 Section 11 of the Outline of Science, Volume 1. In the story of evolution, there is no chapter more interesting than the emergence of mind in the animal kingdom. But it is a difficult chapter to read, partly because mind cannot be seen or measured, only inferred from the outward behavior of the creature, and partly because it is almost impossible to avoid reading ourselves into the much simpler animals. Section 1. Two extremes to be avoided. The one extreme is that of uncritical generosity which credits every animal, like Burr Rabbit, who by the way was the hare, with human qualities. The other extreme is that of thinking of the animal as if it were an automatic machine, in the working of which there is no place or use for mind. Most these extremes are to be avoided. When Professor Wiseman took the eggs of the passenger pigeon, which became extinct not long ago with starking rapidity, and placed them a few inches to one side of the nest, the bird looked a little uneasy and put her beak under her body as if to feel for something that was not there. But she did not try to retrieve her eggs, close at hand as they were. In a short time she flew away altogether. This shows that the mind of the pigeon is in some respects very different from the mind of man. On the other hand, when a certain clever dog carrying a basket of eggs with the handle in his mouth came to a style which had to be negotiated, he laid the basket on the ground, pushed it gently through a low cap to the other side, and then took a running leap over. We dare not talk of this dog as an automatic machine, a caution in regard to instinct. In studying the behaviour of animals, which is the only way of getting at their mind, for it is only of our own mind that we have direct knowledge. It is essential to give prominence to the fact that there has been throughout the evolution of living creatures a strong tendency to enregister or ingrain capacities of doing things effectively. Thus certain abilities come to be inborn. They are parts of the inheritance which will express themselves whenever the appropriate trigger is pulled. The newly born child does not require to learn its breathing movements, as it afterwards requires to learn its walking movements. The ability to go through the breathing movements is inborn, ingrained, and registered. In other words, there are hereditary prearrangements of nerve cells and muscle cells which come into activity almost as easily as the beating of the heart. In a minute or two the newborn pigling creeps close to its mother and sucks milk. It has not to learn how to do this any more than we have to learn to cough or sneeze. Thus animals have many useful ready-made or almost ready-made capacities of doing apparently clever things. In simple cases of these inborn prearrangements we speak of reflex actions. In more complicated cases of instinctive behavior. Now the caution is this, that while these inborn capacities usually work well in natural conditions, they sometimes work badly when the ordinary routine is disturbed. We see this when a pigeon continues sitting for many days on an anti-nest or when it fails to retrieve its eggs only two inches away. But it would be a mistake to call the pigeon, because of this, an unutterably stupid bird. We have only to think of the achievements of homing pigeons to know that this cannot be true. We must not judge animals in regard to those kinds of behavior which have been handed over to instinct and go badly agree when the normal routine is disturbed. In ninety-nine cases out of a hundred the unregistered instinctive capacities work well and the advantage of their becoming stereotyped was to leave the animal more free for adventures at a higher level. Being a slave of instinct may give the animal a security that enables it to discover some new home or new food or new joy. But in the same way a man of methodical habits which he has himself established may gain leisure to make some new departure of racial profit. When we draw back our finger from something very hot or shut our eye to avoid a blow from a rebounding branch, we do not will the action. And this is more or less the case probably when a young animal sucks its mother for the first time. Some mounds-birds of celibus lay their eggs in warm volcanic ash by the shore of the sea. Others in a great mass of fermenting vegetation. It is inborn in the newly hatched bird to struggle out as quickly as it can from such a strange nest, else it will suffocate. If it stops struggling too soon it perishes, for it seems that the trigger of the instinct cannot be pulled twice. Similarly when the eggs of the turtle that have been laid in the sand of the shore hatch out, the young ones make instinctively for the sea. Some of the crocodiles bury their eggs two feet or so below the surface, among sand and decaying vegetation, an awkward situation for a birthplace. The young crocodile is ready to break out of the eggshell, just as a chick does at the end of the three weeks of brooding, it utters instinctively a piping cry. On hearing this the watchful mother dicks away the heavy blanket, otherwise the young crocodile would be buried alive at birth. Now there is no warrant for believing that the young mound-birds, young crocodiles and young turtles have an intelligent appreciation of what they do when they are hatched. They act instinctively as to the manner born, but this is not to say that their activity is not backed by endeavor or even suffused with a certain amount of awareness. Of course it is necessarily difficult for man, which is so much a creature of intelligence, to get even an inkling of the mental side of instinctive behavior. In many of the higher reaches of animal instinct, as in courtship or nest building, in hunting or preparing the food, it looks as if the starting of the routine activity also rang up the higher centers of the brain and put the intelligence on the key-weave, ready to interpose when needed. So the two-fold caution is this. One, we must not depreciate the creature too much, if, in unusual circumstances, it acts in an ineffective way along lines of behavior which are normally handed over to instinct. And two, we must leave open the possibility that even routine instinctive behavior may be suffused with awareness and backed by endeavor. Part two. A Useful Law. But how are we to know when to credit the animal with intelligence and when with something less spontaneous? Above all, how are we to know when the effective action, like opening the mouth the very instinct it is touched by food, in the mother's beak, is just a physiological action like coughing or sneezing, and when there is behind it a mind at work? The answer to this question is no doubt that given by Professor Lloyd Morgan, who may be called the founder of comparative psychology, that we must describe the piece of behavior very carefully, just as it occurred, without reading anything into it, and that we must not describe it to a higher faculty if it can be satisfactory accounted for in terms of a lower one. In following this principle, we may be sometimes niggardly, for the behavior may have a mental subtlety that we have missed, but in nine cases out of ten our conclusions are likely to be sound. It is the critical scientific way. Bearing this law in mind, let us take a survey of the emergence of mind among back-boned animals, senses of fishes. Fishes cannot shut their eyes, having no true lens, but the eyes themselves are very well developed, and the vision is acute, especially for moving objects. Except in gristly fishes, the external opening to the ear has been lost, so that sound waves and coarser vibrations must influence the inner ear, which is well developed, through the surrounding flesh and bones. It seems that the main use of the ear in fishes is in connection with balancing, not with hearing. In many cases, however, the sense of hearing has been demonstrated, that fishes will come to the side of a pond to be fed when a bell is rung, or when a whistle is blown by someone not visible from the water. The fact that many fishes pay no attention at all to loud noises does not prove that they are deaf, for an animal may hear a sound and yet remain quite indifferent or irresponsible. This merely means that the sound has no vital interest for the animal. Some fishes, such as bull-head and dog-fish, have a true sense of smell, detecting by their nostrils very dilute substances, permeating the water from a distance. Others, such as members of the cod family, perceive their food in parts at least by the sense of taste, which is susceptible to substances near at hand and present in considerable quantity. The sense of taste may be located on the