Chapter XII: Mental Evolution (2)

And what, we may now proceed to ask, is the physiological or kinetic aspect of this metakinetic process? The answer to this question involves the conception of what I would term "interneural evolution." Just as the environment of a conceptual idea is constituted by other conceptual ideas, so is the environment of its neural concomitant constituted by the other neural processes in the brain. Just as no idea can get itself accepted if it be in incongruity with the system of ideas among which it is introduced, so, too, can no neural process become established if it be not in harmony with the other neural processes of the cerebral hemispheres. The brain is a microcosm; its neural processes are interrelated; and _the environment of any neural process is constituted by other neural processes_.

A little consideration will show that this must be so; that it is only the physical or kinetic aspect of what is freely admitted when the mental or metakinetic aspect is under consideration. If it be admitted that states of consciousness are determined by other states of consciousness, and that states of consciousness are the concomitants of certain neural processes in the brain, it follows as a logical necessity that brain-neuroses, however originating, are determined in their evolution by other brain-neuroses; and that there has been a brain or interneural evolution, distinct from and yet intimately associated with the evolution of other bodily structures and activities. The more closely and directly brain-neuroses are associated with immediate activities, the more closely implicated is interneural evolution in the process of organic elimination through natural selection. But when long trains of neuroses take place in only remote and distant connection with other bodily activities, they are removed from the process of elimination through natural selection, and interneural evolution is allowed to proceed comparatively untrammelled.

I have already indicated my belief that abstraction (isolation), analysis, and conceptual ideas have been rendered possible through language, and are excellences unto which the lower animals do not attain. Hence I regard this comparatively untrammelled phase of interneural evolution as something essentially human, something which differentiates man from brute. And I would correlate man's greatly developed brain--inexplicable, I think, by natural selection alone--with this later and special phase of interneural evolution. Even in the lowest savage this brain-evolution has proceeded a long way. I am not fitted in this matter to offer an opinion which would carry much weight. But from all that I have read I gather that savages have in all cases elaborated a complex--often a highly complex--interpretation of nature and theory of things. The interpretation may seem _bizarre_ and incongruous enough _to us_, full of fetishism and strange superstitions, but it is an interpretation; to the savage it presents no incongruity; to him the incongruity is in the oddly assorted beliefs of the missionary. His system of ideas is, in fact, one of the many possible systems to which mental evolution may give rise.

For what we call systems of thoughts, interpretations of nature, theories of things, are so many genera and species which have resulted from this later phase of metakinetic evolution. Our methods are at present too coarse, our powers too limited, to enable us to determine these species from their kinetic aspect. The brains of Kaffir and Boer, of ploughboy and merchant, of materialist and idealist, are too subtly wrought to enable us to trace the systems of kineses which were the concomitants of their scheme of beliefs. But we can learn something of the genera and species from their metakinetic aspect as symbolized through language and other bodily activities. They fall into certain groups, fetishistic, spiritualistic, materialistic, idealistic, monistic, and so on, and within these groups there are sub-divisions. This is not the place to consider them or discuss their characteristics. What I wish to note about them is that, diverse as they seem and are, each is a coherent product of mental evolution. In each, all that is incongruous to itself has been or is being eliminated.

There are some people, however, who are surprised at the incongruity of interpretations of nature among each other. Fetishism, they say, has been proved to be utterly false. It constitutes a hideous and grotesque delirium. How can that which is utterly and completely false to nature have had a natural evolution? Now, for the _élite_ of the Aryan race, whose systems of ideas have been moulded in accordance with the conceptions of modern science, no doubt the fetishism of the poor savage seems sufficiently incongruous and grotesque. So, too, does the system of ideas of the Right Rev. Bishop of ---- appear no doubt, to the learned and eminent Professor ----, and _vice versâ_. And so, too, no doubt, does the system of ideas of the white man (who introduces firearms and firewater, and preaches the gospel of forgiveness and temperance) appear to the poor savage. Each in his degree wonders how this falsity, this incongruity, can have had a natural genesis. But in each case the falsity and the incongruity is not within the system itself, but between different systems.

Once more, I repeat that if the individual nature of the systems of ideas be not adequately grasped, the nature of mental evolution will not be apprehended. States of consciousness can only be determined by other states of consciousness; and states of consciousness are for the individual subject, and for him alone. Conceptual ideas are states of consciousness; and "falsity to nature" means, and can only mean, incongruity with the environing states of consciousness in the individual mind. For the savage there is no falsity to nature in his fetishism. The idea presents no incongruity with his system of ideas; no more incongruity than filed teeth, flattened head, or pierced nose do to his standard of beauty. It is with _our_ system of ideas (i.e. mine or yours) that his fetishism is false and incongruous. The falsity or incongruity, I repeat, is not within the system itself, but between different systems.

It may still, however, be said--Only one interpretation of nature can be true; all others must be false. And the falsity is not merely incongruity with other ideas in other systems of thought or belief; it is falsity to the plain and obvious facts of nature.

We may freely admit that only one interpretation of nature can be true. But who is to determine which? Who can decide the question between monist and materialist? Who dare arbitrate between the bishop and the professor? The criterion of fitness in this case, as in others, is survival; and who can say what existing interpretation of nature (if any) shall outlive all its competitors? Who can say what will be the nature of the further evolution of any existing philosophical creed? The elimination of the false is a slow and gradual process; and many degenerate systems of ideas may linger on in the darker corners of the world of men. False or out of harmony as they seem to be with the higher phases of development; false or out of harmony as they would be with a different and more exalted environment; they are not false or out of harmony with the environment in the midst of which we find them; they are not false or out of harmony with "the plain and obvious facts of nature," as these exist for the ill-developed or savage mind.

The plain and obvious facts of nature, as interpreted by men of science in 1890, have simply no existence for the untutored or the savage intellect. For him they have not emerged into the light of consciousness. But while we cannot blame the savage for entertaining ideas which are false to facts which for him have no existence, we may none the less believe that his system of ideas is not among those which are destined to become predominant species. So far as we can judge, the winning species among systems of ideas and interpretations of nature are those in which the greatest number of ideas are fused into harmonious synthesis; in which all the ideas are congruous, few or none neutral; and in which the abstract or conceptual ideas, when brought into contact with concrete or perceptual states of consciousness, are found to be in harmony and congruity therewith.

There is one more question in this connection on which I must say a few words. How, it may be asked, has the world become peopled, for many primitive and savage folk, with a crowd of immaterial spiritual essences, so that it is scarcely too much to say that, for some of these peoples, everything has its double; and there is no material existence that has not its spiritual counterpart?

