by the ants them- selves. In vain I tried them with roots of grass, 'cH Uing off us species liefly directed against the legs of its enemies, three, four, or Ive uniting in the effort. They understjind barricade fighting irticularly well in their largo well-built dwellings, and if it 3mes to the worst fly by subterranean passages. They are i-ired by most ants on account of their numerical superiority, [orcl one day poured the contents of ten nests of pratenses in Innt of a tree trunk inhabited by Lasius fuliginoaus (jet ant). le siege at once began ; but the jet ants called in help from |e nests connected with their colony, and thick black columns pre at once seen coming out from the surrounding trees. The \aten8e8 were obliged to fly, and left behind them a mass of dead I well as their pupae, which last were carried off by the victors their nests to be eaten. Battles, however, are not confined to species of ants iving warlike and slave-making habits. The agricultural [ts likewise at times wage fierce wars with one another. le importance of seeds to these ants, and the consequent [lue which they set upon them, induce the animals, len supplies are scarce, to plunder each other's nests. ms Moggridge says, — By far the most savage and prolonged contests which I 'e witnessed were those in which the combatants belong to different colonies of the same species. . . . The most Igular contests are those which are waged for seeds by A. \hara, when one colony plunders the stores of an adjacent \i belonging to the same species, the weaker nest making llonged though, for the most part, inefl&cient attempts to )ver their property. In the case of the other species of ant which I have watched iting, the strife would last but a short time — a few hours or lay — but A. Barbara will carry on the battle day after day week after week. I was able to devote a good deal of time vatching the progress of a predatory war of this kind, waged )ne nest of harhara against another, and which lasted for [ysix days, from January 18 to March 4 ! 11 cannot of course declare positively that no cessation of tilities may have taken place during the time, but I can ^m that whenever I visited the spot — and I did so on twelve 3, or as nearly as possible twice a week — the scene was one ^ar and spoliation such as that which I shall now describe. n active train of ants, nearly resembling an ordinary nesting train, led from the entrance of one nest to that of ler lower down the slope, and fifteen feet distant ; but on 80 ANIMAL INTELLIGENCE. closer examination it appeared that though the great mafjs oi seed-bearers were travelling towards the upper nest, some fei were going in the opposite direction and making for the loweJ Besides this, at intervals, combats might be seen taking pla«J one ant seizing the free end of a seed carried by another, m endeavouring to wrench it away, and then frequently, as noitli would let go, the stronger ant would drag seed and opponeij towards its nest. At times other ants would interfere and seu one of the combatants and endeavour to drag it away, this oft^ resulting in terrible mutilations, and especially in the loss of tij abdomen, which would be torn off while the jaws of the victci retained their indomitable bull-dog grip upon the seed. Tlitj the victor might be seen dragging away his prize, while its i versary, though now little more than a head and legs, offereilj vigorous though of course ineffectual resistance. I frequenJ observed that the ants during these conflicts would endeMvoi to seize one another's antennae, and that if this were effectff the ant thus assaulted would instantly release his hold, whetti of seed or adversary, and appear utterly discomfited. No doiii the antennse are their most sensitive parts, and injuries inflictj on these organs cause the greatest pain. It was not until I had watched this scene for some daystk I apprehended its true meaning, and discovered that the antl the upper nest were robbing the granaries of the lower, the latter tried to recover the stolen seeds both by fighti for them and by stealing seeds in their turn from the of their oppressors. The thieves, however, were eviden the stronger, and streams of ants laden with seeds arrii safely at the upper nest, while close observation showed very few seeds were successfully carried on the reverse jou into the lower and plundered nest. Thus when I fixed my attention on one of these robbed a surreptitiously making its exit with the seed from the tliiej nest, and having overcome the opposition and dangers meti on its way, reaching, after a journey which took six minute accomplish, the entrance to its own home, I saw that iti violently deprived of its burden by a guard of ants stationed til apparently for the purpose, one of whom instantly started! and carried the seed all the way back again to the upper ne^ This I saw repeated several times. After March 4 I never saw any acts of hostility heU\ these nests, though the robbed ncot was not abandoned. another case of the same kind, however, where the strii lasted thirty-one days, the robbed nest was at length complfll c ANTS— WARS. 81 Ibandoned, and on opening it I found all the gi-anaries empty nth one single exception, and this one was pierced by the latted roots of grasses and other plants, and must therefore we been long neglected by the ants. Strangely enough, not ]e of the seeds in this deserted granary showed traces of ermination. No doubt some very pressing need is the cause of these Istematic raids in search of accumulations of seeds, and there ^n be little doubt that the requirements of distinct colonies of its of the same species are often different even at the same Dii and date. Thus these warring colonies of ants were ktive on many days when the m.ojority of the nests were com- (etely closed ; and I have even seen these robbers staggering 3ng, enfeebled by the cold, and in wind and rain, when all aer ants were safe below ground. The agricultural ants of Texas do not appear to be BS pugnacious than their European congeners. Thus [acCook says : — A young community has sometimes to struggle into perma- it prosperity through many perils. The following example [found in the unpublished Lincecum manuscripts. One day a ant-city was observed to be located within ten or twelve rds of a long-established nest, a distance that the doctor ought would prove too near for peaceable possession — for the iculturals seem to pre-empt a certain range of territory Dund their formicary as their own, within which no intrusion allowed. He therefore concluded to keep these nests under observation, and visited them frequently. Only a day or |o had elapsed before he found that the inhabitants of the old had made war upon the new. They had surrounded it in it numbers, and were entering, dragging out and killing the Izens. The young colonists, who seemed to be of less size jin their adversaries, fought bravely, and, notwithstanding ky were overwhelmed by superior numbers, killed and maimed ly of their assailants. The parties were scattered in strug- ag pairs over a space ten or fifteen feet around the city gate, the ground was strewed with many dead bodies. The new Dnists aimed altogether at cutting off the legs of their larger which they accomplished with much success. The old-city riors, on the contrary, gnawed and clipped off the heads and lomens of their enemies. Two days afterward the battle- was revisited, and many ants were found lying dead locked together by legs and mandibles, while hundreds G m 82 ANIMAL INTELLIGENCE. of decapitated bodies and severed heads were strewed over ti.J ground. Another exam i)le, which is given in the published paper,; quite similar, and had like result. In forty-eight hours theolj settlers had exterminated the new. The distance between ttJ nests was about 20 feet. While the young colonists remainf[ in concealment they were not disturbed, but as soon as tliej began to clear away their open disk war was declared. MacCook, however, says that * these ants are not alwaJ so jealous of territorial encroachment, or at least m\il have different standards of rights.' For he observed maj cases of nests situated within twenty, and even ten fh of one another, without a battle ever occurring betwetj members of the two communities. Therefore, withoJ questioning the accuracy of Lincecum's observation^ which, indeed, present no scope for inaccuracy — he adiij *That neighbouring ants, like neighbouring nations civilised men, will fall out and wage war Lincecum's eJ amples show. Perhaps we should be quite as unsuccessf[ in case of these ants as of our human congeners, shon we seek a sufficient reason for these wars, or satisfactoi cause for these differences in dealing with neighbou which appear from the comparison of Lincecum's obsenj tions with mine.' In connection with the wars of these ants, the folloj ing quotations may also be made from the same author:] The erratic ants do not appear to be held as common eJ mies by the agricultural, and they are even permitted [ establish their formicaries within the limits of the open Sometimes, however, the diminutive hillocks which marki entrance to an erratic ant-nest multiply beyond the limit of tj agriculturals' forbearance. But they do not declare war, lesort to any personal violence. Nevertheless, they get rid them, oddly enough, by a regular system of vexatious obstn tions. They suddenly conclude that there is urgent demaj for improving their public domain. Forthwith they sally foi in large numbers, fall eagerly to work gathering the little bli balls which are thrown up by the earth-worms in great quantiij everywhere in the prairie soil, which they bring and heap m the paved disk until all the erratic ant-nests are covered ! entire pavement is thus raised an inch or so, and pains are tall ANTS — KEEPING PETS. 83 1 overtlj d paper, ; urs the etween til i remainej 3n as tlifj d. not alwa [east nui' jrved mail ;n ten fi ig betwetl •e, witho ervation^ f — he adi nations cecum's ei msuccess) lers, sho satisfacto! neighboi n's obsen Itleposit more balls upon and around the domiciles of their [y neighbours than elsewhere. The erratics struggle vigor- ply agai^^'^* *^^^ Pompeian treatment ; they bore through avalanche of balls, only to find barriers laid in their way. obstructions at length become so serious that it is impos- le to keep the galleries open. The dwarfs cease to contend [inst destiny, and, gathering together their household stores, [etly evacuate the premises of the inhospitable giants. It is triumph of the policy of obstruction, a bloodless but effec- opposition. Lastly, MacCook records the history of an interesting agement which he witnessed between two nests of Iramorium ca^spitum. It took place between Broad eet and Penn Square in Philadelphia, and lasted for ly three weeks. Although all the combatants belonged he same species, however great the confusion of the t, friends were always distinguished from foes — ap- ntly by contact of antennae. Habit of keeping Domestic Peis.— Many species of display the curious habit of keeping in their nests Idry kinds of other insects, which, so far as observation nds, are of no benefit to the ants, and which there- have been regarded by observers as mere domestic . These * pets ' are for the most part species which r nowhere else except in ants' nests, and each species pet' is peculiar to certain species of ants. Thus gridge found ' a large number of a minute shining beetle moving about among the seeds ' in the nests e harvesting ant of the south of Europe, ' belonging e scarce and very restricted genus Golnocera, called raatz (7. attce, on account of its inhabiting the nests ts belonging to the genus Atta.^ He also observed biting the same nests a minute cricket * scarcely r than a grain of wheat' {Gryllus myrmecophilus), h had been previously observed by Paolo Savi in the le little bliBg of several species of ants in Tuscany, where it lived eat quantii^g ^^^^ terms with its hosts, playing round the nests rm weather, and retiring into them in stormy weather, allowing the ants to carry it from place to place g migrations. Again, Mr. Bates -observes that G 2 , the folk e author; common ei permitted le opendi ich mark e limit of are war, ley get riw ious obsti gent del ley sally foi nd heap uj overed ! ■ains aie tal 84 ANIMAL INTELLIGENCE. ■i * some of the most anoiualous fcniiis of coleopterous in.s,,| are those which live solely in the nests of ants.' John Lubbock also, and other observers whom we n& not wait to cite, mention similar facts. The Rev. White says that altogether 40 distinct species of Coleopte most of which he has in his own collection, are knoi to inhabit the nests of various species of ants, anfl| occur nowhere else. As in all these cases the ants live on amicable ten with their guests, and in some cases even bestow lal>| upon them (as in carrying them from one nest to anot{ during migration), it is evident that these insects are J only tolerated, but fostered by the ants. Moreover, al seems absurd to credit ants with any mere fancy or caprf such as that of keeping pets, we can only conclude ti| these insects, like the aphides, are of some use to tt hosts, although we are not yet in a position to sim what this use can be. Habits of Sleep and Cleanliness. — It is probable t| all species of ants enjoy periods of true sleep alternatf with those of activity; but actual observations on subject have only been made on two or three spec! The following is MacCook's account of these habits inf harvesting ant of Texas : — The observation upon the ants now before me begai 8 o'clock; at 11 p.m. the cluster had nearly dissolved, oii| few being asleep. To illustrate the soundness of this sle take the quill pen with which I wi'ite, and apply the fej end of it to an ant who is sleeping upon the soil. Shel chosen a little oval depression in the surface, and liesi abdomen upon the raised edge, and face toward the lamp, legs are drawn up close to the body. She is perfectly stilll gently draw the feather tip along the body, stroking * witil fur,' if I may so say. There is no motion. Again and i this action is repeated, the stroke gradually being made hei although always quite gentle. Still there is no change, strokes are now directed upon the head, with tho same re^ Now the tip is applied to the neck, the point at which thel is united to the pro-thorax, with a waving motion intendej produce a sensation of tickling. The ant remains motion After continuing these experiments for several minutJ ANTS— SLEEP AND CLRANLINESS. 85 luse the sleeper by a sharp touch of the quill. She stretches It her head, then her legs, which she also shakes, steps nearer ]the lij,'ht, and begins to cleanse lierself in the manner nlroady scril)es Forel, 'thatljtural selection affair must seem marvellous to those who have not seenBjjf „..„ fk^^ -pi, especially when we remember that sexual attraction can t" play no part.' [ion. When tli Jill the forest. T ulumns, at thois (ions ; but instea li^rht and left, tl .uddon fit of hizii noro brushing i liDllest sight WW il»ove-quoted pasi iiinplo indulgence he»e hours of rel \i') effective perfc .)king at them, erely in play wa Funereal Ho ten stated thai icry careful in c MacCook also gives an account of habits of play asj dulged in among ants of the other Hemisphere : — There is nothii ihe life-history of inereal habits. bserved are quite ead, and for the ppear to treat wi nt of giving the At one formicary half a dozen or more young queens out at the same time. They would climb up a large pel near the gate, face the wind, and assume a rampant posti» mi i , , Several having ascended the stone at one time, there ©i^suaK ' ii ^ ' little plaj^ul passage-at-arms as to position. They nipped «{ j ,.^ ®P°'' other gently with the mandibles, and chased one another m^'^ „ x ^ fiivourite spots. They, however, never nipped the workM^. . 4- j These latter evidently kept a watch upon the sportive pffgi„i>i. f ^Y^^"^ cesses, occasionally saluted them with their antennae in Ku^j. i /. ^^" . , usual way, or touched them at the abdomen, but appare- ^^^ ^ allowed them full liberty of action. t As to leisure, Bates writes : — The life of these Ecitons is not all work, for I frequently] them very leisurely employed in a way that looked like ery soon after tl iewhome,anumbe nd began carrying 'he next day this ' Zoc. cit. face of th« ,h tbt'ir foi .luUblos, lit u let go, r lien one « iimbled ib ANT.S FUNERKAL HABITS. 89 tion. When this hnppeucd the pUor was always a suiuiy noolc in the forest. The main coliiiim of the aniiy and tho branch ^ . "V , IroUiinnH, at those times, were in tlicir ordinaiy rehitive posi raised tliei .. i... • „i„..,i ^v ..- :...- c. i _...i i -,i i. ...:.. . lany popui mce from liber's C^i ntil I m several tu it careful s, rolled of Lid each otl again, ami ly spurting tions; but instead of pressing forward eagerly and plundering ii'ht and left, they seemed to have ln't-n all smitten with a uddcn fit of laziness. Some were walking sternly about, othors ttcio brushing their antenna) with their fore-feet ; but the holiest sight was their cleaning each other. [Hero follows the ilK)ve-quoted pjissage.] Tlie actions of these ants looked like iiuplo indulgence in idle amusement It is probable that hese hours of relaxation and cleaning may be incfispensable to h'! effective performance of their harder burdens ; but whilst iking at them, the conclusion that the ants were engaged „erely in play was irresistible.* ugh to put )rel, 'that ) not seen tion can )f play as jre: — queens ^ L large pel pant posti here ensue y nipped « another fi the work Funereal Habits, — In another connection it has already It'll stated that Sir John Lubbock found his ants to be ry careful in disposing of the dead bodies of their com- ades. This habit seems to be pretty general among many piendly. 