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Lecture 19. The Control of Life: Lessons of Evolution.

§ 1. The Idea of the Controllability of Life. § 2. Heredity the First Determinant of Life. § 3. Nurture the Second Determinant of Life. § 4. Selection the Third Determinant of Life. § 5. Importance of Correlating Organismal, Functional, and Environmental Betterment. § 6. Dangers of False Simplicity or Materialism. § 7. Science for Life.

A STUDY of human history which yielded no practical counsel to mankind would be self-condemned, and the same must be true of a study of animate evolution. What are the lessons of evolution?

§ 1. The Idea of the Controllability of Life.

There is practical suggestiveness in the very idea of organic evolution. Darwin changed a relatively static conception of the Realm of Organisms into an intensely dynamic one. The forms of life which seemed so fixed were shown to be in racial flux—though the movement might be as imperceptible as a glacier's flow. What Man could do in a relatively short time by breeding from selected variants was shown by his success with domesticated animals and cultivated plants. Thus the whole aspect of things was changed. The outlook became kinetic, and this led on naturally to the practical idea of the controllability of life. If flowers and pigeons and the like can be controlled, and controlled so well, then why not human life also? If Man can evolve from out of a crab-apple all the treasures of the orchard, may he not replace sourness by sweetness in human character? If Man can evolve from out of a wolf-like creature the domesticated dog, the trusty guardian of his flocks, may he not hopefully try to evolve the wolfish out of mankind? A few Darwinians were indeed inclined to be too sanguine, overlooking the fact that all that Man did in his domestication and cultivation was to use with discretion the variational material which the organisms themselves put into his hands.

Moreover, investigation brought to light many instances of marked modifiability. So much can be done by training, by exercise, by dieting, by altering the surroundings that we cannot wonder that there was for a time an exaggeration of the transforming power of function and environment. The fact is, however, that what is expressed from within is much more important than what is impressed from without; the range of variability is much wider than that of modifiability. Moreover, we do not know that the individually acquired modifications of the parents can be entailed as such or in any representative degree on the offspring.

It was pre-eminently Pasteur who made the idea of controllability glow. He may be taken as type of the many illustrious investigators who have been inspired to great achievements by the idea of the biological control of life. Beginning with measures for getting rid of the silkworm disease, which was ruining the south of France, Pasteur proceeded to attack such terrible scourges as splenic fever and hydrophobia, and conquered by understanding them. With object-lessons on a grand scale he convinced every open mind that the days of folded hands and resignation were over, and that it was for Man, with Science as torch, and with Mercy in his heart, to enter courageously into the fuller possession of his Kingdom.

It was the beginning of a new era for mankind, and it influenced thought and feeling as well as practice. If there be almost no constitutional disease in wild nature, why should it persist in mankind? Why should Man and his stock have a monopoly of senility? If certain microbic diseases can be got rid of, why do we allow them to linger in our midst? And we have, of course, practically ousted some terrors from their lairs, as in the cases of smallpox and typhus. If we cannot alter the span of human life, we can at any rate make sure what we shall not die of. The practical corollary of the doctrine of evolution is the controllability of life.

We have argued that Nature is crowned in Man, not merely because he has an all-round excellence of differentiation and integration, but especially because he is the finest expression of those qualities which mark the main trend of organic evolution,—such as freedom, awareness, mastery. Speaking metaphorically, we may say that Nature finds herself in Man, who understands, appreciates, and enjoys her in a sense that is certainly not true of the grazing herd. But the anomaly is that Man, minister and interpreter of Nature as he is, is subject to inhibitions and disharmonies which are not tolerated in wild nature. If there be an underlying purpose or meaning in organic Evolution, is not Man hindering it by his slowness to understand and fall in with the principles of its accomplishment? If the central fact in evolution be “the slowly wrought-out dominance of mind in things”, it is surely man's fundamental task to use this expanding mind to control his own life. If the process of Evolution suggests any lesson, it is surely that “the sharpened life commands its course”,—by brains, correlation, organisation. At lower levels the organisation that succeeds may be reflex, tropistic, instinctive; for Man it must be intelligent, at least; rational, if possible. But what the evolution-process points to with firmness is that Brains pay—Brains that include Love as well as Logic.

§ 2. Heredity the First Determinant of Life.