I would connect this almost universal tendency with the origin of abstract ideas (isolates) through language. When the named predominant gave rise to the isolate (see p. 374), it could scarcely fail that the primitive speakers and thinkers should tend to regard those qualities or properties which they could isolate in thought (conceptually) as also isolable in fact (perceptually). And we may well suppose, though this is, of course, hypothetical, that one of the earliest severances to be thus effected through isolation was the severance of mind and body. The first phenomena that the nascent reason would endeavour to explain would probably be those of daily life and almost hourly experience. Many familiar facts would seem to point to the temporary or permanent divorce of the part which is conscious and feels, from the part which is tangible and visible. During wakeful life the two are closely associated. The visible part, or body, is conscious. But during sleep, or under the influence of a heavy blow, the visible part, which before was conscious, is conscious no longer. The conscious part is, therefore, absent, but returns again after a while. On death the conscious part returns no more. The divorce of the two has become permanent.

And then comes in the confirmatory testimony of dreams. In dreams the savage has seen his enemy, though that enemy's body was far away. Here, then, is the spirit which has left the body during sleep. In dreams also the slain enemy or the dead chief appears. The spirit, permanently divorced from the body, still walks the earth in spirit-guise.

Many occurrences would seem like the fulfilled threats of dead enemies or the fulfilled promises of dead ancestors. How can these be explained? Are they not produced by the ghost of the departed enemy, by the spirit of the deceased ancestor? And if these spirits are still powerful to act, why not petition them to act in certain ways?

Probably primitive man would explain all activities anthropomorphically. What knows he of gravitation or the laws of the winds? He knows himself as agent, and attributes his activities to the immaterial spirit within him; for when this is absent during sleep or in death these activities cease. All acting things might, therefore, come to be regarded as dual in their nature--possessed of a sensible material bodily part, and an insensible active spiritual part. And thus the whole world might be peopled with living existences of the spiritual order.

Now, whether the fetishistic faith arose in some such way as this or not--and we can never know how it arose, but can only guess--there would be nothing in such primitive explanations which would violate the law of congruity. They would have, therefore, a perfectly natural genesis. The attempted interpolation at such a stage of primitive reason of any modern scientific conception would be futile. It would at once be rejected through incongruity.

The history of scientific conceptions seems to show that they were first adopted with regard to phenomena on the very horizon of thought--in regions, that is to say, most remote from the central citadel of the soul. Only gradually have they, little by little, encroached upon this centre; and the application of them to physiology and psychology is a matter of quite modern times. Even to-day only a minority, but an increasing minority, of thinkers are prepared indissolubly to unite the mind and body, so long divorced in thought, so completely united, as many of us believe, in their essential being.

I have now, I trust, illustrated at sufficient length the principle of elimination through incongruity in interneural and its associated metakinetic or mental evolution. This, however, like natural selection, is a matter of guidance; we have still to consider the question of origin.

In truth, we know too little on the subject to enable us to discuss it with much profit. From the kinetic or organic point of view, neural variations take their place among the other variations, the origin of which, as we have already found, is so hard to account for. There may be a tendency for neural vibrations to mutually influence each other (like two clocks placed side by side), and thus gradually to drag each other into one harmonious and congruous rhythm. But this, though not improbable, is purely hypothetical. There is the hypothesis of the inheritance of acquired variations, the increased congruity acquired by the parent being in some degree transmitted to the offspring. There is the view which Mr. Wallace adopts[KM] with regard to the origin of accessory plumes, that such variations may be due to "a surplus of strength, vitality, and growth-power, which is able to expend itself in this way without injury," and not without profit. The development of the social habit, the mutual aid and protection thus afforded, may well have left a balance of the life-energy, previously employed in individual self-preservation, available for this purpose. And then there is always the hypothesis of favourable fortuitous variations to fall back upon.

On only one of these points do I propose to say a few words--that of the possible inheritance of acquired variations.

Let us restate the problem here for the sake of clearness. There is, according to the suggestion put forward in this chapter, an interneural evolution, leading to an harmonious development of the neuroses in the individual brain. But this special evolution of the brain is nowise independent of the more general evolution of the body. The human being, as an organism, is still subject to natural elimination and human selection. Elimination through the action of surrounding physical conditions, although it has played some part in the evolution of man, is not a factor of the first importance. Elimination through enemies is more important, but has not much bearing on the question at present before us--the evolution of the conceptual. Elimination by competition, again, though a factor of yet greater importance in human evolution, has, nevertheless, so far as individuals are concerned, but little bearing on our present question. Few are eliminated through the absence of the conceptual faculty. Natural elimination, then, is, as Mr. Wallace well pointed out, practically excluded in this matter. No doubt, in the struggle between tribes and nations, that community is most likely to be successful in which there is rational guidance. No doubt, during the earlier phases of the development of man on our islands, the elimination of the irrational was a factor in progress. But if we take the last three centuries of English history, I doubt whether it can be shown that there has been much elimination determined by the relative absence of conceptual ideas and emotions.

Human selection has been a much more important factor. Those individuals which showed the higher types of intellectual thought have been constantly selected. Riches, rank, and social position have been bestowed upon them. Of course, there have been exceptions; great intellects have been allowed to languish in their lifetime, and have only obtained recognition through their works after death. But every day there is less chance of a genius dying in a garret. And the best intellects, being thus selected and chosen out from among their fellow-men, form to some extent a distinct social class. Segregation is thus effected; and intermarriage takes place within this intellectual caste, with the result that the conditions are eminently favourable for the inheritance of intellectual qualities.

Now, is this process of selection of the intellectual, this segregation into a caste, and the inheritance of innate intellectual qualities sufficient to account for the facts of intellectual progress; or must we call in to our aid the inheritance of individual increments? I confess I cannot say. Direct and satisfactory evidence, one way or the other, is almost impossible to obtain.

Must we, then, leave the question undecided? I think we must so far as direct evidence is concerned. I may have a general belief that there has been some transmission of acquired increment of intellectual faculty. But unless I can substantiate it by definite facts, I cannot expect to convince any one who holds the opposite view. And definite facts of sufficient cogency I am unable to adduce. It is practically impossible to exclude the influence of human selection; and unless we can do this the followers of Dr. Weismann will not be satisfied.

Still, general belief--which means the net result of one's consideration of the subject--counts for something. We must remember the question is one of origin, and not of guidance. The guidance of human selection is unquestioned and unquestionable. But when we consider the intellectual progress of the last three centuries, and ask whether all this has originated in fortuitous brain-variations, which human selection has simply picked out from the total mass of available material, an affirmative answer seems to me a little difficult of acceptance. There seems to have been a definite tendency to vary in this particular direction, a general raising of the intellectual level, which is difficult to account for unless it be due to the persistent employment of the intellectual faculties.

