The old problem of Nature versus nurture that meets us in studying the life history of any organism becomes especially interesting in dealing with the biography of men of eminence. Are their achievements the inevitable expression of the natural forces innate in them at birth, or the product of environmental influences, or some resultant of these two factors? And how much may we in each case assign to one factor or to the other?

These difficult questions naturally suggest themselves in glancing at the life of the subject of this sketch. Like so many men who have won prominence in comparatively new countries, he seemed, in an environment that had no apparent relation to his future, to grow from innate tendencies toward something not suggested by the circumstances about him, even to grow in opposition to the molding influences of these, and to conquer them. Later, however, we find him surrounded by influences that made a particular mode of self-expression easy, if they may not be said to have forced such expression. It was then that the casual observer might say that the circumstances made the man; yet, looking backward, we can trace the initiative in the man that led him into the congenial environment. A selection of proper environment to express Nature has been rightly claimed as a potent factor in all organic life; nurture, then, comes as a secondary power to mold, or rather to translate, the inherent power.

William Keith Brooks, the second son of Oliver Allen Brooks and Eleanora Bradbury, daughter of the Rev. Phineas Kingsley, was born in Cleveland, Ohio, in 1848. In 1877 he married Amelia Katherine, daughter of Edward T. Schultz and Susan Rebecca, daughter of David L. Martin. He has two children.

Brooks grew up amid the stimulating influences of a relatively new country, where freedom of development was not so sharply restricted but that all paths of life seemed equally open to one who would work. As a boy he was not one of those precocious naturalists of the common sort whose collecting instincts find expression in the hoarding of dead animals or plants rather than the neater postage stamp; names and authorities, classes and species, neatly arranged mummies, were not his delight. At first there seemed no sign that zoÖlogy would claim him as a most ardent admirer. Yet he was fond of live things and their ways, and introduced into his home that most delightful microcosm, the fresh-water aquarium (so much neglected in this country), in which he could observe at ease the habits and slow changes of living things when their native haunts were not accessible. Such early interest in the essential wonders of livingness rather than in man's artificial classification of phenomena was thus prophetic of much of his later originality of thought and view.

He has never forgotten how much he owes to the instruction of the earnest and broad-minded teachers in the public schools of Cleveland.

His college life began at Hobart, where two years left a deep impression from an acquaintance with Berkeley's thought, gained in browsing in the library, and long treasured up to produce fruit in philosophic views of maturer years. Then at Williams College, where the notable Natural History Society was sending out its expedition across South America, his love of Nature matured and specialized for two years longer, until he received the A. B. degree in 1870. It was Williams also that later, in 1893, bestowed upon him the LL. D. degree. For him the completion of college life was truly the "commencement" and not the finish of his intellectual training. His strong trend toward pure science and abstract mental life forced him onward into post-graduate work. But this required funds, and America was not Germany; the struggle for existence was not here so intense that one might not win bread in many walks of life without special training, and parents did not need to extend the larval period of support for offspring beyond the completion of college life to gain for them a place in any rank, social or intellectual. Now, a rapidly increasing need for the Ph. D. degree as entrance to professional life, necessitating several years of post-graduate study, often forces parents to take up their share in the increased burden. Then, however, few were agreed as to the advisability of prolonging an unpractical life devoted to study beyond what seemed the maximum limit of unproductive preparation for life—the day of graduation at college. Beyond that the young man must make his own way as best he might. The subject of this sketch chose to work his way by his own unaided efforts into the fullest measure of academic training.

That was before the day of competition between universities, and there was no temptation to go here rather than there in order to live a semi-parasitic existence as scholar or fellowship holder.

First in his father's counting house, and then at a boy's school near Niagara, young Brooks bravely gained the means to pursue higher branches of natural history, and to devote himself to research. In the former position he realized how futile for him would be a life given to money-getting, and he palliated the uncongenial nature of that life by such abstract thought as seemed useful, one immediate result of which was the invention of a mechanical device for computing interest and discounts in sterling money, that had considerable circulation. This, though it scarcely indicated a stronger bias for mathematics than for Nature study, showed a latent possibility that was not to be developed. In the latter position, which brought him in close contact with the wonders of time action, so plainly read in one of Nature's books for the blind—Niagara Falls—he found food for thought, as well as a deep interest in the action of young minds. Here was much material for philosophical study of wood life too, as well as for growth of conceptions of the way to learn and to teach.