fins as well as about to the mouth. At this low level, the senses of smell and taste do not seem to be very readily separated. The chief use of the sensitive line or lateral line, seen on each side of a bony fish, is to make the animal aware of slow vibrations and changes of pressure in the water. The skin responds to pressures, the ear to vibrations of high frequency. The lateral line is between the two in its function. Interesting ways of fishes. The brain of the ordinary bony fish is at a very low level. Thus, the cerebral hemispheres, destined to become more and more the seeds of intelligence, are poorly developed. In grisly fishes, like skates and sharks, the brain is much more promising. But although the state of the brain does not lead one to expect very much from a bony fish, like trout or eel, haddock or herring, illustrations are not wanting of what might be called pretty pieces of behavior. Let us select a few cases. The sticklebacks nest. The three spined and two spined sticklebacks live equally well in fresh or salt water. The larger 15 spined stickleback is entirely marine. In all three species, the male fish makes a nest. In fresh or brackish water, in fresh or brackish water in the first two cases. In shore proves, in the third case. The little species use the leaves and stems of water plants. The larger species use seaweed and zoo fight. The leaves or fronds are entangled together and fastened by glue-like threads, secreted, strange to say, by the kidneys. It is just as if a temporary disease condition had been regularized and turned to good purpose. Going through the nest several times, the male makes a little room in the middle. Partly by corrosion and partly by coaxing, he induces a female. First one and then another, to pass through the nest with two doors, depositing eggs during her short sojourn. The females go on their way and the male mounts guard over the nest. He drives off intruding fishes much bigger than himself. When the young are hatched, the male has for a time much to do, keeping his charges within bounds until they are able to move about with agility. It seems that sticklebacks are short-lived fishes, probably breeding only once, and it is reasonable to suppose that their success as a race depends to some extent on the paternal care. Now, if we could believe that the nesting behavior had appeared suddenly in its present form, we should be inclined to credit the fish with considerable mental ability. But we are less likely to be so generous if we reflect that the routine has been in all likelihood the outcome of a long racial process of slight improvements and critical testings. The secretion of the glue probably came about as a pathological variation. Its utilization was perhaps discovered by accident. The types that had wit enough to take advantage of this were most successful. The routine became unregistered hereditarily. The stickleback is not so clever as it looks. The mind of a minnow. To find solid ground on which to base an appreciation of the behavior of fishes, it is necessary to experiment, and we may refer to Ms. Gertrude White's interesting work on American minnows and sticklebacks. After the fishes had become quite at home in their artificial surroundings, their lessons began. Cloth packets, one of which contains meat and the other cotton, were suspended at opposite ends of the aquarium. The mud minnows did not show that they perceived either packet, though they swarmed close by them. The sticklebacks were intrigued at once. Those that went towards the packet containing meat darted furiously upon it, and pulled at it with great excitement. Those that went towards the cotton packet turned sharply away when they were within about two inches off. They then perceived what those at the other end were after, and joined them. A common habit amongst fishes. Although the minnows are not interested in the tiny bags of mystery, they were even more alert than the sticklebacks in perceiving moving object, in or on the water. And there is no doubt that both these shallow water species discovered their food largely by sense of sight. The next set of lessons had to do with color associations. The fishes were fed on minced snail, chopped earthworm, fragments of liver, and the like, and the food was given to them from the ends of forceps held above the surface of the water so that the fishes could not be influenced by smell. They had to leap out of the water to take the food from the forceps. Discs of colored cardboard were slipped over the end of the forceps, so that what the fishes saw was a morsel of food in the center of a colored disc. After a week or so of preliminary training, they were so well accustomed to the colored discs that the presentation of one served as a signal for the fishes to dart to the surface and spring out of the water. When bates of paper were substituted for food, the fishes continued to jump at the disc. When, however, a blue disc was persistently used for the paper bait in a red disc for the real food, or vice versa, some of the minnows learned to discriminate infallibly between shadow and substance. Both when these were presented alternatively and when they were presented simultaneously. This is not far from the dawn of mind. In the course of a few lessons, both minnows and sticklebacks learned to associate particular colors with food, and other associations were also formed. A kind of lava that a minnow could make nothing of after repeated trials was subsequently ignored. The approach of the experimenter, or anyone else, soon began to serve as a food signal. There can be no doubt that in the ordinary life of fishes there is a process of forming useful associations and suppressing useless responses. Given an inborn repertory of profitable movements that require no training, given the power of forming associations such as those we have illustrated, and given a considerable degree of sensory alertness along certain lines, fishes do not require much more. And in truth they have not got it. Moving with great freedom in three dimensions in a medium that supports them and is very uniform and constant, abled in most cases to get plenty of food without fatiguing exertions and to dispense with it for considerable periods if it scars, trying usually in great abundance so that the huge infantile mortality hardly counts, rarely dying a natural death but usually coming with their strength unabated to a violent end. Fishes hold their own in the struggle for existence without much in the way of mental endowment. Their brain has more to do with motion than with mentality, and they have remained at a low psychical level. Yet, just as we should greatly misjudge our own race if we confine our attention to everyday routine, so in our total, as distinguished from our average, estimate of fishes, we must remember the Solomon surmounting the falls, the worry trout eluding the angler's skill, the common mudskippet, perioftalmus, of many tropical shores which climbs on the rocks and the roots of the mangrove trees, or actively hunts small shore animals. We must remember the adventurous life history of the eel and the quaint ways in which some fishes, males especially, look after their family. The male seahorse puts the eggs in his breast pocket. The male curses carries them on the top of his head. The cockpedal, or lump-sucker, guards them and aerates them in a corner of a short pole. Part 3 The Mind of Amphibians Towards the end of the age of the old red sandstone, or Devonian, a great step in evolution was taken, the emergence of amphibians. The earliest representatives had fish-like characters even more mocked than those which may be discerned in the tadpoles of our frogs and toads, and there is no doubt that amphibians sprang from a fish-stock. But they made great strides associated in part with their attempts to get out of the water on too-dry land. From fossils, forms, we cannot say much in regard to soft parts, but if we consider the living representatives of the class, we make credit amphibians with such important acquisitions as fingers and toes, a three-chambered heart, true ventral lungs, a drum to the ear, a mobile tongue, and vocal cords. When animals began to be able to grasp an object, and when they began to be able to utter sufficient sounds, two new doors were opened, apart from insects, whose instrumental music had probably begun before the end of the Devonian age, and amphibians were the first animals to have a voice. The primary meaning of this voice was doubtless, as it is today in our frogs, a sex call, but it was the beginning of what was distant to play a very important part in the evolution of the mind. In the course of ages, the