To put the matter in another way. I do not think that, during the last three centuries, there has been a large amount of elimination of the unintellectual. Such elimination as there has been of this nature has probably been more than compensated by the slower rate of multiplication of the intellectual classes. Elimination, then, in this matter may be practically disregarded. But it is obvious that selection, without the removal or exclusion of the non-selected, does nothing to alter the _general level_[KN] with regard to the particular quality or faculty concerned. It is merely a classification of the individuals in order of merit in this particular respect. It is, in a word, a segregation-factor. It arranges the individuals in classes, but it does not alter the position of the mean around which they vary.

Let me explain by means of an analogous case. Fifty boys, who have been admitted to a public school, await examination in a class-room. They are at present unclassified, but there is a mean of ability among the whole fifty. A week afterwards they are distributed in different forms. Some are selected for a higher form, others have to take a lower place. But though selection has classified the material, it has not altered the position of the mean of ability among the fifty boys. This can only be done by expelling a certain number or excluding them from the school.

Granted, therefore, that elimination is practically excluded, human selection can at most classify the individuals according to their intellectual faculties. It cannot raise the mean standard of intellectuality. If, therefore, this mean standard has been raised during the last three centuries, there has been a tendency to vary in this particular direction, which _may_,[KO] to say the least of it, be due to the inheritance of individual increment.

I am, of course, aware that the matter is complicated by the increased and increasing diffusion of knowledge through the printing-press and by the extension and improvement of education. But education, to take that first, though it may raise the level of each generation, can have no cumulative effect. For the effects of education cannot, on Professor Weismann's hypothesis, be inherited. You may educate brain and muscle in the individual, but his heir will inherit no good or ill effects therefrom. Each generation goes back and starts from the old level. There is no summation of effect; or, if there is, it tells so far against Professor Weismann.

And with regard to the diffusion of knowledge, this, though it brings more grist to the intellectual mill, can have no effect in raising the mean standard of excellence in the mill itself. There is more to grind; but this does not improve the grinding apparatus; or, if it does, it tells so far against Professor Weismann's hypothesis. To vary the analogy, the diffusion of knowledge increases the store of available food; but it does not bring with it any additional power of digesting the food; or, if it does, it may be through inherited increments of mean digestive power.

It may, however, be maintained that there is no conclusive proof that the mean intellectual level of Englishmen to-day is any higher than it was in the days of the Tudors. If so, of course, my argument falls to the ground. I have no desire to dogmatize on the subject. I merely set down the reasons, such as they are, and for what they are worth, which lead me to entertain a general belief that the intellectual progress of Englishmen during the past three hundred years has been in part due to the inheritance of individually acquired faculty.

* * * * *

Mental evolution, then, is the metakinetic equivalent of interneural, or, in us vertebrates, brain-evolution. The brain forms a kinetic system in some sense independent of, and yet in constant touch with, the kinetic system of the world around. Its kineses, though they do not resemble, yet more or less accurately represent or symbolize, the kineses of the surrounding universe. As the kineses of the world around are interdependent and harmonious, so are the neural kineses of the brain interdependent and harmonious. And no modification of this kinesis which is out of harmony with the kinetic system already established in the brain can be incorporated with that existing system. Such attempted modification is eliminated through incongruity.

Associated with this brain-kinesis, and forming its inner aspect, is a metakinetic system in which the higher manifestations rise to the level of full consciousness; others form sub-conscious states; others are unconscious. But the whole form a coherent system answering to the coherent kinetic system.

Consciousness is thus associated only with the phenomena of that kinetic microcosm which we call the brain (or other interneural system). Obviously, therefore, it does not and cannot deal directly with anything outside the brain. Its knowledge is solely and entirely a knowledge of the representative occurrences of the interneural system. But out of these occurrences a surrounding world of phenomena is constructed in mental symbolism.

The brain itself, however, is part of the world of phenomena thus constructed in mental symbolism; and the world, therefore, dissolves in pure idealism, leaving only a fleeting series of states of consciousness, if we do not assume the existence of a system of "things in themselves" (noumena), of which kineses and metakineses are the phenomenal manifestations. Whether the "things in themselves" in any sense resemble their phenomenal manifestations, we cannot say. It is as difficult philosophically to conceive that they can as it is practically to conceive that they do not. And since, whether they do or do not, the world we live in is phenomenal; since it is to phenomena that we have to adapt our conduct; since it is with phenomena that all our thoughts and emotions have reference; since the world we construct in mental symbolism is the world in which we live and move and have our being; it is not only convenient, but logically justifiable, to call this world of phenomena the really existing world for us human-folk and other sentient organisms.

As in the kinetic interneural system, or brain, so, too, in the metakinetic system, no modification of the metakinesis which is out of harmony with the existing metakinesis can be incorporated therewith. Such attempted modification is eliminated through incongruity.

In the lower stages of mental evolution, those which belong to the perceptual sphere, where the neuroses are closely connected with the life-preserving activities of the organism, the survival or non-survival of the system of neuroses is largely dependent on the fitness of the associated activities to the conditions of life. But in the higher stages of mental evolution, those which belong to the conceptual sphere, the connection of certain brain-neuroses with life-preserving motor-activities becomes less close and direct. The corresponding ideas, thoughts, and emotions become floated off into a more abstract region. Here the system of ideas, as such, that is to say, so far as they are removed from life-preserving activities, is determined mainly by the law of congruity. But there are several such systems. There are, indeed, as many systems as there are minds; but these may be classified in several distinct groups, which we may liken to genera and species. These are the various interpretations of nature, theories of things, and the like; the systems of ideas, thoughts, conceptions, emotions, beliefs, which, as we say, belong to us, each and all, and which determine to which metakinetic species we belong. These are the highest products of mental evolution; and among them there is, so to speak, a struggle, if not for existence, at any rate for prevalence. Which shall eventually prevail--a spiritual interpretation of nature, a material interpretation, a monistic interpretation, or other, who shall say? But, so far as we can judge, the winning species among systems of ideas and interpretations of nature are likely to be those in which the greatest number of ideas are fused into harmonious synthesis; in which all the ideas are congruous; and in which the abstract or conceptual ideas, when brought into contact with concrete or perceptual states of consciousness, are found to be in harmony and congruity therewith.

NOTES

[JY] "Contributions to the Theory of Natural Selection," p. 365.

[JZ] I consider that an apology is needed for the coinage of this and
of two or three other words, such as "construct," "isolate," and
"predominant." I can only say that in each case I endeavoured to
avoid them, but found that I could not make my meaning clear, or
bring out the point I wished to emphasize without them.

[KA] "Science of Thought," pp. 286, 287.

[KB] "Science of Thought," p. 279.

[KC] I use "substance" here in its philosophical sense.

[KD] Quoted in Professor Veitch's "Hamilton," p. 77.