The first determinant of life is the natural inheritance—the past living on in the present, often with something new superadded. Nothing seems further from the possibility of control than heredity: as the satirical poet observed, “a man cannot be too careful in the choice of his parents”. But while we cannot choose our parents, we can, more or less, choose our partners in life, and this may mean controlling heredity. We cannot create a desirable variation by taking thought, but we may perhaps be able to prevent a very undesirable one from being continued. Parents have also some opportunity and responsibility in regard to the partners whom their children may choose. The days of coercion are over, but there is no coercion in the garrisoning (probably most effective when least direct) of the affections against the advances of the ignoble, the inefficient, and the hereditarily handicapped. This again means controlling heredity. The inheritance from the past is beyond control, except in so far as its expression may be influenced by nurture; but the inheritance handed on to the future is in some measure within control, since the mating of fittest with fittest, of fit with fitter, of fit with fit can be encouraged by common sense and good feeling, while the mating of fit and unfit, and of unfit with unfit can be discouraged. This has, of course, been done over and over again by peoples—such as the Hebrews—with pride of race and an enthusiasm for vigour. But now it can be done with fuller and finer knowledge. Certain it is that there can be no secure progress which does not recognise that Heredity, the past living on in the present, is the first Fate, and the greatest of the three. “Bless not thyself,” said Sir Thomas Browne, “that thou wert born in Athens; but, among thy multiplied acknowledgments, lift up one hand to heaven that thou wert born of honest parents, that modesty, humanity, and veracity lay in the same egg, and came into the world with thee.”

§ 3. Nurture the Second Determinant of Life.

The second determinant of life is Nurture—all manner of environing influences, whether due to surroundings, or to use and disuse, or to the social fabric. This nurture is largely within control—especially for the more prosperous, or more enlightened, or more idealistically ambitious members of the community; and the fullness of expression that the inheritance finds in development depends in part on the abundance and appropriateness of the nurture. If the nurture be opulent the buds may blossom richly. Conversely, buds which are detrimental may be kept dormant if the appropriate wakening stimulus be withheld; and for the individual at least this may be well. More than a few of us may have to confess with the poet that we are “stuccoed all over with quadrupeds”, including some reptiles; but, happily, these may remain in a starved state if we refuse them the appropriate nurture. Thus “the ape and tiger” in Man may die,—in the individual at least. It comes to this, that the controllability of nurture gives us some hold on the expression of our inheritance. We cannot alter the number of talents that we get to start with, but we certainly have some freedom in our trading with them. Not very often can a man truthfully say that he was hereditarily compelled to put his inherited talent in a napkin and bury it in the ground.

As the result of well-chosen influences and strenuous discipline, an individual may acquire some desirable quality,—usually a nurtural modification of an inherent predisposition. Now, as we have seen, it seems unlikely that this sort of personal gain can as such get into the racial treasure-box. The possibility remains, however, of re-acquiring the gain in each successive generation; or, contrariwise, of saving a generation from a gratuitous loss. This is peculiarly important for Man, where the extra-organismal social heritage counts for so much in nurture, especially as regards the higher human qualities.

On another line of thought, it is doubtful whether those who are not accustomed to look at life biologically are quite aware of the value of variations. These new departures, idiosyncrasies, eccentricities, individualities, originalities are the most precious things in the world,—when they are on the upgrade. If we do not understand them we call their possessors cranks; if they are ahead of the race, yet appreciated, we speak of genius. In their finest human expression they mean Teachings forwards to super-man. No one can offer a recipe for their production, but this practical point is clear, that, given a promiseful new departure, we may fail to make anything like the best of it if the nurture be not likewise evolving. Good nurture gives a progressive variation more chance of realisation, success, and transmission. It is a sad waste when a fascinating new plant is choked in a sluggard's garden. Nurture determines in part the sort of reception that a new variation meets with, and nurture consists in part of a subtle complex of liberating stimuli, which are to our potentialities as sunshine and rain to buds. “As is the world on the banks, so is the mind of man.” “What we have inherited from our ancestors we must put to use, if it is to become our very own.” When a belief in the transmission of individually acquired somatic modifications was general, reformers tended to exaggerate the directly ameliorative value of good nurture. Now that the belief in the transmission of individually acquired modifications has been badly shaken, many thinkers have swung to the opposite extreme, and the role of nurture is depreciated. But its individual importance remains, and its indirect importance also.

Prof. Karl Pearson and his collaborators have concluded that “the degree of dependence of the child on the characters of its parentage is ten times as intense as its degree of dependence on the character of its home or uprearing”. “It is five to ten times as profitable for a child to be born of parents of sound physique and of brisk, orderly mentality, as for a child to be born and nurtured in a good physical environment.” It may be doubted, however, whether it is possible to discriminate so precisely between what is due to hereditary nature and what is due to available nurture. It is also important to inquire when the nurture is supposed to begin: there is much nurture before birth.