significance of the voice broadened out. It became a parental call. It became an infant's cry. Broadening still, it became a very useful means of recognition amongst kindred, especially in the dark and in the intricacies of the forest. Ages passed, and the voice rose in another turn of the evolutionary spiral, to be expressive of particular emotions beyond the immediate circle of sex. Emotions of joy, and of fear, of jealousy, and of contentment. Finally we judge the animal, perhaps the bird was first, began to give utterance to particular words, indicative not merely of emotions, but of particular things with an emotional halo, such as food, enemy, home. Long afterwards, words became, in man, the medium of reasoned discourse. Sentences were made and judgments expressed, but was not the beginning in the croaking of amphibia, senses of amphibians. Frogs have good eyes, and the toad's eye are jewels. There is evidence of precise vision in the neat way in which a frog catches a fly, flickering out its tongue, which is fixed in front and lose behind. There is also experimental proof that a frog discriminates between red and blue, or between red and white. And an interesting point is that while our skin is sensitive to heat rays, but not to light, the skin of the frog answers back to light rays as well. Professor Yerkes experimented with a frog which had to go through a simple labyrinth if it wished to reach a tank of water. At the first alternative between two paths, a red card was placed on the wrong side and a white one on the other. When the frog had learned to take the correct path, marked by the white card, Professor Yerkes changed the cards. The confusion of the frog showed how thoroughly it had learned its lesson. We know very little in regard to sense of smell or taste in amphibians, but the sense of hearing is well developed, more developed than might be inferred from the indifference that frogs show to almost all sounds except the croaking of their kindred and splashes in the water. The toad looks almost sagacious when it is climbing up a bank, and some of the three frogs are very alert, but there is very little that we dare say about the amphibian mind. We have mentioned that frogs may learn the secret of a simple maze, and toads sometimes make for a particular spawning pond from a considerable distance. But an examination of their brains occupying a relatively small part of the broad, flat skull warns us not to expect much intelligence. On the other hand, when we take frogs along a line that is very vital to them, namely the discrimination of palatable and unpalatable insects, we find by experiment that they are quick to learn and that they remember their lessons for many days. Frogs sometimes deposit their eggs in very unsuitable pools of water, but perhaps that is not quite so stupid as it looks. The egg laying is a matter that has been, as it were, handed over to instinctive registration. Experiments in parental care. It must be put to the credit of amphibians that they have made many experiments in methods of parental care, as if they were feeling their way to new devices. A common frog lays her clumps of eggs in the cradle of the water, sometimes far over a thousand together. The toad wins two long strings round and between water weeds, and in both cases that is all. There is no parental care and a prolific multiplication covers the enormous infantile mortality. This is the spawning solution of the problem of securing the continuance of the race. But there is another solution, that of parental care associated with an economical reduction of the number of eggs. Thus the male of the nurse-rog, allies, not uncommon on the continent, fixes a string of 20 to 50 eggs to the upper part of his hind legs, and retires to his hole, only coming out at night to get some food and to keep up the moisture about the eggs. In three weeks, when the tadpoles are ready to come out, he plunges into the pond and is freed from his living burden and his family cares. In the case of the thoroughly aquatic serename toad Piper, the male helps to press the eggs, perhaps a hundred in number, on to the back of the female, where each sinks into a pocket of skin with a little lid. By and by fully formed young toads jump out of the pockets. In the South American tree frogs called nototrema, there is a pouch on the back of the female in which the eggs develop, and it is interesting to find that in some species what come out are ordinary tadpoles, while in other species the young emerge as miniatures of their parents. Stranges of all, perhaps, is the case of Darwin's frog, Rhinoderma of Chile, where the young, about 10 to 15 in number, develop in the male's croaking sacs, which become, in consequence, enormously distended. Eventually the strange spectacle is seen of miniature frogs jumping out of their father's mouth. Needless to say, we are not citing these methods of parental care as examples of intelligence, but perhaps they correct the impression of amphibians as a rather humdrum race. Whatever be the mental aspect of the fact, there has certainly been some kind of experimenting, and the increase of parental care so marked in many amphibians with associated reduction of the number of offsprings is a finger post on the path of progress. Part four, the reptilian mind. We speak of the wisdom of the serpent, but it is not very easy to justify the phrase. Among all the multitude of reptiles, snakes, lizards, turtles, and crocodiles, a motley crowd, we cannot see much more than the occasional traces of intelligence. The inner life remains a tiny rill. No doubt many reptiles are very effective, but it is an instinctive rather than an intelligent efficiency. The well known soft shell toy-toys of the United States swims with powerful strokes and runs so quickly that it can hardly be overtaken. It hunts vigorously for crayfish and insect larvae in the rivers. It buries itself in the mud when cold water comes. It may lie on a floating log ready to slip into the water at a moment's notice. It may bask on a sunny bank or in the warm shallows. Great wariness is shown in choosing times and places for egg laying. The mother trumps the earth down upon the buried eggs. All is effective. Similar statements might be made in regard to scores of other reptiles, but what we see is almost wholly of the nature of instinctive routine, and we get little glimpse of more than efficiency and endaver. In a few cases there is proof of reptiles finding their way back to their homes from a considerable distance, and recognition of prisons is indubitable. Gilbert White remarks of his toy-toys, whenever the good old lady came in sight who had waited on it for more than thirty years, it always hobbled with awkward alacrity towards its benefactress, all two strangers. It was altogether inattentive. Of definite learning there are a few records. Thus Professor Yerkes studied a sluggish turtle of retiring disposition, taking advantage of its strong desire to efface itself. On the path of the darkened nest of damped grass he interposed a simple maze in the form of a partitioned box. After wandering about constantly for thirty-five minutes the turtle found its way through the maze by chance. Two hours afterwards it reached the nest in fifteen minutes, and after another interval of two hours it only required five minutes. After the third trial the routes became more direct, there was less aimless wandering. The time of the twentieth trial was forty-five seconds, that of the thirtieth forty seconds. In the thirtieth case the path followed was quite direct, and so it was on the fiftieth trip, which only required thirty-five seconds. Of course the whole thing did not amount to very much, but there was a definite learning, a learning from experience, which has played an important part in the evolution of animal behaviour. Comparing reptiles with amphibians we may recognise an increased masterliness of behaviour and a hint of greater plasticity. The records of observers who have made pets of reptiles suggest that the life of feeling or emotion is growing stronger, and so do stories, if they can be accepted, which suggests the beginning of conjugal affection. The error must be guarded against of interpreting in terms of intelligence what is merely the outcome of long-continued structure adaptation. When the limbless lizard, called the slow worm, is suddenly seized by the tail, it escapes by surrendering the appendage, which breaks across a preformed weak plane. But this is a reflex action, not a reflective one. It is comparable to our sudden withdrawal of our finger from a very hot cinder. The egg-eating African snake, Daisy Peltis, gets the egg of a bird into its