[KE] T. M. Herbert, "The Realistic Assumptions of Modern Science
Examined," 2nd edit., p. 123.

[KF] "Science of Thought," p. 571.

[KG] Strictly speaking, of the brain; but since the brain has no
organic independence of the body, it is best here to focus
attention on the unity of the organism.

[KH] I ought not to pass over without notice the "psychological scale"
which Mr. Romanes introduces in a table prefixed to "Mental
Evolution in Animals." It would be unjust to criticize this too
closely, for it is admittedly provisional and tentative. If such a
scheme is to be framed, I would suggest that the various phyla of
the animal kingdom be kept distinct. I question, however, whether
any one can produce a scheme which any other independent observer
will thoroughly endorse. And I am inclined to think that the
wisest plan is to tabulate the kinetic manifestations which we can
actually observe rather than the metakineses of which we can have
no independent knowledge.

[KI] _Contemporary Review_, July, 1886. See Clifford's "Lectures and
Essays," vol. i. pp. 72 and 248; vol. ii. p. 67.

[KJ] _Contemporary Review_, July, 1886.

[KK] "Darwinism," p. 467.

[KL] In both cases, the question to which an answer is suggested is
not--What variations will arise? but--What variations will
survive?

[KM] "Darwinism," p. 293. It is strange that Mr. Wallace did not apply
this view to the mathematical and artistic faculties discussed in
his last chapter. It is true that such application tends to
undermine the argument there developed. But Mr. Wallace is far too
great and conscientious a thinker to be influenced by such a
consideration.

[KN] If elimination of the unintellectual (not necessarily of the
unintelligent) may be excluded, and if the unintellectual increase
by natural generation more rapidly than the intellectual, the
general level of intellectuality must, on Professor Weismann's
principles, be steadily _falling_.

[KO] It _may_ also, in part, be due to "organic combination."

INDEX.

A

Abstract ideas, 322, 363

Acceleration, sense of, 269

Acceleration and retardation, 221

_Achirus pellucidus_, 83

Acquired characters, are they transmitted? 147;
habits, are they inherited? 436;
variations in the intellectual sphere, 497

_Acræa_, 203

Activities, organic basis of comparative psychology, 337;
of animals, 415;
voluntary and involuntary, classification of, 462

Adaptation, analogous, 117;
modes of, 119;
special, examples of, 179;
to varying environment, 183

Advantage must be particular, 184;
must be immediate and not prospective, 186;
must be "available," 188, 211

_Æschna_, 289

Æsthetic preferences in insects and birds, 207;
aspect of sensation, not primary, 243;
motive not present to animal consciousness, 409

ALEXANDER, Mr. S., "Moral Order and Progress," 463

ALLEN, Mr. Grant, on evolution of flowers, 206;
on pleasure and pain, 380

ALLEN, Mr. J. A., on colour and humidity, 164

Alternation of generations, 46

_Amblyopsis spelæus_, 271

American school of evolutionists, 221

Am[oe]ba, how it feeds, 5;
reproduction of, 12, 38;
diagram of, 12;
protoplasmic functions of, 142

Amphibia, labyrinthodont, 288

Anabolism, constructive process, 32

Analysis (mental), 321

Ancon sheep, 226

ANDERSON, Mr., on one-eared rabbits, 226

Anemone, sea, reproduction of, 41;
marginal beads of, 298;
discrimination by, 359

Anger and rage, 389

Animal life, nature of, 1;
diversity of, 177

Animal intelligence, differs generically from man's reason, 350

Animals, characteristics of, 1;
divided into protozoa and metazoa, 15;
and plants, their relation to food-stuffs, the atmosphere,
and energy, 15;
intelligent not rational, 373;
capacities for pleasure and pain, 391

Animistic ideas of savages, how developed, 494

_Anisognathus_, 226

_Anomia_, 265

Ant, sauba, of South America, 213;
sense of taste in, 253;
sense of smell in, 258;
auditory organ of, 267;
intelligence of, 357;
activities often described as instinctive, 425;
neuter insects, 440;
Siamese, 449

Antagonism, advantages of, 394

Antennæ of insects, modifications of, 178;
of emperor moth, 199;
organ of hearing in, 267;
modified hairs of, 297

Antennule of crayfish, 259

_Anthophora_, 438

Anticipation, 327

Antlers of deer in illustration of growth, 28

Aphides, absence of fertilization in reproduction, 44

Appetence and aversion, 343, 384

_Apus_, 46

Aquatic organisms, respiration in, 4;
sense of smell in, 256

ARAGO, M., observation on turnspit dog, 404

Arctic hare and fox, 84;
animals, colours of, 165;
fox, cunning of, 366

ARGYLE, Duke of, on humming-birds, 110

_Artemia salina_ and _milhausenii_, 164

Artistic faculties and natural selection, 484;
products, evolution of, 489

Association a tendency to integration, 183;
perceptual and mimicry, 202;
and recognition marks, 203

_Ateles_, 210

Atmosphere, relations of animals and plants to, 15

Attacus, 179

Attention, 342

_Attidæ_, 208

Auditory apparatus in man, 262

Aurelia, life-cycle of, 45

Australian mammals and others convergent, 117

Automatic action, 415

Available advantage, 188, 211

Aversion and appetence, 343, 384

B

Baboon, experiments with, 352

Bacilli attacked by leucocytes, 439

_Bacillus violaceus_, 80

BAILEY, Mr. E. H. S., on taste, 251

BALBIANI on _Chironomus_, 137

_Balistes_, 179

BARRETT, Mr. W. F., on sensitive-flame experiment, 298

Barrier, geographical, 99;
time, in physiological isolation, 105

BARRINGTON, The Hon. Daines, on song of linnet, 454

BATESON, Mr. W., on lateral line, 252;
on fishes hunting by scent, 256;
on smell in shrimps, etc., 260;
on hearing in fishes, 264;
on hearing in _Anomia_, 265;
on sight in fishes, 286;
on rockling and sole, 352;
on fascination in fishes, 388

Bats, tabulated measurements of wing-bones of, 65-73;
wings, fortuitous variations in, 235;
experiment with, 247

Beauty, standard of, 206;
sense of, 407

Beaver, change of habit in, 445

BECCARI on gardener bower bird, 408

BECKER, Alexander, on variations in the balance of life, 112

Bees, divergent development of, 58;
cuckoo, 90;
latency in, 228;
sense of taste, 253;
sense of smell, 257;
smell-hollows, 259;
eyes and eyelets of, 289;
intelligence of, 357;
colour preferences in, 408;
homing faculty in, 428;
neuter insects, 440

Beetles of Madeira, 81;
stag-, variability of male, 180;
observations on dung-, 368

