Chapter III: Preface (3)

The influence of man on the vegetation of a favoured locality like the Riviera is more striking than in the North. But it is worth remembering that the most familiar tree in England—the common elm—is not a native, but introduced from South Europe. Our native elm is the wych-elm, or mountain elm—a much handsomer tree, in the opinion of many, than the so-called “common elm.” There are doubts as to whether both the spruce and the larch were not introduced by man at a very remote time, so that the Scotch fir would be our only aboriginal pine. The oak, beech, birch, ash, hawthorn, poplar, and alder are undoubted native English trees. The holly-oak or evergreen oak, the sycamore, plane-tree, sweet chestnut, horse chestnut, walnut, and probably the lime or linden tree have been introduced by migrating men at various periods into our islands. With the exception of rye and oats none of the plants which we cultivate for food are derived from our own wild plants, and none of our domesticated animals have been produced from native wild kinds.

VIII

FRESH-WATER JELLY-FISHES

Most people nowadays know a jelly-fish when they see one—and recognise that it is eminently a product of the sea—one sees them washed up on the seashore, soft discs of transparent jelly of the size of cheese-plates (Fig. 2). They have a mouth in the centre of the disc, often at the end of a depending trunk, like the clapper of a bell. Some have tentacles, sometimes yards long, which sting like nettles. They also have eye-spots, an internal system of canals and muscles which enable them to swim by causing the edge of the disc or bell to contract and expand in alternate strokes. There are hundreds of kinds of marine jelly-fish varying in size from a sixpence to that of a dinner table, and until twenty-five years ago none were known to live in ponds, lakes, or rivers. Although they often are carried up estuaries, and may stay for a time in brackish water, or even in fresh water, none were known which really lived and bred in fresh water. They were regarded, as are star-fishes and sea-urchins, as distinctively marine, and debarred by the delicacy of their watery jelly-like substance from tolerating the change from sea water to fresh water as a permanent thing. All fresh-water animals—fishes, shell-fish, cray-fish, worms, and polyps—are derived from closely similar marine animals, are in fact sea-things which have suffered a change, and been able to stand it.

These being our preconceptions about jelly-fish, great was the excitement when, in 1880, hundreds of beautiful little jelly-fish were suddenly discovered briskly expanding and contracting, rising and sinking in the water of a large fresh-water tank in the middle of London (Fig. 3). You never know who or what may turn up in London. A badger, a green parakeet, a whale, an African pigmy, an Indian scorpion, and a voice worth ten thousand a year, have all, to my knowledge, been stumbled upon unexpectedly at different times in the highways of London. A new jelly-fish was perhaps one of the least expected “casual visitors.” It was found in the large tank four feet deep in which the great tropical water-lily—the Victoria regia—and other tropical water plants are grown in the Botanic Gardens, Regent’s Park. It came up by hundreds every year for some ten years after its first appearance, dying down in six weeks or so each season.

All the specimens were males, and the puzzle was to find out how it reproduced itself. After a few seasons had passed I determined to solve this problem. I made the guess that perhaps the jelly-fish were budded off from a fixed weed-like polyp growing in the depths of the tank—as is the case with many of the marine jelly-fishes. I remember that one leading member of the council, which still presides over the destinies of the Botanic Gardens, confided to me in a hushed whisper his belief that Providence created this new jelly-fish year by year in the tank in honour of the august patroness of the Botanic Society—Her Royal Highness the Duchess of Teck. I was obliged to make an end of this flattering theory when I discovered, after long searching with my assistant—attached to the rootlets of floating water weeds a minute three-branched polyp (Fig. 4), from which, as we subsequently were able to observe, the jelly-fish were pinched off as tiny spheres about one-sixteenth of an inch in diameter. No females of this jelly-fish were ever discovered. The polyps lived on from year to year, and budded off each season a swarm of pretty but futile male jelly-fish. They ripened and died on attaining a diameter somewhat less than that of a shilling. There were many most interesting points made out as to their structure, mode of feeding, and growth. You could keep them in a tall glass jar supported over a small gas-jet (they lived best at a temperature of 80° Fahr.), and they would swim up by a series of strokes to the top of the water, and then drop like little parachutes through the eighteen inches of depth to the bottom—taking in water-fleas and such food on the way—and immediately would start upwards again. I used to take them alive in my pocket corked up in a test-tube to show to friends.

After they had disappeared from the tank in Regent’s Park (owing to some unhappy cleaning of the tank) they suddenly, in 1903, appeared—it seems incredible—at Sheffield! Then they briefly showed up in 1905 at Munich, and at Lyons had been captured in 1901—always in a tepid water-lily tank! We never could make out where they came from originally. Of course, the polyp must have been brought into the tank with some bundle of water plants from a tropical lake or river, but we never had any indication as to when or which.

Since the days of the fresh-water jelly-fish of Regent’s Park, which was called (a name, but why should it not have a name?) _Limnocodium Sowerbii_—a jelly-fish of about the same size (Fig. 5) but very different in shape and tentacles—was discovered in the great African fresh-water lake Tanganyika—in enormous numbers, and was named _Limnocnida Tanganyikæ_. Only five years ago the same jelly-fish was discovered in the Victoria Nyanza, and a little earlier in backwaters of the Niger. It is a curious and significant fact bearing upon the history of these three areas of fresh water connected with the three greatest African rivers—the Congo, the Nile, and the Niger—that the same little jelly-fish is found in all of them.