gullet unbroken, and cuts the shell against downward projecting sharp points of the vertebrae. None of the precious contents is lost, and the broken empties are returned. It is admirable, indeed, unsurpassable, but it is not intelligent. Part 5. Minds in Birds Sight and hearing are highly developed in birds, and the senses, besides polling the triggers of inborn efficiencies, supply the raw materials for intelligence. There is some truth, though not the whole truth, in the ill philosophical dictum, that there is nothing in the intellect which was not previously in the senses. Many people have admired the certainty and the liquidity with which goals pick up a fragment of viscuit from the white wake of a streamer, and the incident is characteristic. In their power of rapidity, alerting the focus of the eye, birds are unsurpassed. To the sense of sight in birds, the sense of hearing comes a good second. A twig breaks under our feet, and out sounds the dagger-call of the bird we were trying to catch. Many young birds, like partridges, respond when two or three hours old to the anxious warning note of the parents, and squat motionless on the ground, though other sounds, such as the excited clucking of a foster mother hen, leave them indifferent. They do not know what they're doing when they squat. They are obeying the living hand of the past which is within them. Their behavior is instinctive. But the present point is the discriminating quality of the sense of hearing, and that is corroborated by the singing of birds. It is emotional art, expressing feeling in the medium of sound. On the part of the females who are supposed to listen, its bitokens a cultivated ear. As to the other senses, touch is not highly developed except about the bill, where it reaches a climax in birds like the woodcock, which probe for unseen earthworms in the soft soil. Taste seems to be poorly developed, for most birds bolt their food, but there is sometimes an emphatic rejection of unpalatable things like toads and caterpillars. Of smell in birds little is known, but it has been proved to be present in certain cases, e.g. in some nocturnal birds of prey. It seems certain that it is by sight, not by smell, that the eagles gather to the carcass. But perhaps there is more smell than birds that they are usually credited with. One would like to experiment with the oil from the preen gland of birds to see whether the scent of this does not help in the recognition of kin by kin at night, or emit the darkness of the forest. There may be other senses in birds, such as a sense of temperature and a sense of balance, but no success has attended the attempts made to demonstrate a magnetic sense, which has been impatiently postulated by students of bird migration in order to explain how birds find their way. The big fact is that in birds there are two widely open gateways of knowledge, the sense of sight and the sense of hearing. Instinctive aptitudes. Many a young water bird, such as a coot, swims right away when it is tumbled into water for the first time. So chicks peck without any learning or teaching. Very young ducklings catch small moths that flit by and young clovers lie low when the danger signal sounds. But birds seem strangely limited as regards many of these instinctive capacities. Limited when compared with the little-brained ants and bees, which have from the first such a rich repertory of ready-made cleverness. The limitation in birds is of great interest, for it means that intelligence is coming to its own and is going to take up the reins at many corners of the daily round. Professor Lloyds Morgan observed that his chickens incubated in the laboratory had no instinctive awareness of the significance of their mother's cluck when she was brought outside the door. Although thirsty and willing to drink from a moistened fingertip, they did not instinctively recognize water, even when they walked through a saucer-fall. Only when they happened to peck their toes as they stood in the water did they appreciate water as the stuff they wanted and raised their bills up to the sky. Once or twice they actually stuffed their crops with worms of red worsted. Instinctive aptitudes then, the young birds have, but these are more limited than in ants, bees, and wasps. And the reason is to be found in the fact that the brain is now evolving on the track of what Sir Ray Lancaster has called educability. Young birds learn with prodigious rapidity. The emancipation of the mind from the tyranny of hereditary obligations has begun. Young birds make mistakes, like the red worsted mistake, but they do not make the same mistakes often. They are able to profit by experience in a very rapid way. We do not mean that creatures of the little brain type, like ants, bees, and wasps are unable to profit by experience or are without intelligence. There are no such hard and fast lines. We mean that in the ordinary life of insects the unregistered instinctive capacities are on the whole sufficient for the occasion, and that intelligent educability is very slightly developed. Nor do we mean that birds are quite emancipated from the tyranny of ingrained instinctive obligations, and can always ring up intelligence in a way that is impossible for the stereotyped bee. The sight of a pigeon brooding on an empty nest while her eggs lie disregarded only a couple of inches away is enough to show that along certain lines birds may find it impossible to get free from the trammels of instinct. The particular interest of birds is that they have many instincts and yet a notable power of learning intelligently, intelligence cooperating with instinct. Professor Lloyd Morgan was forced to parent to two more hands which grew up in isolation from their kindred. They swam instinctively, but they would not dive, neither in a large bath nor in a current. But it happened one day when one of these more hands was swimming in a pool on a Yorkshire stream that a puppy came barking down the bank and made an awkward faint towards the young bird. In a moment the more hand dived disappeared from view and soon partially reappeared, his head just peeping above the water beneath the overhanging bank. This was the first time the bird had dived and the performance was absolutely true to type. There can be little doubt as to the meaning of this observation. The more hand has an irreditary or instinctive capacity for swimming and diving, but the latter is not so easily called into activity as the former. The particular more hand in question has enjoyed about two months of swimming experience, which probably counted for something, but in the course of that experience nothing had pulled the trigger of the diving capacity. On an eventful day the young more hand saw and heard the dog. It was emotionally excited. It probably did to some extent intelligently appreciate a novel and meaningful situation. Intelligence cooperated with instinct and the bird dived appropriately. Birds have inborn predispositions to certain effective ways of pecking, scratching, swimming, diving, flying, crouching, lying low, nest building and so on, but they are marked off from the much more purely instinctive ants and bees by the extent to which individual nurture, seems to mingle with the inherited nature. The two together result in the fine product, which recalled the bird's behavior. After Lloyd Morgan's chicks had tried a few conspicuous and unpalatable caterpillars, they had no use for any more. They learned in their early days with prodigious rapidity, illustrating the deep difference between the pig brain type, relatively poor in its endowment of instinctive capacities, but eminently educable and the little brain type, say of ants and bees, richly endowed with instinctive capacities, but very far from being quick or glad to learn. We owe it to Sir Ray Lancaster to have made it clear that these two types of brain are, as it were, on different tax of evolution, and should not be directly pitted against one another. The little brain type makes for climax in the ant, where instinctive behavior reaches a high degree of perfection. The big brain type reaches its climax in horse and dog, in elephant and monkey. The particular interest that attaches to this behavior of birds is in the combination of a good deal of instinct with a great deal of intelligent learning. This is well illustrated when birds make a nest out of new materials or in some quite novel situation. It is clearly seen when birds turn to some new kind of food, like the key parrot, which attacks the sheep in New Zealand. Some young woodpeckers are quite clever in opening fur cones to get at the seeds, and this might be hastily referred to as well-defined