Begging in dogs, 345

BERKELEY, Bishop, quoted, 475

BERT, M. Paul, limits of sensibility to light, 296

BIDIE, Mr. George, anecdote of cat, 370

BINET, M., "Psychic Life of Micro-organisms," 360

Birds, influence of food-yolk on development of, 56;
divergence among, 97;
breeding area of comparatively restricted, 101;
humming, Duke of Argyle on, 110;
destruction of eggs of, 189;
game-, white and black crossed, 225;
taste in, 251;
smell in, 256;
hearing in, 264;
sight in, 284;
colour-vision in, 285;
gardener bower, 408;
humming, nests of, 408;
perfect instincts of pr[oe]coces, 424;
love antics of satin bower, 450;
nests of, 453;
song of, 454

BLOCHMANN on the development of the drone, 153

Blood, circulation of, 22

Body as distinguished from reproductive cells, 131

BOLL and KÜHNE, Messrs., on retinal purple, 276

BOLTON, Miss Caroline, on the bat, 247

_Bombus muscorum_, 90;
_lapidarius_, 91

_Bombyx quercus_, 258

Bower bird, 408, 450

Brain, 31;
decreased, of rabbits and ducks, 171;
a microcosm, 491

BREHM'S, Thierleben, quotation from, 405

Brine shrimp, modified by salinity of water, 164

BROOKS, Prof. W. K., his modification of pangenesis, 134;
on the greater variability of the male, 237

BROWN, Prof. Crum, on sense of acceleration, 270

BROWNE, Sir J. Crichton, on ducks, 171

Budding, reproduction by, 42;
in relation to heredity, 128

Bull, "Favourite," prepotent, 227;
reversion in, 229

BUNYAN, John, on gateways of knowledge, 311

BUTLER, Mr. Samuel, on organic memory, 62, 475

Butterfly, protective resemblance in, 86;
mimicry in, 87

C

Camel, wounded, 392

Canary, crested, 225;
nest building of, 453

Capon, taking to sitting, 228

Capuchin monkey, Miss Romanes's observation on, 367;
sympathy in, 397

CARLYLE, quoted, 331, 335

Carp at Potsdam, 265

CARTER, Dr. Brudenell, quoted, 285

Caste, idea of, in dog, 400

Cat, effect of African climate on, 164;
defining its percept, 339;
communication, 345;
intelligence of, 370;
and mouse, 399;
punishing kitten, 405

Caterpillars, protective resemblance in, 82

Cattle of Falkland Islands, 203

Causation, 327

Cell, diagram of animal, 10;
controlled explosions in, 31

Cessation of selection, effects of, 172

_Chætodon_, 83

_Chætogaster limnæi_, reproduction of, 42

Chaffinch, nest of New Zealand, 454

Chamæleon, 286

Chance, 236

Change of conditions, 163

Characters, specific, 110

CHARBONNIER, Mr, Henry, measurements of bats, 63

CHATTOCK, Mr. A. P., his experiments on colour-vision, 280;
letter to, on dog and picture, 341

CHESHIRE, Mr., on smell-hollows in bees, 259

Chickens' aversion to protected caterpillars, 352;
perfectly instinctive activities, 424

_Chironomus_, reproductive cells of, 137

Choice, 458

Circulation of the blood, 22

Classification, 323

CLIFFORD, W. K., on human consciousness, 341;
on the eject, 476;
on "world-consciousness," 479

Clover and bees, 113

_Clytus arietis_, 87

Cockchafer, smell-hollows of, 259

COCKERELL, Mr., on variations in snails, 75;
on effects of moisture, 239

Cockroach, diagram of trachea or air-tubes of, 3;
sense of taste in, 253;
sense of smell in, 258

Cocoon, collective, 429

_Colobus_, 210

Colour, protective resemblance in, 82;
warning of inedibility, 82;
dependent on humidity, 164;
direct action of climate on, 164;
development of, 202;
blindness, 273, 279;
phenomena of, 278

Combination, organic, hypothesis of, 150, 240

Communication in dogs, 345;
in bees, 358

Compensation of growth, 155

Competition, elimination through, 89

Concept, 325, 326

Conception, 325

Conceptual conduct and evolution, 488

Condor, rate of increase of, 57

Conduct, 463;
influence of thought and æsthetics on, 483;
conceptual, and natural selection, 488

Congruity, principle of, 486

Conjugation in protozoa, 39;
of ovum and sperm-cell, 42

Consciousness, 32;
and consentience, 326, 362;
as a criterion of instinct, 432

Consentience, 326, 362

Construct and construction (mental), 312;
three stages of, 324;
inevitable nature of, 332;
in mammals, 338

Continuity of reproductive cells, 131;
germ-plasm, 138;
cellular, 142;
in mental development, 373

Convergence, phenomena of, 117

Co-ordinants, 303

COPE, Prof., on the effects of use, 210;
and HYATT, Prof., on retardation and acceleration, 221

Correlated variation, 59, 216

CORTI, organ of, 263

_Coryne_, Prof. Weismann on, 139

COUCH, Mr., on goldfinch song, 454

Crab, protective resemblance in, 87;
hermit, 195;
habit of decking itself, 457

Crayfish, smell in, 259;
auditory organ of, 266

Crossing, effect on reversion, 230

Cruelty in cat, objective, 400

Crustacea, eyes of, 292

_Ctenomys_, 194

Cuckoo, the name onomatopoetic, 322;
habits intelligent, 436;
ejecting young birds, 437

Curiosity in prong-horn, 339

Cuttlefish, eyes of, 293

_Cyclas_, 265

_Cycloptera speculata_, locust resembling leaf, 86

D

DALLINGER, Dr., his temperature-experiments on monads, 147

_Danais_, 203

Daphnids, absence of fertilization in reproduction of, 45;
colour-vision in, 292, 296;
leucocytes of, 439

DARWIN, Charles. Natural selection and the struggle for existence, 77;
divides the principle of selection into three kinds, 78;
on selection of flowers and fruits by insects, 93;
on sexual selection, 94;
on prevention of free crossing in breeding, 99;
on differential fertility, 104;
on London rats, 106;
on Galapagos archipelago, 109;
on diverse adaptation, 111;
on the influence of old maids on clover crops, 113;
on the influence of parent on offspring, 122;
on the co-ordinating
power of her organization, 125;
hypothesis of pangenesis, 131;
on fur of arctic animals, 165;
changes of structure attributed to use and disease, 171;
on blindness of tuco-tuco, 194;
on the principle of economy, 194;
on sexual selection, 198;
on preferential mating, 204;
on evolution of flowers, 205;
on co-ordinated variations in the elk, 213;
on acceleration, 222;
on ancon sheep, 226;
on prepotency, 227;
on reversion, 229;
on the effects of crossing, 230;
on fortuitous variation, 236;
on the subordination of the conditions to the organism, 236;
on the greater variability of male, 237;
on attention in monkeys, 342;
on brain of ant, 358;
on gestures of anger and rage, 389;
on pleasures and pains of animals, 394;
on bravery of a monkey, 396;
on Abyssinian baboons, 405;
on sense of humour in the dog, 406;
on neuter insects, 440;
on selection of oxen, 441;
on acquisition of fear of man by birds, 443;
on satin bower bird, 450