And now we have just been reminded of _Limnocodium_, the Regents Park jelly-fish, from a remote and unexpected source. A thousand miles up the Yang-tse-Kiang River, in China, in the province of Hupi, the Japanese captain of a river steamer, plying there and belonging to a Japanese company, captured ten jelly-fish in the muddy waters of the river. He brought them home, preserved, I suppose, in alcohol or formalin, and they have been described by Dr. Oka, a Japanese zoologist of Tokio, in a publication bearing the Latin title _Annotationes Zoologicæ niponenses_, issued in December 1907. European sea captains have not rarely been ardent naturalists, but I think the Japanese is the first captain of a river steamboat who has discovered a new animal on his beat. I have not heard of Mississippi steamboat captains amusing themselves in this way—other rivers, other tastes.

Dr. Oka describes the jelly-fish thus brought to him as a _Limnocodium_, differing in a few details from that of Regent’s Park, so that he distinguishes this Chinese species as _Limnocodium Kawaii_, naming it after the naturalist captain, who must have a rare taste for picking up strange and new things, and a rare goodwill in bringing them home with him. So here is another fresh-water jelly-fish, for it is not the same as the Regent’s Park one, though closely like it. Possibly _Limnocodium_ is an Asiatic genus, and the original Sowerby’s _Limnocodium_ will be found in another Chinese river. But it may prove to be South American, as is the water-lily Victoria regia.

A very small fresh-water jelly-fish was found some twelve years ago—in 1897—in the Delaware River at Philadelphia, United States, and was lately described by the well-known naturalist, Mr. Potts. It was budded off from a very minute polyp resembling that found in the Regent’s Park, but the jelly-fish was totally different from _Limnocodium_. Only four or five specimens of this jelly-fish have ever been seen, and the Philadelphian naturalists ought certainly to look it up again.

An account of the Philadelphian jelly-fish and of other fresh-water jelly-fishes, with illustrative plates, will be found in the _Quarterly Journal of Microscopical Science_, 1906. Mr. Charles Boulenger has, in the same Journal, 1908, described yet another fresh-water jelly-fish from the Fayoum Lake in Egypt.

IX

THE STORY OF THE COMMON EEL

Though the Scotch Highlanders are said to have a profound objection to eating eels on account of the resemblance of these fish to snakes (not a very good reason, since the quality and not the shape of what one eats is the important thing), yet eels have been a very popular delicacy in England in past days. Eel-pie Island, at Richmond, is known to most Londoners, and eel-pie shops were familiar in London less than a century ago. A good Thames eel is still appreciated by the few people who nowadays take some small amount of intelligent interest in what they eat. Abroad, eels are still popular. Eel-traps are still worked in the rivers. In such districts as the flat country, on the shores of the Adriatic, near Venice, millions of young eels are annually “shepherded” in lagoons and reservoirs, and reared to marketable size. The inland eel-fisheries of Denmark and Germany are carefully regulated and encouraged by the Government in those States.

The fact is that railways, ice-storage, and steam-trawling have, in conjunction, revolutionised our habits in regard to the use of fish as a daily article of diet. Fresh-water fish are now almost unknown as a regular source of food in the British Islands. The splendid fish of the North Sea, the Channel, and the Atlantic coast have pushed them out of the market. Thirty-eight years ago, when I was a student in Leipzig and Vienna, “baked carp” was the only fish to be had in the dining-rooms we frequented. Once a week there were fresh haddock, for those who fancied them, in the celebrated Auerbach’s Keller. Now the railway and packing in ice have brought North Sea fish to the centre of Europe, and created a taste for that excellent food. Even on the Mediterranean at Nice, I lately saw North Sea turbot, soles, and haddock lying on the marble-slabs in the fish market side by side with the handsome but small bass, mullet, gurnards, and sea-bream of the local fishery, and the carp, pike, trout, and eels of the fresh waters of the South of France.

Nevertheless the eel—the common fresh-water eel—is still valued on the Continent, as is proved by the fact that the German Imperial Government has recently sent an important official of the Fisheries Department to Gloucester in order to make extensive purchases of the “elvers,” or young eels which come up the river Severn in millions at this season. The purpose of the German fisheries officials is to place many hundred thousands of these young eels in German rivers which are not so well supplied by natural immigration as is the Severn, and by so doing to increase the supply of well-grown eels hereafter in the river fisheries of North Germany.

This interesting practical attempt to increase the supply of eels in Germany will be further appreciated when I relate what has been discovered within the last twenty years as to the reproduction, migrations, and habits of the common fresh-water eel. It has been known, time out of mind, that in the early months of every year millions of young eels a little over two inches in length, called “elvers” in English and “civelles” in French, come up the estuaries of the rivers of Europe in a dense body. They are so closely packed together as the narrower parts of the stream are reached, that thousands may be taken out of the water by merely dipping a bucket into the ranks of the procession. I obtained a few thousand of these “elvers” lately from the Severn and placed them on exhibition in the central court of the Natural History Museum in London. The Anglo-Saxon name “eel-fare” is given to this annual march or “swim” of the young eels from the sea to the fresh waters.