hereditary capacity. But the facts are that the parents bring their young ones first to the seeds themselves, then partly open cones, and then intact ones. There is an educative process, and so it is in scores of cases, using their wits. When the Greek eagle lifts the Greek tortoise in its talons and lets it fall from a height so that the strong carapace is broken and the flesh exposed, it is making intelligent use of an expedient. Whether it discovered the expedient by experimenting, as is possible, or by chance, as is more likely, it uses it intelligently. In the same way, herring-goals lift sea urchins and clams in their bills, and let them fall on the rocks so that the shells are broken. In the same way, rooks deal with freshwater mussels. The Thrust Anvil. A very instructive case is the behaviour of the song thrush when it takes a wood snail in its beak and hammers it against the stone. It's so-called anvil. To a young thrush, which she had brought up by hand, Miss Francis Pitt offered some wood snails, but it took no interest in them until one put out its head and began to move about. The bird then pecked at the snail's horns, but was evidently puzzled when the creature retreated within the shelter of the shell. This happened over and over again, the thrush inquisitive interest increasing day by day. It pecked at the shell and even picked it up by the lip, but no real progress was made till the sixth day when the thrush seized the snail and beat it on the ground as it would a big worm. On the same day, it picked up a shell and knocked it repeatedly against the stone, trying first one snail and then another. After fifteen minutes' hard work, the thrush managed to break one, and after that it was all easy. A certain predisposition to beat things on the ground was doubtless present, but the experiment showed that the use of an anvil could be arrived at by an untutored bird. After prolonged trying, it found out how to deal with a difficult situation. It may be said that in more natural conditions this might be picked up by imitation, but while this is quite possible, it is useful to notice that experiments with animals lead us to doubt whether imitation counts for nearly so much as used to be believed. Recording by J. C. Guan, The Outline of Science, Volume 1 by J. Arthur Thompson, Section 12. When we watch a collie at the sheep-driving competition, or an elephant helping the forester, or a horse shunting wagons at a railway sighting, we are apt to be too generous to the mammal mind, for in the cases we have just mentioned, part of man's mind has, so to speak, got into the animals. On the other hand, when we study rabbits and guinea pigs, we are apt to be too stingy, for these rodents are under the average of mammals, and those that live in domestication illustrate the stupefying effect of a too sheltered life. The same applies to domesticated sheep, contrasted with wild sheep, or even with their own lambs. If we are to form a sound judgment on the intelligence of mammals, we must not attend too much to those that have profited by man's training, nor to those whose mental life has been dulled by domestication. What is to be said of the behavior of beavers who gnaw the base of a tree with their chisel-edged teeth till only a narrow core is left to snap in the first gale, bringing the useful branches down to the ground? What is to be said of the harvest mouse constructing its nest, or of the squirrel making cash after cash of nuts? These and many similar pieces of behavior are fundamentally instinctive, due to inborn predispositions of nerve cells and muscle cells. But in mammals, they seem to be often attended by a certain amount of intelligent attention, saving the creature from the tyranny of routine so marked in the ways of ants and bees. Sheared Exterity. Besides instinctive aptitudes, which are exhibited in almost equal perfection by all members of the same species, there are acquired dexterities which depend on individual opportunities. They are also marked by being outside and beyond ordinary routine, not that any rigorous boundary line can be drawn. We read that at Mestera and the Gemna, those of food are provided by the piety of pilgrims for the sacred river toy-toises, which are so crowded when there is food going that their smooth carepices form a more or less continuous raft across the river. On that unsteady slippery bridge, the langher monkeys, Semnapitecus and Telus venture out and in spite of vicious snaps secure a share of the booty. This picture of the monkeys securing a footing on the moving mass of turtle-backs is almost a diagram of sheer dexterity. It illustrates the spirit of adventure, the will to experiment, which is, we believe, the main motive force in new departures in behavior. Power of Association. A bull terrier called Jasper, studied by Professor J. B. Watson showed great power of associating certain words with certain actions. From a position invisible to the dog, the owner would give certain commands, such as, go into the next room and bring me a paper lying on the floor. Jasper did this at once, in a score of similar things. Lord Avesbury's dog, Van, was accustomed to go to a box containing a small number of printed cards and select the card T, or out, as the occasion suggested. It had established an association between certain black marks on a white background and the gratification of certain desires. It is probable that some of the extraordinary things horses and dogs have been known to do in the way of stamping a certain number of times in supposed indication of an answer to an average medical question, in the case of horses, or the name of an object drawn, in the case of dogs, are dependent on clever associations established by the teacher between minute signs and a number of stampings. What is certain is that mammals have in varying degrees a strong power of establishing associations. There is often some delicacy in the association established. Everyone knows of cases where a dog, a cat, or a horse will remain quite uninterested to all appearance in its owner's movement until some little detail, such as taking a key from its peg, pulls the trigger. Now the importance of this in the wildlife of the fox or the hare, the otter or the squirrel is obviously that the young animals learn to associate certain sounds in their environment with definite possibilities. They have to learn an alphabet of woodcraft, the letters of which are chiefly sounds and sense, the dancing mouse as a popple. The dancing or waltzing mouse is a Japanese variety with many peculiarities, such as having only one of the three semicircular canals of the ear well developed. It has a strong tendency to waltz round and round in circles without sufficient cause and to drip sideways towards its dormitory instead of proceeding in the orthodox head-on fashion. But this freak is a very educable creature, as Professor Euricks has shown. In a careful way, he confronted his mouse-popple with alternative pathways marked by different degrees of illumination or by different colors. If the mouse chose compartment A, it found a clear passage direct to its nest. If it chose compartment B, it was punished by a mild electric shock and it had to take a roundabout road home. Needless to say, the A compartment was sometimes to the right hand, sometimes to the left. Else mere position would have been a guide. The experiments showed that the dancing mice learned to discriminate the right path from the wrong and similar results have been got from other mammals, such as rats and squirrels. There is no proof of learning by ideas, but there is proof of learning by experience, and the same must be true in wildlife. Many mammals, such as cats and rats, learn how to manipulate puzzle boxes and how to get at the treasure at the heart of a Hampton court maze. Some of the puzzle boxes, with a reward of food inside, are quite difficult for the various bolts and bars have to be dealt with in a particular order, and yet many mammals master the problem. What is plain is that they gradually eliminate useless movements, that they make fewer and fewer mistakes, that they eventually succeed, and that they register the solution within themselves so that it remains with them for a time. It looks a little like the behavior of a man who learns a game of skill without thinking. It is a learning by experience, not by ideas or reflection. Thus it is very difficult to suppose that a rat or a cat could form any idea or even picture of the Hampton court maze, which they nevertheless master. Learning tricks. Given sufficient inducement, many of the cleverer mammals will learn to do very sensible things, and no one is wise enough to say that they