Death, natural introduction of, 186, 193

Deceit in dogs, 400

Degeneration, 183

Desert animals, inconspicuousness of, 89

DESCARTES on pineal gland, 288

Desire, 460, 463

Destruction, indiscriminate, as opposed to elimination, 76

Development of organisms distinct from growth, 6;
reproduction and, 36;
is differential growth, 49;
of a vertebrate, diagrammatic account of, 51;
comparative, of some vertebrates, 220

DE VRIES, 132, 159

Differentiation in protozoa, 40;
in metazoa, 41;
during development, 49;
of reproductive cells, 143;
and integration, 183;
of tissues, 232

_Difflugia_, 360

Dimorphism in larvæ, 187

Discrimination in the sense of touch, 245;
hearing, 262;
sight, 275;
its fundamental nature, 338;
in sea-anemone, 359

Disease, elimination by, 80

Display, 207

Disuse, panmixia and, 189;
negative and not positive, 196;
use and, 209

Divergence among birds, illustrated
from Wallace, 97;
through diverse adaptation, 111

DIXON, Mr. Charles, effects of climate on the colours of birds, 164;
on chaffinch nests, 454

Dog, effect of Indian climate on, 164, 167;
greyhounds in Mexico, 167;
sense of smell in, 255, 338;
vague percept of, 339;
and the feelings of other animals, 340;
and pictures, 341;
powers of communication, 344;
swimming rivers, 365;
cleverness of, 367;
sympathy in, 397;
idea of caste, deceit, 400;
endurance of pain, 402;
sense of justice in, 404;
punishing pup, 405;
sense of humour in, 406;
swimming a deferred instinct in, 423;
turning round to make a couch, 444

Dog-fish, sense of smell in, 257

Domestication, variations effected by, 171, 215;
crossing and reversion, 230

_Doris tuberculata_, 84

Dreaming, 341;
and the animistic hypothesis, 495

_Dromia vulgaris_, 457

Drones developed from unfertilized ova, 45;
second polar cell extruded, 153

DUBOIS, M., on _Proteus_, 294

Ducks, Sir J. Crichton Browne on, 171;
Dr. Rae on instinctive wildness of, 435

Duration of life, 186

E

Eagle, sclerotic plates of, 437

Ear, 263

Earthworm, respiration in, 4, 24;
regeneration of lost parts, 41;
sensitive to light, 293;
outward projection in, 359

EATON, Rev. A. E., on insects of Kerguelen Island, 81

Ecitons, 427

Economy, principle of, 194

Education of ants, 428;
of young animals, 455

Egg and hen, problem of, 130

Egg-cell and sperm-cell, diagram of, 13;
conditions which determine production of, 60

Eggs, influence of food-yolk on mode of development of, 56;
destruction of birds, 189

Ego, or self, 475

EIMER, Prof., on inhabitants of Nile valley, 165;
on _Helix hortensis,_ 226;
on instinct, 436;
on differential dread in birds, 444

Eject, meaning of, 476

Elaboration, 183

Elephant, rate of increase of, 57;
intelligence of, 363, 369;
use of tools by, 370;
vindictiveness in, 401

Elimination, as opposed to selection, 79;
its three modes, 80;
as a factor in the origin of instinct, 447;
of ideas through incongruity, 486;
as applied to the intellectual faculties, 497

Embryology negatives preformation, 50

Emotions exemplified, 382;
the expression of, 385;
three orders of, 391;
in vertebrata, 395

Encystment, 38, 49

Ends and means, 371

Energy, relations of animals and plants to, 16

_Ennomos tiliaria_, caterpillar, protective resemblance of, 85

Environment, direct effects of on the organism, 163;
changes of, in relation to the organism, 183;
are effects of direct or indirect? 233;
instances of effects of, 238

_Equus_, 118

_Eristalis tenax_, 87

Ethics in animals, 413

_Euplæa_, 203

Evolution of older writers, 50;
and revolution, 119;
organic, 177;
meaning of term, 182;
mental, 464;
organic and mental not continuous, 488;
interneural, 490

Excrement of birds, resemblance of spider to, 90

Excretion, an essential life-process, 3, 29

Expectation, 327

Experience dependent on memory, 305

Expression of the emotions, 385

Eye, structure of in man, 274;
in mole, 284;
pineal, 287;
in insects, 288;
facetted, 289;
in crustacea, 292;
in molluscs, 292;
four types of, 294

F

FABRE, M., on _Sitaris_, 439

Facetted eye, 289

Factors of phenomena, laws of, 61

Falkland Islands, cattle of, 102;
birds of, 443

Fear, dread and terror, 387;
instinct of, 443

Feelings of animals, 8, 378

Female. _See_ Sex-differentiation.

Female and male insects, differences between, 179;
vigour expended on offspring, 238

Fertilization, nature of, 42;
absent in parthenogenetic forms, 44

Fertility, differential, Darwin and Romanes on, 104;
of hybrids, 105

Fetishism, its natural genesis, 492

FISCHER, Dr. Emil, on smell, 254

Fish, respiration in, 24;
protective resemblance in, 83;
amount of food-yolk in eggs of, 220;
skate and turbot compared, 220;
sense of taste in, 252;
sense of smell in, 256;
sense of hearing in, 264;
sense of sight in, 286;
fascination in, 388;
love-antics of, 450

FISK, Rev. G. H. R., on sympathy in cat, 397

Fission, a process of cell-division, 37;
in protozoa, 38;
in metazoa, 41

Flight, instinctive nature of, 425

FLOURENS, M., on function of semicircular canals, 269

Flowers and fruits, selection of, 93;
evolved through insect agency, 206

_Folliculina_, 360

Food-stuffs, relations of animals and plants to, 15;
nature of and digestion of, 25

Food-yolk, influence of, on development, 55;
the result of parental sacrifice, 57

FORBES, H. O., on Javan spiders, 90

FOREL, M., on taste of ants, 253;
on vision of daphnids, 296;
on happy family of ants, 428