Though riverside folk have never doubted that the elvers are young eels which have been hatched from spawn deposited by parent eels in the sea, and are “running up” to feed and grow to maturity in the rivers and streams inland, yet country folk away from the big rivers have queer notions as to the origin and breeding of eels. They catch large, plump eels a couple of feet long in stagnant ponds hundreds of miles from the sea, far from rivers, and more than a thousand feet above the sea-level. They have no notion that those eels originally “ran up” as little eels from the sea, nor that many of them make their way across wet grass and by rain-filled ditches back to the rivers and to the sea when they are seven years old. But that is now known to be the fact. Just as there are fish, like the salmon, which “run down” to the sea to feed and grow big and “run up” to breed in the small pools and rivulets far from the river’s mouth, so there are other fishes, of which the eel is one, which run up to feed and grow and run down to breed—that is to say, to deposit and fertilise their eggs in the depths of the ocean.

Fishermen who work river-fisheries for eels (far more valued abroad than in England) distinguish “yellow eels” and “silver eels” (see Plate I. opposite title page). We used to distinguish also snigs and grigs, or narrow-nosed and broad-nosed eels (probably males and females). The remarkable fact, admitted by both fishermen and anatomists, was that you could not really tell male from female, nor, indeed, ever find an eel (that is, a common eel, as distinguished from the much larger and well-known conger eel) which was ripe, or, indeed, showed any signs of having either roe or milt within it. A popular legend exists that eels are produced by the “vivification” of horse-hair. Occasionally in summer a long, black, and very thin threadworm (called _Gordius_ by naturalists) suddenly appears in great numbers in rivers, and these are declared by the country-folk to be horse-hairs on their way to become eels! I remember a sudden swarm of them one summer in the upper river at Oxford. Really, they are parasitic worms which live inside insects for a part of their lives, and leave them in summer, passing into the water. Fanciful beliefs about aquatic creatures are common, because it is not very easy to get at the truth when it is not merely at the bottom of a well but at the bottom of a river or of the deep sea! The fishermen of the east coast of Scotland, who think very highly of their own knowledge and intelligence, believe that the little white sea-acorns or rock-barnacles are the young of the limpets which live side by side with them, and are scornful of those who deny the correctness of what they consider an obvious conclusion!

A few years ago the Scandinavian naturalist, Petersen, showed that the “silver” eels are a later stage of growth of the “yellow” eels; that they acquire a silvery coat, and that the eye increases in size—as a sort of “wedding dress,” just before they go down to the sea to breed. I owe to Petersen’s kindness the coloured drawings of the heads of the yellow and the silver eel reproduced in Plate I. These silver eels are caught in some numbers about the Danish coast and river mouths, moving downwards; and Petersen has been able to distinguish the males from the females by finding the still incompletely formed milt and roe within the silver eels. Not only that, but one of Petersen’s assistants at the Danish Biological Station has found that you can tell the age of an eel by the zones or rings shown by its scales, when examined with a microscope, just as the age of trees can be told by the annual rings of growth in the wood. Most people, even if familiar with eels, even cooks who have skinned an eel, do not know that they have scales; but they have,—very small ones. The age of other fishes has been similarly ascertained by annual zones of growth marked on the scales; and lately the age of plaice has been found to be conveniently given by zones of growth formed annually on the little ear-stones which we find in the liquid-holding sac of the internal ear. I am afraid many of my readers will be surprised to learn that fishes have an internal hearing apparatus similar to our own, also that they have olfactory organs, and, in some cases, a well-grown tongue!

The power thus obtained of telling the age of an eel has led to the following knowledge about them, namely, that female eels do not become “silver” eels and “run down” before they are seven years old, and often not till eight and a half years of age, or even sometimes eleven or twelve years, when they are nearly 3 feet long. The male eel becomes “silver” (instead of “yellow”) at an earlier age—four and a half years,—and rarely defers his nuptial outburst until he is seven or eight years old. The females of the same age are larger than the males; a usual size for silver females of seven years old is a little over 2 feet, and of a silver male of the same age 20 inches.

The further facts which I am about to relate as to the migration and reproduction of the common eel are of great interest. The common “yellow” eels of our ponds and rivers, as we have seen, when they are from five to seven years old and over, put on, as it were, a wedding dress. They become “silver” eels, and descend the rivers to the sea. There they produce their spawn. The young eels thus produced, when only 2 inches long, leave the sea. Every year they ascend the estuaries and rivers of Europe as “elvers” in enormous numbers, their procession up the rivers being known as “the eel-fare.”

Some eels, shut up in moats and ponds, never escape—they become more or less “silver” and restless, but fail to get away. Others crawl up the banks in wet, warm weather, when the ponds are full to the brim, and over the meadows. They are found sometimes on their journey when they

“... have to pass
Through the dewy grass,”

and so to the river, and on to the marriage feast in the deep sea. The fact is, that usually eels inhabit in large numbers the rivers and streams, and have no difficulty in getting down to the sea when they are adult. Those who, as young elvers, have wandered far off into sunken ponds and reservoirs, are eccentric spirits who have lost the normal way of life; like fellows of colleges in the old days, they have cut themselves off from the matrimonial “running down,” but they have compensations in quietude, abundant food, and a long life.