1 pecies of ants, and is no doubt due to sanitary require- iients, thus becoming developed as a beneficial instinct by i;itiiral selection. The funereal habits of the agricultural nt are thus related by MacCook : ^ — There is nothing which is apt to awaken deeper interest in he life-history of ants than what may properly he called their unereal habits. All species whose manners I have closely bserved are quite alike in their mode of caring for their own ead, and for the dry carcasses of aliens. The former they ppear to treat with some degi*ee of reverence, at least to the ex- ent of giving them a sort of sepulture without feeding upon hem. The latter, after having exhausted the juices of the body, hey usually deposit together in some spot removed from the est. I did not see any of the * cemeteries ' of the agricul- iiral ant upon the field, nor, indeed, observe any of their ehaviour towards the dead, but my artificial nests gave me some ^P^^^®. J isight of this. In the first colony had been placed eight agri- ulturals of another nest, which were literally cut to pieces. ut apparei t^^^ ^^^^^ after the ants were comfortably established in their ewhome,a number of them laid hold upon these disjecta memhraf nd began carrying them hack and foi-th around the formicarium. he next day this continued, and several of their own number frequently :ed Uke n ' Loc. cit. Loe. cit. p. 337. '^ 90 ANIMAL INTELLIGENCE. h who had died were being treated in like manner. Back and forth, up and down, into every corner of the box the bearers I wandered, the very embodiment of restlessness. I'or four day* " this conduct continued without any intermission. No sooner I would a body or fragment thereof be dropped by one bearer | than another would take it up and begin the restless circuit, The difficulty, I easily understood, was that there was no point I to be found far enough removed from the living-rooms of the insects in which to inter these dead. Their desire to have their dead buried out of their sight was strong enough to keep them I on this ceaseless round, apparently under the continuous influ ence of the hope that something might turn up to give them a I more satisfactory burial-ground. It does not appear greatly t- the credit of their wisdom that they were so long discovering! that they were limited to a space beyond their power to enlarge,! When, however, this fact was finally recognised they gave their} habit its utmost bent, and began to deposit the carcasses in thel extreme comer of the flat, as distant as possible from thel galleries on the terrace above. Here a little hollow was madel in the earth, quite up against the glass, wherein a number ofl bodies were laid. Portions of bodies were thrust into the chinks! formed in the dry sod. This flat became the permanent charnel-house of the colony, and here, in corners, crevices, and holes, for the most part out of sight, but not always so, the dead were deposited. But the living never seemed quite recon ciled to their presence. Occasionally, restless resurrectionists! would disentomb the dead, shift them to another spot, or start them once more upon thair unquiet wanderings. Even afterl the establishment of this cemetery, the creatures did not seem I able to lay away their newly deceased comrades — for there wewl occasional deaths in the formicary — without first indulging IqI this funereal promenade. In the formicaries established in glass jars, both of barbatwl and crudelis, the same behaviour appeared. So great was thel desire to get the dead outside the nest, that the bearers wouliil climb up the smooth surface of the glass to the very top of thel jar, laboriously carrying with them a dead ant. This was sevei-el work, which was rarely undertaken except under the influencel of this funereal enthusiasm. The jar was very smooth a73d quite| high. Falls were frequent, but patiently the little * undertaker' would follow the impulse of her instinct, and try and try agahil Finally, as in the large box, the fact of a necessity seemed tol dawn upon the ants, and a portion of the surface opposite fronil the entrance to the galleries, and close up against the glass, wasl ANTS — FUNEREAL HABITS. 91 ss circuit, used as burial-ground and sort of kitchen-midden, where all the refuse of the nest was deposited. Mrs. Treat has informed me that her artificial nests of crudelis behaved in precisely the Isame way. An interesting fact in the funereal habits of Formica san- \guinea was related to me by this lady. A visit was paid to a large jcolony of these slave-makers, which is established on the grounds ladjoining her residence at Vineland, New Jersey. I noticed |that a number of carcasses of one of the slave species, Formica fusca, were deposited together quite near the gates of the nest. [These were probably chiefly the dry bodies of ants brought in from recent raids. It was noticed that the dead ants were all af one species, and thereupon Mrs. Treat informed me that the slave-makers never deposited their dead with those of ^heir black servitors, but always laid them by themselves, not groups, but separately, and were careful to take them a considerable distance from the nest. One can hardly resist Uinting here another likeness between the customs of these }ocial h)nnenopters and those of human beings, certain of whom irry their distinctions of race, condition, or religious caste, even the gates of the cemetery in which the poor body moulders ito its mother dust ! It will be observed that none of these accounts furnish Evidence of ants burying their dead, as Pliny asserts to lave been the case with ants in the south of Europe. In [he Proceedings of the Linnaean Society, however (1861), lere is a very definite account of such a practice as [btaining among the ants of Sydney ; and although it is rom the pen of an observer not well known, the observa- lioii seems to have been one about which there could ^arcely have been a mistake. The observer was Mrs. [utton, and this is her account. Having killed a number ' soldier ants,' and returning half an hour afterwards to le place where the dead bodies were lying, she says : I saw a, large number of ants surroutding the dead ones. I termined to watch their proceedings closely. I followed four five that started oflf from the rest towards a hillock a short ''^ance off, in which was an ants' nest. This they entered, and out five minutes they reappeared, followed by others. All 1 into rank, walking regularly and slowly two by two, until ey arrived at the spot where lay the dead bodies of the soldier ts. In a few minutes two of the ants advanced and took up 92 ANIMAL INTELLIGENCE. '1': 1' the dead body of one of their comrades ; then two others, and so on, until all were ready to march. First walked two ant> I bearing a body, then two without a burden ; then two others with another dead ant, and so on, until the line was extended j to about forty pairs, and the procession now moved slowly on- wards, followed by an irregular body of about two hundred ant, I Occasionally the two laden ants stopped, and laying down the dead ant, it was taken up by the two walking unburdened behind! them, and thus, by occasionally relieving each other, theTJ arrived at a sandy spot near the sea. The body of ants nod commenced digging with their jaws a number of holes in the) ground, into each of which a dead ant was laid, where they now! laboured on until they had filed up the ants* graves. Thiij did not quite finish the remarkable circumstances attendiDol this funeral of the ants. Some six or seven of the antJ had attempted to run off without performing their share otj the task of digging ; these were caught and brought back, wbeil they were at once attacked by the body of ants and killed upoEJ the spot. A single grave was quickly dug, and they were alij dropped into it. The Key. W. Farren White also, in his papers on ant« published in the * Leisure Hour' (1880), after alluding t(i the above case, corroborates it by some interesting obser- vations of his own. He says : — Several of the little sextons I observed with dead in theiil mandibles, and one in the act of burying a corpse. . I should mention that the dead are not interred without cocJ siderable difficulty, in consequence of the sides of the trays beinJ almost perpendicular. The work of the sextons continued until no dead bodies remained upon the surface of the nest, but alj were interred in the extramural cemeteries. Afterwards removed the trays, and turned the contents of the formicariun upside down, and then I placed six trays on the surface of tlj earth, two of which I filled with sugar for food. All six weif used freely as cemeteries, being crowded with the corpses! the little people and their young, the larvse which had perisbe in the disruption of their home. I have noticed in one of my formicaria a subterraneaj cemetery, where I have seen some ants burying their dead i placing earth above them. One ant was evidently much affect* and tried to exhume the bodies, but the united exertions of thi yellow sextons were more than sufficient to neutralise the effoj of the disconsolate mourner. The cemetery was now convera LEAF-CUTTING ANTS. 93 into a large vault, the chamber where the dead were placed, together with the passage which led to it, being completely covered in. Habits Peculiar to Certain Species. Leaf'Owtting Ants of the Amazon (CEcodoma cephal- otes). — The mode of working practised by these ants is thus described by Mr. Bates : — They mount a tree in multitudes. . . . Each one places I itself on the surface of a leaf, and cuts with its sharp scissor- i like jaws a nearly semicircular incision on the upper side ; it I then takes the edge between its jaws, and by a sharp jerk detaches the piece. Sometimes they let the leaf drop to the ground, where a little heap {iccumulates, until carried off by another relay of workers; but generally each marches off with the piece it has operated on, and as all take the same road to the colony, the path they follow becomes in a short time smooth and bare, looking like the impression of a cart-wheel through 1 the herbage. Each ant carries its semicirculsir piece of leaf upright lover its head, so that the home-returning train is rendered [very conspicuous. Nearer observation shows that this Ihome-returning or ladened train of workers keeps to one [side of the road, while the outgoing or empty-handed train keeps to the other side ; so that on every road there is a double train of ants going in opposite directions, ^hen the leaves arrive at the nest they are received by a smaller kind of workers, whose duty it is to cut up the )ieces of leaf into still smaller fragments, whereby the Reaves seem to be better fitted for the purpose to which, IS we shall presently see, they are put. These smaller l^vorkers never take any part in the outdoor labours ; but they occasionally leave the nest, apparently for the sole 3urpose of obtaining air and exercise, for when they leave ^he nest they merely run about doing nothing, and fre- quently, as if in mere sport, mount some of the semi- circular pieces of leaf which the carrier ants are taking to pe nest, and so get a ride home. From his continued observation of these ants. Bates con- cludes — and his opinion has been corroborated by that 94 ANIMAL INTELLIGENCE. both of Belt and Miiller — that the object of all this labour is highly interesting and remarkable. The leaves when gathered do not themselves appear to be of any service to the ants as food ; but when cut into small fragments ard stored away in the nests, they become suited as a nidus for the growth of a minute kind of fungus on which the ants feed. We may therefore call these insects the ' gardening ants,' inasmuch as all their labour is given to the rearing of nutritious vegetables on artificially prepared soil. They are not particular as to the material which they collect and store up for soil, provided that it is a material on which the fungus will grow. Thus they are very partial to the inside white rind of oranges, and will carry ofif the { flowers of certain shrubs while leaving the leaves untouched, j But, to quote again from Bates, — They are very particular about the ventilation of their under- gi'ound chambers, and have numerous holes leading up to the I surface from them. These they open out or close up, apparently to keep up a regular degree of temperature below. The grea; care they take that the pieces of leaves they carry into the nest should be neither too dry nor too damp, is also consistent with the idea that the object is the growth of a fungus that re- quires particular conditions of temperature and moisture to ensure its vigorous growth. If a sudden shower should come on, the ants do not carry the wet pieces into the burrows, but throw them down near the entrances. Should the weather clear up again, these pieces are picked up when nearly dried, and taken inside : should the rain, however, continue, they get sodden down into the ground, and are left there. On the con- trary, in dry and hot weather, when the leaves would get dried up before they could be conveyed to the nest, the ants, when in exposed situations, do not go out at all during the hot hours, but biiug in their leafy burdens in the cool of the day and during the night. As soon as the pieces of leaves are carried in thev must be cut up by the small class of workers into little pieces, Some of the ants make mistakes, and carry in unsuitable leaves, f Thus grass is always rejected by them, but I have seen some ants, perhaps young ones, carrying leaves of grass ; hut after a while these pieces are always brought out again and thrown [ away. I can imagine a young ant getting a severe ear-wigging from one of the major-domos for its stupidity. When a nest is disturbed and the masses of ant-food spread I LEAF-CUTTING ANTS. 95 ibout, the ants are in great concern to carry every morsel of it inder shelter again ; and sometimes, when I had dug into a nest, found the next day all the earth thrown out filled M^th little 3its that the ants had dug into it to get out the covered-up lood. When they migrate from one part to another, they ilso CJirry with them all the ant-food from their old habita- tions. In Biichner's ' Geistesleben der Thiere ' there is pub- lished an interesting description of the habits of these ants, ;hieh was communicated to the author by Dr. Fr. Ellen- iorf of Wiedenbriick, who has lived many years in Central Lraerica. Dr. EUendorf says that — [t would be quite impossible for them to creep even through lort grass with loads on their heads for miles. They therefore [>ite off the grass close to the ground for a breadth of about five iches, and throw it on one side. Thus a road is constructed, rhich is finally made quite smooth and even by the continual Massing to and fro of millions upon millions night and day. . . the road is looked down upon from a height with these lillions thickly pressed together, and all moving along with leir green bannerets over their heads, it looks as though a mt green snake were gliding slowly along the ground ; and lis picture is all the more striking in that all these bannerets re swaying backwards and forwards.* This observer made the experiment of interrupting the ivance of a column of these ants, with the interesting isult which he describes : — I wished to see how they would manage if I put an obstacle their way. Thick high grass stood on either side of their in-ow road, so that they could not pass through it with the [ad on their heads. I placed a dry branch, nearly a foot in [ameter, obliquely across their path, and pressed it down so ?htly on the ground that they could not creep underneath. le first comers crawled beneath the branch as far as they fuld, and then tried to climb over, but failed owing to the sight on their heads. Meanwhile the unloaded ants from ke other side came on, and when these succeeded in climbing |er the bough there was such a crush that the unladen ants |d to clamber over the laden, and the result was a terrible luddle. I now walked along the train, and found that all the p with their bannerets on their heads were standing still, ' Loo. cit. p. 97. 96 ANIMAL INTELLIGENCE. thickly pressed together, awaiting the word of command froul the front. When I turned back to the obstacle, I saw witj astonishment that the loads had been laid aside by more than J foot's length of the column, one imitating the other. AiJ now work began on both sides of the branch, and in about hi an hour a tunnel was made beneath it. Each ant then took rj its burden again, and the march was resumed in the most |)eij feet order. A migration of these ants is thus described by the saiij observer : — The road led towards a cocoa plantation, and here I socj discovered the building which I afterwards visited daily. As again went thither one day I was met, at a considerable dij tance from the nest, by a closely pressed column coming thencj and all the ants laden with leaves, beetles, pupae, butterflies &c. ; the nearer I came to the nest, the greater was tii activity. It was soon plain to me that the ants were in act of leaving their dwelling, and I walked along the tniii to discover the new abode. They had gone for some distanJ along the old road, and had then made a new one through til grass to a cooler place, lying rather higher. The grass on tii new road was all bitten off close to the ground, and thousani were busy carrying th© path on to the new building. At til new home itself was an unusual stir of life. There were: sorts of labourers — architects, builders, carpenters, sappenj helpers. A number were busy digging a hole in the grouij and they carried out little pellets of earth and laid tbei together on end to make a wall. Others drew along little twi; straws, and grass-stalks, and put them near the place of builJ ing. 1 was anxious to know why they had quitted their oj home, and when the departure was complete, I dug it up m a spade. At a depth of about a foot and a half I found seven tunnels of a large marmot species, the terror of cocoa planter! because in making their passages they gnaw off the thickej roots of the cocoa plants. The interior of the ant-hill had parently fallen in through these mines. Unfortunately I wj unable to follow further the progress of the new building, for j was obliged to leave the noxt day for San Juan del Sur. \V1 I returned at the end of a week the building was finished, i the whole colony was again busy with the leaves of the cof| plants. Harvesting Ants (Atta). — The ants which, so far as HARVESTING ANTS. 97 )resent known, practise the peculiai* and distinctive iabits to be described under this division belong for the nost part to one genus, ^^to, which, however, comprises a lumber of species distributed in localised areas over all the [our quarters of the globe. Hitherto nineteen species- |ave been detected as having the habits in question. These consist of gathering nutritious seeds of grasses iuring summer, and storing them in granaries for winter lonsumption. We owe our present knowledge concerning ■hese insects to Mr. Moggridge," who studied them in the )uth of Europe, Dr. Lincecum,^ and Mr. MacCook,^ who tudied them in Texas, and Colonel Sykes* and Dr. Jerdon,** [bo made some observations upon them in India. They kso occur scattered over a great part of Europe and in [alestine, where they were clearly known to Solomon and ther classical writers of antiquity,^ whose claim to accu- Lte observation, although long disputed (owing to the ithority of Huber), has now been amply vindicated. Mr. Moggridge, who was a careful and industrious 3server, found the following points of interest in the ibits of the European harvesters. From the nest in Jirious directions there proceed outgoing trains, which lay be from twenty to thirty or more yards in length, and |ch consists of a double row of ants, moving, like the if-cutting ants, in opposite directions. Those in the Jitgoing row are empty-handed, while those in the in- Iming row are laden. But here the burdens are grass leds. The roads terminate in the foraging ground, or [t-fields, and the insects composing the columns there [come dispersed by hundreds among the seed-yielding isses. The following is their method of collecting seeds ; juote from Moggridge : — ' Harvesting Ants and Trap-door Spiders, London, 1873 and Sup- ^ment, 1874. ^ Jowmal Linn Soc, vol. vi. p. 29, 1862. ' Agricultural Ant of Texas, Philadelphia, 1880 * Trans. Ent. Soc Land., i. 103, 1836. ' Madras Journ. Lit. So. 1851. ' For this see Moggridge, loc. cit. pp. 6-10, where, besides Prov. iv. 8, and XXX. 25, quotations are given from Horace, Virgil, Plautus, '. others. 