Upward—still upward—still upward to the highest! Such is the claim of modern man for the story of himself and the lower inhabitants of the globe. The zoologists have gone so far as to confer upon him the surname Sapiens—Homo Sapiens. Learned indeed he is, and heir of all the ages, but whether or not his assumed surname be warranted the doctrine of descent with modifica­tion can never again be questioned. The work of Darwin was crowned when he compelled a general acceptance of that doctrine, and now the Descent of Man and the Ascent of Man are equivalent terms for a natural process which has converted man from a thing to a person, and is the founda­tion of all modern thought. The biologist works secure in the knowledge that he is studying some portion of a chain of life stretching back for incalculable ages, and is not careful to produce those missing links demanded by the once formidable foes of his fundamental principle. Haeckel may announce that Pithecanthropus Erectus of Dubois is truly a Pliocene remainder of that famous group of highest Catarrhines which were the immediate pithecoid ancestors of man. This may or may not be true, but if true it makes the descent of man from a lower stock none the surer, the increasing verifica­tion of which is not found to rest on missing links.

Many of the discoveries of modern science are made by proceeding from known phenomena to the unknown, or, more precisely, from the well-known through the little-known to the hitherto unknown.

As to the validity of knowledge it is enough to say this—and pass on—all our knowledge is provisional and imperfect, and much of our ignorance is as transient as ourselves.

There are two chief ways in which historians deal with their subject-matter, though the moderns combine them. When oral tradition gives place to written records the lineal descendant of the bards and annalists collects his scanty authorities and compiles his story from them from beginning to end. The Anglo-Saxon Chronicle of Bede and Alfred, the Book of Howth, the works of Giraldus Cambrensis, the Chronicles of Froissart and the Memoirs of de Comines were composed in the only way that was then possible. But the muse of history entered on a deeper and more fruitful course when about ninety years ago the study of documents became an essential feature of historical work. It was then that the historian grew up, entered upon his finest inheritance and assumed his Greek title, Enquirer, Student of facts, Man of research. He is now nothing if not a man of science as well as of letters. With a wealth of documents within his reach so great that the 3239 Vatican cases full of them formed by no means the richest collec­tion in the archives of Europe, he proceeds to read backwards correctly what many an earlier annalist read forwards falsely. “We are still at the beginning of the documentary age which is destined to make history independent of historians, to develop learning at the expense of writing, and to accomplish a revolu­tion in other sciences as well.”1

The Historian a Biologist.

It is not too much to say that he who studies history, national, political, constitutional, ecclesiastical, military or economic is as much a biologist in the widest sense as the botanist and zoologist. Indeed these were till recently termed students of natural history, until the advance of knowledge gave us the various special groups of workers, conveniently called biologists. Though the study of human history by documents is an essential part of the historical method and the student may read his subject backwards, this would not of itself warrant the technical biologist in doing so, even though he be a child of Nature and part of her—“Nature’s insurgent son.” But some reflec­tion on the facts of certain provinces of science affords ample justifica­tion for the method. It is chiefly in questions of origin that it avails, while it fails in that form of research by experiment which is the glory of modern science. A few examples of the process of passing from the known to the unknown will illustrate the method.

Darwin.

Much of the Origin of Species and all of the Descent of Man was founded on this method; thus in the former the conceptions of struggle took their main rise from the work of Malthus on Human Popula­tion, and of variation from domesticated animals and plants, and this is true also of Wallace. A mere glance at the divisions of The Descent of Man shows that it could never have been attempted in any other than the backward way.

Geology.