We now know where the silver eels go when they run down the rivers. They go into the sea, of course; but we know more than that. It has now been discovered that they make their way for many miles along the sea-bottom—in some cases hundreds of miles—to no less a depth than 500 fathoms. In the Mediterranean they don’t have very far to go, for there is very deep water near the land, and Professor Grassi found evidence of their presence in the depths of the Straits of Messina. But the eels of the rivers which empty into the North Sea and English Channel have much farther to go; they have to go right out to the deep water of the Atlantic, off the west coast of Ireland. That is the nearest point where 500 fathoms can be touched; there is no such depth in the North Sea nor in the Channel. They never come back, and no one has ever yet tracked them on their journey to the deep water. Yet we know that they go there, and lay their eggs there, and that from these remote fastnesses a new generation of eels, born in “the dark unfathomed depths of ocean,” return every year in their millions as little “elvers” to the rivers from which their parents swam forth in silver wedding dress. Soon, we have reason to hope, by the use of suitable deep-sinking nets, we shall intercept, in the English Channel, some of the silver eels on their way to the Atlantic deeps. They must go in vast numbers, and yet no one has yet come across them. How, then, do we know that the silver eels ever go to this 500-fathom abysm?

The answer is as follows: A very curious, colourless, transparent, absolutely glass-like, little fish, 2½ inches long, oblong and leaf-like in shape, has been known for many years as a rarity, to be caught now and then, one at a time, floating near the top in summer seas (Fig. 6). I used to get it at Naples occasionally many years ago, and it has sometimes been taken in the English Channel. It is known by the name “Leptocephalus.” Placed in a glass jar full of sea-water it is nearly invisible on account of its transparency and freedom from colour. Even its blood is colourless. The eyes alone are coloured, and one sees these as two isolated black globes moving mysteriously to the right and the left as the invisible ghostly fish swims around. Twenty years ago one of these kept in an aquarium at Roscoff, in Brittany, gradually shrunk in breadth, became cylindrical, coloured and opaque, and assumed the complete characters of a young eel! To cut a long story short, these Leptocephali were found twelve years ago in large numbers in the deep water (400 fathoms) of the Straits of Messina by the Italian naturalists Grassi and Calandruccio, and they conclusively showed that they were the young phase—the tadpole, as it were—of eels. They showed that different kinds of eels—conger eels, the Muræna, and the common eel—have each their own kind of transparent “Leptocephalus-young-phase,” living in but also above the very deep water, in which they are hatched from the eggs of the parent eels. The Leptocephalus-young when hatched, grow rapidly, and ascend to near the surface immediately above the deep water, and are caught at depths of ten to a hundred fathoms. To become “elvers,” or young eels, they have to undergo great change of shape and colour, and actually shrink in bulk—a process which has now been completely observed and described. It is not surprising that their true nature was not at first recognised. The proof that the silver eels of North and West Europe go down to the 500-fathom line off the Irish coast, in order to lay their eggs, is that the Danish naturalist Schmidt and his companions discovered there two years ago, above these great depths (and nowhere else), by employing a special kind of fine-meshed trawling net, many thousands of the flat, glass-like “Leptocephalus-young-stage,” or tadpole of the common eel, and traced them from there to their entrance into the various rivers. They showed that the Leptocephali gradually change on the way landward into eel-like “elvers.”

The rivers nearest the deep water, such as those opening on the west coast of Ireland and on the Spanish and French shores of the Bay of Biscay, get their elvers “running up” as early as November, December, and January. The farther off the river the farther the elvers have to travel from the deep-sea nursery, so that in Denmark they don’t appear until May. Not the least curious part of the migration of the eel is the passage of the young elvers into the higher parts of rivers and remote streams. They are sometimes seen a hundred miles from the sea, actually wriggling in numbers up the face of a damp rock or wall ten or fifteen feet high, pushing one another from below upwards, so as to scale the obstacle and reach higher waters, like Japanese soldiers at a fort. I found them (so long ago that I hesitate to name the date—it was a year of cholera in London, followed by a great war) in a little rivulet which comes down the cliff at Ecclesbourne, near Hastings, close to a cottage frequented at that time by Douglas Jerrold. They were wriggling up in the damp grass and overflow of the driblet 150 feet above the shore, a stone’s throw below. They must have come out of the sea, attracted by the tiny thread of fresh water entering it at this spot.

The Danube and its tributary streams contain no eels, although the rivers which open into the Mediterranean are well stocked with them. This is supposed to be due to the fact that the Black Sea does not afford a suitable breeding-ground, and that the way through the Dardanelles is closed to eels by some natural law, as it has been to warships by treaty. Probably, however, it will be found that the geological changes in the area of sea and land are intimately connected with the migrations of the eel, and that the eel is originally a marine fish which did not in remote ages travel far from the deep waters. Its gradually acquired habit of running up fresh waters to feed has led it step by step into a frequentation of certain rivers which have become (by changes of land and sea) inconveniently remote from its ancestral haunts. An interesting question is whether at the not very distant period when there was continuous land joining England to France and the Thames and the Rhine had a common mouth opening into the North Sea, eels existed in the area drained by those two rivers; and, if so, by what route did they pass as silver eels to the deep sea, and by what route did the new generations of young eels hatched in the deep sea travel to the Thames and Rhine. It seems most probable that in those days there were no eels in the Thames and other North Sea rivers.