Form-characteristics of animals, 2

Fortuitous variation, 235

Fosterage and protection, 219;
result of female self-sacrifice, 238

FOTHERGILL, Mr., on dogs swimming rivers, 364

Fowl, variations in, attributed by Darwin to use, 171;
crossing of, 227, 230

Fox, cunning of, 366

FRANCIS, Mr. H. A., 90

FRITSCH, Dr., Fig. of skull of _Melanerpeton_, 288

Frog, development of, 6;
arrest of life in, 21;
respiration in, 24;
fishing, or angler-fish, 91;
modified development of, 214;
effects of simple stimulus on, 305

Fruits and flowers, selection of, 93

G

GABET, Messrs. HUC and, on Llama cow, 333

Galapagos Archipelago, species and varieties in, 99;
climate of, 109

_Gallus bankiva_, 230

GALTON, Mr. Francis, on the coloration of the zebra, 84;
his modification of pangenesis, 135;
numerical estimate of inheritance, 150, 192;
his investigations on twins, 169;
on blended characters, 225;
on the steps of evolution, 227

Ganglia, 31

Gannet, rate of increase of, 57

Gas-engine, analogy of, 30

GAUTIER, Théophile, his cat, 264

GEDDES, Prof. Patrick, and THOMSON, J. A., on anabolism and
katabolism, 44;
quoted, 50, 137, 237

Gemmules, pangenetic, 131

Generations, alternation of, 46

Generic idea, 326

Geographical barriers a means of segregation, 99

Geological changes, influence on natural selection, 113

Germ-plasm, continuity of, 138;
convenience of, 140

Gills of mussel, 4;
as respiratory organs, 24

Giraffe, co-ordinated variations in, 212

Glacial epoch, effects of, 113

Gland, pineal, 288

Goldfinch, song of, 454

GOLDSCHNEIDER, on temperature-sense, 249

GOULD, Dr., on humming-birds' nests, 408

GRABER, Dr., on colour-sensitiveness of earthworm, 293

GRANT, Mr. G. L., on New Zealand sparrows, 445

Grasshopper, auditory organ of, 266

_Gregarina_, reproduction in, 38

GRENACHER, Dr., experiment on moth's eye, 290

Grouse, white plumage in, due to reversion, 229

GROVE, Sir W. R., on antagonism, 394

Growth of organisms, 5;
illustration of a deer's antler, 28;
law of, after mutilation, 126

Guidance distinguished from origin, 242

Guillemot, eggs of, 410

GULICK, Rev. J. T., on landshells of Sandwich Islands, 109;
on tendency to divergence, 151

GUPPY, Mr., on crab of Solomon Islands, 87

H

Habits of animals, 415

Habitual activities, 420;
sense of satisfaction in performance of, 421

HAECKEL, Prof., plastidules of, 125;
theory of perigenesis, 159

_Halictus cylindricus_, 90

HAMERTON, Mr. P. G., on the ignorance of animals, 333

HAMILTON, Sir Wm., quoted, 470

HANCOCK, Mr. John, on instinct of cuckoo, 437

HASSE, E., on bumble-bees, 259

HAUSER, on cockchafer, 259

HAYCROFT, Mr. J. B., on taste, 250

Hearing, sense of, 261

_Heliconia_, 203

_Helix_, _nemoralis_ and _hortensis_, variation of, 75, 217, 226, 239

HELMHOLTZ, Von, on colour, 277;
on local signs of retina, 308

Hen and egg, problem of, 130

HENSEN, on shrimps, 266

HERBERT, Prof. T. M., quoted, 471

HERDMAN, Prof., on sea-slug (_Doris_), 84;
his modification of pangenesis, 135;
on warning coloration in nudibranchs, 252

Heredity, an organic application of the law of persistence, 62;
and the origin of variations, 122;
in protozoa, 123;
and regeneration of lost parts, 124;
failure of, 192;
and instinct, 435

HERING, Edward, on organic memory, 62, 475

HERON, Sir R., on crossing rabbits, 225

HERSCHELL, Sir John, on colour, 277

HERTWIG, Richard, observations on Infusoria, 39

HICKS, on Capricorn beetle, 267

HICKS' organ, 267

HICKSON, Dr., Fig. of eye of fly, 290

_Hipparion_, 118

Hippopotamus, instinctive activities in, 423

HOLLAND, Sir Henry, on inheritance, 223

Homing faculty of bees, 428

Horse, two different evolutions of, 118;
effects of use on digits of, 210;
sense of pain in, 392

HOWSE, Prof., antennule of crayfish, 259

HUBER, Pierre, on smell in bees, 257;
judgment and instinct, 452

HUC and GABET, Messrs., on Llama cow, 333

HUGGINS, Dr., his dog Kepler, 396

Humming-birds, 110

Humour, sense of, in dog, 406

HUXLEY, T. H., on limitation of variations, 151;
on neurosis and psychosis, 465

HYATT, Prof., on acceleration and retardation, 221

Hybrids, fertility of, 105

Hydra, reproduction of, 14, 41;
diagram of, 43;
artificial division of, 124;
budding in, 128;
sexual reproduction of, 129

Hydra tuba, and medusa of aurelia, 45

Hydroids, development of, 46;
Weismann on, 139

Hymenoptera, antennary structures of, 297;
instincts of social, 441, 448

I

Ichneumon fly, instinct of, 430

_Ichthyosaurus_, pineal eye of, 288

_Icteridæ_, 454

Idea of an object, 313

Ideas, conceptual, their environment, 485;
the law of their evolution, 486

Idealism, 474

Ignorance of animals, 333

Image, inverted in retina, 311

Imagination, constructive, 325

Imitation as a factor in habit or instinct, 443, 453

Immortality of protozoa, 12

Incongruity, elimination by, 486

Increase, law of, 58

Incubation, instinct of, 434

Individuality, a tendency to differentiation, 183

Inference, conscious and unconscious, 328;
in animals, 361

Infertility of isolated forms, 108

Infusoria, reproduction in, 39

Inheritance, exclusive, a means of isolation, 104;
of variations, 223;
of acquired habits, 435;
of acquired increments of intellectual faculty, 497

Inhibition, 385;
as a condition of volition, 459

Innate capacity, 422;
its importance, 429

Insects, tracheal respiration of, 3, 24;
wingless, of Madeira, 81;
of Kerguelen Island, 81;
mimicry and protective resemblance in, 85, 88;
segregation by colour, 101;
antennæ of, 178;
mouth-organs of, 179;
and the evolution of flowers, 206;
sense of touch in, 248;
taste in, 253;
smell in, 257;
hearing in, 266;
sight in, 288;
perceptual powers of, 357;
neuter, 440

Instinct and available advantage, 211;
consideration of, 415;
perfect, imperfect, and incomplete, 422;
deferred, 423;
blind prevision in, 429;
gratification in performance of, 430;
consciousness and, 432;
primary and secondary, 434;
three factors in the origin of, 447;
as influenced by intelligence, 452;
by imitation, 453;
by education, 455;
as distinguished from intelligence, 457