never understand what they are doing. Yet it is certain that trained animals often exhibit pieces of behavior which are not nearly so clever as they look. The elephant, at the Bellevue Gardens in Manchester, used to collect pennies from benevolent visitors. When it got a penny in its trunk, it put it in the slot of an automatic machine which delivered up a biscuit. When a visitor gave the elephant a half penny, it used to throw it back with disgust. At first sight this seemed almost wise, and there was no doubt some intelligent appreciation of the situation. But it was largely a matter of habituation, the outcome of careful and prolonged training. The elephant was laboriously taught to put the penny in the slot and to discriminate between the useful pennies and the useless half pennies. It was not nearly so clever as it looked, using their wits. In the beautiful zoological park in Adenburg, the polar bear was wont to sit on a rocky peninsula of a water-filled quarry. The visitors threw in buns, some of which floated on the surface. It was often easy for the polar bear to collect half a dozen by plunging into the pool. But it had discovered a more interesting way. At the edge of the peninsula, it scooped the water gently with its huge paw, and made the occurrence which brought the buns ashore. This was a simple piece of behavior, but it has the smack of intelligence, of putting two and two together in a novel way. It suggests the power of making what is called a perceptual inference. On the occasion of a great flood in a meadow, it was observed that a number of mares brought their foals to the top of Ignal, and stood round about them protecting them against the rising water. A dog has been known to show what was at any rate a plastic appreciation of a varying situation in swimming across a tidal river. It changed its starting point, they say, according to the flow or ebb of the tide. Architect foxes and some other wild animals show great cleverness in dealing with traps, and the manipulative intelligence of elephants is worthy of all our admiration. Why is there not more intelligence? When we allow for dexterity and power of association, when we recognize a certain amount of instinctive capacity, and a capacity for profiting by experience in an intelligent way, we must admit a certain degree of disappointment when we take a survey of the behavior of mammals, especially of those with very fine brains, from which we should naturally expect great things. Why is there not more frequent exhibition of intelligence in the stricter sense? The answer is that most mammals have become in the course of time very well adapted to the ordinary conditions of their life, and tend to leave well alone. They have got the repertory of efficient answers to the ordinary questions of everyday life, and why should they experiment? In the course of the struggle for existence, what has been established is efficiency in normal circumstances, and therefore even the higher animals tend to be no cleverer than is necessary. So, while many mammals are extraordinarily efficient, they tend to be a little dull. Their mental equipment is adequate for the everyday conditions of their life, but it is not on sufficiently generous lines to admit of, let us say, an interest in nature or adventurous experiment. Mammals always tend to play for safety. We hasten, however, to insert here some very interesting saving clauses. Experimentation in play. A glimpse of what mammals are capable of, where it is necessary, may be obtained by watching those that are playful, such as lambs and kids, foals and calves, young foxes and others. For these young creatures let themselves go irresponsibly. They are still un-stereotide. They test what they and their fellows can do. The experimental character of much of animal play is very marked. It is now recognized by biologists that play among animals is the young form of work, and that the playing period, often so conspicuous, is vitally important as an apprenticeship to the serious business of life and as an opportunity for learning the alphabet of nature. But the playing period is much more. It is one of the few opportunities animals have of making experiments without too serious responsibilities. Play is nature's device for allowing elbow room for new departures, behavior variations, which may form part of the raw materials of progress. Play, we repeat, gives us a glimpse of the possibilities of the mammal mind, other glimpses of intelligence. A squirrel is just as clever as it needs to be and no more. And of some vanishing mammals, like the beaver, not even this can be said. Humdrum, non-plastic efficiency, is apt to mean stagnation. Now, we have just seen that in the play of young mammals, there is an indication of unexhausted possibilities. And we get the same impression when we think of three other facts. A, in those mammals, like dog and horse, which have entered into active cooperative relations with man, we see that the mind of the mammal is capable of much more than the average would lead us to think. When man's sheltering is too complete and the domesticated creature is passive in his grip, the intelligence deteriorates. B, when we study mammals, like the otter, which live a versatile life in very complex and difficult environment, we get an inspiring picture of the play of wits. C, thirdly, when we pass to monkeys where the forelimb has become a free hand, where the brain shows a relatively great improvement, where words are much used, we cannot fail to recognize the emergence of something new. A restless inquisitiveness, a desire to investigate the world, an unsatisfied tendency to experiment, we are approaching the dawn of reason, the mind of monkeys. Part eight. There is a long gamut between the bushy-tailed almost squirrel-like marmosets and the big-brained chimpanzee. There is a great variety of attainment at different levels in the Simeon tribe. Keen senses. To begin at the beginning, it is certain that monkeys have a first-class sensory equipment, especially as regards sight, hearing, and touch. The axes of the two eyes are directed forwards as in man, and a large section of the field of vision is common to both eyes. In other words, monkeys have a more complete stereoscopic vision than the rest of the mammals enjoy. They look more and smell less. They can distinguish different colors, apart from different degrees of brightness in the colored objects. They are quick to discriminate differences in the shapes of things, e.g. boxes similar in size, but different in shape, for if the prize is always put in a box of the same shape, they soon learn by association to select the profitable one. They learn to discriminate cards with short words or with signs printed on them, coming down when the yes card is shown, remaining on their perch when the card says no. Bread to a forest life where alertness is life or death quality, they are quick to respond to a sudden movement or to pick out some new feature in their surroundings. And what is true of vision holds also for hearing, power of manipulation. Another quality which separates monkeys very markedly from the ordinary mammals is the manipulative expertness, the coordination of hand and eye. This great gift follows from the fact that among monkeys the foreleg has been emancipated. It has ceased to be indispensable as an organ of support. It has become a climbing, grasping, lifting, handling organ. The forelim has become a free hand, and everyone who knows monkeys at all is aware of their zest with which they use their tool. They enjoy pulling things to pieces, a kind of dissection, or screwing the handle of a brush and screwing it on again. Activity for activity's sake. Professor Thorndike hits the nail on the head when he lays stress on the intensity of activity in monkeys. Activity both of body and mind. They are pent up reservoirs of energy which almost any influence will tap. Watch a cat or a dog, Professor Thorndike says. It does comparatively few things and is content for long periods to do nothing. It will be splendidly active in response to some stimulus such as food or a friend or a fight. But if nothing appeals to its special makeup, which is very utilitarian in its interest, it will do nothing. Quote. Watch a monkey, and you cannot enumerate the things he does, cannot discover the stimuli to which he reacts, cannot conceive the raison d'être of his pursuits. Everything appeals to him. He likes to be active for the sake of activity. This applies to mental activity as well, and the quality is one of extraordinary interest, for it shows the experimenting mood at a higher turn of the spiral than in any other creature, save man. It points