98 ANIMAL INTELLIGENCE. ■k'i It is not a little surprising to see that the ants bring in nq only seeds of large size and fallen grain, but also green capsule the torn stalks of which show that they have been freshjj gathered from the plant. The manner in which they accompliijl this feat is as follows. An ant ascends the stem of a fruitJD plant of shepherd's-purse {Capsella bursa-pastoris), let us i and selects a well -filled but green pod about midway up stem, those below being ready to shed their seeds at a touciJ Then, seizing it in its jaws, and fixing its hind legs firmly a^ j pivot, it contrives to turn round and round, and so strain tli fibres of the fruit-stalk that at length they snap. It then scends to the stem, patiently backing and turning upwa again as often as the clumsy and disproportionate burdd becomes wedged between the thickly set stalks, and joins line of its companions on their way to the nest. In this mar capsules of chickweed {Stellaria media) and entire calyces, taining the nutlets of calamint, are gathered ; two ants sometimes combine their efforts, when one stations itself nei the base of the peduncle and gnaws it at the point of great< tension, while the other hauls upon and twists it. I never seen a capsule severed from its stalk by cutting aloj and the mandibles of this ant are perhaps incompetent to | form such a task. I have occasionally seen ants engi cutting the capsules of certain plants, drop them, and allow 1 companions below to carry them away ; and this correspod with the curious account given by ^^lian of the manner! which the spikelets of corn are severed and thrown down ■ the people below,* tw Si^fuo t<3 Karo>. The recognition of the principle of the division I labour which the latter observation supplies, is furti] proved by the following quotation from the same auth A dead grasshopper which was being carried into tH nest was — Too large to pass through the door, so they tried to dismemj it. Failing in this, several ants drew the wings and legs asj back as possible, while others gnawed through the mu^ where the strain was greatest. They succeeded at last in l pulling it in. The same thing is strikingly shown by the follow quotation from Lesp^s : — If the road from the place where they are gathering I HAEVESTING ANTS. 99 ^est to the nest is very long, they make regular depots for eir provisions under large leaves, stones, or other suitable ces, and let certain workers have the duty of carrying them Im depot to depot. Biichner (loc, cit, p. 101) also makes the following Jerenees to the statements of previous observers : — [The subterranean workers of this remarkable genus are veiy jer. The Rev. H. Clark reports from Rio de Janeiro, that Sa-ubas have made a regular tunnel under the bed of the ^r Parahyba, which is there as broad as the Thames at jidon, in order to reach a storehouse which is on the opposite Bates tells us that close to the Magoary rice-mills, near i, the ants bored through the dam of a large i-eservoir, and I water escaped before the mischief could be remedied. In [Para Botaiiical Gardens an enterprising French gardener Bverything he could to drive the Sa-uhas away. He lit fires le chief entrances of their nests, and blew sulphur vapour I their galleries by means of bellows. But how astonished I Bates when he saw the vapour come out at no less a dis- than seventy yards ! Such an extension have the sub- (mean passages of the Sa-uhUs. Phe recognition of the principle of the division of ir, which is shown by the above observations, is further pborated by the following quotation from Belt : — ^etween the old burrows and the new one was a steep Instead of descending this with their burdens, they cast down on the top of the slope, whence they rolled down to 3ttom, where another relay of labourers picked them up irried them to the new burrow. It was amusing to watch its hurrying out with bundles of food, dropping them over lope, and rushing back immediately for more. [he same thing has been observed, as already stated, le leaf-cutting ants — those engaged in cutting fre- bly throwing down the fragments of leaf which they the carriers below. The prevalence of this habit Ig various species of ants therefore renders credible [ollowing statements of Vincent Gredler of Botzen, are thus recorded in * der Zool. Gart.,' xv. p. 434 : — Herr Gredler's monastery one of the monks had been )med for some months to put food regularly on his window- H 2 ^i 100 ANIMAL INTELLIGENCE. .''.5 sill for ants coming up from the garden. In consequence Herr Gredler's communications he took it into his head top^ the bait for the ants, pounded sugar, into an old inkstand, hung this up by a string to the cross-piece of his window, ; left it hanging freely. A few ants were in with the These soon found their road out over the string with their grJ of sugar, and so their way back to their friends. Before loiiJ procession was arranged on the new road fi'om the window «j along the string to the spot where the sugar was, and so tliiij went on for two days, nothing fresh occurring. But onec the procession stopped at the old feeding-place on the wind] sill, and took the food thence, without going up to the pemii sugar-jar. Closer observation revealed that about a dozer| the rogues were in the jar above, and were busily and unwe ingly carrying the grains of sugar to the edge of the potj throwing them over to their comrades down below. Many other instances of the division of labour be given besides these, and those to be mentioned \i\ after in other connections throughout the course of j present chapter ; but enough has been said to show i the principle is unquestionably acted upon by si species of ants. That ants are liable to make mistakes, and, when i do, that they profit by experience, is shown by the folll ing experiment made by Moggridge ; and many otheij stances might be given were it desirable : — It sometimes happens that an ant has manifestly made al selection, and is told on its return that what it has brof home with much pains is no better than rubbish, and is hu out of the nest, and forced to thi-ow its burden away. In i to try whether these creatures were not fallible like mortals, I one day took out with me a little packet of giejj white porcelain beads, and scattered these in the path of a vesting train. They had scarcely lain a minute on thee before one of the largest workers seized upon a bead, andi some difficulty clipped it with its mandibles and trotted a great pace to the nest. I waited for a little while, my i tion being divided between the other ants who were vainlj deavouring to remove the beads, and the entrance down i the worker had disappeared, and then left the spot. Oil return in an hour's time, I found the ants passing unconcen by and over the beads which lay where I had strewed tliij HARVESTING ANTS. 101 nparently undiminished quantities ; and I conclude from this [at they had found out their mistake, and had wisely returned their accustomed occupations. When the grain is thus taken into the nest, it is 3red in regular granaries, but not until it has been de- ided of its ' husks ' or * chaff.* The denuding process is rried on below ground, and the chaff is brought up to le surface, where it is laid in heaps to be blown away by |e wind. It is a remarkable thing, and one not yet understood, k the seed, when thus stored in subterranean chambers ^t far enough below the surface to favour germination, 3S not germinate. Moggridge says that out of twenty- nests and among many thousands of seeds that he imined, he only found twenty-seven cases of incipient rmination. Moreover, all these cases occurred in months |in November to February, while in the nests opened in tober, March, April, and May, no sprouted seeds were covered, though these are the months highly favourable termination. He is at a loss to suggest the treatment rhich the ants expose the seeds in order to prevent [ir sprouting. ' Apparently it is not that moisture or ^mth or the influence of atmospheric air is denied to seeds, for we find them in damp soil in genial weather, oftoii at but a trifling distance below the surface of ground ; ' and he has proved that the vitality of the is is not impaired, for he succeeded in raising crops of [ng plants from seeds removed from the granaries. [He also says, — ?y a fortunate chance T have been able to prove that the Is will germinate in an undisturbed granary when the ants Iprevented from obtaining access to it : and this goes to show [only that the structure and nature of the granary chamber ]>t suflScient of itself to prevent germination, but also that the |ence of the ants is essential to secure the dormant condition le seeds. discovered in two places portions of distinct nests of Atta dor which had been isolated owing to the destruction of the Dw wall behind which they lay, and then the granaries well up and literally choked with growing seeds, though the in which they lay completely enclosed and concealed them 102 ANIMAL INTFXLI0P:NCE. until by chance I laid them bare. In one case I knew that i destruction of the wall had only taken place ton days before,] that the seeds had sprouted in the interval. My experiments also tend to confirm this, and to favour; belief that the non-germination of the seeds is due to soil direct influence voluntarily exercised by the ants, and merely to the conditions found in thf» nest, or to acid vapod which in certiiin cases are given 03" by the ants themselves. These experiments consisted in confining a laij number of harvesting ants with their queen and larv» a glass test-tube partly filled with damp soil and varij seeds, the whole being closed with a cork in the inoj of the test-tube. Under these circumstances the sej all sprouted, showing that mere confinement in an atu sphere of exhalations from the ants did not prevent ger nation. Another series of experiments, undertaken att suggestion of Mr. Darwin, on the eflfects of an atmospttj of formic acid, showed that although this vapour was vj injurious to the seeds, it did not prevent their incipiJ germination. Therefore it yet remains to be ascertain why the seeds do not germinate in the granaries of ants. But in whatever way the ants manage to prevent g mination, it is certain that they are aware of importance in this connection of keeping the seeds! dry as possible ; for Moggridge repeatedly observed til when the seeds which had been stored proved over-mcs the ants again took them out and spread them in the: to dry, to be again brought into the nest after a suffici^ exposure. Lastly, he also repeatedly observed the most surpri: and interesting fact that when, as we have seen was sionally the case, the seeds did begin to germinate inc nests, the ants knew the most effective method of venting the germination from proceeding ; for he fod that in these cases the ants gnawed off the tips ofi radicles. This fact deserves to be considered as onei the most remarkable among the many remarkable factij ant-psychology. Passing on now to the harvesting or agricultural i HARVESTING ANTS. 103 Texas, attention was first called to the habits of this isect by Mr. Buckley in I860,' and by Dr. Lincecum, ^ho sent an account of his observations to Mr. Darwin, whom they were communicated to the Linnsean Society 1861. Five years later a paper was published in the [roceedings of the Academy of Natural Sciences of [hiladelphia from the MS. of Dr. Lincecum. Lastly, in m Mr. MacCook went to Texas expressly to study the ibits of these insects, and he has recently embodied the Isults of his observations in a book of three hundred iges.* These observations are for the most part confir- (atory of those of Lincecum, and for this as well as for isons to be deduced from the work itself, they deserve I be accepted as trustworthy, notwithstanding that in some 888 they are provokingly incomplete. The following is epitome of these observations. The ants clear away all the herbage above their nest in form of a perfect circle, or 'disk,' 15 or 20 feet in imeter, by carefully felling every stalk of grass or weed it may be growing thereon. As the nests are placed in Sckly grown localities, the eflfect of these bald or shaven tks is highly conspicuous and peculiar, exactly resembling I miniature the clearings which the settlers make in the lerican backwoods. The disk, however, is not merely |ared of herbage, but also carefully levelled, all inequali- |s of the surface being reduced by building pellets of into the hollows to an extent sufficient to make a tformly flat surface. The action of rain and the constant )tion of multitudes of ants cause this flat surface to borne hard and smooth. In the centre of the disk is the Jeway of the nest. This may be either a simple hole hollow cone. From the disk in various directions there radiate ant- [ds or avenues, which are cleared and smoothed like the itself, and which course through the thick surround- grass, branching and narrowing as they go till they ^ntually taper away. These roads are usually three or in number before they begin to branch, but may be l+nrnl 9^B ^°°- ^^^^- -^cad. Nat. Sci., xli. p. 445. ■•iCUlturdi ^^ Agricultural Ant of Texas (Lippincott & Co., Philadelphia,1880). 104 ANIMAL INTELLIGENCE. as many as seven. They are usually two to three inchesi wide at their origin, but in large nests may be as much ju| five. MacCook found no road longer than sixty feet, but! Jjincecum describes one of three hundred feet. AIodJ these hard and level roads there is always passing, durirjl the daytime of the harvesting season, a constant streattl of ants — those going from the nest being empty-handedl and those returning to it being laden with seeds, m course the incoming ants, converging from all quarterif upon the road, and therefore increasing in numbers as theJ approach the nest, require greater space for free locomil tion ; while the outgoing ants, diverging as they get furthJ from home, also require greater proportional space i\\ less their distance from the nest: hence the gradi] swelling in the width of the roads as they approach tij nests. The manner of collecting the seeds in the jungle suij rounding the roads is thus described by MacCook : — At last a satisfactory seed is found. It is simply lifted froJ the ground, or, as often happens, has to be pulled out of t!( soil into which it has been tightly pressed by the rain or I passing feet. Now follows a moveruent which at first] thought to be a testing of the seed, and which, indeed, mayl partially that; but finally I concluded that it was the adjustii of the burden for safe and convenient carriage. The ant pu at the seed-husk with its mandibles, turning and pinching i * feeling * it on all sides. If this does not satisfy, and commoij it does not, the body is raised by stifiening out the legs, i abdomen is curved underneath, and the apex applied to the see] I suppose this to be simply a mechanical action for the betii adjusting of the load. Now the worker starts homeward, has not lost itself in the mazes of the grass forest. It tu directly towards the road with an unerring judgment. Tliej are many obstacles to overcome. Pebbles, pellets of earth, Hj of wood, obtruding rootlets, or bent-down spears of grass hh up or hinder the way. These were scarcely noticed wheni ant was empty-handed. But they are troublesome barriers noj that she is burdened with a seed quite as thick, twice as wi| and half as long as herself. It is most interesting to see i skill, strength, and rapidity with which the little harvess swings her tieasure over or around, or pushes it beneath thJ obstacles. Now the seed has caught against the herbage as i HARVESTING ANTS. 105 Di-ter dodges under a too naiiow oijening. She backs out and tries another passage. Now the sharp points of the husk are pntangled in the grass. She jerks or pulls the burden loose, and lUiTies on. The road is reached, and progress is comparatively pasy. Holding the grain in her mandibles well above the surface, she breaks into what I may describe with suffi- cient accuracy as ' a trot,' and with little fuither interruption reaches the disk and disappears within the gate. There are variations from this behaviour, more or less marked, according the nature of the grounds, the seex:ls, and (I suppose) the indi ^duality of the harvesters ; but the mode of ingathering the t;rop is substantially as above. Each ant operated independently. )nc9 only did I see anything like an effort to extend sympathy id aid. A worker minor seeming to have difficulty in testing br adjusting a large seed of buffalo-grass, was assisted (ap- pai-ently) by one worker major, and then by another, after v'hich she went on her way. But these ants do not confine their harvesting opera- [ions to gathering fallen seeds ; they will, like the ants of ilurope, also cut seeds from the stalk. In order to test the disposition of cruddis to garner the eeds from the stem, bunches of millet were obtained from the forth, and stalks eighteen inches high, crowned by the boll of llose-set seeds, were stuck in the mound of an active formicary. The ants mounted the stems and set to work vigorously to ecure the seeds, clusters of twenty or more being engaged at Ince upon one head. The seeds were carried off and stored dthin the nest. This experiment proved pretty conclusively lat in the seeding season crudelis does not wait for the seeds drop, but harvests them from the plant. The ' granaries ' into which the seeds are brought are [ept distinct from the * nurseries ' for the pupae. Their rails, floor, and roof are so hard and smooth, that MacCook links the insects must practise upon them * some rude lason's craft.' He traced these granaries to a depth of four feet [elow the surface of the ground, and believes, firora the tatements of a native peasant, that they, or at least the )rmicaries, extend to a depth of fifteen feet. As regards the care that the ants take of the gathered rain, Lincecum describes the same habit as Moggridge id Sykes describe — viz., the sunning of wet seeds to 106 ANIMAL INTELLIGENCE. dry. MacCook, however, neglected to make any experi- ments on this subject. Neither has he been able to throw I any light upon the question as to why the stored seeds do not germinate, and is doubtful whether the habit ofl gnawing the radicle of sprouting seeds, which prevail; I in the European species, is likewise practised by tM American. On two other points of importance MacCook'sl observations are also incomplete. One of these has referf ence to an alleged statement, which he is disposed t(i believe, that when some ants in a community have beeii| killed by poison, the survivors avoid the poison : he, howj ever, made no experiments to test this statement. The other main point on which his observations art! defective has reference to a remarkable statement madfl by Lincecum in the most emphatic terms. This statel ment is that upon the surface of their disk the antil sow the seeds of a certain plant, called ant-rice, for iU purpose of subsequently reaping a harvest of the graiil There is no doubt that the ant-disks do very often sup-j port this peculiar kind of grass, and that the ants artl particularly fond of its seed; but whether the plant iJ actually sown in these situations by the insects, or groiJ there on account of these situations being more opei| than the general surface of the ground — this questi MacCook has failed to answer, or even to further. Wc arei therefore, still left with Dr. Lincecum's emphatic assur- ance that he has witnessed the fact. His account is tk\ the seed of the ant-rice, which is a biennial plant, is sorJ in time for the autumnal rains to bring up. At the bl ginning of November a green row or ring of ant-ricfJ about four inches wide, is seen springing up round the cirj cumference of the disk. In the vicinity of this circukj ring the ants do not permit a single spire of any othej grass or weed to remain a day, but leave the aristida, ant-rice, untouched until it ripens, which occurs in Juneol the next year. After the maturing and harvesting of tli| seed, the dry stubble is cut away and removed from ttj pavement or disk, which is thus left unencumbered untij the ensuing autumn, when the same species of grass agaii appears as before, and so on. Lincecum says he has seeil HARVESTING ANTS. 107 the process go on year after year on the same ant-farms, and adds, — There can be no doubt of the fact that the particular species of grain-bearing grass mentioned above is intentionally planted. In farmer-like manner the ground upon which it stands is care- fully divested of all other grasses and weeds during the time it is growing. When it is ripe the grain is taken care of, the dry stubble cut away and carried off, the paved area being left un- encumbered until the ensuing autumn, when the same * ant-rice * reappears within the same circle, and receives the same agri- cultural attention as was bestowed upon the previous crop — and so on year after year, as I know to be the case, in all situations when the ant's settlements are protected from graminivorous animals. In a second letter Dr. Lincecum, in reply to an inquiry I from Mr. Darwin whether he supposed that the ants plant I seeds for the ensuing crop, says : — I have not the slightest doubt of it. And my conclusions [have not been arrived at from hasty or careless observation, nor from seeing the ants do something that looked a little like it, md then guessing at the results. I have at all seasons watched the same ant-cities during the last twelve years, and I know that what I stated in my former letter is true. I visited the kme cities yesterday, and found the crop of ant-rice growing inely, and exhibiting also the signs of high cultivation, and not blade of any other kind of grass or weed was to be seen dthin twelve inches of the circular row of ant-rice. — {Journ. 