Free, after serving three years, to follow his genius, Agassiz's romantic venture at Pennikese drew this young naturalist, as it did so many of that epoch; and henceforth marine life, with its revelation of fundamental problems, fascinated him. Working on at Agassiz's museum, learning its collections by heart, absorbing from this center of American natural history and from its founder both stimulus and method, influenced deeply also by the unobtrusive teachings of McCrady and others who helped to make Cambridge the Mecca of naturalists, he was already an active contributor to the discussion of problems in the embryology of animals when he won his Ph. D. degree in 1875.

Quiet, diffident, slow to speak, leaving hasty action, too, for those of other constitution, with thoughtful brow and keen eye to look outward, as well as to regard inner thought, this young man with flowing beard was a noticeable person. At this time he was to be seen always accompanied by his faithful "Tige"; for, wiser than Ulysses, he shared all the hardships and joys of life with this loved companion.

Now he sought his true environment, and found it in the new university starting in 1876—the Johns Hopkins University. There he was appointed Fellow, an honor subsequently won by many who are well known to biological science, as W. T. Sedgwick, E. B. Wilson, K. Mitsukuri, A. F. W. Schimper, H. H. Donaldson, H. L. Osborn, J. McKeen Cattell, H. H. Howell, A. T. Bruce, E. S. Lee, H. E. Nachtrieb, W. Noyes, J. Jastrow, E. B. Mall, H. V. Wilson, C. E. Hodge, S. Watase, and T. H. Morgan. Like C. O. Whitman, in 1879, he did not enter upon the privileges of that position, but as instructor and associate became at once a guiding element in the new growth. In the freedom from old traditions, from fixed conventions and routines offered by this new university, this peculiar original mind found its best environment, and while the opportunity doubtless did much for the man, the man certainly reacted most favorably for the welfare of the highest ideals of his new home.

We find him at once outspoken in emphasis of the philosophical aspect of animal morphology, contributing thoughts upon "inductive reasoning in morphological problems," upon "the relation between embryology and phylogeny," upon "the causes of serial and bilateral symmetry," and upon the "rhythmic nature" of the cleavage of an egg. Yet this period was also, and pre-eminently, one of acquisition of hard-earned and detailed facts. The development of Pulmonates and Lamellibranchs, of Crustacea and of MedusÆ, as well as of the marvels of Salpa's life history, became absorbing studies.

This great field of the morphology of nonvertebrates could be properly worked only with access to the marine fauna, and at that date there were few facilities for seaside study in America. A true disciple of Louis Agassiz, Professor Brooks saw the need of a marine laboratory, and devoted himself, as Dohrn did at Naples, to the accomplishment of an end so necessary for the advance of natural science. Encouraged by the aid of a few citizens of Baltimore, in 1878 there was started an experiment—"The Chesapeake ZoÖlogical Laboratory," at Fort Wool, Va., with Professor Brooks as director. With the absolute devotion of its director to research as example, and with the liberal aid of the trustees of the Johns Hopkins University, this laboratory became a most important adjunct to the university and a virile center of zoÖlogical study. So great was its success as a factor in the advance of zoÖlogical knowledge that the trustees bravely continued to support it whenever financial disaster did not rob them of the last penny. For eight years in the Chesapeake, or in the remoter waters of North Carolina, the station flourished; then, in 1886, we find the director, with a few enthusiastic students, venturing in a small schooner to the but little known Bahama Island, Green Turtle Cay, there to enlarge their experiences with such delightful realization of naturalists' dreams of the tropics as Haeckel experienced in his Journey to Ceylon. Subsequent annual expeditions to Nassau, the Bemini Islands, and to various parts of Jamaica served as marked eras in the lives of many young naturalists who will not soon forget the contact with life thus obtained.