Since hereditary nature and liberating nurture are both essential, there is no rigid antithesis. Nurture is important as a condition of normal development, and on the richness of its liberating stimuli the degree of development in part depends.

Gudernatsch has shown that in tadpoles fed on thyroid gland there is differentiation without growth, while in tadpoles fed on thymus and spleen there is growth without differentiation. A character known to be part of the inheritance may remain entirely unexpressed in the individual development because certain environmental conditions are lacking, yet the heritable character may be handed on all the same. Thus fruit-flies (Drosophila) of a Mendelian race with a peculiar abnormality may appear perfectly normal if raised in a dry environment, but the presence within them of the ‘factor’ for the abnormal feature may be demonstrated by rearing their offspring in a damp place. This shows the importance of nurture for the individual.

A diagrammatic illustration, concerns the red Chinese primrose (Primula sinensis rubra). Reared at 15°—20° C. it has red flowers. Reared at 30°—35° C., with moisture and shade the same plants have pure white flowers like those of Primula sinensis alba, which always has white flowers. Thus we see that the development of colour in the red Chinese primrose depends on its nurture.

Take another illustration from the fruit-fly. There is a mutant stock that produces supernumerary legs, in considerable percentage in winter, few or none in summer. Miss Hoge finds that when the flies are kept in an ice-chest at a temperature of about 10° C, a high percentage of individuals with supernumerary legs occurs. In a hot climate there would be no evidence that the peculiarity was part of the inheritance; in a cold country it would be obvious. This shows that the expression of the inheritance as regards a particular character sometimes depends on nurture.

In estimating the importance of nurture for the individual man, we must remember how largely the human mind is a social product. As Prof. George H. Parker (1914) puts it, “Our intellectual outfit comes to us more in the nature of a social contribution than an organic one.” Perhaps it is going too far to suggest that as regards our minds we are more ‘made’ than ‘born’; but this is certain, that while our mental capacities are primarily determined by heredity, they can be encouraged and augmented, or inhibited and depressed, within wide limits, by nurture.

On no account are we to countenance, if we can help it, spoiling good stock by bad, for that is the worst thing man can do. But we must beware of confusing veneer with hereditary nature. We must not too readily assume that people are as good as they look, or as bad as they look. In regard to the last, in an interesting study entitled Environment and Efficiency, Miss Mary Horner Thomson tells of her investigation of 265 children, mostly of “the lowest class” (Class A, fourth below the poverty level!), who had been sent to institutions and trained. She found that 192 (72 per cent.) turned out well; that 44 (16 per cent.) were doubtful; and that only 29 (less than 11 per cent.) were unsatisfactory, and of these 13 were defective. These figures, which should of course be checked and extended, afford some evidence of the controllability of the individual life.

Less extremely than some other Mendelians, Professor Punnett writes: “Hygiene and education are influences which can in some measure check the operation of one factor and encourage the operation of another. But that they can add a factor for a good quality or take away a factor for an evil one is utterly opposed to all that is known of the facts of heredity.”

But a practical note may be here permitted. It is very difficult for us to know all that is in a man's inheritance. Indeed we cannot, for we can see only what is expressed, and the condition of expression is appropriate nurture. Therefore in Man's formative periods the common-sense view is surely this. We cannot be quite sure what we have in our inheritance, therefore let us give every chance to such qualities as are liberated by ameliorative nurture. We cannot be quite sure what may not be in our inheritance, therefore we take no chances; let us avoid the kind of nurture that arouses sleeping dogs. The theory of the control of life is here quite plain: the practice, we admit, is no easier than before, save that we understand the issues better.

§ 4. Selection the Third Determinant of Life.