'jirM. Soc.j vol. vi. p. 30-1.) Now, MacCook found the ant-rice growing as described, )ut only on some nests. Why it does not grow upon all [he nests he does not understand. So far, then, as his jbservations go, they confirm those of Dr. Lincecum ; but ie does * not believe that the ants deliberately sow a crop [s Lincecum asserts ;' he thinks * that they have for some iason found it to their advantage to permit the aristida grow upon their disks, while they clear off all other lerbage ; ' but finally concludes ' that there is nothing reasonable, nor beyond the probable capacity of the imet intellect, in the supposition that the crop is actually )wn. Simply, it is the Scotch verdict — " Not proven." ' 108 ANIMAL INTELLIGENCE. H '^ The following facts with regard to * modes of mining' are worth quoting from MacCook : — In sinking the galleries the difficulty of carrying is not great in a moist or tough soil, which permits the ant to obtain goodly-sized pellets for portage. But when the soil is light and dry, so that it crumbles into dust as it is bitten off, the diffi- culty is greatly increased. It would be a very tedious task! indeed to take out the diggings grain by grain. This difficulty the worker overcomes by balling the small particles against the surface of the gallery, the under side of the head, or within and against the mandibles. The fore-feet are used for this purpose, being pressed against the side face, turned under, and pushed upward with a motion similar to that of a man putting his hand upon his mouth. The abdomen is then swung undemeati the body and the apex pressed against the little heap of graiiii| of dirt massed against the under side of the mandibles, or bei tween that and the smooth under surface of the head. Thus the dust is compressed into a ball which is of sufficient size to justifjl deportation. The same operation is observed in the side-galleries, where! the ants work very frequently upon their sides or backs, prej cisely as I have seen colliers do in Pennsylvania coal-mines. The following is likewise worth quoting from the samej author : — Seeds are evidently not the only food of our agriculturalJ When the ants at disk No. 2 had broken through the sligli mud-sediment that sealed up their gate, as described above] they exhibited a peculiar behaviour. Instead of heading foil the roads and pressing along them, they distributed themselye«| at once over the entire disk, radiating from the gate to all points in the circumference, from which they penetrated tlif jungle of grass beyond. In a moment a large number wenj returning across the roads, out of the grass, over the pavemeEJ toward the entrance. They bore in their mandibles objectj which I presently found to be the males and females of whit] ants {Termes Jlavipes), which were filling the air, diulng at I after the rain, in marriage flight. They had probably swarmej just before the shower. The agricultural were under excitement, and hurried forth and back at the top of theiJ speed. The number of ants bearing termites was soon so greil that the vestibule became choked, and a mass of strugglii anthood was piled up around the gate. A stream of eag^ insects continually poured out of the door, pushing their wi HAEVESTING ANTS. 109 through the crowd that vainly but persistently endeavoured to aet in with their burdens. The outcoming ants had the ad- vantage, and succeeded in jostling through the quivering rosette of antennae, legs, heads, and abdomens. Occasionally a worker gained an entrance by dint of sheer physical force and perse- verance. Again and again would the crowd rush from all sides upon the gate, only to be pushed back by the issuing throng. In the meanwhile quite a heap of termites, a good handful at least, had been accumulated at one side of the gate, the ants having evidently dropped them, in despair of entrance, and hurried off to garner more. In due time the pressure upon the vestibule diminished, the laden workers entered more freely, and in the end this heap was transferred to the interior. The rapidity with which the ants were distributed to aU parts of their roads, after the first opening of the gates, was truly surprising. I was greatly [puzzled, at the first, to know what the cause of such a rush might be. The whole behaviour was such as to carry the con- I viction that they knew accurately what effect the rain would I have, had calculated upon it, and were acting in accordance with previous experience. I had no doubt at the time, and have none now, that the capturing of insects beaten down by the rain is one of the well-established customs of these ants. I saw a few other insects taken in, and one milliped, but chiefly ithe white ants. That very afternoon I found in a formicary which I then lopeued several large colonies, or parts of one colony of ter- Imites, nested within the limits of the disk and quite at home. [The next day numbers of the winged white ants were found stored within the granaries of a large formicary. There is no reason to doubt that these insects were intended for food, in accordance with the quite universal habit of the Formicarice. A curious habit has been noticed by most observers to 3ceur in many species of ant, and it is one on which Mr. [acCook has a good deal to say. The habit in question Bonsists in the ants transporting one another from place to place. The carrying ant seizes her comrade by the middle, md hurries along with it held aloft — the ant which is carried remaining quite motionless with all her legs drawn together. Huber supposed the process to be one enjoy- ible to both the insects concerned, and to be performed by mtual understanding and consent; but MacCook, in jommon with most other observers, supposes that it is 110 ANIMAL INTELLIGENCE. merely a rough and primitive way of communicating to fellow-workers the locality where their services are re-] quired. He says : — Keeping these facts in mind, we have a key to the solution of the press-gang operations which Lincecum observed among j the agriculturals, and which have been fully described in other species. In the absence of any common head or directory, and | of all executive officers, a change of location or any other con- certed movement must be carried forward by the willing co I operation of individuals. At first sight, the act of seizing and carrying off* workers does not appear like an appeal to free-will, I It is indeed coercive, so far as the first act goes. But, in point of fact, the coercion ceases the moment the captive is set down within the precincts of the new movement. The carrier-ant has depended upon securing her consent and co-operation by thus bringing her within the circle of activity for which her I service is sought. As a rule, no doubt, the deported ant once yields to the influence around her, and drops into the I cuiTcnt of fresh enterprise, in which she moves with as entire | freedom and as independently as any other worker. But she is apparently under no restraint, and if she so please, may retiu'D| to her former haunts. Gertaw, Ants of Africa. — Livingstone says of certain ants of Africa : — They have established themselves on the plain where water stands so long annually as to allow the lotus and other aqueous I plants to come to maturity. When all the ant-horizon issul>l merged a foot deep, they manage to exist by ascending to little houses built of black tenaceous loam on stalks of grass, and! placed higher than the line of inundation. This must havel been the result of experience, for, if they had waited till the! water actually invaded their terrestrial habitations, they would I not have been able to procure materials for their aerial quarters] unless they dived down to the bottom for every mouthful ol j clay. * The Tree Ant of India and New South Wales, — Thesel ants are remarkable from their habit of forming rests onljl in trees. According to Col. Sykes' account^ the shape oil the nest is more or less globular, and about ten inches inl diameter. It is formed entirely of cow-dung, which the| * Missionary Travels, p. 328 HONEY-MAKING ANTS. Ill Insects collect from the ground beneath, and work into |he form of thin scales. These are then built together in In imbricated manner, like tiles or slates upon the roof of a buse, the upper or outer scale, however, being one un- broken sheet, which covers the whole nest like a skull-cap. jelow this the scales are placed one upon another in a ?avy or scalloped manner, so that numerous little arched jntrances are left, and yet, owing to the imbricated lanner in which the scales are arranged, the interior of le nest is perfectly protected from rain. This interior insists of a number of irregular cells, the walls of which re formed by the same process as the exterior. In New South Wales there is another species of ant [hich also frequents trees, but builds within the stem and ranches. In the report of Captain Cook's expedition its ibits are thus described : — * Their habitations are the isides of the branches of a tree, which they contrive to tcavate, by working out the pith almost to the extremity the slenderest twig ; the tree at the same time flourish- |g as if it had no such inmate.' On breaking one of the iches the ants swarm out in legions. Some of our |tive species also have the habit of excavating the in- jrior of trees, though not on so extensive a scale. Honey-Tnaking Ant (Myrmecocystus mexicanus). — lis ant is found in Texas and New Mexico. Capt. W. Fleeson has observed its habits, and his observations Ive been communicated to the Californian Academy of [iences, and also, by Mr. Henry Edwards, to Mr. Darwin. ^e following are the chief points of interest in Capt. meson's results : — The community appears to consist of three distinct kinds of fs, probably of two separate genera, whose offices in the aeral order of the nest would seem to be entirely apart from ^h other, and who perform the labour allotted to them with- the least encroachment upon the duties of their fellows. [ese three kinds are — I. Yellow workers ; nurses and feeders of II. IT. Yellow honey-makers ; sole function to secrete a kind of honey in their large globose abdomens, on which the other ants are supposed to feed. They never quit the nest, and are fed and tended by I. 112 ANIMAL INTELLIGENCE. III. Black workers, guards, and purveyors ; surround ttJ nest as guards or sentinels, in a manner presents to be described, and also forage for the food requii-ej for I. They are much larger and stronger insf^J than either I. or II., and are provided with verj formidable mandibles. The nest is placed in sandy soil in the neighbourhooi of shrubs and flowers, is a perfect square, and occupit about four or five square feet of ground, the surface which is kept almost unbroken. But the boundaries the nest are rendered conspicuous by the guard of hki workers (III.), which continuously parade round three its sides in a close double line of defence, moving opposite directions. In the accompanying diagram tl sentry path is represented by the thick black lines. Theii always face the same points of the compass, and direction in which the sentries march is one column h south-west to south-east, and the other column from soutj east to south-west — each column, however, moving regular order round three sides of a square. The southe side of the encampment is left unguarded ; but if enemy approaches on this or any other side, a number! the guards leave their stations, and sally forth to face til foe — raising themselves on their hind tarsi on meeting! enemy, and moving their large mandibles in defia Spiders, wasps, beetles, and other insects, if they venttj too near the nest, are torn to pieces by the guard i:| most merciless manner, and the dead body of the vif quished is speedily removed from the neighbourhood of ti nest — the guard then marching back to resume ttj places in the line of defence, their object in destroji] other insects being the defence of their encampment, s not the obtaining of food. The object of leaving the southern side of the sqi^ encampment open is as follows. While some of the bli workers are engaged on duty as guard, another and laii division are engaged on duty as purveyors. These en and leave the quadrangle by its open or southerns along the dotted line marked a to the central pokj The incoming line is composed of individuals eachbea HONEY-MAKING ANTS. 113 burden of fragments of flowers or aromatic leaves. these are all deposited in the centre of the quadrangle Along the other diagonal e there is a no less incessantly loving double line of yellow workers (I.), whose office it to convey the supplies deposited by the black workers c to 6, which is the gateway of the fortress. It is re- larkable that no black ant is ever seen upon the line r, w N e E 6 / \ \e a % :i / s Fig. 7. no yellow one upon the line a ; each keeps his own ite station, and follows his own particular duty with beadfastness and apparent adherence to discipline that [most astonishing. The hole at d seems to be a venti- ig shaft ; it is never used as a gateway. Section of the nest reveals, besides galleries, a small (mber about three feet below the surface, across which jread, like a spider's web, a network of squares spun the insects, the squares being about J inch across, and I H 114 ANIMAL INTELLIGENCE. the ends of the whole net being fastened to the eartheil walls of the chamber. In each one of the squares, siip.1 ported by the web, sits one of the honey-making ants (II. j Here these honey makers live in perpetual confinemenj and receive a constant supply of flowers, pollen, &c., whiei is continually being brought them by (I.), and which, U a process analogous to that performed by the bee, thei| convert into honey. Such is an epitome of the only account that the worij has yet received of the habits and economy of this wondeii ful insect, whose instincts of military organization seeij to be not less wonderful than those of the Ecitons, thoug in this case they are developed with reference to defeDc^l and not to aggression. It is especially noteworthy tk] the black and yellow workers are believed to belong! * two separate genera ;' for if this is the case, it is the onll one I can recall of two distinct species co-"r)erating fori common end ; for even the nearest parallel which we fii( supplied in other species of ants maintaining aphides, not quite the same thing, seeing that the aphides merely passive agents, like Class II., of the honey-makiii ant, and not actively co-operating members of the coij munity, like Class I. Ecitons, — We have next to consider the habits of wonderful ' foraging,' or, as it might be more appropriatJ called, the military ant of the Amazon. These insec| which belong to several species of the same genus, 1 been carefully watched by Belt, Bates, and other nnti ists. The following facts must therefore be accepted] fully established. Eciton legionis moves in enormous armies, and eveij thing that these insects do is done with the most perfj instinct of military organization. The army marches [ the form of a rather broad and regular column, hundrfj of yards in length. The object of the march is the capt] and plunder of other insects, &c., for food, and as well-organised host advances, its devastating legions | all other terrestrial life at defiance. From the m column there are sent out smaller lateral columns, composing individuals of which play the part of MILITARY ANTS. 115 inching oflf in various directions, and searching about Ith the utmost activity for insects, grubs, &c., over every f under every fallen leaf, and in every nook and cranny lere there is any chance of finding prey. When their rand is completed, they return into the main column. (the prey found is sufficiently small for the scouts them- ]v'es to manage, it is immediately seized, and carried ?k to the main column ; but if the amount is too large the scouts to deal with alone, messengers are sent back the main column, whence there is immediately dis- tched a detachment large enough to cope with the re- irements. Insects which when killed are too large for [gle ants to carry, are torn in pieces, and the pieces iveyed back to the main army by different individuals. Lny insects in trying to escape run up bushes and shrubs, jre they are pursued from branch to branch and twig twig by their remorseless enemies, until on arriving at le terminal ramification they must either submit to lediate capture by their pursuers, or drop down amid murderous hosts beneath. As already stated, all the |ils that are taken by the scouts or by the detachments (t out in answer to their demands for assistance, are lediately taken back to the main column. When they [ve there, they are taken to the rear of that column by smaller columns of carriers, which are constantly Ining, one on either side of the main column, with the [plies that are constantly pouring in from both sides. }h of these outside columns is a double line, the ants iposing one of the two lines all running in the same [ction as the main army, and the ants composing the sr line all running in the opposite direction. The ler are empty-handed carriers, which having deposited burdens in the rear, are again advancing to the J for fresh burdens. Those composing the other line lall laden with the mangled remains of insects, pupse ither ants, &c. On either side of the main column |e are also constantly running up and down a few in- luals of smaller size and lighter colour than the other which seem to play the part of officers ; for they sr leave their stations, and while running up and I 2 UG ANIMAL INTELLIGENCE. down the outsides of the column, they every now ail again stop to touch anteniue with some member of d rani^ and tile, as if to give instructions. When the scoi] discover a wasp's nest in a tree, a strong force is sentf IVom the main army, the nest is pulled to pieces, and tlie larva? carried to the rear of the army, while the wA Hy around defenceless against the invading multitiJ i)v, if the nest of any other species of ant is found, | similarly strong force, or perhaps the whole army is. fleeted towards it, and with the utmost energy the iD[| merable insects set to work to sink shafts and dig niij till the whole nest is rifled of its contents. In m mining operations the ants work with an extraordiiu display of organized co-operation ; for those low do^vnl the shafts do not lose time by carrying up the earth wli they excavate, but pass on the pellets to those above ; ; the ants on the surface, when they receive the pelltj carry them, * with an appearance of forethought thatqc staggered ' Mr. Bates, only just far enough to ensure i they shall not roll back again into the shaft, and, af| depositing them, immediately hurry back for mi But there is not a rigid division of labour, although 1 work * seems to be performed by intelligent co-operad amongst a host of eager little creatures ; ' for soine| them act * sometimes as carriers of pellets, and at anotj as miners, and all shortly afterwards assume the officj conveyors of the spoil.' Again, as showing the instiif of co-operation, the following may also be quoted Bates's account : — On the following morning no trace of ants could be I near the place where I had seen them the preceding dav,j were there signs of insects of any description in the thiol but at the distance of eighty or one hundred yards, I upon the same army, engaged evidently on a razzia of a kind to that of the previous evening ; but requiring other! sources of their instinct, owing to the nature Of the grot[ They were eagerly occupied on the face of an incUned light earth in excavating mines, whence, from a depth of i or ten inches, they were extracting the bodies of a bulky sp of ant of the genus Formica. It was curious to see them cr ing round the orifices of the mines, some assisting their MILITARY ANTS. 117 iles tx) lift out the bodies of tho Formicte, anfl others tearing Coin in pieces, on account of thoir weight being too great for a HL'lo Eciton ; a number of carriera seizing each a fmgment, id currying it off down tho slope. These Ecitons have no fixed nest themselves, but live, it were, on fi perpetual campaign. At night, however, ey call a halt and pitch a camp. For this puipose they suivlly select a piece of broken ground, in the interstices [ which they temporarily store their plunder. In the [orning the army is again on the march, and before an 1)01' or two has passed not a single ant is to be seen lere the countless multitudes had previously covered le ground. Another and larger species of Eciton (E. humata) mts sometimes in dense armies, and sometimes in lumns, according to the kind of prey of which they are search. When in columns they are seeking for the Ists of a certain species of ant which have their young ] holes of rotten logs. These Ecitons when seeking for 3se nests hunt about, like those just described, in lumns, which branch ofif in various directions. When a lien log is reached, the column spreads over it, search- through all the holes and cracks. Mr. Belt says of 3m: — The workers are of various sizes, and the smallest are here [iise, for they squeeze themselves into the narrowest holes, search out their prey in the furthest ramifications of the bts. When a nest of the Uypoclinea is attacked, tho ants p out, carrying the larvae and pupae in their jaws, but are lediately despoiled of them by the Ecitons, which are i-un- jig about in every direction with great swiftness. Whenever fey come across a Hypoclinea can-ying a larva or pupa, they pe it from it so quickly, that I could never ascertain exactly it was done. As soon as an Eciton gets i. 