From these sources and from his connection with the United States Fish Commission, as director of the Marine Station at Woods Holl, Mass., in 1888, Professor Brooks drew inspiration and fact for the work and thought by which he is so well known to the working naturalist. There are few great divisions of the animal kingdom that have not excited his special interest and claimed his long-sustained labor upon the problems they express. Like McCrady, deeply fascinated by the HydromedusÆ and their wonderful changes, many smaller papers, as well as the Memoir of the Boston Society of Natural History, entitled The Life History of the HydromedusÆ and the Origin of Alternation of Generations, testify to his success in unraveling plots that thickened with new discoveries.

An early interest in the mollusca, shown by his doctor's dissertation upon the embryology of the fresh-water mussels, printed in part in the Proceedings of the American Association, 1875, continued to be expressed in his contributions to many problems in the embryology of the fresh-water Pulmonates, of Gasteropods, of Lamellibranchs, and of the Squid. The Crustacea also rightly claimed a large share of the attention of a philosophic naturalist, bringing him face to face with the rigid formulations of law which these creatures present. The discovery of the very exceptional method of cleavage in the egg of the decapod Lucifer, and the demonstration of the existence of a free Nauplius stage there (published in the Philosophical Transactions of the Royal Society in 1882), marked a most important advance in the morphological interpretation of all Crustacea, and brought its author to the first rank as an authority upon this much-studied group. Studying and capturing at Beaufort those phantom-like sand burrowers, the Squilla, gained him an insight into and an interest in this strange division of Crustacea that enabled him to undertake that difficult task, the description of Stomatopods collected by the Challenger Expedition—a task completed in 1886. The report, published in such a magnificent series as only the British Government could have consummated, is noticeable for the author's clear, free illustration of the creatures described and classified. In it we find a classification of the numerous, weird, glassy larvÆ, agreeing with the classification of the adults and marking the success of the solution of the problem—the reference of chance collections of various stages of many species to their proper places in the life history of each species.

When the fever for ancestral trees had spread among naturalists in a much more virulent form than that endemic in Wales, and when the Ascidians were brought into line as ancestral vertebrates, it was no wonder to find Professor Brooks laboring upon these interesting creatures, but his work in this group started from a different point of view. As early as 1875, when studying in the laboratory of Alexander Agassiz, he contributed to the Boston Society of Natural History a description involving a most novel interpretation of the embryology of a remarkable Ascidian, Salpa. This form is known to many not naturalists as that beautiful animal chain which is sometimes so common in the clear waters of Newport Harbor as to be dipped up in every bucket of water, but more often not there at all. The female buds forth male branches and gives each an egg (which is fertilized to form a second generation of females). There is thus no alteration of sexual and non-sexual generations at all; and, with characteristic appreciation of a paradox, Professor Brooks subsequently emphasized the fact that the poet naturalist Chamisso, in discovering, in 1814, "Alternation of Generations" in Salpa, had discovered a phenomenon where it did not exist, though subsequently found common enough in many other animals. With the continuity of interest so marked in him, the life history of Salpa, as thus revealed, continued to be one of the living thoughts in Professor Brooks's mind for a long period of years, and, with the accumulation of material and results of researches afforded by his summer work, culminated in the monograph Salpa—a quarto of nearly four hundred pages and fifty odd plates—published in 1893, or after nearly twenty years of sustained interest in this complex problem. In this volume we find first a coherent view of the intricate life history of this animal illuminated by such metaphors as make the necessary technicalities both readable and thinkable. For instance, "A chain of Salpa may be compared to two chains of cars on two parallel tracks, placed so that the middle of each car on one track is opposite the ends of two cars of the other track, and each joined by two couplings to the car in front of it on its own track, and in the same way to the one behind it, and also to those diagonally in front of it and behind it on the other track." Again, in speaking of that startling process of egg development that makes the embryology of Salpa one of the apparently insoluble problems of this branch of inquiry, he says: "Stated in a word, the most remarkable peculiarity of the Salpa embryology is this: It is blocked out in follicular cells, which form layers and undergo foldings and other changes which result in an outline or model of all the general features in the organization of the embryo. While these processes are going on the development of the blastomeres is retarded, so that they are carried into their final position in the embryo while still in a rudimentary condition. Finally, when they reach the places they are to occupy, they undergo rapid multiplication and growth and build up the tissues of the body, while the scaffolding of follicle cells is torn down and used up as food for the true embryonic cells. An imaginary illustration may help to make the subject clear. Suppose that while carpenters are building a house of wood the brick-makers pile clay on the boards as they are carried past, and shape the lumps of clay into bricks as they find them scattered through the building where they have been carried with the boards. Now, as the house of wood approaches completion, imagine the bricklayers build a brick house over the wooden framework and not from the bottom upward, but here and there wherever the bricks are to be found, and that as fast as parts of the brick house are finished the wooden one is torn down. To make the analogy complete we must imagine that all the structure which is removed is assimilated by the bricks, and is thus turned into the substance of new bricks to carry on the construction."