In their researches on the crust of the earth Playfair, Hutton and Lyell did not pursue them by going down a coal mine till they came to the lowest available beds and work upward from these to the highest. Though for purposes of exposi­tion a great geologist, as Sir Archibald Geikie, may expound the making of the earth from the lowest to the highest levels, and Professor Bonney tell us the Story of our Planet from beginning to end as if he had watched it unfolding, Lyell in his Principles of Geology shows how the studies of his great province began. There we have the backward reading of its story pursued by himself and other great ones, and where it led them. Commencing with the Pleistocene period and passing through Neocene and Eocene periods through the Mesozoic Era and its cretaceous, jurassic and triassic systems to the Newer PalÆozoic Era and its Permian, carboniferous, and Devonian systems, the older PalÆozoic Era and its Silurian Ordovician and Cambrian systems, he reaches the unknown. But before all this patient research and its record is reached he treats, as he must, of consolida­tion and altera­tion of strata, of petrifica­tion of organic remains, elevation of strata, horizontal and inclined stratifica­tion, of faulting, denuda­tion, upheaval and subsidence as they combine to remodel the earth’s crust. The title of his classical work is significant—An Attempt to Explain the Former Changes of the Earth’s Surface by Reference to Causes now in Operation (it may be noted that in 1830 they were fond of capital letters and of underlining their words). If these great men had been condemned to the sole use of the method of the annalist in his treatment of human history, that of the coal mine in geology, this great province of knowledge would never have been what it is to-day.

At this point I think it well to state that this illuminating principle of Lyell is pursued in nearly all the matters of fact and their interpreta­tion contained in the following chapters, so that from time to time I shall have to employ the verb, coined for the purpose, when I attempt to “Lyell” them on behalf of Lamarck.

Anthropology.

The anthropologist could hardly make a start with his research, if, knowing nothing of his own anatomy, physiology, customs and beliefs, he tried to interpret the physical features, habits, manners, customs and rites of an African tribe. Without such prior knowledge he would find it a profitless task to journey to the banks of the Zambesi and bring back any intelligible history of the aborigines. If he did not know the games of a European child how could he understand the variants of them such as the writer of Savage Childhood2 expounds so well?

The Sources of Rivers.

To trace the course and source of a river is a simple task through the work of modern geographers, and such a pursuit illustrates well the two methods here considered, but it is doubtful if any river was ever traced originally from its fountain head to its mouth. The backward way of such explora­tion, from the nature of the case, has always been taken, and men have traced the more or less finished products of the lower stretches, backward, still backwards, even as in the Indus, to the still-unknown. The earliest thinkers and seekers in the plains of Bengal were familiar with much of their great sacred and composite river as it flowed into its delta. Slowly, laboriously, here a little and there a little, they learned its stupendous story. They found the plateau of Tibet in the Himalayas where the twin-sisters, Brahmaputra and Ganges were born, and saw how from the one high cradle they parted on their eastward course for a thousand miles with the mountain-chain between them, and how, coming together again, the one descending through Assam and the other flowing through the plains, reinforced by the Jumna, they united to form the Ganges-Brahmaputra. A great subject indeed for the early geographer, but one which he could only follow in the backward way. Again how well known and revered in Egypt was the Nile for thousands of years before its source in Victoria Nyanza could be traced, even though Nero might send his explorers as far as the marshes of the White Nile, and Ptolemy’s search for it might lead him to guess the riddle, and assign it to two great lakes!

Genealogy.

Not many of us can trace our ancestry in the direct male line to the 8th century by authentic and written documents as did a Hebrew friend of mine, thus effectually meeting the doubts of a prospective brother-in-law who asked him as to his fitness to enter a family which was able to produce a stray peer of the realm in its roll. On the other hand a man who has lost his parents in childhood may know nothing of them but that his father’s name was A. Mann, and that he was buried in a Kentish churchyard. He may go on a pilgrimage and find there recorded the fact that A. Mann was the son of A. Mann, Gent, who came from Northumberland. He will doubtless make another pilgrimage and find there a large vault, and over it an imposing record of many a Mann, and yet further he may go, and from the Heralds’ College find out the still earlier deriva­tion of his ancestors.

Detection of a Crime.

There are two chief ways of detecting a crime. By oral evidence from eye-witnesses or confession of the accused you may get direct proof, though even here are pitfalls from careless and hasty witnesses on the one hand, or on the other from a strange perversion of mind of the confessing person which is well enough known to forensic medicine. You may thus bring home to the accused his guilt by the method of the annalist. Or you may employ the more common method of studying circumstantial evidence; the story of the crime is read backwards and a verdict of guilty is given. This is the main stuff of which the prevalent detective story is composed.

A Parable.

A plain parable may well conclude this chapter.