The third determinant of life is Selection, and this is of peculiar importance in the human sphere, where Natural Selection is largely in abeyance and the sifting is in great part rational and social. We call it rational and social because it is more or less deliberate and thought-out and because it is effected by social sieves; unfortunately this does not mean that it may not be terribly mistaken. In early days mankind was much in the sieve of Natural Selection—the meshes being wild beasts, changes of climate, scarcity of food, unchecked disease, and so on, and we are the better for that sifting to-day. But, as every one knows, the whole trend of human evolution since civilisation began has been to throw off the yoke of natural selection. Some of its thraldom remains, as in cases of differential death-rate, where the inherently weaker succumb in larger numbers, but we are continually interfering—necessarily and rightly—with the sifting operations of disease, hard times, and the like. This interference has been in great part prompted by the strengthening and diffusion of the humaner sentiments and a realisation of our solidarity; but it involves, as every one recognises more or less clearly, the terrible danger of relaxed sifting. In regard to that the records of organic and social evolution are alike eloquent. No one has stated the dilemma more poignantly than Spencer: “Any arrangements which, in a considerable degree, prevent superiority from profiting by the rewards of superiority, or shield inferiority from the evils it entails—any arrangements which tend to make it as well to be inferior as to be superior, are arrangements diametrically opposed to the progress of organisation, and the reaching of a higher life.” That way perdition lies. It is a dilemma of civilisation that we cannot tolerate Nature's régime, the individual life means so much to us; and yet we have not replaced it by any sufficiently strict, and consistent, and carefully thought-out sifting methods of our own.

There is satisfaction inhealing the sick and preventing wastage of life; we cannot but try to alleviate suffering; but there is no gainsaying the danger of being cruel to future generations by being kind in the present. There is the undeniable risk of helping too much, of coddling the undesirable and unwholesome so that they get strength enough to multiply, often spoiling good stock with the infiltration of bad. The wheat may have too much sympathy for the tares, and societies for the amalgamation of heaven and hell do not commend themselves to the wise.

This is a large and difficult question—the transition from Natural Selection to some other kind of selection which will grip the germ-plasm. The following three considerations are submitted.

In a number of cases the diseases and miseries with which civilised man is successfully coping are indiscriminate in their elimination. They thin the ranks, but they do not weed out or sift. The checking of such diseases and miseries will not, therefore, especially encourage the survival of types who are a source of weakness to human society. Hygienic endeavours which interfere with indiscriminate elimination—as in the case of much infantile mortality—may be pushed on unhesitatingly.

As things are, there ought to be no question of drastic social surgery or of accepting Plato's proposals for the purgation of the state. For, on the one hand, we do not know enough to go far with safety, and, on the other hand, we are forbidden by the social sentiment of the most moralized types. What can be done is to work back to the old and wholesome pride of race, and to work away from whatever tends to encourage the multiplication of the diseased and the unwholesome. For a long time to come reformers will have enough to do along negative lines,—in seeking to prevent the spoiling of good stock with bad. Much may also be achieved by educating public opinion, replacing baseless prejudices by convictions founded on facts. It is not in the 20th century too much to ask that the quaint lists of forbidden degrees which used to be prefixed to copies of the Scriptures should be replaced by sound eugenic information.

The commonplace must be borne in mind that man a social person, and that what is biologically commendable may be socially disruptive. Many of those who are seriously handicapped by inheritance, and who ought not to be encouraged to have offspring, are in other respects valuable citizens. Many of the weaklings whom the social surgeon threatens are strong in spirit. As poets and artists, reformers and preachers, many of the weaklings have been among the “makers and shakers” of the world.

A useful office is the careful criticism of all the methods of discriminate elimination—whether deliberate or not—that are at work in mankind. Some economists have wisely urged upon us the importance of criticism of consumption, for it is plain that in our expenditure we are willy-nilly selective. Thus a tradition of consistent expenditure along restricted materialistic lines must make for the elimination of artists, musicians, and similar types who are the salt of the earth. It condemns them to celibacy; it lets them slowly starve. Considerations of this sort may be exaggerated so as to make life a burden too.heavy to be borne, but it is plain that a community which is spending solely on things that perish in the using cannot be on a sound line of evolution. All expenditure that consistently promotes unhealthy occupations rather than healthy ones, that helps to foster and multiply the feckless rather than controlled types, that makes for sweated labour and slums rather than for well-paid work and gardens, is necessarily anti-evolutionary. From founding celibate fellowships at colleges down to advertising for gardeners “without encumbrances”, every form of selection that tends to prevent good types from duly contributing to the composition of succeeding generations is to be condemned in the court of applied biology, often called eugenics. That there may be a higher court of appeal is not denied.

An outstanding fact of Animate Evolution is, that new departures making for the welfare of the race become ingrained and entailed as part of the adaptive organisation of the creature. In the case of Man there has been a similar enregistration; it is idle to deny that there has been a hereditary organisation of kindliness, helpfulness, cheerfulness, and so on. But this hereditary organisation proceeds slowly, and so we must trust greatly to the extra-organismal heritage of traditions, conventions, ideals, and the like which works very potently both as a stimulating nurture, prompting us to seek after virtue and understanding, and also as a selective agency, leaving us behind if we fail too utterly of what society expects of its members.