'd of its prey, it rushes off back ig the advancing column, which is composed of two sets, hurrying forward, the other returning laden with their bty, but all and always in the gi-eatest haste and apparent pry. About the nest which they are harrying, all appears in fusion, Ecitons running here and there and everywhere in greatest haste and disorder ; but the result of all this ap- 118 ANIMAL INTELLIGENCE. li ♦ .■.':-i parent confusion is that scarcely a single Hypoclinea gets ay with a pupa or larva. I never saw the Ecitons injure t;l Hypoclineas themselves, they were always contented with spoiling them of their young. The columns of this species ' are composed almcs entirely of workers of different sizes ; ' but, as in species previously mentioned, *at intervals of two three yards there are larger and lighter coloured iai viduals that often stop, and sometimes run a little bacil ward, stopping and touching some of the ants with thJ antennas,' and looking ' like ojBficers giving orders and i] recting the march of the column.' Concerning the other habits of this species, the sau author writes ; — The eyes in the Ecitons are very small, in some of i species imperfect, and in others entirely absent ; in this tlJ differ greatly from the Paeudomyrma ants, which hunt m^ and which have the eyes greatly developed. The imperfedJ of eyesight in the Ecitons is an advantage to the commiinit| and to their particular mode of hunting. It keeps them gether, and prevents individual ants from starting off aid after objects that, if their eyesight was better, they might ( cover at a distance ; the Ecitons and most other ants M\ each other by scent, and, I believe, they can communicate presence of dangei", of booty, or other intelligence, to a diata by the different intensity or qualities of the odours given off. one day saw a column of Eciton ha/mata running along the fcJ of a nearly perpendicular tramway cutting, the side of whiij was about six feet high. At one point I noticed a sort i assembly of about a dozen individuals that appeared in const| tation. Suddenly one ant left the conclave, and ran with gn speed up the perpendicular face of the cutting without stoppii! It was followed by others, which, however, did not keep straij| on like the first, but ran a short way, then returned, then ag followed a little further than the first time. They were eij dently scenting the trail of the pioneer, and making it manently recognisable. These ants followed the exact taken by the first one, although it was far out of sight. Whfi ever it had made a slight detour they did so likewise. I scrap with my knife a small portion of the clay on the trail, and tlj ants were completely at fault for a time which way to Those ascending and those descending stopped at the scrap MILITARY ANTS. 119 rtion, and made short circuits until they hit the scented trail ain, when all their hesitation vanished, and they ran up and iwn it with the greatest confidence. On gaining the top of e cutting, the ants entered some brushwood suitable for hunt- In a very short space of time the information was com- unicated to the ants below, and a dense column rushed up to rch for their prey. The Ecitons are singular amongst the ts in this respect, that they have no fixed habitations, but lOve on from one place to another, as they exhaust the hunting ■oundfi around them. I think Edton hamata does not stay ore than four or five days in one place. I have sometimes ime across the migratory columns ; they may easily be known, ere and there one of the light-coloured officers moves back- rds and forwards directing the columns. Such a column is enormous length, and contains many thousands if not millions individuals. I have sometimes followed them up for two or lee hundred yards without getting to the end. They make their temporary habitations in hollow trees, and etimes underneath large fallen trucks that offer suitable Hows. A nest that I came across in the latter situation was en at one side. The ants were clustered together in a dense 1, like a great swarm of bees, hanging from the roof but ihing to the ground below. Their innumerable long legs ked like brown threads binding together the mass, which st have been at least a cubic yard in bulk, and contained ndreds of thousands of individuals, although many columns re outside, some bringing in the pupae of ants, others the legs id dissected bodies of various insects. I was surprised to see this Hving nest tubular passages leading down to the centre the mass, kept open just as if it had been formed of inorganic terials. Down these holes the ants who were bringing in ty passed with their prey. I thrust a long stick down to centre of the cluster, and brought out clinging to it many holding larvae and pupae, which probably were kept warm the crowding together of the ants. Besides the common k-coloured workers and light-coloured officers, I saw here ny still larger individuals with enormous jaws. These y go about holding wide open in a thi'eatening manner. It was this ant which, as previously stated, showed ipathy and fellow-feeling with companions in diffi- Ities. The habits of E, drepanophora are closely similar I those of the species already described ; and, indeed. -i 120 ANIMAL INTELLIGENCE. ! I except in matters of detail, all the species of Ecitons havei much the same habits. Mr. Bates records an interestinj observation which he made on one of the moving coluniii;| of this species. He says : ' When I interfered with M column or abstracted an individual from it, news of tlj disturbance was quickly communicated to a distance o:j several yards to the rear, and the column at that poinf commenced retreating.' The main column is in tlii| species narrower, viz., * from four to six deep,' but extendi to a great length, viz., half a mile or more. It was tHi species of Eciton that the same naturalist describes as en. joying periods of leisure and recreation in the * sudei| nooks of the forest.' Next we have to consider E. jprcedator, of which tlj same observer writes : — This is a small dark reddish species, very similar to common red stinging ant of England. It differs from all othd Ecitons in its habit of hunting, not in columns, but in de phalanxes consisting of myriads of individuals, and was first m^ mth at Ega, where it is very common. Nothing in movements is more striking than the rapid march of tka large and compact bodies. Wherever they pass, all the rest] the animal world is thrown into a state of alarm. They strea: along the ground and climb to the summits of all the M trees, searching every leaf to its apex, and whenever theye counter a mass of decaying vegetable matter, where booty] plentiful, they concentrate, like other Ecitons, all their fon upon it, the dense phalanx of shining and quickly-mod bodies, as it spreads over the surface, looking like a flood : dark- red liquid. They soon penetrate every part of the coj fused heap, and then, gathering together again in marchi^ order, onward they move. All soft-bodied and inactive insft fall an easy prey to them, and, like other Ecitons, they td their victims in pieces for facility of carriage. A phalanx this species, when passing over a tract of smooth ground, occj pies a space of from four to six square yards ; on examin the ants closely they are seen to move, not all together in oij straightforward direction, but in variously spreading contiguoi columns, now separating a little from the general mass, wl reuniting with it. The margins of the phalanx spread outf times like a cloud of skirmishers from the flanks of an aii| 1 was never able to find the hive of this species. MILITAEY ANTS. 121 Lastly, there are two species of Eciton totally blind, ind their habits dififer from those of the species which re have hitherto considered. Bates writ s of them : — The armies of E. vastator and M. erratica move, as far as I could learn, wholly under covered roads, the ants constructing them gradually but rapidly as they advance. The column of foragers pushes forward step by step, under the protection of these covered passages, through the thickets, and on reaching a totting log, or other promising hunting-ground, pour into the crevices in search of booty. I have traced their arcades, occa- sionally, for a distance of one or two hundred yards ; the grains )f earth are taken from the soil over which the column is pass- ling, and are fitted together without cement. It is this last- lentioned feature that distinguishes them from the similar covered roads made by termites, who use their glutinous saliva to cement the grains together. The blind Ecitons, working in lumbers, build up simultaneously the sides of their convex ircades, and contrive, in a surprising manner, to approximate them and fit in the key-stones without letting the loose un- cemented structure fall to pieces. There was a very clear di- nsion of labour between the two classes of neuters in these oUnd species. The large-headed class, although not possessing lonstrously lengthened jaws like the worker-majors in U. kamata and B. drepanophora, are rigidly defined in structure from the small-headed class, and act as soldiers, defending the (working community (like soldier termites) against all comers. Whenever I made a breach in one of their covered ways, all the ants underneath were set in commotion, but the worker- linors remained behind to repair the damage, whilst the large- 3eads issued forth in a most menacing manner, rearing their leads and snapping their jaws with an expression of the fiercest rage and defiance. Annornia arcens. — This is the so-called ' driver ' or marching ' ant of West Africa, which in habits and intel- ligence closely resembles the military ants of the other lemisphere. I shall therefore not wait again to describe these habits in detail. Like the Ecitons, the marching luts of Africa have no fixed nest, but make temporary halts in the shade of hollow trees, overhanging rocks, &c. They march in large armies, and, like the Ecitons, always fn the form of a long close column ; but in this case the relative position of the carriers of spoil and larvae is re- '11 t i 122 ANIMAL INTELLIGENCE. versed, for while these occupy the raiddle place the soldiers and officers march on either side. These have! large heads armed with powerful jaws, and never takj part in carrying ; their function is to maintain order, act as scouts, and attack prey. The habits of these ant; I resemble most closely those of the blind Ecitons in thai I they very frequently, and indeed generally, build covered I ways ; they do so apparently in order to protect themselvejl from the heat of the African sun. Their line of marcli| is therefore marked by a continuous arch or tunnel, whicll is always being constructed by the van of the columiiJ The structure is made of earth moulded together btl saliva, and is very quickly built. But it is only built iil places where the line of march is exposed to the suiif light ; at night, or in the shadow of trees or long grass, i;| is not made. If their camp is flooded by a tropical rain storm, the ants congregate in a close mass, with tlicl younger ants in the centre ; they thus form a floatinff island. It is remarkable that ants of different hemisphere;! should manifest so close a similarity with respect to alll these wonderful habits. The Chasseur ants of Trinidadj and, according to Madame Merian, the ants of visitatioD| of Cayenne, also display habits of the same kind. 'i General Intelligence of Various Species, Many of the foregoing facts display an astonishing de-l gree of intelligence as obtaining among ants ; for I tliiDl;| that however much latitude we may be inclined to allow tol * blind instinct ' in the way of imitating actions elsewherel due to conscious purpose, some at least of these foregoing facts can only be fairly reconciled with the view that the I insects know what they are doing and why they are doing I it. But as I am myself well aware of the difficulty thaij arises in all such cases of drawing the line between pin- poseless instinct and purposive intelligence, I have thought I it desirable to reserve for this concluding division of the present chapter several isolated facts which have been ob- served among sundry species of ants, and which do not I ANTS — GENERAL INTELLIGENCE. 123 geem to admit of being reasonably comprised under the Icategory of instinctive action, if by the latter we mean laction pursued without knowledge of the relation between Ithe means adopted and the ends attained. It will be remembered that our test of instinctive as distinguished from truly intelligent action is simply Iwhether all individuals of a species perform similar adap- Itive movements under the stimulus supplied by similar laud habitual circumstances, or whether they manifest in- dividual and peculiar adaptive movements to meet the lexigencies of novel and peculiar circumstances. The im- portance of this distinction may be rendered manifest by the following illustrations. We have already seen that the ants which Sir John jubbock observed display many and complex instincts, rhich together might seem to justify us in anticipating that animals which present such wonderful instincts must dso present sufficient general intelligence to meet simple though novel exigencies by such simple adaptations as the mfamiliar circumstances require. Yet experiments which w» L ^"^^ji^:.^ I Fig. 8. le made in this connection seem to show that such is not the case, but that these ants, with all their wealth of Instinctive endowments, are utterly destitute of intelli- gent resources; they have abundance of common and letailed knowledge (supposing the adaptations to be made Consciously) how to act under certain complex though [amiliar circumstances, but appear quite unable to origi- aate any adaptive action to obviate even the simplest |!onceivable difficulty, if this is of a kind which they have lot been previously accustomed to meet. Thus, on a lorizontal rod b supported in a saucer of water s, and therefore inaccessible to the ants from beneath, he placed [ome larvae A. On the nest N he then placed a block of rood c D, constructed so that the portion D should touch 'Hi 1^ 124 ANIMAL INTELLIGENCE. the larvae at a. When the ants had made a number of journeys over c D A and back again, he raised the block ci so that there \ras an interval -p^ of an inch between tlicj end of the block d and the larvae at A. The ants kept on coming, and tried hard to reach dowi from D to A, which was only just out of their reach. . . . Afterl a while they all gave up their efforts and went awavj losing their prize in spite of most earnest efforts, because ii did not occur to them to drop j^ of an inch. At the mo ment when the separation was made there were fifteen ants oil the larvae. These could, of course, have returned if one hacl stood still and allowed the others to get on its back. This,l however, did not occur to them ; nor did they think of lettinjj themselves drop from the bottom of the paper (p) on to the I nest. Two or three, indeed, fell down, I have no doubt bjl accident ; but the remainder wandered about, until at lengti| most of them got into the water. In another experiment he interposed a light strai bridge on the way between the nest and the larvae, aDd when the ants had well learnt the way, he drew thei bridge a short distance towards the nest, so that a small chasm was made in the road. The ants tried hard andl ineffectually to reach across it, but it did not occur t«| them to push the straw into its original position. The following experiment is still more illustrative oil the absence of intelligence, because the adjustive actioDl required would not demand the exercise of such higll powers of imagination and abstraction as would have beecl required for the moving forwards of the paper drawbridge; To test their intelHgence I made the following experiments; I suspended some honey over a nest of Lasius Jlavus at a| height of about ^ an inch, and accessible only by a paper bridge | more than 10 feet long. Under the glass I then placed al small heap of earth. The ants soon swarmed over the eaitli| on to the glass, and began feeding on the honey. I then re | moved a little of the earth, so that there was an interval ( about ^ of an inch between the glass and the earth; but,! though the distance was so small, they would not jump downf but preferred to go round by the long bridge. They tried in I vain to stretch up from the earth to the glass, which, however, was just out of their reach, though they could touch it witil ANTS— GENERAL INTELLIGENCE. 