forward to the scientific spirit. We cannot indeed believe in the sudden beginning of any quality, and we recall the experimenting of playing mammals, such as kids and kittens, or of inquisitive adults like Kipling's mongoose, Rikki Tikki Tavi, which made it his business, in life, to find out about things. But in monkeys, the habit of restless experimenting rises to a higher pitch. They appear to be curious about the world. The psychologist whom we have quoted tells of a monkey which happened to hit a projecting wire so as to make it vibrate. He went on repeating the performance hundreds of times during the next few days. Of course he got nothing out of it, save fun, but it was grist to his mental mill. Quote, the fact of mental life is to monkeys its own reward. End quote. The monkey's brain is, quote, tender all over, functioning throughout, set off in action by anything and everything. End quote. Sheer quickness. Correlated with the quality of restless inquisitiveness and delight in activity for its own sake, there is the quality of quickness. We mean not merely the locomotor agility that marks most monkeys, but the quickness of perception and plan. It is the sort of quality that life among the branches will engender, where it is so often a case of neck or nothing. It is the quality which we describe as being on the spot, though the phrase has slipped from its original moorings. Speaking of his bonnet monkeys, an Indian macaque, second cousin to the kind that lives on the rock of Gibraltar, Professor S. J. Holmes writes, quote, for keenness of perception, rapidity of action, facility in forming good practical judgment about ways and means of escaping pursuit and of attaining various other ends, Lizzie had a few rivals in the animal world. Her perceptions and decisions were so much more rapid than my own that she would frequently transfer her attention, decide upon a line of action, and carry it into effect before I was aware of what she was about. Until I came to guard against her nimble and unexpected maneuvers, she succeeded in getting possession of many apples and peanuts which I had not intended to give her except upon the successful performance of some task, end quote, quick to learn. Quite fundamental to any understanding of animal behavior is the distinction so clearly drawn by Sir Ray Lancaster between the little brain type, rich in inborn or instinctive capacities, but relatively slow to learn, and the big brain type with a relatively poor endowment of specialized instincts, but with great educability. The little brain type finds its own climax in ants and bees, the big brain type in horses and dogs, elephants and monkeys, and of all animals, monkeys are the quickest to learn if we use the word learn to mean the formation of useful associations between this and that, between a given sense presentation and a particular piece of behavior. The case of Sally. Some of us remember Sally, the chimpanzee at the zoo with which Dr. Romanus used to experiment. She was taught to give her teacher the number of straws he asked for and she soon learned to do so up to five. If she had handed a number not asked for, her offer was refused. If she gave the proper number, she got a piece of fruit. If she was asked for five straws, she picked them up individually and placed them in her mouth, and when she had gathered five, she presented them together in her hand. Attempts to teach her to give six to ten straws were not very successful. For Sally, above six meant many, and besides, her limits of patience were probably less than her range of computation. This was hinted at by the highly interesting circumstances that, when dealing with numbers above five, she very frequently doubled over a straw so as to make it present two ends and thus appear as two straws. The doubling of the straw looked like an intelligent device to save time, and it was persistently resorted to in spite of the fact that her teacher always refused to accept a double straw as equivalent to two straws. Here we get a glimpse of something beyond the mere association of a sound, five, and that number of straws, the case of Lizzie. The front of the cage in which Professor Holmes kept Lizzie was made of vertical bars which allowed her to reach out with her arm. On a board with an upright nail as handle there was placed an apple out of Lizzie's reach. She reacted immediately for the nail, pulled the board in, and got the apple. There was no employment of the method of trial and error. There was direct, appropriate action following the perception of her relation to board, nail, and apple. Of course her ancestors may have been adepts at drawing a fruit-laden branch within their reach, but the simple experiment was very instructive. All the more instructive because in many other cases the experiments indicate a gradual sifting out of useless movements and an inventful retention of the one that pays. When Lizzie was given a Vaseline bottle containing a peanut and closed with a cork, she at once pulled the cork with her teeth, obeying the instinct to bite at new objects. But she never learned to turn the bottle upside down and let the nut drop out. She often got the nut, and after some education she got it more quickly than she did at first. But there was no indication that she never perceived the fit and proper way of getting what she wanted. In the course of her intent efforts her mind seemed so absorbed with the object of desire that it was never focused on the means of attaining that object. There was no deliberation and no discrimination between the important and the unimportant elements in her behavior. The gradually increasing facility of her performances depended on the apparently unconscious illuminations of useless movements. This may be called learning, but it is learning at a very low level. It is far from learning by ideas. It is hardly even learning by experiment. It is not more than learning by experience. It is not more than fumbling at learning, trial and error. A higher notice struck in the behavior of some more highly endowed monkeys. In many experiments, chiefly in the way of getting into boxes difficult to open, there is evident, one, of attentive persistent experiment, two, of the rapid elimination of ineffective movements, and three, of remembering the solution when it was discovered. Kineman taught two macaques the Hampton Court's maze, a feat which probably means a memory of movement. And we get an interesting glimpse in the observation that they began to smack their lips audibly when they reached the latter part of their course, and began to feel, dare one say, we are right in this time. In getting into puzzle boxes and into combination boxes, where the barriers must be overcome in a definite order, monkeys learned by the trial and error method much more quickly than cats and dogs do. And a very suggestive fact emphasized by Professor Thorndike is, quote, a process of sudden acquisition by a rapid, often apparently instantaneous abandonment of the unsuccessful movement and selection of the appropriate one, which reveals in suddenness the selections made by human beings in similar performances, end quote. A higher note still was sounded by one of Thorndike's monkeys, which opened a puzzle box at once, eight months after his previous experience with it. For here was some sort of a registration of a solution, imitation. Two chimpanzees in the Dublin Zoo were often to be seen washing the two shelves of their cupboard and wringing the wet cloth in the approved fashion. It was like a caricature of a washerwoman, and someone said, what mimics they are? Now we do not know whether that was or was not the case with the chimpanzees, but the majority of the experiments that have been made do not lead us to attach to imitation so much importance as is usually given to it by the popular interpreter. There are instances where a monkey that had given up a puzzle in the spear returned to it when it had seen its neighbor succeed, but most of the experiments suggested that the creature has to find out for itself. Even with such a simple problem as drawing food near with a stick, it often seems of little use to show the monkeys how it is done. Placing a bit of food outside the monkey's cage, Professor Holmes poked it about with a stick so as to give her a suggestion of how the stick might be employed to move the food within reach, but although the act was repeated many times, Lizzie never showed the least inclination to use the stick to her advantage. Perhaps the idea of a tool is beyond the bonnet monkey, yet here again we must be cautious, for Professor L. T. Hophouse had a monkey of the same macaque genus, which learned in the course of