Following that descriptive portion of the work comes a most interesting interweaving of facts gathered in wide experience with a scientific imagination possible only to one who had lived and thought in close sympathetic contact with tropical marine life. It is an account of the present conditions of life along tropical shores and the probable steps that led to the evolution of the innumerable sedentary and creeping things from the ancestral forms that floated on the surface of the ocean before there were shores. Charming reading for the layman, and for the specialist a broadening poetic insight into life as it is and as it was when the world was young and the pelagic forbears of the vertebrates competed with their simpler associates in the annexation of the bottom as a vantage ground for the "benevolent assimilation" of later immigrants. The third portion of the work follows a most commendable plan: "Scientific controversy is so unprofitable that I shall try to make it as subordinate as possible, that the reader may devote all his attention to the life history of Salpa, without interruption at every point where my own observations confirm or contradict the statements of others." This section deals with the refutation of criticism of the author's interpretations, and endeavors to harmonize the discords that in this, as in all complex morphological research, make progress slow though surer.

The above brief references to the research work of the subject of this sketch would be too incomplete did we omit mention of his papers upon that very interesting and extremely ancient inhabitant of the Chesapeake, the Lingula, or of the beautifully illustrated memoir of the National Academy of Sciences, describing the crania of the Lucayan Indians, an unfortunate race of gentle beings discovered by the Spaniards and treated as part of the live stock of the New World and soon annihilated, leaving but a few bones, and, as Professor Brooks tells us, our familiar and pleasant word "hammocks," as evidences of their having been.

Coming to maturity in the period of general acceptance of the Darwinian hypothesis of organic evolution, Professor Brooks was naturally deeply influenced, and no one who has read his works can doubt his allegiance to natural selection as a powerful factor in the formation of the present order of living things. In the American Naturalist for 1877 he published the first outlines of a provisional hypothesis of pangenesis that sought to "combine the hypotheses of Owen, Spencer, and Darwin in such a way as to escape the objections to which each is in itself liable, and at the same time to retain all that renders them valuable." In 1883 the same hypothesis—that variations are perpetuated chiefly through the male line by special gemmules, and that the female is essentially conservative—was elaborated in book form under the title of The Law of Heredity.

Thenceforth, in intervals of research work, Professor Brooks has contributed to various periodicals, notably the Popular Science Monthly, such essays upon kindred topics as spontaneously arose in his mind in connection with current work here and abroad. Some of these of a general philosophical interest have been incorporated with lectures, originally given to students in Baltimore, as The Foundations of ZoÖlogy, brought out this year by the Macmillan Company as Volume V of the Columbia University Biological Series. This, it will be noted, is dedicated "To Hobart College, where I learned to study, and, I hope, to profit by, but not blindly to follow, the writings of that great thinker on the principles of science, George Berkeley," and its keynote might be said to be difficult to hold, expressing the standpoint of one who says "The proof that there is no necessary antagonism between mechanical explanations of human life and belief in volition and duty and moral responsibility seems to me to be very simple and easy to understand."

Though thus active in pushing forward the limit of fact and theory in the domain of pure science, Professor Brooks has not shirked the duty that falls to every member of society, but has labored earnestly to build a sound basis for immediate practical application of zoÖlogical research. In 1876 he organized a summer zoÖlogical laboratory for teachers and others in Cleveland, with the co-operation of two other young Clevelanders—A. H. Tuttle, now Professor of Biology in the University of Virginia, and I. B. Comstock, Professor of Geology in the University of Arizona.