Our present knowledge of the romantic history of the common eel of our own rivers we owe in large part to the work done by the International Committee for the Investigation of the North Sea. Who would ever have imagined when he caught a wriggling eel, with a hook and worm thrown into a stagnant pool in the Midlands, that the muddy creature was some five or six years ago living as a glass-like leaf-shaped prodigy in the Atlantic depths, a hundred miles from Ireland? Who would have dreamed that it had come all that long journey by its own efforts, and would probably, if it had not been hooked, have wriggled one summer’s night out of the pond, across wet meadows, into a ditch, and so to the river, and back to the sea, and to the far-away orgy in the dark salt waters of the ocean-floor, to the consummation of its life and its strange, mysterious ending?

There are two points of interest to be mentioned in regard to the rivers Danube and Thames in connection with eels. I have trustworthy reports of the very rare occurrence of eels in streams connected with the Danube. Since the young elvers do not ascend the Danube, where do these rare specimens come from? There can be no doubt that they have made their way individually into the Danube “system” by migration through canals or ditches from tributaries of the Rhine or the Elbe. A similar explanation has to be offered of the eels which at present inhabit the Thames. I cannot find any evidence of the existence to-day of an “eel-fare”—that is, “a running up of elvers” in the river Thames. Probably about the same time as the foul poisoning of the Thames water by London sewage and chemical works put an end to the ascent of the salmon (about the year 1830), the entrance of the myriad swarm of young eels in their annual procession from the sea also ceased. The elvers were caught and made into fish-cakes in London before the nineteenth century, just as they are to-day at Gloucester. It would be interesting to know exactly when they ceased to appear in the Thames. A curious fact, however, is that young eels—not so small as “elvers,” but from three inches in length upwards—are taken close above London even to-day. Four years ago I obtained a number of this small size from Teddington. The question arises as to whether these specimens represent just a small number of elvers which have managed to swim through the foul water of London and emerge into the cleaner part of the river above. This is improbable. It is more likely that they have come into the Thames by travelling up other rivers such as the Avon—which are connected by cuttings with the Thames tributaries. But it certainly is remarkable that eels of only three inches in length—and therefore very young—should have managed to get not merely “into” the Thames (to the upper parts of which no doubt many thus travel and remain during growth), but actually “down” the Thames so far in the direction of its tidal water as is Teddington lock. The specimens from Teddington were placed by me in the Natural History Museum.

X

MODERN HORSES AND THEIR ANCESTORS

The ever-increasing development of motor traffic leads to speculation as to what is to be in the immediate future the fate of the horse. What is its history in the past?

It is in nearly all cases a matter of great difficulty to trace the animals and plants which mankind has domesticated or cultivated to the original wild stock from which they have been derived. Lately we have gained new knowledge on the origin of the domesticated breeds of the horse. It is generally agreed that the Mongolian wild horse represents the chief stock from which the horses of Europe and those conveyed by Europeans to America were derived. This wild horse was formerly known as inhabiting the Kirghiz steppes, and was called the Tarpan. It became extinct there some seventy years ago. The natives of that district asserted that the pure breed was only to be met with farther East in the Gobi Desert of Central Asia. The Tarpan itself showed signs of mixed blood in having a mouse-coloured coat, which is a sure indication amongst horses of cross-breeding. Prevalsky, a Russian traveller, was the first to obtain specimens of the pure-bred wild horse of the Gobi Desert, which still exists. Live specimens have been brought to Europe, and some are in the possession of the Duke of Bedford. A female is mounted and exhibited in the Natural History Museum, and also a skeleton and skulls. Prevalsky’s horse, or the Mongolian wild horse, is of small stature, standing about twelve hands at the shoulder. The root of the tail is short-haired, the mane short and upright, without forelock. The body colour is yellow dun, the mane and tail black, as well as the lower part of the legs, and there is a dark stripe down the back. The muzzle in pure-bred specimens is white. The head is relatively large and the muzzle thick and relatively short. A very decided character is shown by the great size and relative length of the row of cheek-teeth, it being one-third larger than the same row of teeth in a Dartmoor pony of the same stature.

A very interesting fact, which goes a long way to establish the view that the European domesticated horse is derived from the Mongolian wild horse, comes to us in a most striking way from some of the most ancient records of the human race. In the South of France the contents of caves formerly inhabited by men have been dug out and examined with increasing care and accuracy of late years, though first investigated fifty years ago. Similar caves, though not so prolific of evidences of human occupation, have been explored in England (Kent’s Cavern at Torquay, and others). The astounding fact has now become quite clear that these caves were inhabited by men of no mean capacity from 50,000 to 250,000 years ago, when bone harpoons, flint knives, flint scrapers, and bone javelin-throwers were the chief weapons in use, when these islands were solidly joined to the European continent, when a sheet of glacial ice, alternately retreating and extending, covered the whole of Northern Europe, and when the mammoth, rhinoceros, hyena, lion, bear, bison, great ox, horse, and later the reindeer, inhabited the land and were hunted, eaten, and utilised for their bone, tusks, and skin by these ancient men. I revert to this subject in a later article (page 371), but would merely say now that it is all as certain and well-established a chapter in man’s history as that of the ancient Egyptians, who are really quite modern (dating from 8000 years at most) as compared with these cave-men of 50,000 years ago, and the even earlier races which preceded them in Europe.

