Popular Science Monthly/Volume 75/October 1909/The Service of Zoology to Intellectual Progress
|THE SERVICE OF ZOOLOGY TO INTELLECTUAL PROGRESS|
UNDOUBTEDLY the progress of zoology has played an important part in the intellectual development of civilized mankind, but the way in which it has moulded thought is but vaguely appreciated by most people. On that account it is my purpose to discuss the question of the service of zoology to intellectual progress.
We speak of the intellectual development of civilized mankind, meaning thereby the general level of mental development that any people has attained; and we observe that the circumstance that chiefly sets one people on a pinnacle higher than another people is their degree of intellectual development.
There is nothing that afflicts us all more closely than that our young people should learn to think straight, and that they should ally themselves with the thought of their time, and take part in it, because this mental life of ours is remaking for us our ideas of the universe in which we live. It is not peopling it withand dreams so much as with realities. There was never a time before when realities were so carefully sought after.
If we look into history we shall see that there has been a ruling power in the mental life of different peoples characteristic of every age, such as the mental devotion of the Romans to law and government, of the Greeks to art and philosophical disquisitions, of the people of the middle ages to mystical metaphysics and theological dogma, and so on.
Let us now ask: "What is the dominant note in intellectual life today?" Is it not a greater care to determine the truth? Is it not the investigating spirit? Is it not that spirit which we may designate generically as the scientific spirit? Perhaps great material prosperity is the most evident aspect of life to-day, but in the mental sphere there is certainly a disposition to analyze, to experiment and to arrive at conclusions by the method of observation and reasoning.
This situation is very different from the one from which the civilized world has recently emerged. A former state prevailed in which authority was declared to be the source of knowledge. In the sixteenth century, and earlier, men believed things not because they could be shown to be true, but because some one had said they were true. In order to crush out dissent the authority for a certain statement was quoted, and the authority cited was usually one of the ancient writers.
The Revival of Learning.—But the human mind, ever restive to discover the relation between causes and effects in the production of natural phenomena, would not permanently brook this restraint. The minds of the more energetic and independent thinkers revolted against the reign of authority, and, under the leadership of such minds, there began a reform that is known to us all under the title of the revival of learning, a reform of wide extent and of great importance to the human race. I wish to take a few minutes to point out that the essence of this reform consisted in a change in the method of the pursuit of knowledge.
This so-called revival of learning affords a striking illustration of how a change in mental interests may have great consequences for those who engage in it. Let us first picture to ourselves the fruits of the mental life of the middle ages, and then contrast this with the results of the changed method of ascertaining truth introduced at the time of the revival of learning.
It is an old, oft-repeated story, how with the overthrow of ancient civilization the torch of learning was nearly extinguished. Not only was there a complete political revolution; there was also a complete change in the mental interests of mankind. The situation was complex, and it is true that there were many influences at work, but the extinction of all scientific activity which occurred at this time was due to a complete arrest of inquiry into the phenomena of nature. The physicist no longer experimented, the naturalist no longer sought for relation and causes in living beings.
One circumstance that played a considerable part in the cessation of scientific investigation at this time was the rise of the christian church and the dominance of the priesthood in intellectual as well as in spiritual life. The world-shunning spirit, so scrupulously cultivated by the early christians, promoted a spirit that was hostile to observation. The behest to shun the world was acted upon too literally. The eyes were closed to nature and the mind was directed towards spiritual matters, which truly seemed of higher importance. Presently the observation of nature came to be looked upon as proceeding from a prying and impious curiosity—as an attempt to search out the concealments of the Almighty.
Books were scarce, schools of philosophy were reduced, and any general dissemination of learning ceased. The priests who had access to the books assumed the direction of intellectual life. But they were largely employed with the analysis of the supernatural, and without the wholesome checks of observation and experiment, mystical explanations were invented for natural phenomena, while metaphysical speculation became the dominant form of mental activity.