In education—intellectual, physical, and moral—we do of course habitually seek to utilise nurture in the widest sense which includes the social heritage—as a means towards making the most of the individual development, and what, it may be asked, have we to offer in the way of new suggestion? Simply this, that we might to advantage he more scientific and less vague; that we should utilise with resoluteness and conviction the suggestions which expert science has to offer in regard to manifold problems in the control of life. We are convinced that many of the so-called “cosmic shadows”, such as the wastefulness of Nature, are misunderstandings; we are convinced that many of the shadows of human life are gratuitous, that they would be scattered if we let in more of the light of science. Our forefathers had to deal with these shadows in an indirect way or not at all; often the only thing to do was to try to get moral discipline out of them. But now we have made great advances towards understanding many of the human shadows, and it is only inertia that keeps us from directly dispelling them. Much is being done every day, but much more requires to be done, and our point is that the first and foremost lesson of evolution is: Let in more light,—more scientific light. Another lesson, of course, is: Let in more Love.

We know that a normal development of the human organism—in mind and body—demands an appropriate nurture; and yet we are implicated in human environments which are not up to the normal standard. In these environments, which make us ashamed, good men and women do indeed live, but there are surely many of the dwellers in darkness who find the great task of happiness altogether too hard.

Similarly, in regard to functional fatigue, there is a very considerable body of experimental fact in regard to the profitable length of a school-lesson, the profitable length of a school-day, the profitable length of a working-day, but how slow we are to utilise expert advice. In regard to occupational fatigue it is well known that H is the last straw that breaks the camel's back, and that what gives a push towards the danger-zone is often the entirely remediable delay in procuring appetising food.

These are familiar instances which we use simply as diagrams of the sad fact that we have got so accustomed to folding the hands when we did not know what to do, that we continue our resigned acquiescence even when the path of effective action is clear.

Professor Ward has spoken warmly of what man may achieve by an increased control of life (Realms of Ends, p. 112). “What the schoolmaster, the physician, and the philanthropist effect for the amelioration of the masses needs no description. Here again we have definite direction overriding the random and untrained impulses of the natural man. While the progress already made in the physical and social amelioration of human life is inestimable, it is as nothing compared with what is still possible. Nine-tenths of our physical ills are due to ignorance and perhaps a still greater proportion of our social evils are due to selfishness. Present scientific knowledge is adequate to remedy a very large proportion of the former, and the ordinary prudential maxims of utilitarian morality, if they were only observed as they might be, would go far towards extinguishing the latter: they would put an end to the worships of Venus, Bacchus, and Mammon, if even they did not establish peace and chain up the dogs of war for ever.” This was 1907-1910.

In the cases where the issue is relatively clear we have of course made great progress. We think of malaria and Malta fever, of diphtheria and plague, and many other diseases now coming under control. Not many years ago a number of religious and worthy Boer farmers—unconsciously impious—refused to join with an effective Anti-Locust League which depended for success on concerted action; they gave for their reason that it was attempting to stay the hand of God. But already this sounds like ancient history. Not in regard to diseases and pests alone, but in regard to depressing environment, ugliness, and dirt; in regard to dangerous and deteriorative occupations; in regard to poverty and unemployment, and, in short, all manner of objective evils, we have a determination rapidly growing stronger in our midst to get at the facts, to understand the operative factors, and to put brains into the task of betterment. Knowledge is foresight, and foresight is power. Science is for the ameloriation and control, as well as for the enlightenment of life. To have this conviction strongly is surely to show no profane depreciation of the things of the spirit which are beyond the scientific universe of discourse.

It is the complaint of most of us that scientific efforts for the alleviation of misery and the scattering of gratuitous shadows move so very slowly. On the other hand, there is some reason to be afraid of movements that make people more comfortable without making them more ambitious in the quest for the True, the Beautiful, and the Good; and of reforms which save guilty people from the consequences of sin, selfishness, and sloth.