The bones of the animals killed and eaten by the cave-men are found in some cases in enormous quantities. In one locality in France the bones of as many as 80,000 horses (which had been cooked and eaten) have been dug up and counted! The most wonderful and extraordinary thing about these cave-men is that they carved complete rounded sculptures, high reliefs, low reliefs, and line-engravings on mammoth’s ivory, on reindeer horn, on bones, and on stones—the line-engravings being the latest in date, as shown by their position in the deposits on the floor of the caves, which are often as much as twenty feet or thirty feet in thickness! Not only that, but these carvings are often real works of art, extremely well drawn, and showing not mere childish effort but work which was done with the intention and control of an artist’s mind.

An immense number of these carvings are now known. I have before me one of the most recent publications on the subject—a series of plates showing the carvings collected from caves in the Pyrenees, the Dordogne, and the Landes by M. Piette, who recently died. I have examined his collection and others of the same kind in the great Museum of St. Germain, near Paris. We have in London some of the earlier collections, and especially that of the Vicomte de Lastic, to purchase which my old friend Sir Richard Owen journeyed to the Dordogne in the winter of 1864. Many animals, as well as some human beings (Fig. 7), are represented in these carvings—the mammoth itself, carved on a piece of its own ivory, is among them, and a good many represent the horse (Fig. 8). Now it is a fact that the carvings of the horses of that period undoubtedly represent a horse which is identical in proportions, shape of head, mane, and tail, with the wild Mongolian horse, and is unlike in those points to modern European horses, or to the Arabian horse.

It was, until the discoveries of M. Piette, held that though the cave-men killed, ate, and made pictures of the horse of those remote days, yet that they did not tame it, put a halter or a bridle on it, and make use of it. Some of the carvings figured by M. Piette leave, however, no room for doubt that the cave-men fitted a bridle to the head and muzzle of the horse. These carvings (Fig. 9) show a twisted thong placed round the nose and passing near the angle of the mouth where it is possible, though not certain, that a “bit” was inserted. Connected to this main encircling thong are four twisted cords (on each side of the head), which run horizontally backwards, and the two lower of these are joined by a flat, plate-like piece, which is ornamented. The whole apparatus is further connected to a twisted cord on each side, which runs towards the back of the head, but it is not shown in the carving what becomes of it. Thus it seems clear not only that the cave-men of these remote ages were wonderful artists, but that they mastered and muzzled the horse.

Some of the engravings of horses’ heads seem to indicate the existence of a horse alongside the commoner form with a narrower, more tapering face, and may possibly be due to the introduction, even at that remote period, of another race distinct from the Northern or Mongolian wild horse. That this admixture of a distinct and more slender horse with the Northern horse has taken place over and over again in historical times is a matter of knowledge. The question is, when did it first take place, and where did the more slender horse come from? In later days we know this more shapely breed as the Arab and the Barb, and the introduction of its blood at various times into the more Northern stock is well ascertained. The latest great historical case of such admixture is the production of the English thoroughbred in the eighteenth century by such sires as the Darley Arabian, the Godolphin Barb, and the Brierley Turk, whose blood is transmitted to modern racehorses through the great historic sires, Herod, Matchem, and Eclipse, the ancestors of practically all modern racehorses.

The horse of more Southern origin thus recognised as distinct from the prehistoric European horse, it is now convenient to speak of as the Southern or Arabian horse. There are certain curious structural features which seem to mark these horses and their offspring, even when their strain is blended with that of the more Northern horse. Probably from the time of the cave-men onward the selective breeding of horses has been carried on, so that in many breeds size has been vastly increased. It is an important fact that the English racehorse has never been selected and bred for “points” (as cattle and sheep are), but always by performance on the racecourse. Thus it becomes an extremely interesting matter to see what are the changes which the breeder of thoroughbred stock has unconsciously produced—what are the differences between the racehorse of to-day and that of 50, 100, and 150 years ago. This was pointed out to me by the late Duke of Devonshire as a reason for supporting my proposal to secure and place in the Natural History Museum the skulls, limb-bones, hoofs, and other indestructible parts of great racehorses (and of other breeds), and also for having very accurately measured reduced models made of such horses, in order that we may after some years compare the proportions and structure at present arrived at with the later developments which the continual selection of winner’s blood in breeding must unconsciously produce. Such a collection was started by me in the museum, but it needs the assistance of owners of horses—both as to placing record specimens in the museum and in paying for the preparation of accurately reduced models by competent artists. It already comprises the skulls of Stockwell, Bend Or, and Ormonde, and several carefully made reduced models of celebrated horses. There is no doubt that the English racehorse has increased in size. He is a bigger animal to-day than he was 200 years ago, and the opinion of the best authorities is that he has increased on the average an inch in height at the withers in every twenty-five years. The racehorse has a much longer thigh-bone and upper-arm bone (in proportion to the rest of the leg) than has the cart-horse, and it is probable that this length has been continually increased by the selection of winners for breeding.