Authority declared the Source of Knowledge.—In this atmosphere free inquiry could not live, controversies over trivial points were en gendered and the ancient writings were quoted as sustaining one side or the other. All this led to referring questions as to their truth or error to authority as the source of knowledge, and resulted in a complete eclipse of the reason.
This was a barren period, not only for science, but also, curiously enough, for those studies which were especially engaged in. Notwithstanding the fact that for more than a thousand years all the new works were written by theologians, there was no substantial advance in their field of learning, and the reflection comes to us that the reciprocal action of free inquiry is an essential condition for the growth of any department of learning.
We should remember that the mental life of the Middle Ages was active. It is a mistake to suppose that men of those times differed much in their mental powers from those of to-day. The medieval philosophers were masters of the metaphysical method of argument, and their ingenuity and mental alertness were great. The principal thing that held progress in check was the method of setting about to ascertain truth.
Renewal of Observation.—It was an epoch of great importance, therefore, when men began again to observe, and to attempt, even in an unskilful way, hampered by intellectual inheritance and habit, to unravel the mysteries of nature and to trace the relation between causes and effects in the universe. The new movement was, as previously said, a Tevolt of the intellect against existing conditions. In this movement were embraced all the benefits that have resulted from the development of modern science. The invention of printing, the voyages of mariners, the growth of universities, all helped in a general way, but just as the pause in science a thousand years or more earlier had been owing to the turning away from nature and to new mental interests, so the revival was a return to nature and to the method of science.
The Widening Horizon.—The reign of authority in intellectual matters lasted for twelve centuries, and then gave way gradually to the reign of observation and reason. Under the influence of the new method we have been moving generation by generation into a state of clearer discernment and into an intellectual atmosphere of wider horizon.
There is an inspiration in this ever-widening horizon. We must recognize, I think, that there has been a reconstructive force accompanying scientific progress. Wherever traditional opinion has been uprooted something more helpful to humanity has been planted. When rightly understood, we see that this freer life of thought has been constructive and helpful, not merely iconoclastic. Man has once again taken his high place in the world as the interpreter of nature, and as investigation widens his comprehension of the laws of natural phenomena, he is extending his control in the sphere of nature and turning natural forces to his advantage.
The Study of Nature.—I now turn to another phase of the subject, viz.: to a consideration of the effect upon mental life of advances in the knowledge of natural phenomena. Let us, if possible, catch a glimpse of the edifice that has been built upon the foundation since the early naturalists broke ground and began operations.
One of the most notable things of the last half century has been the mental evolution produced by the great extension of knowledge of organic nature. This more intimate acquaintance with natural phenomena, and of living nature in particular, has altered our way of looking at the world, and especially of our relation to it. The whole fabric of thinking has been so profoundly changed by the biological advances to which I refer that all educated people ought to make themselves acquainted with the generalizations of biology and with the foundations upon which they rest. This science is not a remote branch of learning; it touches every-day life at many points, and affects our well-being more closely than is generally realized.
The study of nature and the explanation of natural phenomena possess an inherent interest to which most minds respond. The physicist and chemist have for their territory the field of inorganic nature, but the biologist has the advantage of dealing with the living world. There is, in reality, nothing in the sphere of knowledge more fascinating than the study of life. Any reference to the part that bacteria play in the world awakens a responsive interest. References to the doctrine of evolution, and the light it throws on the origin of the human body as well as on the races of animals, arouse attention. The teachings of science in reference to the life of the globe have awakened wonder, sometimes dissent, but always interest.
Zoology the Central Subject.—Now the kind of knowledge to which I am referring belongs to the domain of biology, and in that domain zoology is the central subject. Many people think of zoology as it was in the time of Linnæus, or, at best, as it was in the early part of the nineteenth century, when the spiritless activity of species-making was its prominent feature. It is no longer merely a mass of knowledge that enables its devotees to name animals and to arrange systematically a cabinet. Zoology of to-day is vastly different; it has become one of the leading departments of science. While dealing with the structure, the development and the evolution of animal life, it at the same time brings one into contact with those changes in human opinion for which its own advances have been largely responsible.