§ 5. Importance of Correlating Organismal, Functional, and Environmental Betterment

A consideration of organic evolution suggests that progressive change depends on the correlation of functional and environmental with organismal improvement. We see writ large the lesson that a promising organisation may undergo involution in conditions of ease and safety, that the parasite is branded by degeneration, that unused organs dwindle away. We have seen that the development of characters is in some measure dependent on nurture, that progressive variations are apt to be short-lived unless the environment be also progressive, that the sifting is always in relation to a definite here and now—namely, the surrounding web of life in which some of the great advances of the past are always in some measure systematised. What is true of organic progress is yet more abundantly true of human progress, physical and social, as well as organic: that there must be a correlation of three kinds of endeavour,—that which aims at the improvement of the organism or breed (Eugenics), that which concerns itself with the ameloriation of the environment (Eutopias or Euthenics), and that which seeks to bring about the betterment of functions, especially occupations (Eutechnics). Different sides of progress appeal to different minds, and few of us can work more than one thing at a time, but perhaps we should give greater prominence than we do to the simple lesson of Evolution that lasting betterment must be realised in place and work as well as in people, in environment and function (including leisure-time activity) as well as in organism.

§ 6. Dangers of False Simplicity or Materialism.

When we turn to the consideration of practical problems, we reap the reward of the time devoted to the discussion of the essential characters of the living organism. The conclusion that the category ‘Mechanism’ requires in Animate Nature to be supplemented by the category ‘Organism’, warrants us in carefully scrutinising all proposals which are tarred with the mechanistic or materialistic brush. They are bound to be fallacious in their incompleteness and perhaps also in the clear-cut definiteness which makes false simplicity seductive.

The conclusion that, among the higher animals at least, we have certainly to do with mind-bodies or body-minds, with individualities having at least a rill of inner life, justifies us in looking with suspicion at projects which declare the uselessness of the soul. The “false simplicity” error of materialism may be repeated at a higher level in a biologism which leaves out mentality in its account and treatment of a dog, or in a theromorphism which treats men as “bipedal cattle”—often of considerable ferocity.

It is not merely a theoretical question of giving the most accurate description of a dog or a horse or a man, it is also a practical question of making the most and the best of the creature. And in this respect the conclusion of thoughtful experts is unanimous, that the truer conception is also that which works best.

There are many higher reasons (religious, ethical, artistic, and others) for taking a big view of Man, but what we have been concerned with in this course is to show that the crude view is bad science. When Prof. Jacques Loeb says, “We eat, drink, and reproduce, not because mankind has reached an agreement that this is desirable, but because, machine-like, we are compelled to do so”, he does not make a good antithesis. It is a familiar fact that Man often inhibits these organised impulses, and does so in reference to ideals which mankind has built up in a manner almost as far from the average animal's ways as these are from a machine's. When Le Dantec says, “The fact of being conscious does not intervene in the slightest degree in directing vital movements”, we think that he is departing from the first canon of scientific work—accuracy. Often in man's experience it is just the being conscious that makes all the difference.

It may be useful to give two or three examples to show that proposals fundamentally biological need not be narrow or materialistic. Many authorities on education have emphasised on various grounds the importance of Play, but discussion, passed to a firmer basis after the important work of Groos on the play of animals, for he showed that play was no mere safety-valve for superabundant energy and spirits, no mere relaxation, no mere recapitulation, but that it was a joyous apprenticeship to the business of life, a time for replacing instinctive predispositions by learning from experience, a time of elbow-room for variations, a time for experimenting before criticisms prune, before casualties induce caution, and before hard work brings on “life-harming heaviness.”

Or again, it may be well for us, on our own behalf and for our children, to ask whether we are making what we might of the well-springs of joy in the world; and whether we have begun to know what we ought to know regarding the Biology or Psycho-biology of Joy. Have we given attention, for instance, to the work of the famous physiologist of Petrograd, Prof. Ivan Petrovich Pavlov, who was the first to demonstrate the influence of the emotions on the health of the body? That a good circulation is associated with cheerfulness is a familiar fact,—and how this organic jauntiness sometimes jars on the tired and sorrowful! But there is the converse proposition that cheerfulness makes for health. It was said of old time: “he that is of a merry heart hath a continual feast”, and “a merry heart is the life of the flesh”. Now, what the researches of Pavlov, Cannon, Carlson, Crile, and others have done is to demonstrate experimentally that pleasant emotions favour the secretion of the digestive juices, the rhythmic movements of the food-canal, and the absorption of the aliment Contrariwise, unpleasant emotional disturbance and worry of all sorts have been proved to have a retardative influence on the digestive processes. When the hungry man sees the well-laid table his mouth waters, but every one knows that a memory or an anticipation will also serve to move at least the first link in the digestive chain. “It is now well known,” says Professor Dearborn, “that no sense-experience is too remote from the innervations of digestion to be taken into its associations, and serve as a stimulus of digestive movements and secretions.” Emotion may influence the production of adrenalin by the core of the adrenal glands, and a slight increase in this potent substance constricts the smaller blood-vessels, raises the blood pressure, excites and freshens the muscles, increases the sugar content of the blood, and so on. From the non-mechanistic position which we have defended in these lectures, it is of great interest and importance that good news, psychical if anything is, may set in motion a series of physico-chemical and vital processes, complex beyond the ken of the wisest And the cheerful man, who cultivates the habit of happiness, finding good reasons for rejoicing—in the sunshine and stars, in flowers and birds, in works of art and the faces of his friends—will have his ‘joy-reward’ or euphoria added unto him unless he is fool enough to pursue it Our point is, that, open to at least a large number of our fellow-creatures, there are sights and sounds that make for joy and that increasingly, as some of the Psalmists were well aware, and that one of the obvious lessons of evolution—and of common sense—is that we should use these well-springs freely.