125 )t occur tol their antennae ; but it did not occur to them to heap the eai-th up a 'ittle, though if they had moved only half a dozen particles ofef th they would have 3cured for themselves direct access to the food. This, however, never occurred to them. At length they gave up all attempts to reach up to the glass, and went round by the paper bridge. I left the arrangement for several weeks, but they continued to go round by the long paper bridge. Another and somewhat similar experiment consisted in placing an upright stick A, supporting at an angle another stick B, which nearly but not quite touched tlie ground at C. At the end of the stick B there were placed some larvae in a horizontal glass cell at D. Into this cell were also placed a number of ants along with the larvae. The drop from D to c was only | an inch ; ' still, though the ants reached over and showed a great anxiety to take this short cut home, they none of them faced the leap, but all went round by the sticks, a distance of nearly 7 feet.' Sir John then reduced the interruption to f of an inch, so that the ants could even touch the glass cell with their antennae ; yet all day long the ants continued to go the long way round rather than face the drop. Next, therefore, he took still longer sticks and tapes, and ar- ranged them as before, only horizontally instead of verti- cally. He also placed some fine earth under the glass cell containing the larvae. The ants as before continued to go the long way round (16 feet), though the drop could not have hurt either themselves or the larvae, and though even this drop might have been obviated by heap- ing up the fine earth into a little mound J of an inch high, so as to touch the gla^s cell. It is desirable, however, here to state that all species of ants do not show this aversion to allowing themselves to drop through short distances ; for Moggridge describes the harvesting ants of Europe as seeming rather to enjoy acrobatic performances of this kind ; and the same fact is recorded by Belt of the leaf-cutting ants of the Amazons. Dr. Bastian, in his work on * Brain as an Organ of Mind,* suggests that the * seeming lack of intelligence betrayed by our English ants, from their disinclination to take a small leap, may be due simply to their defective sight * 126 ANIMAL INTELLIGENCE. (pp. 241-2). But even this consideration does not ex.' tenuate the stupidity of the ants which failed to heap up the fine earth to reach the glass cell which they were able | to touch with their antennae. That the species of ants on which Sir John Lubboel^ experimented were not, however, quite destitute of intel- ligence is proved by the result of the following expeii- ment : — I put some provisions in a shallow box with a glass top and a single hole in one side ; I then put some specimens of Lasim niger to the food, and soon a stream of ants was at work busilv carrying supplies off to the nest. When they had got to know their way thoroughly, and from thii'ty to forty were so occupied, I poured some fine mould in front of the hole, so as to cover it to a depth of about ^ an inch. I then took out the ants which were actually in the box. As soon as the ants had recovered from the shock of this unexpected proceeding on my part, they began to run all round and about the box, looking for some other place of entrance. Finding none, however, they begi digging down into the earth just over the hole, carrying off the I grains of earth one by one and depositing them without anj order all round at a distance of from ^ to 6 inches, until they had excavated down to the doorway, when they again begai] carrying off the food as before. This experiment was several times repeated on L. nig&\ and on L.flavus, always with the same result. Thus, then, we may conclude that the reasoning power I of these ants, although shown by the first experiments to be almost nil, is shown by this experiment to be not quite nil ; for the attempt to meet the exigencies of the case by first going round the box to seek another entrance, before taking the labour to remove the earth from the I known entrance, implies a certain rudimentary degree of adaptive capacity which belongs to the category of the rational. Another point of considerable interest, as bearing on I the general intelligence of ants, is one that was brought I out as the result of a laborious series of hourly observa- 1 tions, extending without intermission from 6.30 a.m. to 10 P.M. for a period of three months. The object of these observations was to ascertain whether the principle of the ANTS— GENERAL INTELLIGENCE. 127 livision of labour is practised by the ants. The result of lese observations was to show that during the winter- Ime, when the ants are not active, certain individuals are 3ld off to forage for supplies, and that when any casualty ^ertakes these individuals, others are told off to supply leir places. Thus, in the words of Sir John Lubbock's [nalysis of his lengthy tables, — The feeders at the beginning of the experiment were those lown to us as Nos. 5, 6, and 7. On the 22nd of November a kend, registered as No. 8, came to the honey, and again on the |lth December ; but with these two exceptions the whole of le supplies were carried in by Nos. 5 and 6, with a little help torn No. 7. Thiiiking now it might be alleged that possibly these fere merely unusually active or greedy individuals, I im- risoned No. 6 when she came out to feed on the 5th. As will seen from the table, no other ant had been out to the honey [ir some days ; and it could therefore hardly be accidental that that very evening another ant (then registered as No. 9) ime out for food. This ant, as will be seen from the table, len took the place of No. 6 (No. 5 being imprisoned). On the |ltb January No. 9 took in all the supplies, again with a little elpfrom No. 7. So matters continued until the 17th, when I iprisoned No. 9, and then again, i.e. on the 19th, another ant Jo. 10) came out for the food, aided, on and after the 22nd, ' another (No. 11). This seems to me very curious. From the 1 st i'ovemher to the 5th January, with two or three casual excep- [ons, the whole of the supplies were carried in by three ants, le of whom, however, did comparatively little. The other two re imprisoned, and then, but not till then, a fresh ant appears the scene. She carries in the food for a week, and then she Bing imprisoned, two others undertake the task. On the kher hand, in nest 1, when the first foragers were not im- risoned, they continued during the whole time to carry in le necessary supplies. The facts, therefore, certainly seem to indicate that 3rtain ants are told off as foragers, and that during ^nter, when but little food is required, two or three such Dragers are sufficient to provide it. Although Sir John Lubbock's ants showed such meagre ssources of intelligent adjustment, other species of ants, ^hich we have already had occasion to consider, appear to as remarkable in this respect as they are in respect of 128 ANIMAL INTELLIGENCE. 1 their instinctive adjustments. Unfortunately observatioj on this subject are very sparse, but such as they are the{ hold out a strong inducement for any one who has tli| opportunity to experiment with the view of testing tl >| intelligence of those species in connection with which tj following observations have been made, u Reaumur states that ants will make no attempt to enter a;| inhabited beehive to get at the contained honey, knowing tb the bees will slaughter them if they do so. But if the hivei| uninhabited, or the bees all dead, the ants will swarm into i hive as long as any honey is to be found there. P. Huber records that a wall which had been partj erected by ants was observed by him — As though it were intended to support the still unfinishs arched roof of a large room, which was being built from tti opposite side. But the workers which had begun the arch M given it too low an elevation for the wall on which it was rest, and if it had been continued on the same lines it woulil have met the partition wall halfway up, and this was to M avoided. I had just made this criticism to myself, when a nei arrival, after looking at the work, came to the same concIusioJ For it began at once to destroy what had been done, and tt| heighten the wall on which it was supported, and to make new arch with the materials of the old one under my very eyd When the ants begin an undertaking it seems exactly as if ai| idea slowly ripened into execution in their minds. Thus if oiii of them finds two stalks lying crosswise on the nest, which possible the formation of a room, or some little rafters whicll suggest the walls and the corners, it first observes the varioi parts accurately, and then quickly and neatly heaps little pelled of earth in the interspaces and alongside the stalks. It bringj from every side materials that seem appropriate, and somi times takes such from the uncompleted works of its companiod so much is it urged on by the idea which it has once conceivel and by the desire to execute it. It goes and comes and turisl back again, until its plan is recognisable by the others. Ebrard, in his * Etudes de Moeurs ' (p. 3), gives m following remarkable instance of the display of intellij gence of F. fusca : — The earth was damp and the workers were in full swi ANTS — GENERAL INTELLIG EXC E. 129 was a constant coming and going of ants, coming forth foiii their underground dwelling, and carrying back little ellcts of earth for building. In order to concentrate my kention I fixed my gaze on the largest of the rooms which [ere being built, wherein several ants were busy. The work made considerable progress; but although a projection ul(i be plainly seen along the ui>per edge of the wall, there iiuained an interspace of about twelve or fifteen millimetres fill in. Here would have been the place, in order to support e earth still to be brought in, to have had recourse to those liars, buttresses, or fragments of dried leaves, which many ts are wont to use in building. But the use of this expedient not customary with the ants I was obsei'ving {F. fnsca). Ii:r ants, however, were sufficient for the occasion. For moment they seemed inclined to leave their work, but ■m turned instead to a grass-plant growing near, the long Lrrow leaves of which ran close together. They chose the Rarest, and weighted its distal end with damp earth, until its ex just bent down to the space to be covered. Unfortunately Pe bend was too close to the extremity, and it threatened to eak. To prevent this misfortune, the ants gnawed at the se of the leaf until it bent along its whole length and covered [e space required. But as this did not seem to be quite enough, ley heaped damp earth between the base of the plant and that ' the leaf, until the latter was sufficiently bent. After they ^d thus attained their object, they heaped on the buttressing Elf the materials required for building the arched roof. The characteristic trait of the building of ants, says Forel, the almost complete absence of an unchangeable model, culiar to each species, such as is found in wasps, bees, and lers. The ants know how to suit their indeed little perfect 3rk to circumstances, and to take advantage of each situation, sides, each works for itself and on a given plan, and is only sionally aided by others when these understand its plan, iturally many collisions occur, and some destroy that which iera have made. This also gives the key to understanding |e labyi'inth of the dwelling. For the rest, it is always those )rkers which have discovered the most advantageous method, which have shown the most patience, which win over to their the majority of their comrades and at last the whole colony, though not without many fights for supremacy. But if one iceeds in obtaining a second to follow it, and this second iws the others after it, the first is soon lost again in the )wd. ;* it 130 ANIMAL INTELLIGENCE. Espinas also observed (' Thierischen Gesellschafte German translation, 1879, p. 371) that each single , made its own plan and followed it until a comrade, wlij had caught the idea, joined it, and then they worked i gethor in the execution of the same plan. Bloggridge says of the harvesters of Europe, — I have observed on more than one occasion that when] digging into an ants' nest I have thrown out an elater lar the ants would cluster round it and direct it towards soa small opening in the soil, which it would quickly enlarges disappear down. At other times, however, the ants would no notice of the elater ^ and it is my belief that the attentifj paid to it on former occasions were purely selfish, and ilj they intended to avail themselves of the tunnel thus m down into the soil, with the view of reopening communicatiij with the galleries and granaries concealed below, the approaq to which had been covered up. I have frequently watched t ants make use of these passages mined by the e later on thd occasions. And again, as showing apparently intelligent adaptatij of their usual habits to altered circumstances, he gives s account of the behaviour of these ants when a gra crowd of them were confined by him in a glass jar coj taining earth. He says : — On the following morning the openings were ten in numh and the greatly increased heaps of excavated earth showed i they must probably have been at work all night. The amoui of work done in this short time was truly surprising, for I must be remembered that, eighteen hours before, the earth pij sented a perfectly level surface, and the larvae and ants, nij housed below, found themselves prisoners in a strange pla bounded by glass walls, and with no exit possible. It seems to me that the ants displayed extraordinary intel] gence in having thus at a moment's notice devised a planf which the superabundant number; of workers could be e^ ployed at one time without coming in one another's way. soil contained in the jar was of course less than a tenth part] that comprised within the limits of an ordinary nest, while t number of workers was probably more than a third of the toij number belonging to the colony. If therefore but one or entrances had been pierced in the soil, the workers would bj been for ever running against one another, and a great numlf ANTS— GENERAL INTELLIGENCE. 131 luM never have got below to help in the all-important task I preparing passages and chambers for the accommodation of 1} larva). These numerous and funnel-shaped entrances ad- jtted of the simultaneous descent and ascent of large numbers [ants, and the work progressed with proportionate rapidity, ftcr a few days only t' oe entrances, and eventually only one, mined open. Concerning the harvesting ant of Texas, the following lotation may be made, under the present head, from lacCook. After remarking that these ants always select Inny places wherein to build their nests, or disks, he \es on to say that within a few paces of his tent — A nest was made which was partly shaded by a small mea- ^te tree that stood just beyond the margin of the clearing, [le sapling had probably grown up after the location of the imunity, and for some reason had been permitted to remain ^til too old to kill off. The shadow thrown upon the pave- Dnt was very slight ; nevertheless, fifteen feet distant a new miicary was being established. The path from the ranch to spring ran between this new hill and the old one, and ants Ere in commimication between the two. An opening had en made in the ground, and the beginnings of a new formicary ^re quite apparent. This is the only instance observed of aat seemed an attempt at colonising or removing, and I as- ciated it with the presence of the small but growing shadow [the young tree. He also gives us a still more remarkable observation, lich indeed, I must candidly say, does not appear to me Bdible. I am, therefore, glad to add that it does not ipear very distinctly from the account whether the jthor himself made the observation, or had it narrated him by his guide. But here is the observation in his words : — While studying the habits of the cutting ant I was tempted I make a night visit to a farm some distance from camp, by farmer's story of depredations made by these insects upon btaui plants and vegetables. A long, dark tramp, a blind Id vain search among the fields, compelled us at last to call |t the countryman from his bed. He led us directly to one the cutting ants* nests, which was overshadowed by a |ung peach tree. * There they be, sir,' cried he triumphantly. K 2 132 ANIMAL INTELLIGENCE. They were agriculturals ! So also were the other nests sho\t The reason for this confounding of the two ants on the panj the people hereabouts, and the reason for the ' cutting ' operatif* of our harvesters, will be explained farther on. It is oiilv] point here to say that the farmer affirmed that the ants unJ the peach tree had stripped off the first tender leaves last spiiil so that scarcely one had been left upon the limbs. I am vinced that the reason for this onslaught was the desire toljej of the obnoxious shade, and open the formicary to the full H- of the sun. From this account it is not very clear whether writer himself saw evidence of the former denudation I the tree, and if so whether there was any indicatifi other than the word of the farmer, that the deniidati had been effected by the ants. To make this conclui!;] credible the best conceivable evidence would be requmj and this, unfortunately, is just what we find wantii^ Somewhat the same remarks may be made on the follcii ing quotation from the same writer, though in this cJ his view is to some extent supported by an observationj Moggridge, as well as by that of Ebrard already quoted J Here I observed what appeared to be a new mode of opeij tion. The workers, in several cases, left the point at wtii they had begun a cutting, ascended the blade, and passed far out toward the point as possible. The blade was tliusboiJ downward, and as the ant swayed up and down it real seemed that she was taking advantage of the leverage gained, and was bringing the augmented force to bear upon! fracture. In two or three cases there appeared to be a divisil of labour ; that is to say, while the cutter at the roots keptJ with her work, another ant climbed the grass blade and applii the power at the opposite end of the lever. This position have been quite accidental, but it certainly had the appearai of a voluntary co-operation. I was sorry not to be able to« tablish this last inference by a series of observations, as facts were only observed in this one nest. The observation of Moggridge, to which I have alludtl as in some measure rendering support to the foregoing, as follows. Speaking of European harvesters which kept in an artificial nest for the purposes of close obse| vation, he says :— A.NTS -GENERAL INTELLIGENCE. 133 I was also in this way able to see for myself much that I lerwise could not have seen. Thus I was able to watch the Bration of removing roots which had pierced through their [Ueries, belonging to seedling plants growing on the suiface, Id which was performed by two ants, one pulling at the free (d of the root, and the other gnawing at its fibres where the hun was gi'eatest, until at length it gave way. And again, — Two ants sometimes combine their efforts, when one stations 3lf netir the base of the peduncle, and gnaws it at the point of patest tension, while the other hauls upon and twists it. . . . liave occasionally seen ants engaged in cutting the capsules [certain plants, drop them, and allow their companions below [carry them away. Lastly, the statements of these three observers taken rether serve to render credible the following quotation m Bingley,^ who says that in Captain Cook's expedition |Xew South Wales ants were seen by Sir Joseph Banks others — green as a leaf, which live upon trees and build their )ts of various sizes, between that of a man's head and his fist. jese nests are of a very curious structure : they are formed by ading down several of the leaves, each of which is as broad |a man's hand, and gluing the points of them together so as form a purse. The viscous matter used for this purpose is laiiimal juice. . . . Their method of bending down leaves we no opportunity to observe ; but we saw thousands uniting [their strength to hold them in this position, while other busy [Ititudes were employed within, in applying this gluten, that to prevent their returning back. To satisfy ourselves that 1 leaves were bent and held down by the efforts of these dimi- live artificers, we disturbed them in their work ; and as soon they were driven from their station, the leaves on which they re employed s]n'ang up with a force much greater than we jld have thought them able to conquer by any combination |heir strength. This remarkable fact also seems to be corroborated I the following independent observation of Sir E. inent: — .