There are other points of scientific interest as to modern horses and their forefathers which are illustrated by valuable specimens and preparations placed by me in the Natural History Museum.

All those hairy warm-blooded quadrupeds which suckle their young, and are hence called mammals, are the descendants of small five-toed ancestors about the size of a spaniel. This is equally true of the elephant, the gorilla, the horse, and the ox. In the sands and clays deposited since the time of the chalk-sea, the remains (bones and teeth) of the ancestors of living mammals are found in great abundance. These sands and clays are called “the Tertiaries,” and are divided into lower, middle, and upper—whilst we recognise as “Post-Tertiaries” (or Quaternary) the later formed gravel and cave deposits in which the remains and weapons of the cave-men have been found. The Tertiaries consist of a series of deposits amounting to about 3000 feet in thickness, and they have taken several million years in depositing—no one can say how many.

FIG. 10.—To the left, the fore-foot of the horse-ancestor, Hipparion, showing three toes: to the right, the back view of a long bone of a modern horse’s foot, with rudiments of outer toes, called splint-bones.]

In the upper Tertiary we find the remains of a kind of horse (the Hipparion), with well-developed “petti-toes” (like those of a pig) on each side of the big central toe (Fig. 10). In the middle Tertiary we find smaller ancestral horses, with three toes of nearly equal size, and in the lower Tertiary a horse-ancestor as small as a fox-hound (the Hyracotherium), with four toes on its front foot and three on its hind foot. Coming very close to this in general character is another small extinct animal of the same age, with five toes on each foot. As the toes have dwindled in number and size, leaving at last only the big central toe (as we pass upward from the small ancestors to the big modern horse), so the cheek-teeth, too, have changed. At first they had shallow crowns and divided fangs, and showed four prominences on the crown which were little, if at all, worn down during life. But as the horse became a bigger animal and took to eating coarse tooth-wearing grass, his teeth became deeper, and continued to grow for a long time, whilst the crown was rubbed down by the hard food, and a curiously complex pattern was brought into view by the exposure of the irregular bosses of the crown in cross section. And, meanwhile, the size and proportions of the horse-ancestors changed until, after being pig-like, then tapir-like, they acquired the perfect form and size for fleet and prolonged movement over firm, grass-grown plains. Horses and other large animals have to run, not only to escape pursuit by carnivorous enemies, but in order to travel, before they die from thirst, from a region suddenly dried up by drought to a region where water can be had. Many thousands of wild animals perish every year from local droughts in Africa. No small animals can exist in regions liable to be affected by sudden drought.

Three-toed horses, like the upper Tertiary Hipparion, are occasionally born as “monstrosities” from ordinary horses at the present day. All horses have the remnant of a toe on each side of the big central toe—in the form of splint-bones—concealed beneath the skin. In some breeds, for instance, in the “Shire” horses, which have enormous hairy feet in proportion to their huge strength and weight, these splint-bones tend to develop three little toe-joints, which are immovable, but obviously are “petti-toes.” It is related by Suetonius that Julius Cæsar used to ride a favourite horse which had several toes on each foot with claws like a lion. This was one of the “monstrosities” alluded to above, a throw-back to the ancestral many-toed condition. Specimens illustrating these, and all else which I am here relating concerning horses, and much more which I have not space to tell, may be seen in the North Hall of the Natural History Museum.

The three-toed ancestral horse, Hipparion, attained a fair size (that of a big donkey), and was shaped like the recent fleet one-toed horses. In the skull in front of the orbit, the Hipparion has a strongly marked depression in the bone, as long and broad as a hen’s egg, and in shape like one-half of an egg cut through longwise (see Fig. 11 _pf_). These pre-orbital cavities are known in deer, sheep, and antelopes; they lodge a gland resembling the tear-gland, which has, itself, a separate existence. Similar “glands” are found in the feet and ankle-joints of sheep and deer. The fluid which they secrete probably has an odour (not readily noticed by man) which helps to keep the herd together, or, on certain tracks when the fluid is smeared on to herbage. It is a remarkable fact that the skulls of the wild Mongolian horse and of the fossil horse of the cave-men, as also those of the commoner European breeds, have no trace of this pre-orbital cup or of the gland which Hipparion, their three-toed ancestor, possessed. Nor, indeed, have the asses and zebras. But the Southern horse, the Arab, and all the breeds into which his blood has prominently entered—as, for instance, the English racer (so-called “thoroughbred”) and the “Shire” horse (which is derived from the old English war-horse, in the making of which certainly four hundred years ago Arab blood and heavy Northern stock were mingled), do show, as a rule, a well-marked if shallow, cup-like depression in front of the orbit! In fact, as Mr. Lydekker has pointed out, the presence of this “pre-orbital cup” is evidence of the descent of its possessor from Arab ancestry. Many specimens of horses’ skulls showing this “cup” are exhibited in the Natural History Museum. We have not been able to find any trace of a gland like the “larmier” of deer and the “crumen” of antelopes on examining the soft tissues which overlie this cavity in horses of Arab descent, but it is not improbable that occasional instances of such survival will some day come to light. A very interesting fact in connection with this concavity and its indication of a distinction between the Northern (Mongolian) and the Southern (Arabian) horse is that in India a fossil horse of very late Tertiary date has been found, a true one-toed horse, not a Hipparion, which has the pre-orbital cup well marked, and is possibly the ancestor of the Arab.