What is true in regard to digestion applies also to other functions. Wordsworth knew this when he spoke of his heart responding to the sight of the rainbow and the recollection of the daffodils by the lakeside. He may not have known much about the complex pathways of the pneumogastric, but he was sure about the influence of joy on the circulation. Professor Dearborn has worked at the factors altering blood-pressure and he makes the notable statement that in the “general stimulation of the essential circulation in all constructive parts of the body, such as the brain, the muscles, and the digestive organs, joy exerts one of its most conspicuous benefits, and one that no one can doubt or ignore”.

There are facts which point to the conclusion that a gladsome mind may also increase the integrative function of the nervous system. It is an indubitable fact that a joy—say of maternity, or discovery, or artistic creation—may become an exhilaration and enthusiasm of thought and will; but the same is true of bodily welfare. Good tidings will invigorate the flagging energies of a band of explorers; an unexpected visit will change a wearied homesick child, as if by magic, into a dancing gladsome elf; a religious joy will make men and women transcend the ordinary limits of our frail humanity. How it comes about is not yet quite clear; but somehow the oil of joy, as the Scriptures call it, operates so as to make the limbs more supple and the face to shine. Emotion has its physical accompaniment in motions throughout the body, in changes in secretion and circulation, and also in some other way whereby influences from some emotional ‘centre’ such, perhaps, as the optic thalamus (the second great division of the brain) surge up Into the cerebral cortex, the seat of the higher mental processes, where joy and activity may be correlated.

We have referred to recent work on the physiology of joy simply as an illustration of the way in which science may be utilised in the control of life—not merely as regards exercise, fresh air, diet, and so on, but in the subtler task of developing the personality on what one may call direct lines.

The danger ahead is well known, that, just as the direct pursuit of health is apt to engender hypochondria and valetudinarianism, and just as the direct pursuit of happiness is apt to defeat its own end, so the direct pursuit of joy for the sake of the ‘joy-reward’ may prove consummately futile. But it is possible to make a bogey of this risk. We are not made of such friable material.

Forced cheerfulness is, of course, a horror, but the persistent will to be glad, if worthily satisfied with some of the real joys of life, may soon become a habit that requires no artificial stimulation. A conventional approach to Nature and Art is often rewarded much beyond its deserts, and men who began by taking walks for duty's sake have often become genuine enthusiasts for the open country. The pursuit of joy may be futile and the faking of it an abomination, but there is nothing absurd or morbid, for instance, in humbly learning to know more about the endless things of beauty which are joys for ever. If we make sure of these, the euphoria will look after itself.

It is surely for the guidance of youth to recognise that at levels far below Man's there is an enhancing of physical fondness by æsthetic embroideries and emotional tenderness, and the sobering of all by a working together of mates in the discharge of parental duties.

It is surely for the guidance of all to realise the extent to which animal life rises above a struggle around the platter of subsistence, and illustrates the raw material, at least, of domestic virtues. We cannot believe that animals “think the ought”, so that in the strict sense the ethical note is not sounded, but when we consider their expenditure of energy towards results that are other-regarding not self-regarding, we seem to hear an ethical undertone. In any case it is not from Natural History that we learn the “Might is Right” doctrine.

§ 7. Science for Life.

Let us sum up the general argument.

There is no doubt whatever that many of the human shadows that blot out the sun and make our feet stumble are gratuitous, and may be got rid of whenever man pleases. That this condition, “whenever man pleases”, is not easily fulfilled we are well aware. But there is no doubt that we can get rid of many social handicaps, and go on to higher adventures, discovering more and more of the goodness of God in the land of the living.