•1; th Animal J)wf/raj)Jft/, *Ants.' 134 ANIMAL INTELLIGENCE. The most formidable of all is the great red ant, or DimiJ It is particularly abundant in gardens and on fruit-trees;] constructs its dwellings by gluing the leaves of such species are suitable from their shape and pliancy into hollow balls, these it lines with a kind of transparent paper, like that mar] factured by the wasp. I have watched them at the interest!; operation of forming these dwellings ; — a Hne of ants standi! on the edge of one leaf bring another into contact with it, hold both together with their mandibles till their companid within attach them firmly by means of their adhesive paper, assistants outside moving along as the work proceeds. If itj necessary to draw closer a leaf too distant to be laid hold ofl the immediate) workers, they form a chain by depending from the other till the object is reached, when it is at leu;] brought into contact, and made fast by cement. I shall now pass on to the remarkable observation ccj municated to Kirby by Colonel Sykes, F.R.S., and ^\ is thus narrated by Kirby in his * History, Habits, Instincts of Animals : ' — When resident at Poena, the dessert, consisting of fn cakes, and various preserves, always remained upon a smalls table, in a verandah of the dining-room. To guard agaiJ inroads, the legs of the table were immersed in four basins fiil with water ; it was removed an inch from the wall, anAJ keep ofi" dust from open windows, was covered with a tableckl At first the ants did not attempt to cross the water, but as ( strait was very narrow, from an inch to an inch and a half.s the sweets very tempting, they appear, at length, to have braij all risks, to have committed themselves to the deep, to 1 scrambled across the channel, and to have reached the oVi of their desires, for hundreds were found every morning revelli in enjoyment : daily vengeance was executed upon them uij out lessening their numbers ; at last the legs of the table t| painted, just above the water, with a circle of turpentine, at first seemed to prove an efiectual barrier, and for some ( the sweets were unmolested, after which they were again i tacked by these resolute plunderers ; but how they got them seemed totally unaccountable, till Colonel Sykes, whoofj passed the table, was surprised to see an ant drop from the i about a foot above the table, upon the cloth that covered! another and another succeeded. So that though the turpenq and the distance from the wall appeared efiectual barriers,! ANTS — GENER.iL INTELLIGENCE. 135 le resources of the animal, when determined to carry its point, Rre not exhausted, and by ascending the wall to a certain [jffht with a slight effort against it, in falling it managed to id in safety upon the table. Colonel Sykes was a good observer, so that this state- lent, standing upon his authority, ought not, perhaps, to questioned. But in all cases of remarkable intelligence [splayed by animals, we naturally and properly desire Irroboration, however good the authority may be on lich the statement of such cases may rest. I will, there- add the following instances of the ingenious and ttermined manner in which ants overcome obstacles, and lich so far lend confirmation to the above account. Professor Leuckart placed round the trunk of a tree, lich was visited by ants as a pasture for aphides, a broad )th soaked in tobacco-water. When the ants returning \me down the trunk of the tree arrived at the soaked )th, they turned round, went up the tree again to some the overhanging branches, and allowed themselves to [op clear of the obnoxious barrier. On the other hand, le ants which desired to mount the tree first examined |e nature of the barrier, then turned back and procured )m a distance little pellets of earth, which they carried their jaws and deposited one after another upon the bacco-cloth till a road of earth was made across it, over lich the ants passed to and fro with impunity. This interesting, and indeed surprising observation of bckart's is, in turn, a corroboration of an almost entical one made more than a century ago by Cardinal leury, and communicated by him to Reaumur, who Iblished it in his 'I'Histoire des Insect 93' (1734). |ie Cardinal smeared the trunk of a tree with birdlime order to prevent the ants from ascending it ; but the sects overcame the obstacle by making a road of earth, lall stones, &c., as in the case just mentioned. In lother instance the Cardinal saw a number of ants make Dridge across a vessel of water surrounding the bottom an orange-tree tub. They did so by conveying a Imber of little pieces of wood, the choice of which iterial instead of earth or stones, as in the previous case, 1 I 136 ANIMAL INTELLIGENCE. seems to betoken no small knowledge of practical engineer! ing. Biichner, after quoting these cases, proceeds to sail (loc, cit, p. 120), — The ants behaved in yet more ingenious fashion under tij following very similar circumstances. Herr G. Theuerka the painter (Wasserthorstr. 49, Berlin), writes to the authoi November 18, 1875: *A maple tree standing on the grounj of the manufacturer, Vollbaum, of Elbing (now of Dantzicl swarmed with aphides and ants. In order to check the mij chief, the proprietor smeared about a foot width of the grouil round the tree with tar. The first ants who wanted to ciosl naturally stuck fast. But what did the next ? They turiitf back to the tree and carried down aphides, which they stuck do? on the tar one after another until they had made a bridge ovJ which they could cross the tarring without danger. The aboJ named merchant, Yollbaum, is the guarantor of this stonj which I received from his own mouth on the very spot wherei it occurred. Biichner also gives the following case on the authoritJ of Karl Vogt (loc, cit., p. 128). An apiary of a friend waf invaded by ants : — To make this impossible for the future, the four legs of \i beehive-stand were put into small, shallow bowls filled wit| water, as is often done with food in ant-infested places, ants soon found a way out of this, or rather a way into theil beloved honey, and that over an iron staple with which ta stand was attached to a neighbouring wall. The staple ra removed, but the ants did not allow themselves to be defeats They climbed into some linden trees standing near, the branctsl of which hung over the stand, and then dropped upon it froJ the branches, doing just the same as their comrades do witf respect to food surrounded by water, when they drop upon il from the ceiling of the room. In order to make this imp sible, the boughs were cut away. But once more the an*! were found in the stand, and closer investigation sho^v« that one of the bowls was dried up, and that a crowd of affJ had gathered in it. But they found themselves puzzled howtJ go on with their robbery, for the leg did not, by chance, rest oi the bottom of the bowl, but was about half an inch from ill The ants were seen rapidly touching each other with tlieii antennae, or carrying on a consultation, until at last a rathej ANTS— GENERAL INTELLIGENCE. 137 ifctev ant came forward and put an end to the difficulty. It ose to its full height on its hind legs, and struggled until at ist it seized a rather projecting splinter of the wooden leg, and janaf'ed to take hold of it. As soon as this was done other [nts ran on to it, strengthened the hold by clinging, and so made little living bridge, over which the others could easily pass. The same author publishes the following very remark- Ible observation, quoted from a letter to him by Dr. EUen- lorf: — It is a hard matter to protect any eatables from these features, let the custody be ever so close. The legs of cup- 3ards and tables in or on which eatables are kept are placed in [essels of water. I myself did this, but I none the less found lousands of ants in the cupboard next morning. It was a luzzle to me how they crossed the water, but the puzzle was 3on solved ; for I found a straw in one of the saucers, which Ly obliquely across the edge of the pan and touched the leg [ tie press : this they had used for a bridge. Hundreds were rowned in the wat«r, apparently because disorder had reigned first, those coming down with booty meeting those going up. ^iit now there was perfect order ; the descending stream used 16 side of the straw, the ascending the other. I now pushed lie straw about an inch away from the cupboard leg ; a terrible tjnfus'-n arose. In a moment the leg immediately over the [ater was covered with hundreds of ants, feeling for the bridge every direction with their antennae, running back again and [iming in ever larger swarms, as though they had communicated I their comrades within the cupboard the fearful misfortune lat had taken place. Meanwhile the new-comers continued run along the straw, and not finding the leg of the cupboard lie greatest perplexity arose. They hurried round the edge of p pan, and soon found out where the fault lay. With united frees they quickly pulled and pushed at the straw, until it jain came into contact with the wood, and the communication [as again restored. Tj This observation is strikingly, though unconsciously, )nfirmed by a recent writer in the Leisure Hour (1880, ). 718-19), who having been much troubled by small red its in the tropics swarming over his provisions, placed 16 latter in a meat-safe detached from the wall and mding on four legs, each of which was placed in a little [n vessel containing water. Eight or ten days afterwards f ! 138 ANIMAL INTELLIGENCE. he found his provisions in the safe swarming with antsai before, and on investigating their mode of access to thee found — Proceeding along the whitewashed wall a string of antil going and coming from the outer door to a height of four feJ on my wall, and corresponding with that of the safe ; and looij ing between it and the wall, I discovered the secret — the brid? which these persevering little insects had made. It consisted J a broken bit of straw, which rested with one end on a nin buttress fixed to the wall, and the other on the overhanging i projecting top of the safe, which came within an inch and a hail of the wall. So they must have carried the straw up from i floor, and resting their end of it on the support they had pn pared, let it fall until its other end reached the safe, and thes crossed and completed the structure, for it was fastened at M ends with the mortar composed of their saliva and fine eartll Ruthlessly I destroyed the bridge, and moving the safe fartteT from the wall, managed to prevent their inroads for that se&scJ at least. Since then I have frequently seen short bridges, con) posed entirely of the concrete or mortar which the white anJ use to cover up their workings, extending from a damp earthef wall to anything not more than three-quarters of an inq from it. Of the Ecitons Mr. Belt says : — I shall relate two more instances of the use of a reasoniiij faculty in these ants. I once saw a wide column trying to pai along a crumbling, nearly perpendicular slope. They woulJ have got very slowly over it, and many of them would ha^ fallen, but a number having secured their hold, and reachliil to each other, remained stationary, and over them the maif column passed. Another time they were crossing a watercouil along a small branch, not thicker than a goose-quill. Tlief widened this natural bridge to three times its width by number of ants clinging to it and to each other on each sid] over which the column passed three or four deep; where excepting for this expedient they would have had to pass ot^ in single file, and treble the time would have been consumei Can it be contended that such insects are not able to determiil by reasoning powers which is the best way of doing a thing ' Another observer, writing from the same part of tlj world to Biichner, gives a still more wonderful account! the ingenuity of Ecitons in crossing water. This observd ANTS— GENERAL INTELLIGENCE. 139 Herr H. Kreplin, of Heidemiihl (Station Ducherom), Fwho lived for nearly twenty years in South America as In engineer, and had often the opportunity of seeing the jriver ants in the forests there.' He writes to Biichner, inder date May 10, 1876, as follows: — On both sides of the train, at about 10 mm. distance from iach othe:', stronger ants are to be seen, distinguishable from le others by their foxy colour and very thick heads with rigantic mandibles. These * thickheads ' play the same r6U in Jhe ant-state for which they are cast in cultured communities. [bey look after the order of the march, and allow none to turn kther to the right or left» The least confusion in the regularity If the march makes them turn round and put things straight itrain. While the procession of the brown workers streams ^n unceasingly with a swarming motion, the ' officers,' as the aatives call these thickheads, run constantly backwards and Ibrwards, ready to take the command on meeting any difficulty. Che crossing of streams by these creatures is the most interest- ig point. If the watercourse be narrow j the thickheads soon ind trees, the branches of which meet on the bank on either ^ide, and after a short halt the column set themselves in motion Dver these bridges, rearranging themselves in the narrow train rith marvellous quickness on reaching the further side. But no natural bridge be available for the passage, they travel silong the bank of the river until they arrive at a fiat sandy fehore. Each ant now seizes a bit of dry wood, pulls it into the rater, and mounts thereupon. The hinder rows push the front raes even further out, holding on to the wood with their feet and to their comrades with their jaws. In a short time the rater is covered with ants, and when the raft has grown too large to be held together by the small creatures' strength, a part Weaks itself off and begins the journey across, while the antis left on the bank busily pull their bits of wood into the water, md work at enlarging the ferry-boat until it again breaks. Phis is repeated as long as an ant remains on shore. I had often heard described this method of crossing riversj but in the fear 1859 I had the opportunity of seeing it for myself. It is remarkable that the military or driving ants of Lfrica exhibit precisely similar devices for the bridging; of Btreams, namely, by forming a chain of individuals over fhich the others pass. By means of similar chains they ilso let themselves down from trees. It must be observed, 140 ANIMAL INTELLIGENCE. I however, that these and all the above observations, beiml independently made and separately recorded, serve to corJ roborate one another so strongly that we can entertain nJ reasonable doubt concerning the wonderful facts whiciil they convey. I shall now bring these numerous instances to a clo>J with a quotation from Mr. Belt, which reveals in the mostl unequivocal manner surprising powers of observation acdl rational action on the part of the leaf-cutting ants oil South America, whose general habits we have already conJ sidered : — A nest was made near one of our tramways, and to get the trees the ants had to cross the rails, over which the waggonjl were continually passing and repassing. Every time.they camel along a number of ants were crushed to death. They perse^l vered in crossing for some time, but at last set to work anji tunnelled underneath each rail. One day, when the waggoDsl were not running, I stopped up the tunnels with stones ; but! although ffreat numbers carrying leaves were thus cut off froml the nest, they would not cross the rails, but set to work making fresh tunnels underneath them. Anatomy and Physiology of Nerve-centres and Sense-organs. The foregoing facts concerning the intelligence ofl ants fully justifies Mr. Darwin's observation that 'the! brain of an ant is one of the most marvellous atoms oil matter in the world, perhaps more so than the brain of man.' It may therefore be interesting in this particular| case to depart from the lines otherwise laid down through- out the present work, and to devote a short section to the | anatomy and physiology of this nerve-centre with its ap- pended organs of sense. The brain of an ant, then, is proportionally larger than I that of any other insect. (See Titus Grraber, ' Insects,' vol i. p. 255.) In structure, also, the brain of an ant is in advance of that of other insects, its nearest analogue beiag the brain of a bee. The superiority of development is particularly remarkable with reference to the ' stalked bodies ' of Dujardin ; and these are largest in neuter ANTS — GENERAL INTELLIGENCE. 141 )rkers, which are the most intelligent members of the ommunity. Injury of the brain causes, as in higher animals, etanic spasms and involuntary reflex movements, followed y stupefaction. An ant, whose brain has been perforated by the pointed anclibles of an amnzon, remains as though nailed to its place ; shudder runs from time to time through its body, and one of ts legs is lifted at regular intervals. It occasionally makes a ihort and quick step, as though driven by an unseen spring, )ut, like that of an automaton, aimless and objectless. If it is ulled, it makes a movement of avoMance, but falls back into ts stupefied condition as soon as it is released. It is no longer apable of action consciously directed to a given object; it either tries to escape, nor to attack, nor to go back to its ome, nor to rejoin its companions, nor to walk away ; it feels either heat nor cold, it knows neither fear nor desire for food. t is merely an automatic and reflex machine, and is exactly imilar to one of those pigeons from which Flourens removed he hemispheres of the cerebrum. Just in the same way behaves he body of an ant from which the head has been taken away. n the numerous fights between amazons and other ants, count- cases have been observed of slight injury to the brain, ess trhich have caused the most remarkable phenomena. Many of [lie wounded were seized with a mad rage, and flung them- elves at every one that came in their way, whether friend or loe. Others assumed an appearance of indifference, and walked Brenely about in the midst of the fighting. Others exhibited sudden failure of strength ; but they still recognised their lemies, approached them, and tried to bite them in cold [lood, in a way quite foreign to the behaviour of healthy ants. They were also often observed to run round and round in a ircle, the motion resembling the manege, or riding-school ction of mammals, when one of the crura cerebri has been emoved. If an ant is cut in half through the thorax, so that the great [erve ganglia of the pro-thorax remain untouched, the behaviour the head shows that intelligence also remains untouched. nts mutilated in this way try to go forwards with their two g legs, and beg with their antennsB for their com- mons' aid. If one of these latter lets itself be stopped, then [e observe a lively interchange of thanks and sympathy ex- ressed by the actively moving antennae. Forel placed near to ( .1 142 ANIMAL INTELLIGENCE. each other two such mutilated bodies of the F. ru/ibarbis. TheJ conversed with each other in the above-described way, and aJ peared each to beg for help. But when he put in some simJ larly mutilated ants of a hostile species, F. sanguinea, M picture was changed; war broke out between these cripple.! just in the same way and with the same fury as between per] feet ants.' The antennae appear to be the most important of til sense-organs, as their removal produces an extraordinarl disturbance in the intelligence of the animal. An ant « [ mutilated can no longer find its way or recognise coul panions, and therefore is unable to distinguish betweeJ friends and foes. It is also unable to find food, ceases t[ engage in any labour, and loses all its regard for larvjj remaining permanently quiet and almost motionless, somewhat similar disturbance, or rather destruction, of til mental faculties is observable as a result of the saif mutilation in the case of bees.