As I mused on the chain of life I found a piece of whipcord which had been lying by for twenty-five years since some of it was used for rigging a model yacht, and this very efficient product of human art seemed to speak to me on the subject of my musings. Perhaps if Huxley could extract from a piece of chalk or lumps of coal two magnificent expositions on geology and biology, this little trifle of cord might afford a text on a way of looking at living things which should be useful in this old case of Lamarck v. Weismann—and others.

Should I learn the story of the whipcord forwards like an annalist, or backward like a modern historian? Clearly it could be done in a measure by either method. Here was a highly finished product of which either might furnish the story, and of which, we may suppose, I knew nothing. I tried the backward way, and by the aid of a needle began to unravel it. The cord was as good as if just made, slender, strong, twisted, with some glazing on the twisted threads. It showed three main bundles, and each of these was composed of two smaller ones. The substance of all these six was found when examined with a lens to consist of minute silky fibres varying from a quarter of an inch to an inch in length. This was all I could learn without a stronger magnifying power or a chemical analysis, and the direct search was at an end. I gathered since then that the first three bundles were called “strands,” and the two composing each of these “yarns,” and that the fibres were from a plant called hemp. This did not carry the story deep or far, and illustrates how often in the backward method facts have to be supplemented by inference. But I had learnt some undoubted facts and some inferences from them nearly as certain. Some mind of man had conceived and hands carried out the division of the bundles of fibres into three strands, had twisted them somehow so as to reduce their length by a quarter and yet not far enough to rupture them, and had thus fitted them the better for their purpose by a reinforcement of tensile strength due to the twisting. I could also see that this same mind had seen it better to divide each of these strands into two yarns before the final twisting, and that in framing the yarns the silky fibres of the plant had been squeezed together by some powerful agency and yet not disintegrated, and that the finished product had been immersed in a protective substance which gave it a slight glaze. In short, I, though a child in these matters, read much of the story of this cord in terms of mind dealing with given organic matter. I may add that I did not imagine myself a little Paley, and that I do not intend to “take in” the reader as to the argument from design and final causes, even though this parable may feebly resemble Paley’s study of a watch. The conclusion was perfectly clear that certain directing grey cells of a certain brain had interfered with and acted upon some plastic vegetable matter, and one could at the “strand” stage, the “yarn” stage, and the “fibre” stage see mind writ large.

The Forward Way.

The limits of the former method are obvious, but I might also attempt to follow the little story as a crime is followed and described by eye-witnesses. So I go to an old-fashioned rope-factory and ask the foreman questions about the making of twine, cords, ropes and cables. He shows me bundles of hemp; he calls them Russian, Italian or American, and goes on to tell me how the fibre is “heckled” or combed, how “tow” is separated from “line,” and how the yarns are pressed together and twisted, how they are at first rough and bristly, and are then dressed, polished, and “sized” with such a starch as that of the potato. When I proceed to ask him about the plant itself his interest flags, and he becomes vague. He says, “You had better ask the Head, young Mr. X., he knows these things better.” I find the Head with his golf clubs over his shoulder and about to start on his “business,” and he is polite, but says he knows very little about the origin of his hemp. “You should go over the way and ask Messrs. Y. if they will let you see the expert who advises them in their business, he will know.” The expert is at home and kindly and fully describes to me the early home of the wild Cannabis Sativa in a moderate climate of Asia, the rich soil it needs for its growth and the various countries of the world into which it has been introduced; and the bast-fibres of the bark of this plant which from remote antiquity has supplied the silky stuff. He then tells me how the stems are dried and crushed, and then of the important stage of fermenta­tion or “retting” in water, how they are again beaten in a “break,” then rubbed and “scutched,” and finally “heckled” or combed; and, as to analytic chemistry, he tells me that the chief constituent is cellulose. This quest is now over and I know much I could not find out by the backward method, though the dependence of its rival upon the presence of honest and capable eye-witnesses is not less obvious. It is not alone in ecclesiastical history that cheats and forgers of documents exist. In the world of Nature there may be, for all we know, biological False Decretals that may lead us far astray, such perhaps as Amphioxous and ArchÆopteryx, and the Pseudo-Isidore who produced them may yet be discovered.