A hundred years ago people shuddered at the name ‘Gaol-fever’, a terrible pestilence, which attacked judge and jury, prisoner and onlooker at Old Bailey. We call it typhus-fever now, and it is rare in Britain, thanks to the enthusiasm of the early nineteenth-century hygienists. It is a dirt disease, it can be controlled by care and cleanliness. It is due to a microbe, not yet isolated, which is transferred from man to man by infected lice. As Sir Kay Lankester says, the Angel of Death they spoke of a hundred years ago is the clothes’ louse, which can be readily exterminated by the use of benzine. We cannot but feel that it was almost contemptible to have submitted for centuries to a tyranny of dirt; but the point is that we are continuing to submit to similar things. We are slow to gird up our loins. We are slow to learn the lesson of the Control of Life.

It has been said that there are two views of this world, that which regards it as a swamp to be crossed as quickly as possible, and that which regards it as a marsh to be drained. The view to which our study of Animate Nature points is emphatically the latter. Man must continue the struggle against inhibitants,—the campaign in which living creatures have been engaged for millions of years, the endeavour to bring the inorganic into the service of the organic, to bring the body-mind into subordination to the mind-body, to eliminate the disorderly, the inharmonious, the involutionary. For we adhere to the thesis that evolution is on the whole integrative, not disintegrate.

To put the same thing in a third way, which is more generalised, we are in profound agreement with the view well expressed by a contemporary philosopher,—that it is Man's part to build up, as he is doing, a scientific systematisation of knowledge which will form the basis of an increasing control of life. The mundane goal of the evolutionary movement is “the mastery by the human mind of the conditions, internal as well as external, of its life and growth. The primitive intelligence is useful to the organism as a more elastic method of adjusting itself to its environment. As the mental powers develop, the tables are turned, and the mind adjusts its environment to its own needs. “Mihi res non me rebus subjungere conor” is the motto that it takes for its own. With the mastery of external nature, applied science has made us all familiar. But the last enemy that man shall overcome is himself. The internal conditions of life, the physiological basis of mental activity, the sociological laws that operate for the most part unconsciously, are parts of the ‘environment’ which the self-conscious intelligence has to master, and It is on this mastery that the regnum hominis will rest” (Hobhouse, 1915, p. 443). Of a truth, Science is for Life, not Life for Science.


The theoretical doctrine of evolution has for its practical corollary the fact of the controllability of life. Darwin was logically followed by Pasteur.

If the central fact in evolution be “the slowly wrought-out dominance of mind in things”, it is surely man's fundamental task to use this expanding mind for the fuller possession of his kingdom, and the better ordering of his life in it. If evolution suggests any lesson it is this. We must inquire, therefore, into the determinants of life.

The first determinant of life is heredity—our relation to preceding generations—which includes not only the past living on in the present, but new departures or variations. We cannot alter our own inheritance, though it is ours to trade with, but we have some measure of control over the inheritance of future generations.

The second determinant of life is nurture—all manner of formative influences from surroundings and from use and disuse—and this is largely controllable in our hands. Nurture determines the fulness of expression that hereditary characters may attain in development; it may re-impress desirable modifications on successive generations; it determines in part the sort of reception a new variation meets with. In mankind ‘nurture’ includes the ‘social heritage’.

The third determinant of life is selection, and this is of peculiar importance in mankind, where natural sifting is largely in abeyance, where the sifting is in great part deliberate, rational, social. The relaxation of natural selection is the inevitable result of the increase of solidarity and sympathy; the difficulty is to find a sufficiently stern substitute. It should be noted that humane interference with indiscriminate elimination (which thins without sifting) cannot harm the race; that drastic social surgery is impossible in the present state of science and social sentiment; and that proposals which are sound biologically may be disruptive socially.

A study of animate evolution points to the conclusion that secure progress implies a correlation of organismal, functional, and environmental improvements. This is even more true as regards progress in the kingdom of man.

The hard-won conclusions that in Animate Nature the category ‘mechanism’ requires to be supplemented by the category ‘organism’, and that among the higher animals at least this requires to be supplemented by the conception of ‘mind-body’ (and in mankind by that of social personality), afford a test for practical projects. The error of materialism (namely, false simplicity) is often a higher level in biologism and theromorphism. The error is not in theory only, but shows itself in practice when the problem is to get the most or the best out of the creature.

It is very interesting to consider the extent to which animal life rises beyond a struggle around the platter of subsistence, and illustrates the raw material, at least, of domestic and social virtues. In the strict sense it may be true that the ethical note is not sounded, but there is often an ethical undertone. Nature has stamped this with her approval, Huxley notwithstanding.