Identifying himself with the interests of the community in which he had cast his lot, he interested himself in the establishment of such educational influences as that of a public aquarium, and it was through no fault of the sower that the seed laboriously sown fell upon stony ground. In the winter of 1880 he gave a course of lectures and of laboratory work for teachers in the schools of Baltimore.

Again, his early studies of the development of the oyster (for which he was awarded the medal of the SociÉtÉ d'Acclimatisation of Paris in 1883), his discovery that the American oyster could be reared like fish from artificially fertilized eggs, since he found it to have a different life history from its European fellow, led him to realize the greater possibilities that awaited our oyster industries when they should be based upon scientific fact. Living amid a population dependent to no small extent upon these industries, Professor Brooks threw himself with enthusiasm into the problem of warding off the ruin that comes to every enterprise expanding faster than its capital is replenished, and eagerly sought the means to magnify without deterioration so important a factor in the existence of the Commonwealth. As chairman of the Oyster Commission appointed by the General Assembly of Maryland in 1882, he drew up the long, detailed, and well-illustrated report, issued in 1884, which set forth the condition of the oyster beds in the Chesapeake Bay and their deterioration from overwork, and suggested a legislative remedy in the form of a bill designed to remove this industry from that primitive, barbaric stage in which our communal ownership of migrant birds and fish still remains, and to place it upon the secure basis of personal ownership underlying other live-stock business. But it is difficult to change the customs of centuries' standing, and prophets rarely see the fulfillment of their predictions. Many lectures and the issue of a popular book—The Oyster, 1891—were necessary labors assumed by Professor Brooks before the public mind was educated to some appreciation of the nature of the problem, and the fruits of his labors are yet to be matured and gathered.

But it is not so much by discovery of new facts or by aid to the community in which one may chance to live that a man exerts his best influence upon mankind; rather by his success in inspiring others to see whatever of good there may be in his point of view and method of attack upon old problems, that his followers may keep alive and enlarge what he stands for in the growth of civilization. As a teacher Professor Brooks has exerted a powerful influence by the stimulus of example in his whole-hearted devotion to research, by originality of suggestion, and by his clear intuition of the essential factors in morphological problems. Convinced that naturalists, like poets, are born and not made—or, if so, then self-made—his teaching has been free from that too easily acquired hallucination that the forcible introduction of facts, and frequent extraction of words by means of examination, are a possible means to the making of zoÖlogists, or what you will to order, to be ticketed and branded as such after a fixed term of the above process. Those who are strong enough to grow in the open have found in him a genial sunshine, but those needing hothouse forcing have sometimes missed, perhaps, the care necessary to bring them to a marketable state.

Many who have followed his lectures will recall the clearness and simplicity with which complex and puzzling questions were presented to their minds; the skull of the bony fish soon lost its terrors, while the homologies of the limb bones were brought to the mind in a graphic way, sure to leave a deep impression. Directness and lucidity, with freedom from investment of unessentials, are characteristics of his teaching and prominent features in his too little known Handbook of Marine ZoÖlogy, which, despite technical faults, was so original and honest, so free from closet natural history, that it marked an era in the advance of biological instruction. It was a direct appeal to the concrete study of living animals at a time when zoÖlogy for students was still the learning of text-books, and text-books were too often in spirit but modernizations of Pliny or of Aldrovandus.

It is this removal of the impeding paraphernalia of custom-bound authority, and a direct, childlike communion with Nature in search of truth by one's unaided labor, that this man has to offer to those who come under his sway as teacher; with what success will be evident from the work of those who recently united to honor his fiftieth birthday with a portrait that might recall him to them as he taught them, and from the work of those who, in coming years, will enjoy the privilege of contact with his genius and be led to "seek admission to the temple of natural knowledge naked and not ashamed, like little children."

Forestry, Professor Fernow said in his paper at the American Association, is not, as it seems to be popularly believed, "Woodman, spare that tree," but "Woodman, cut those trees judiciously." The handling of a slowly maturing crop like forest trees requires especial consideration of a problem quite unlike any other that presents itself to the business man. The trees ripen slowly, a full century often being necessary to the complete development of growth. Obviously it would be inadvisable to cut down the product and then wait a hundred years for further income from the land; another system is necessary, where merely the interest is taken, in trees which are in a condition to cut, while the principal, the forest itself, remains always practically intact.