From the group of the natural sciences there emerges into prominent place the princely science of zoology. As was said before, it is the central subject in all that advance in the knowledge of organic nature to which reference has been made. It is best fitted, it seems to me, to give to the students in our colleges and universities an idea of the results of the activity of the nature seekers. Its sister science, botany, which runs parallel to it, deals with similar phenomena in plants. Still, it is only among animals that we find nervous responses tolerably well developed. The presence of a nervous system in animals in connection with a highly developed state of other organs affords a more comprehensive picture of vital activity. If I seem, in this statement, to show bias, it should be set down to the circumstance that my activities for some years have been taken up mainly with the study of animal life.
The observations in zoology, as carried on to-day, are so illuminating and have such important bearings that we can see why it is that all over the civilized world it has been given such a prominent place in universities and colleges. We begin to understand why great buildings are constructed for its laboratories, and why a number of men in one faculty represent different phases of zoological investigation. This is why in the State University of Iowa, as in other similar institutions, zoology has come to occupy a prominent and an honored place in the curriculum of studies.
It is the ideas of this science woven into the fabric of human thought which I have in mind, rather than merely its details. Disjointed fragments of knowledge are of little worth; they must be combined into a unity before they have much meaning. Isolated facts should be treated as merely specific illustrations of broad truths. The study of one stone in an edifice as to its chemical analysis, its resistance to strain and crushing weight, and its microscopic structure, will not give us an idea of the edifice as a whole. Thus it is that after our students have observed and experimented in the laboratory they must, under the guidance of the lecturer, be brought to see the relation of their specific observations to zoology as a science.
It is owing largely to advances in zoology that we are enabled to formulate theories about the world, the history of living beings on it, and the part they play in the scheme of nature. It is owing to the intellectual progress that zoology has chiefly promoted that we have been able to comprehend the structure of the human body and thereby to discern the means of promoting its well being and assisting in its care. It is owing chiefly to the advances supplied by the study of zoology that one can adequately appreciate the soliloquy that Shakespeare puts in the mouth of Hamlet: "What a piece of work is man! how noble in reason! how infinite in faculty! in form and moving how express and admirable! in action how like an angel! in apprehension how like a god! the beauty of the world! the paragon of animals!"
His structure and his development excite in the mind of the anatomist the same measure of admiration and wonder. And we observe in passing that the most discerning anatomists are the comparative anatomists of zoology.
The Growth of Zoology,—Let us now look at some general phases in the growth of zoology. In its first stages of growth we find a period devoted to descriptions. In the time of Linnæus, for illustration, emphasis was placed on collecting, describing and systematically arranging all the different kinds of animals. This resulted in giving naturalists a knowledge of the form and appearance of the chief animals that inhabit the globe, and formed the basis upon which further progress could be made.
We can not, however, reach general conclusions without the examination of many facts, and there was naturally a long period devoted merely to the accumulation of facts about animals.
The next great step in advance was that of comparison. The contrast between description and comparison is brought out so clearly by I. P. Whipple in his essay on Louis Agassiz that I quote from it. He says:
The moment he contrasted "dees-creep-teeve" with "com-par-a-teeve" one felt the vast gulf that yawned between mere scientific observation and scientific intelligence, between eyesight and insight, between minds that doggedly perceive and describe and minds that instinctively compare and combine.
The descriptive and comparative stages in zoology, of course, overlapped. It was in the early part of the nineteenth century that Cuvier, the great French zoologist and legislator, founded the science of comparative anatomy, and this brought the comparative method into the study of zoology. The beneficent results of this were notable, and zoological knowledge broadened and deepened.
In the last part of the nineteenth century zoologists added another method to the investigation of animal life; they began to study processes by the experimental method. This was not merely the extension of physiology into zoology. The new method involved experiments upon the development of the embryo and sought to trace the modifications resulting from changes in the conditions of growth and development. It opened the way to those extensive experiments on regulation that have been engaged in by some of our American zoologists. Experiments were further extended to the study of heredity and evolution.