time to use a crooked stick with great effect. The case of Peter. Perhaps the cleverest monkey as yet studied was a performing chimpanzee called Peter, which has been generally described by Dr. Leitner Wittmer. Peter could skate and cycle, thread needles and untie nuts, smoke a cigarette and string beads, screw in nails and unlock locks. But what Peter was thinking about all the time, it was hard to guess. And there is very little evidence to suggest that his rapid power of putting two and two together ever rose above a sort of concrete mental experimenting, which Dr. Romanes used to call perceptual inference. Without supposing that there are hard and fast boundary lines, we cannot avoid the general conclusion that, while monkeys are often intelligent, they sell them, if ever, show even hints of reason, i.e. of working or playing with general ideas. That remains man's prerogative, the bustle of the mind. In mammals like otters, foxes, stoats, hares and elephants, what a complex of tides and currents there must be in the brain mind. We may think of a stream with currents at different levels. Lowest, there are the basal appetites of hunger and sex, often with eddies rising to the surface. Then there are the primary emotions, such as fear of hereditary enemies and maternal affection for offspring. Above these are instinctive aptitudes, inborn powers of doing clever things without having to learn how. But in mammals, these are often expressed along with, or as it were through, the controlled life of intelligent activity, where there is more clear cut perceptual influence. Higher still are the records or memories of individual experience and the registration of individual habits, while on the surface it is the in-streaming multitude of messages from the outside world like raindrops and hailstones on the stream, some of them penetrating deeply, being as we say, full of meaning. The mind of the higher animal is in some respects like a child's mind, in having little in the way of clear cut ideas, in showing no reason in the strict sense and in its extraordinary educability. But it differs from the child's mind entirely in the sure effectiveness of a certain repertoire of responses. It is efficient to a degree, quote, until at last arose the man, end quote. Man's brain is more complicated than that of the higher apes, gorilla, orang and chimpanzee, and it is relatively larger. But the improvements in structure do not seem in themselves sufficient to account for man's great advance in intelligence. The real of inner life has become a swift stream, sometimes a rushing torrent. Besides perceptual influence or intelligence, a sort of picturlogic which some animals likewise have, there is conceptual inference, or reason, and internal experimenting with general ideas. Even the cleverest animals it would seem do that get much beyond playing with particulars. Man plays an internal game of chess with universals. Intelligent behavior may go a long way with mental images. Rational conduct demands general ideas. It may be, however, that percepts and concepts differ rather in degree than in kind, and that the passage from one to the other meant a higher power of forming associations. A clever dog have probably a generalized percept of man, as distinguished from a memory image of the particular man it has known. But man alone has the concept man, or mankind, or humanity. Experimenting with concepts or general ideas is what we call reason. Here, of course, we get into deep waters, and perhaps it is wisest not to attempt too much. So we shall content ourselves here with pointing out that man's advance in intelligence and from intelligence to reason is closely wrapped up with his power of speech. What animals began, a small vocabulary, he has carried to high perfection. But what is distinctive is not the vocabulary so much as the habits of making sentences, of expressing judgments in a way which admitted of communication between mind and mind. The multiplication of words meant much. The use of words and symbols of general ideas meant even more, for it meant the possibility of playing the internal game of thinking. But perhaps the most important advance of all was the means of comparing notes with neighbors, of corroborating individual experience by social intercourse. With words also, it became easier to in register outside himself the gains of the past. It is not without significance that the Greek logos, which may be translated, the word, may also be translated mind, part nine, looking backwards. When we take a survey of animal behavior, we see a long inclined plane. The outer world provokes simple creatures to enter back. Simple creatures act experimentally on their surroundings. From the beginning, this two fold process has been going on. Receiving stimuli from the environment and acting upon the environment and according to the efficiency of the reactions and actions living creatures have been sifted for millions of years. One main line of advance has been opening new gateways of knowledge. The senses, which are far more than five in number. The other main line of advance has been in most general terms experimenting or testing, probing and proving, trying one key after another till a door is unlocked. There is progress in multiplying the gateways of knowledge and making them more discriminating. And there is progress in making the modes of experimenting more wide awake, more controlled and more resolute. But behind both of these is the characteristically vital power of in registering within the organism the lessons of the past. In the life of the individual, these in registrations are illustrated by memories and habituations and habits. In the life of the race, they are illustrated by reflex actions and instinctive capacities. Body and mind. We must not shirk the very difficult question of the relation between the bodily and the mental side of behavior. A. Some great thinkers have thought that the mind is a reality by itself, which plays upon the instrument of the brain and body. As the instrument gets worn and dusty, the playing is not so good as it once was, but the player is still himself. This theory of the essential independence of the mind is a very beautiful one. But those who like it, when applied to themselves, are not always so fond of it when it is applied to other intelligent creatures, like rooks and elephants. It may be, however, that there is a gradual emancipation of the mind which has gone furthest in man, and is still progressing. B. Some other thinkers have thought that the inner life of thought and feeling is only, as it were, an echo of the really important activity, that of the body and brain. Ideas are just foam bells on the hurrying streams and circling eddies of matter and energy that make up our physiological life. To most of us, this theory is impossible, because we are quite sure that ideas and feelings and purposes, which cannot be translated into matter and motion, are the clearest realities in our experience, and that they count for good and ill all through our life. They are more than the tickings of the clock. They make the wheels go round. C. There are others who think that the most scientific position is simply to recognize both the bodily and the mental activities as equally important, and so closely interwoven, that they cannot be separated. Perhaps they are just the outer and the inner aspects of one reality, the life of the creature. Perhaps they are like the concave and convex curves of a dome, like the two sides of a shield. Perhaps the life of the organism is always a unity, at one time appearing more conspicuously as mind's body, at another time as body mind. The most important fact is that neither aspect can be left out. By no jugglery, with words, can we get mind out of matter and motion, and since we are in ourselves quite sure of our mind, we are probably safe in saying that in the beginning was mind. This is in accordance with Aristotle saying that there is nothing in the end which was not also in kind present in the beginning. Whatever we mean by beginning. In conclusion. What has led to the truly wonderful result which we admire in a creature like a dog or an otter, a horse, or a hare? In general we may say just two main processes. One, testing all things, and two, holding fast that which is good. New departures occur and these are tested for what they are worth. I do synchrocies, crop up, and they are sifted. New cards come mysteriously from within into the creature's hand, and they are played for better or for worse. So by new variations and their sifting, by experimenting and enriches during the results, the mind has gradually evolved and will continue to evolve.