There is no very great difference between the wild horse and wild asses and zebras. They are distinct “species,” but will breed together and produce “mules,” which in rare cases appear to be themselves fertile, although this is doubtful. The inner causes of the infertility of mules are not really known or understood. Nor, in fact, do we know really and experimentally what are the causes of fecundity and of infecundity in normally paired animals, including mankind. It is of the utmost importance to modern Statecraft that this subject should be studied, and there is a great field for experimental inquiry.

A clear mark of difference between the horse and the other species of the genus Equus (namely, the Asiatic and African asses and the zebras) is found in the curious wart-like knobs[1] on the legs, which are called “chestnuts.” These warty knobs appear to be the remains in a “dried up” condition of glands, such as are found in the legs of deer in a similar position, and secrete a glairy fluid. In new-born colts they sometimes exude a fluid, and also more rarely in adult horses. The fluid attracts other horses (probably by its smell), and also causes dogs to keep quiet. The horse has one of these wart-like “chestnuts” above the wrist joint (so-called knee) on the inner side of the fore-leg. And so have all the asses and zebras. But the horse (Fig. 12) has also a similar “chestnut” on the inner side of each of its hind-legs, below the heel-bone, or “hock.” This hind-leg chestnut is absent in all asses and zebras. This difference between the horse and ass can be tested by my readers on any roadside by their own observation. The hind-leg chestnut is also absent in certain breeds of ponies from Iceland and the Hebrides. Its presence and absence are interesting in connection with the disappearance of the face-gland or pre-orbital gland in all recent horses, asses, and zebras.

The “chestnuts” of the horse have sometimes been compared erroneously to the “pads” on the feet of other animals, and supposed to be survivals of a “pad” in each foot corresponding to the inner of the three toes of the Hipparion. The real representative, in the horse, of the chief pad of the foot of animals which do not (as the horse does) walk on the very tip of the toe, is a little knob called the “ergot.” The diagram, Fig. 13, shows how this ergot corresponds to the chief pad of the three-toed tapir’s foot, and so to that of the dog also.

The absence of living horses, or of any kind of ass or zebra, from the American Continent, when first colonised by Europeans in the sixteenth century, is a very singular fact. For we find a great number and variety of fossil remains of extinct horses in both North and South America. It seems possible that some epidemic disease swept them from the whole Continent not very many centuries before Europeans arrived—for there is evidence in South America of the co-existence there of peculiar kinds of horse with the “Indian” natives. It is even alleged that Cabot, in 1530, saw horses in Argentina, which were the last survivors of the native South American species. And it is also said that the Araucanian Indians of Patagonia have a peculiar breed of ponies, which may be derived in part from a native South American stock. I have never been able to procure a skull of this breed, or any detailed description of it. What is quite certain is that in the great cave of Ultima Speranza, in Patagonia—from which the hairy skin, dried flesh and blood, and unaltered dung as well as the bones, of the giant sloth Mylodon were obtained—a great number of the horny hoofs, and the teeth of a peculiar horse were also found some eight years ago, and are preserved in the Natural History Museum, together with the remains of the giant sloth. The condition of these remains is such that they cannot be many centuries old. The animals appear to have been contemporaneous with an early race of Indians who made use of the cave before the arrival of Europeans. A skull of one and a skeleton of another of the peculiar extinct South American horses (called Onohippidium and Hippidium), which survived until a late period in Patagonia and may possibly have been seen by Cabot, are shown in the Natural History Museum. Their bones are found in the superficial gravel and sand of the pampas.

To revert for a moment to the history of the English thoroughbred. It appears that in England in the middle of the eighteenth century a happy new infusion of the Arab race with that of existing stock (which already contained some Arab blood mixed with that of the Northern race) produced once and for all a very perfect and successful breed. That breed did not derive speed from the Arab, but “stamina,”—probably a powerful heart. It did not derive its size from the Arab, but the cross proved to be a large horse. It has never been improved since by any further admixture of Arab or Southern blood. Hence the (at first sight) misleading name “thoroughbred.” This name is not intended to imply that the breed is not originally a “blend,” but that those horses so called are pure-bred from the happy and wonderful mixture which a hundred and fifty years ago was embodied in the great sires Matchem, Herod, and Eclipse.

FOOTNOTES

[1] The names “malander” and “salander” have been recently applied by zoological writers, apparently by misconception, to these “callosities” or “chestnuts.” Those names are used by veterinary surgeons to describe a diseased condition of this part of the horse’s leg (Italian “_mal andare_”), and do not apply to the “chestnut” itself, which is sometimes called “castor.”

XI

A RIVAL OF THE FABLED UPAS TREE