Thus description, comparison and experiment, came to mark different phases in the progress of zoology. Certain other nineteenth century advances can be merely alluded to. Those that had the greatest influence on the progress of zoology were the establishment of the cell theory, the discovery of protoplasm and the acceptance of the doctrine of organic evolution. If time permitted, a fuller consideration of these great events in the history of zoological science might be profitable, but I must hasten to another division of the subject.
The Idea of Service.—In these days we have come to estimate the worth of achievements in the terms of service. We hear on every hand the inquiry, How is this man or that man fitted to serve his time and generation? When inquiries come to the universities regarding one of their graduates seeking place in the world, the chief inquiry is, what is his promise of service? We do not always mean by this the narrow idea of direct utility—the faculty to make something that will sell—but more often that capacity for usefulness to the state and to society that depends on broad education, on discernment of essentials, that has been gained by freeing the mind from hereditary hindrances and from those grosser misunderstandings of natural phenomena that we class as superstitions. The university is a place where such basal training is carried on. The activity of the university is a crusade not only against ignorance, but also against superstition.
It is this kind of service for which the progress of science is especially conspicuous, and this brings us naturally to the consideration of the service of one science in particular. I wish to maintain that for the past century the progress of zoology has exercised a strong and wholesome influence upon the intellectual development of the race. The date of a century is an arbitrary limit, but the event I have in mind is the publication in 1809 of Lamarck's "Philosophic Zoologique," that contained the first comprehensive theory of organic evolution that has survived to the present day.
Very likely the idea is a novel one to many that the influence of zoology upon intellectual progress has been considerable. While one may not dissent from the proposition, he might very well wish to have it supported by specific illustrations.
Influence of Zoology on General Enlightenment.—Let us consider first the part this science has played in general enlightenment. Its influence has been great in clearing the atmosphere of thought, in dispelling clouds and in freeing the mind from the bonds of inherited prejudice and traditional superstition. At the beginning of the revival of learning there were fantastic and grotesque misconceptions. The idea of the resurrection bone was one of these—the belief that in the body there was an indestructible bone that formed the nucleus of the resurrection body. This view was demonstrated to be untenable by Vesalius, the reformer of anatomy in the sixteenth century and the forerunner of the morphologists of zoology. Other points about the structure of man and animals, equally fantastic, were upheld, and against one who ventured to disbelieve in them the cry of heretic was raised. We may at first sight think that crude misunderstandings are harmless vagaries, but when viewed as to their consequences we see that this class of superstitions has led to intolerance and persecutions. As illustrations there come to mind the horrors of the inquisition, the cruel and harmful ideas of witchcraft, the brutal and wicked persecution of men and women for holding saner views than the majority of mankind of the part played by the Almighty in his universe. It is one of the blessings of progress that mankind has been relatively freed from persecutions of this nature. These grotesque beliefs and superstitions were dispelled by advances in the knowledge of the organization of animals. Wherever investigation in this territory prospered, it shed light and dispelled error.
From one point of view the fossil remains of extinct animals belong to the sphere of the zoologist, for the fossil animals were the ancestors of the living ones. It was two zoologists, Cuvier and Lamarck, that founded the science of paleontology, one that of the vertebrate series, and the other that of the invertebrate. When fossil bones were first unearthed they excited stupid wonder and amazement, and the most fantastic theories were proposed to account for them. They were regarded as bones of giants, as remains deposited by the deluge, etc., but finally were accepted as the remains of former races of animals and were turned to account as supplying an index to the past history of the earth. The constantly increasing collections of fossil remains of animals are enabling us to understand something of the momentous changes that have passed over the succession of animal forms that have lived upon the globe. The accounts of the discoveries of prehuman remains, connecting by gradations with races now living, are extending into remote periods our conception of the antiquity of man. These matters arouse interest and discussion, and the sweep of all these discoveries brings with it a widening of the horizon of human understanding. The historical relations of fossils have been established by a great number of talented observers. Without any disparagement to other men who have done notable work in this field, I mention but one, Henry F. Osborn, of New York, who is one of our most distinguished American zoologists. With the enormous collections at his disposal he has devoted himself with marked success to making out the relations of fossil forms to living forms and he has succeeded in tracing the remote ancestry of a number of living races of mammals.