^ ' Biichner, Geisteslchen der Thiere, English translation, p. 49. 2 While this work is passing through the press, an interesti!i| Essay has been published by Mr. MacCook on the Honey -making Ai I am not here able to refer to this Essay at greater length, but haij done so in a review in Nature (March 2, 1882.) — G. J. R. i 143 CHAPTER IV. BEES AND WASPS. [rranging this chapter under the same general headings the one on ants, we shall consider first — Powers of Special Sense. Bees and wasps have much greater powers of sight mn ants. They not only perceive objects at a greater kstance, but are also able to distinguish their colours. [his was proved by Sir John Lubbock, who placed honey slips of paper similarly formed, but of different colours ; [hen a bee had repeatedly visited a slip of one colour (A), transposed the slips during the absence of the bee ; on Is return the insect did not fly to slip B, although this now [icupied the position which had been previously occupied slip A, but again visited slip A, although this now occu- Eed the position which had been previously occupied by [ip B. Therefore, as these experiments were again and jain repeated both on bees and wasps with uniform re- Its, there can be no question that the insects by their rst visits to slip A established an association between le colour of A and the honey upon it, such that, when ley again returned and found B in the place of A, they ^ere guided by their memory of the colour rather than their memory of the position. It was thus shown that 16 insects could distinguish green, red, yellow, and blue. these experiments also brought out the further fact that 3th bees and wasps exhibit a marked preference for some )loiirs over others. Thus, in a series of black, white, lellow, orange, green, blue, and red slips, two or three lees paid twenty-one visits to the orange and yellow, and i]y four to all the other slips. The slips were then moved, 144 ANIMAL INTELLIGENCE. after which, out of thirty-two visits, twenty-two were the orange and yellow. Another colour to which a simili; preference is shown is blue. As regards scent, Sir John found that on putting a h drops of eau de Cologne at the entrance of a beehivj ' immediately a number (about 15) came out to see wlia was the matter.' Other scents had a similar effect ; bj on repetition several times the bees became accustom^ to the scent, and no longer came out. As in ants, so in bees. Sir John's experiments failed] yield any evidence of a sense of hearing. But in this conne tion we must not forget the well-known fact, fir^t obserw by Huber, that the queen bee will answer by a certain soui;| the peculiar piping of a pupa queen ; and again, by makin a certain cry or humming noise, will strike consteraati] suddenly on all the bees in the hive — these remaining fj a long time motionless as if stupefied. Sense of Direction, The following are Sir John Lubbock's ohservatioii| upon this subject in the case of bees and wasps : — Every one has heard of a * bee-line.* It would be no correct to speak of a wasp-line. On August 6 I marked | wasp, the nest of which was round the corner of the house, that her direct way home was not out at the window by whid she had entered, but in the opposite direction, across the rooii to a window which was closed. I watched her for some ho^l^J during which time she constantly went to the wrong windoJ and lost much time in buzzing about at it. For ten consecutii[ days this wasp paid numerous visits, coming in at the op window, and always trying, though always unsuccessfully, return to her nest in the * wasp-line ' of the closed window- buzzing about that window for hours at a time, thoii^ eventually on finding it closed she returned and went rou through the open window by which she always entered; This observation shows how strong must be the instincl in a wasp to take the shortest way home, and how muc| the insect depends upon its sense of direction in so doina It also shows how long a time it requires to learn by indij vidual experience the properties of a previously unknot BEES AND WA8PH SENSE OF DIKECTION. 14') Ibstance such as glass. But to this latter point we shall lesently have occasion to return. Next we must adduce evidence to show that in way- iding the * sense of direction ' in bees appears to largely supplemented by observation of particular iects. Sir John Lubbock observes : * I never found bees to turn if brought any considerable distance at once. By [ing them, however, some twenty yards each time they me to the honey, I at length trained them to come to room ; ' that is to say, bees require to learn their way tie by little before they can return to a store of honey lich they may have been fortunate enough to find ; their leral sense of direction is not in itself a sutiicient lide. This, at least, is the case where, as in the experi- ^nts in question, the bees are carried from the hive to store of honey (here a distance of less than 200 rds): possibly if they had found the honey by them- Ives flying towards it, and so probably taking note of jects by the way, one journey might have proved suffi- [nt to teach them the way. But, whether or not this iild have been the case, the fact that when carried they mired also to be taught the way piece by piece, is con- [sive proof that their sense of direction alone is not icient to enable them to traverse a route of 200 yards 3cond time. The same result is brought out by other experiments iducted on a different plan, though not apparently |h this object. ' My room is square, with two windows the south-west side, where the hive was placed, and on the south-east.' Besides the ordinary entrance outside, the hive had a small postern door opening the room. 6.50 a bee came out through the little postern door. After she had fed, she evidently did not know her way home ; so I put her back. 7,10 she came out again. I again fed her and put her I back. 110.15 she came out a third time ; and again I had to put her back. L 146 ANIMAL INTELLIGENCE. At 10.55 she came out again, and still did not remember tk. door. Though I was satisfied that she really wisy to return, and was not voluntarily remaining outside f still, to make the matter clear, I turned her out s| a side window into the garden, when she at onj returned to the hive. At 11.15 she came out again ; and again I had to show hertj way back. At 11.20 she came out again; and again I had to show hertJ way back (this makes five times) ; when, however,-! At 11.30 she came out again after feeding, she returned straifj to the hive. At 11.40 she came out, fed, and returned straight to the hive At 11.50 she came out, fed, and returned straight to the hiv she then stayed in for some time. At 12.30 she came out again, but seemed to have forgotten tlJ way back ; after some time, however, she found ti^ door and went in. Again : — August 24 at 7.20 a bee came through the em : I fed her ; and though she was not frightened or disturb when she had finished her meal she flew to the window and 1 evidently lost her way ; so at 8 o'clock I in pity put her b myself. August 29. — A bee came out to the honey at 10.10; atlCJ she flew to the window, and remained buzzing about till 11,!| when, being satisfied that she could not find her way, I her in. Nay, even those who seemed to know the postern, if taksj near the other window, flew to it, and seemed to have themselves. This cost me a great many bees. Those which got intoEi room by accident continually died on the floor near i:j window. These observations show that even when a bee is ii carried from the hive to the honey, but heraeU flies toi her sense of dirf action is not alone sufficient to enable tl to find the way back to the hive — or, rather, to the unaj customed entrance to the hive from which she had coe out. Probably if the side window had been open, the would have returned to the hive round the corner of tlJ house, and through the entrance to which she was nicj accustx)med. But as it was she had to learn, by five BEES AND WASPS — SENSE OF DIRECTION. 147 h ioumeys, the way between the postern entrance and le food. But the following observation on a wasp is in this eon- iection the most conclusive. A marked wasp visited honey exposed in the room [efore mentioned. ' The next morning she came — it 7.25, and fed till 7.28, when she began flying about the room and even into the next ; so I thought it well to put her out of the window, when she flew straight away to her nest. My room, as already mentioned, had windows on two sides ; and the nest was in the direction of a closed window, so that the wasp had to go out of her way in going out through the open one. ^t 7.45 she came back. I had moved the glass containing the honey about two yards ; and though it stood conspi- cuously, the wasp seemed to have much difliculty in finding it. Again she flew to the window in the direction of her nest, and I had to put her out, which I did at 8.2. i.t 8.15 she returned to the honey almost straight. 8.21, she flew again to the closed window, and apparently could not find her way ; so at 8.35 I put her out again. It seems obvious from this that wasps have a sense of direction, and do not find their way merely by sight. it 8.50 back to honey, and 8.54 again to wrong window ; but finding it closed, she took two or three turns round the room, and then flew out through the open window. It 9.24 back to the honey; and 9.27 away, first, however, paying a visit to the wrong window, but without alighting. [t .9.36 back to the honey, and 9.39 away, but, as before, going first to wrong window. She was away therefore 9 minutes. „ 9.53 away, this time straight. „ 11 10. 7 9.50 10 10.19 10.35 10.47 11. 4 11.21 11.34 11.49 5> » J> >5 » )} M 10.22 10.39 10.50 11. 7 11.24 11.37 11.52 i) » >» )) it 1) »> tt j> ») >> )> >j >> 55 11 12 13 9 14 14 10 1 5> 5> » » » >» » »> L 2 148 ANIMAL INTELLIGENCE. \ 12. 3 bock to 12. 5 aw the honey, 12.13 12.15i , 12.25 12.28 , 12.39 12.43 , 12.54 12.57 , 1.15 1.19 , 1.27 1.30 , 12. 5 away. Away therefore U minutiea^»)bstructed to a n it if a a a 8 10 11 11 18 8 minutes,'! &c., &c., the way being now clearly well learnt. But that the sense of direction is of much service t(| bees in finding the locality of their hives seems to k\ indicated by the following observation thus narrated, oil the authority of the authors themselves, by Messrs. KirbJ and Spence : — In vain, during my stay at St. Nicholas, I sallied out a every outlet to try to gain some idea of the extent and formt the town. Trees, trees, trees, still met me, and intercepted ttJ view in every direction ; and I defy any inhabitant bee of M rural metropolis, after once quitting its hive, ever to gain I glimpse of it again until nearly perpendicularly over it. Ikl bees, therefore, .... must be led to their abodes by instinct, iJ The observation, however, is not so conclusive as iJ authors suppose ; for there is nothing to show that tlif bees did not take note of particular objects on their a J customed routes, and so learn these routes by stages, ij would be worth while in this connection to try the effeJ of hooding the eyes of a bee, or, if this were deemed to| disturbing an experiment, removing the hive bodily to i distance from its accustomed site, and observing whethel the bees start away boldly as before for long flights, (J learn their new routes by stages. In this connection I may quote the following. Mr. John Topham, of Marlborough House, Torquajj writing to * Nature,' ^ says : — On October 29, 1873, I removed a hive of bees in ml garden, after it was quite dark, for a distance of 12 yards froij the place in which it had stood for several months; between its original situation and the new one there wasj bushy evergreen tree, so that all sight of its former place ' ' Vol. ix. p. 484. BEES AND WASPS— SENSE OF DIRECTION. 149 11 minuter ^l)bstructed to a person looking from the new situation of the ive. Notwithstanding this change, the bees every day flew to the locality where they formerly lived, and continued flying around ^he site of what had been their home until, as night came on, they many of them sank upon the grass exhausted and chilled W the cold. Numbers, however, returned alive to their new position, after having looked in vain for their hive in its old place. At night I picked the exhausted bees up, and having festered warmth to them (by leaving them for a time on my oat-sleeve), I returned them to their companions. Here was an illustration that the faculty of memory was liiperior to that of observation ; but that was not all. Nearly fevery bee which I picked up during the 23 days through which [his effort of memory lasted was an old one, as was easily de- luced from observing the worn edges of the wings ; showing aat whilst the young insects were quick in receiving new im- pressions and in correcting errors, the nervous system of the fid bees continued acting in the direction which early habit had feded. So true it is that *one touch of nature makes the rhole world kin.* A closely similar observation has been told me by a Hend, Mr. Greorge Tmner. He found that when he |emoved a beehive only a yard or two from its accus- omed site, the bees, on returning home, flew in swarms round the latter, and for a long time were unable to find le hive. And several other similc«r cases might be Iduced. Lastly, Thompson says : — It is highly remarkable that they [bees] know their hive [lore from its locality than from its appearance, for if it be re- loved during their absence and a similar one be substituted, aey enter the strange one. If the position of a hive be changed, lie bees for the first day take no distant flight till they have horoughly scrutinised every object in its neighbourhood.^ On the other hand, the writer of the article on ' Bees ' the * Encyclopaedia Britannica ' says that in certain parts If France it is the habit of bee-keepers to place a number [f hives upon a boat, which, in charge of a man, floats lowly down a river. The bees are thus continuously panging their pasture-ground, and yet do not lose their ocomotive hives. ' Passions of AnimalSy p. 53. f: • i_ f:- u , ■ 1 1- ■ 'r i I ■'- • \ i <: 4 150 ANIMAL INTELLIGENCE. r I It may be here worth while to add, parentheticallj, ^ the only authentic observation with which I am acquaintel concerning the distance that bees are accustomed forage, the following statement of Prof. Hugh BlackburB,[ Writing from Glasgow University to * Nature,' ' he savil that bees ave found in a certain peach-house every spriiJ at the time of blossom, although, so far as he can ascerf tain, the beehives nearest to the peach-house in questk| are his own, and these are at a distance of ten miles. On the whole, then, and in the absence of furtlieii experiments, we must conclude it to be probable that tlj sense of direction with which hymenopterous insects ar?, as shown by some of Sir John Lubbock's experiments, ur, questionably endowed, is of no small use to them in firj; ing their way from home to food and vice versa ; althoiii I it appears certain, from other of his experiments, tliJ this sense of direction is not in all cases a sufficient guid ,1 and therefore requires to be supplemented by the definii:| observation of landmarks. But the most conclusive evidence on this latter poiii] is afforded by a highly interesting observation of )tl Bates on the sand-wasps at Santurem, which may here Ivl suitably introduced, as the insects are not distantly alliedl He describes these animals as always taking a few tiLiI in the air round the hole they had made in the sanl before leaving to se«k for flies in the forest, apparently iil order to mark well the position of the burrow, so that o:| their return they might find it without difficulty. TtiJ observation has been since confirmed in a striking maniit: by Mr. Belt, who found that the sand-wasp takes the luoi precise bearings of an object the position of which sli desires to remember. This observation is so interestiul that it deserves to be rendered in extenso : — A specimen of Polistes carni/ex (i.e. the sand-wasp noticej by Mr. Bates) was hunting about for caterpillars in my gardeJ I found one about an inch long, and held it out towards it o| the point of a stick. It seized it immediately, and eommeno biting it from head to tail, soon reducing the soft body to a niaij of pulp. It rolled up about one-half of it into a ball, and pK » Vol. xii. p. 68. BEES AND WASPS — MEMORY. 151 jired to carry it off. Being at the time amidst a thick mass of fine-leaved climbing plant, it proceeded, before flying away, take note of the place where it was leaving the other half. Fo do this, it hovered in front of it for a few seconds, then took lall circles in front of it, then larger ones round the a\ hole ilant. I thought it had gone, but it returned again, and had Inother look at the opening in the dense foliage down which ae other half of the caterpillar lay. It then flew away, but lust have left its burden for distribution with its comrades at jhe nest, for it returned in less than two minutes, and making be circle around the bush, descended to the opening, alighted In a leaf, and ran inside. The green remnant of the catei- lillar was lying on another leaf inside, but not connected with [he one on which the wasp alighted, so that in running in it lissed it, and soon got hopelessly lost in the thick foliage. boming out again, it took another circle, and pounced down on le same spot again, as soon as it came opposite to it. Three [mail seed-pods, which here grew close together, formed the larks that I had myself taken to note the place, and these the rasp seemed also to have taken as its guide, for it flew directly (own to them, and ran inside ; but the small leaf on which the ragment of caterpillar lay not being du'ectly connected with Iny on the outside, it again missed it, and again got far away rom the object of its search. It then flew out again, and the ime process was repeated again and again. Always when in ircling round it came in sight of the seed-pods down it pounced, [lighted near them, and recommenced its quest on foot. I was kirprised at its perseverance, and thought it would have given »p the search ; but not so, it returned at least half-a-dozen jimes, and seemed to get angry, hurrying about with buzzing rings. At last it stumbled across its prey, seized it eagerly, id as there was nothing more to come back for, flew straight Iff to its nest, without taking any further note of the locality. Such an action is not the result of blind instinct, but of a linking mind ; and it is wonderful to see an insect so differ- itly constructed using a mental process similar to that of lan. Memory. We may here first allude to an observation of Sir [ohn Lubbock already quoted in another connexion (see 147). It is here evident that the wasp, after find- ig the store of honey in the room, and after finding lie window closed in the * wasp-line ' direction to its nest, ■^;f« M. 152 ANIMAL INTELLIGENCE. required three repeated lessons from Sir John before !