Instinctive emotion, 390, 395

Integration and differentiation, 183

Intellectual development, 486

Intelligence involved in selection, 95;
distinguished from reason, 330, 365;
lapsed, 435
involved in instinct, 440;
as influencing instinct, 452;
criteria of, 456

Interbreeding and intercrossing, 97

Interneural evolution, 490

Interpretations of nature, genera and species of, 492

Isle of Man, tortoiseshell butterfly of, 81

Isolates, 322, 364

Isolation, organic, or segregation, 99;
mental, or abstraction, 322

J

JAEGER, Dr., on crossing of pigs, 230

JENKINS, Mr. H. L., on the elephant, 363

Judgment, 330

K

_Kallima paralecta_, leaf-butterfly, 86

KANT, quoted, 476

Katabolism, a disruption or explosive process, 32

Kea, of New Zealand, 446

Keimplasma. _See_ Germ-plasm

Kentish plover, 83, 217

Kepler, Dr. Huggins's dog, 396

Kerguelen Island, wingless insects of, 81

Kinesis, 467

Kingfishers, 446

KIRBY and SPENCE, localization of smell in insects, 258;
on hearing in a moth, 267;
on instinct of ichneumon fly, 430

Kittens, instinctive antipathy to dog, 396

KLEIN, Mr. S., on _Bombyx quercus_, 258

KÜHNE, Messrs. BOLL and, on retinal purple, 276

L

Labyrinthodont amphibia, pineal eye in, 288

LAMONT, on reindeer, 392

LANE, Dr. Arbuthnot, on influence of certain trades on structure, 169

LANGLEY, Prof., On ætherial vibrations, 299

Language, 322;
the instrument of analysis, 349;
its origin and effects, 374

LANKESTER, Prof. E. Ray, his description of perigenesis, 159;
on blind cave-fish, 194

Lapsing of intelligence, 435

LARDEN, W., on the Rhea, 89;
on instinct in a snakelet, 424

Larmarckian school, 209

Larvæ, dimorphism in, 187

Latency, phenomena of, 227

Lateral line of fishes, 252

Leaf-butterfly, 86

LEE, Mr. Arthur, on communication in cat, 345

_Leptalis_, 87

LEROY, on abstract notion of danger in fox, 348

Leucocytes, _role_ of, 439

LEWES, G. H., 437, 462

LEYDIG, on antennule of crayfish, 259

Life, duration of, due to natural selection, 186

Life-area, expansion and contraction of, 114

Limits of vision, 281; of sensation, 299

_Limnæus truncatulus_, 48

LINCECUM, Dr., on habits of Texan ants, 425

Linnet, song of, 454

Lion, observation on, 400

Liver-fluke, life-history of, 47

Local signs, 308

Localization, 307;
in animals, 338;
in medusa, 359

LOCKE, on difference between man and brute, 349

Logos makes man human, 375

LONBIÉRE, on instincts of Siamese ants, 449

LOTZE, quoted, 379

LUBBOCK, Sir J., "Senses of Animals," 246;
sense of smell in ants, 258;
auditory organ of ant, 267;
on Hicks's organ, 267;
on colour-sense in dog, 283;
in insects, 291;
in Daphnia, 292;
on limits of colour-vision, 296;
on antennary structures in hymenoptera, 297;
on power of communication
in dog, 345;
in ants, 358;
on colour preferences in bees, 407;
on instinct of play and sympathy in ants, 414;
on homing faculty in bees, 428;
on sitaris, 439

_Lucanus cervus_, 180

Ludicrous, sense of, in dog, 406

LUMSDEN, Sir Harry, on partridges, 398

LYELL, the necessary precursor of Darwin, 121

M

MACH, Prof., on Macula acustica, 271

_Machetes pugnax_, 110, 178

MACKENNAL, Mr. Alexander, observation on a cat, 405

MACLAGAN, Miss Nellie, on sympathetic action in dog, 398

Madeira, wingless insects of, 81

Male, _See_ Sex-differentiation

Male and female insects, differences between, 179;
greater variability in, 237;
vigour and vitality of, in secondary sexual characters, 237

MALLE, Dureau de la, on starling, 455

Mammals, respiration in, 21;
early nutrition of, the result of parental sacrifice, 57;
convergence in, 117;
sense of smell in, 255;
hearing in, 263;
sight in, 283;
perceptions of, 338

Man, elimination by physical circumstances, 81;
alternation of good and bad times, 117;
reversion in, 229

MANN, Mrs., on sympathetic action of dog, 397;
anecdotes of dogs, 406

Mantis, protective and aggressive resemblance in, 90

Marsupials of Australia, 117

MARTINEAU, Dr., on wants, 382

Materialism, 464, 471

Mathematical faculty and natural selection, 484

MAUPAS, M., observations on infusoria, 39

MAYER, on mosquito, 267

MCCOOK, Dr., sense of smell in ants, 258;
habits of Texan ants, 425

MCCOSH, Dr., quoted, 391

Means and ends, 371

Medusa, 46;
sense of hearing in, 265;
eyes of, 293;
localization by, 359

_Melanerpeton_, 288

MELDOLA, Prof. R., 239

Memory, the revival of past impressions, 304;
organic, Butler and Hering on, 62

Mental evolution, 464

MERCIER, Dr. Charles, on the criteria of intelligence, 456

MERRIFIELD, Mr., experiments on moths, 238

Metabolism, 32

Metakinesis, 467

Metamorphosis and transformation, 7

Metaphyta, 15

Metazoa, 15

_Methona_, 87

MIALL, Prof., Fig. of touch-hair of an insect, 248

Mice, white and grey, crossed, 225

Microbes, elimination among, 80

_Micrococcus prodigiosus_, 81

_Microstomum lineare_, reproduction in, 42

Mimicry, 87;
as evidence of perceptual association, 202, 351

Mind, out of what evolved? 464

Mineral crystals, analogy of, 240

MITCHELL, James, his delicate sense of smell, 255

MIVART, Prof. St. George, on Saturnia, 163;
on common-sense realism, 316;
on ideas, etc., 320;
on "practical intelligence," 362;
on man and brute, 374;
on consciousness and consentience, 461

Modifiability of individual organism, 163

Modifications of antennæ and mouth-organs of insects, 178

Mole, eye of, 284

Mollusks, variety of, 178;
sense of smell in, 260;
hearing in, 265;
sight in, 292

Monads, reproduction of, 38;
temperature experiments with, 147

Mongrelization, 168

Monistic hypothesis, 465

Monkey, _ateles_ and _colobus_ digits of, 210;
examining marsupial pouch, 340;
attention in, 342;
capuchin, intelligence of, 367

_Monospora bicuspidata_, 439