The Constancy of Nature.—As one great result of the investigations of the nature seekers, there was established a belief in the constancy of nature, and from the work of the zoologists in particular came the idea that all animal life is the result of one orderly progress. Animal organization leads up to the structure of the human body, and on this account there has always been a tender point in discussing the evidences as to man's place in nature.
This belief in the constancy of nature was a great step in intellectual development. In its broad application it means that the entire universe and all on it is the result of an orderly and well-directed progress. It leaves no room for the idea of chance. Remote ancestral man did not rise by chance from the animal series. The gill-clefts in the human embryo are not there by chance. Their presence has some significance, if haply we may find it. The great service of establishing the idea of orderly progress in nature is part of the heritage of work already done. The idea, in so far as it involves living and fossil forms of animals, is owing to the progress of zoology.
Some Practical Applications.—Let us now consider secondly some of the applications of zoological advances to the benefit of mankind. It was owing to the cooperation of botany and zoology that the germ theory of disease was established. The bacteria are, of course, plants. The method of studying their action on animals is zoological. There are also diseases produced by minute animal organisms, such as malaria or common fever and ague. As has long been known, this disease is due to an animal parasite that infects the red blood corpuscles. It is only within recent years, however, that the entire life history of these animal parasites has been made out. As you all know, part of their life cycle is passed in a certain kind of mosquito. The disease itself has been shown to be owing to bites of these mosquitoes, and this fact pointed out the way of avoiding malaria. The ingenuous methods by means of which the propagation of mosquitoes is prevented has freed many malarious districts from pestilence. These discoveries opened the entire question of the transmission of disease by insects, and now, thanks to those brilliant observations and experiments in which some men sacrificed their lives, we know the entire life history of the microbe of yellow fever. We know it is transmitted by mosquito bites, and that disease can now be controlled. The Roman fever, once much dreaded by travelers, and the fever of the Campagna may be avoided. Thanks also to zoological studies, these diseases no longer strike in the dark. We can recognize their approach and avoid inoculation. The scourge of the sleeping sickness that attacks the people of the Congo district is due to an animal parasite. The terrible scourge of syphilis has recently been traced to a minute organism that is probably animal. The recognition of these facts is the first step towards gaining control of the disease.
There are other larger animal parasites like trichina, the tape worm, the filaria of the blood, etc., the life history of which is due to zoologists. Some of us recollect that the most comprehensive treatment of these is due to Leuckart, a zoologist. His "Die Menschlichen Parasiten" is a piece of research in pure science. The phagocyte theory, with all its implications, was given to the world by a zoologist—Metchnikoff.
The study of cancer, trypanosomes, opsonins, etc., are being studied by zoologists as well as by medical men, and the work of the medical men with these subjects is chiefly by zoological methods.
Studies of animal behavior, so extensively carried on by zoologists, are reacting on psychology and lighting the way to new advances in that science. Those zoological studies on the wonderful architecture of the nervous system (to which some of your men in the state university have contributed) are bringing a knowledge of the mechanism of the brain, and throwing light on its normal processes and its disorders. Leading up through these studies and the inferences to be drawn from them, we arrive at the science of comparative psychology. Furthermore the study of localization of function in definite areas of the brain substance has opened the way to brain surgery.
The studies of heredity in animals embrace many practical hints to stock breeders and to medical men.
But we can not make a comprehensive list of the large number of practical applications that come from zoological investigation. The illustrations already given are sufficient to indicate that studies in pure science often become of the highest practical value. The practical applications will follow fast enough upon the heels of advancing knowledge. The essential thing, as well as the difficult thing, is, by research, to uncover the facts and to make the first demonstrations.
Encouragement of Scientific Research.—I wish to speak just a word in appreciation of the men who extend the boundaries of knowledge, and a word in favor of the encouragement of pure research. The investigators are necessarily somewhat removed from their fellows and, therefore, often misunderstood. Theirs is a career of intense application and sacrifice. Scientific knowledge is not advanced by happy guesses in moments of inspiration, but only by continuous and well directed effort. He who would wrest from nature her secrets must prepare for the struggle by long training and must follow his calling with intense devotion. Often must he forego the pleasure of social relaxation in order that the discoveries that he is nursing into being may not suffer. When his work is reaching a climax he leads a lonely existence.
The spirit that still animates men of this type is that so long ago exemplified by Agassiz. As Whipple says:
Men of proved capacity who are willing to devote themselves to research will enter upon it with no selfish motives. They should be classed among the benefactors of mankind, engaged in a useful service. They should be encouraged by men of wealth, by state legislatures and by the establishment of endowments to provide the means of carrying on their researches. There are men of this kind in the State University of Iowa; to the citizens of the state I would say: "These men are a valuable asset to the state," and to the university authorities I would say: "Honor these men and encourage the pursuit of graduate studies under their direction." To any in the rising generation of students who have the internal leading to follow a career devoted to scientific investigation, if they are gifted and energetic, let them without hesitation enter upon this career. The compensations will be chiefly internal. Those who enter upon scientific investigation as a life work must forego certain material prizes in the world that await equally well-directed efforts in other lines of activity, but they will have other kinds of compensations—in living close to great truths, and realizing in their discoveries that thrill of the searcher when he has found, and after long years feeling the uplift of their occupation. Nevertheless, they must learn to renounce and not be embittered as Robert Louis Stevenson wrote in that little gem of composition on the attributes of men.
The Doctrine of Organic Evolution.—The crowning service of zoology in extending the boundaries of human understanding is found, perhaps, in the doctrine of evolution. The great sweep of this doctrine makes it one of the greatest acquisitions of human knowledge. There has been no point of intellectual vantage reached which is more inspiring. It is so comprehensive that it enters into all realms of thought. Weismann, as you all know one of its great representatives, expresses the opinion that "the theory of descent is the most progressive step that has been taken in the development of human knowledge "and he says further that this position "is justified, it seems to me, even by this fact alone: that the evolution idea is not merely a new light on the special region of the biological sciences, zoology and botany, but is of quite general importance. The conception of an evolution of life upon the earth reaches far beyond the bounds of any single science, and influences our whole realm of thought."
Its applications are helping man in the knowledge of himself and his destiny. Anything that throws light on man's history and his capabilities affects the question of his duty and his destiny. A prominent theologian (Bishop Creighton, of London) has said: "Religion means the knowledge of our destiny and the means of fulfilling it." I shall not attempt to qualify the statement, as I am not a theologian, but I will point out that progress in zoology has extended the knowledge of the history of man, and has thereby influenced our conception of his relation to the universe. I think these advances are helpful, and are supplying a safer and better basis for our education, our system of morals and our religion. For all these matters of so much importance must be brought into relation with the state of knowledge at different periods of the history of our race. This condition is necessary, it seems to me, to men who think, who read or who investigate.
There is still too often a disposition shown by platform and pulpit speakers to qualify, to antagonize and to belittle scientific advances. But let us open our hearts freely, without fear, to the extensions of truth and let us continue in the belief that the knowledge gained by investigation of nature will be helpful to all departments of human endeavor and aspiration. It is to be expected that the views first of the scholars and then of the great mass of humanity will be modified and will become harmonious with all present and all future advances in knowledge.
The present results of these advances will appeal differently to people according to their temperament and experience, but to many scientific men, like Darwin and Huxley, as well as to those of smaller place, the contemplation of it all is uplifting. We may well be drawn into sympathy with the great nature psalm and feel the beauty and force of those lines of poetry in which all nature is called upon to unite in praise of the Ruling Power that directs the forces of the universe. Inanimate nature, as well as all that is alive:
- The annual address before the Iowa State Academy of Science, April 30, 1909.