ORDER 7. Pachydermata (thick-skinned).
In Greek pachus means thick, and derma skin. Pachyderms, therefore, are thick-skinned animals. It is rather a vague denomination, as you perceive, and does not tell us much about them; but it appears that it was not very easy to find a better term. For my own part I should be very much puzzled to find a name really suitable for such an irregular company as this, in which all the huge beasts of the earth—the elephant, the rhinoceros, the hippopotamus—are heaped one upon the other, side by side with the horse, the ass, and the hog; begging your pardon for an ugly word.
All these creatures live on vegetables, with the exception of the hog, to whom nothing comes amiss; or who, in other words, is omnivorous, like the bear, and also another member of the class Mammalia, which I do not name for fear of making you blush at your companionship. This assures you that, in the order of the Pachydermata, the digestive apparatus is very fully developed. The horse, for instance, has a very voluminous stomach, which extends much farther back than the point at which the oesophagus empties itself; and in which, on close examination, a sort of contraction is observed which appears to divide it in half, producing the false effect of there being two stomachs. But, after all, we do not find, even in this case, any essential difference to remark upon in the internal arrangements; it is always the teeth we must look at if we want to have something to say. There, indeed, we have only to choose; nature has indulged herself in all manner of fantastic freaks.
To begin with the elephant, the grand master of the order, he presents us with one of the most oddly-furnished jaws in existence. Every one knows those two enormous tusks which protrude from his mouth, and which furnish human industry with nearly the whole store of ivory it has need of. Those two teeth are the largest, beyond comparison, of any in the animal kingdom; yet they are two merely ornamental teeth, perfectly useless in the operation of eating, and very ruinous into the bargain to the proprietor. All those stores of the blood which furnish the materials for ivory pass into these tusks, and, as often happens to people who give way to a taste for luxuries, there is nothing left wherewith to provide the animal with serviceable teeth. Those tusks of the elephant are nothing but his upper incisors, the only ones, observe, which curve in coming out of his jaw. In the lower jaw he has no incisors at all; canine teeth are entirely wanting; and by way of dental apparatus, this meagerly-furnished mouth possesses on each side of either jaw one or two molars, enormous in size, but not of ivory. They are composed of a number of enamelled upright layers of tooth-substance (dentine), soldered together with a bony cement; and these are our giant's only resource for chewing the grass, young shoots, and leaves of trees, which are his natural food. [Footnote: These teeth are nevertheless very efficient grindstones.] As a consolation, he has the glory of knowing that he possesses the very finest teeth in the world, the terror of all who approach him; and I can compare him to nothing so well as to a vain woman, who is contented to live on potatoes that she may wear fine clothes and excite the envy of her neighbors.
The hippopotamus also has incisors in the upper jaw, which curve as they come out of the mouth; but these never attain anything like the size of the elephant's tusks, neither do they hinder the development of the other teeth, of which this animal has a very respectable collection. The upper incisors bend downward; those in the lower jaw stand out horizontally, and terminate in sharp points like plough-shares; and indeed the hippopotamus uses them for tearing up the ground in order to get at the roots which form its nutriment. These are, besides, formidable weapons, with which when enraged the animal can tear even boats in pieces; for, as you are aware, the hippopotamus is almost amphibious, and browses on water-plants, and lives in the great rivers of Africa, its native country. Its name alone would have told you this had you understood Greek; [Footnote: Ippos, a horse, and potamos, a river. The Greeks, who had seen the hippopotamus in the Nile, in Egypt, named it the river-horse; as afterwards the Romans called the elephant the ox of Lucania, because they first saw it in Lucania during the war with Pyrrhus.] but I have no complaint to make this time, for it was the Greeks themselves who gave it. You would find it very awkward, would you not? if you had to breakfast at the bottom of the Thames, and could not swallow a morsel without having your nose filled with water? But the hippopotamus labors under no such inconvenience. Its nostrils are provided with two little doors, which it closes at will, and behind this screen the lungs keep quite quiet while the animal goes backwards and forwards in the water. There is generally a hippopotamus in every large menagerie. The next time you visit one look at him. You will see him with a large stomach almost trailing on the ground: and no wonder; he needs plenty of room in which to stow away all the canes, reeds, and water-plants from the bottoms of rivers, which are not very nutritious food. Accordingly the stomach of the river-horse presents the appearance not only of two compartments, like that of the true horse, but looks as if it were divided into three or four.
To conclude my account of this animal, I must add that the ivory of its teeth is even more beautiful than that of the elephant's tusks, and that dentists carve it into very magnificent teeth for their patients. This is not a matter to interest you much at present, but we never know what may happen. I advise you, however, never to make use of hippopotamus's teeth; they turn yellow very quickly, and, when people are driven to buy teeth, the least they can try for, is to get good-looking ones for their money.
I should like to say something about the rhinoceros while we are on the colossal tribes, but it is a very unsatisfactory subject. The animal has no canines, sometimes no incisors even; sometimes it has as many as thirty-six teeth, according to the species, as naturalists aver; and this is all I have to say about this great lump of flesh, so misshapen outside, yet so regularly formed within. He it is who especially deserves the title pachydermata, his skin being so hard and thick that bullets glance off its surface. But this has nothing to do with our present subject, any more than the horn upon his nose, whose turn for description may come if I ever give you the history of the skin and all connected with it.
The hog also has canines, and very strong ones; but it is in the wild state, when it is called a boar, that these appear in their real form. There we find them projecting out of the mouth with a curve, as is so commonly seen among the pachydermata, forming those terrible, sharp, and pointed tusks which have been so often fatal to the hunter. The wild boar of the forest is supposed to be the original ancestor of the domestic pig; and if, as is probable, this is really the case, we have here a remarkable instance of the effect of man's treatment upon the organisation of the animals he collects around him. The wild boar lives only on fruits and roots, which, like the hippopotamus, he tears up with his tusks, those safeguards of his, amid the many perils of his life in the woods. In the service of man, on the contrary, he becomes lazy, cowardly, and greedy; unlearns his energy and combativeness, eats all that is offered to him in the trough, even meat, when it happens to be thrown in; and, in order to do this moreeasily, has recalled toward his mouth those formidable war-tusks of his, so tremendous as weapons, so useless as teeth; has, in fact, turned his sword into a fork. It is the case of a Tartar degenerated into a Chinaman. [Footnote: China, about which we have heard a great deal of late years, has been several times invaded by the warrior hordes of Tartary. But at each time, unto the second and third generations, the vanquishers have taken the effeminate manners, the costume and the usages of the vanquished, and so many conquests have only resulted in converting millions of Tartars into Chinese.]
This suggests to me an idea relative to the horse, the last important member of the pachydermata which remains to be spoken of. It also has its canines, but very small ones; they disappear, so to speak, in a large vacancy between the incisors and the molars, where man inserts the bit, by means of which the animal has been subdued. Small as these are, however, these canines indicate that the horse might eat flesh, canine teeth being the distinctive attribute of the carnivorous mammals. I have read somewhere, but I do not remember where, that an unusual development of strength could be produced in the horse by feeding it on flesh; and the old Greek poets write of a king [Footnote: Diomed, King of Thrace] in the barbarous ages who gave his horses, men for food. If I knew some rich professor who was inclined to spend money in the investigation of a curious fact, I would advise him to set apart a sum for putting horses on a meat diet, from sire to son, gradually increasing the quantity; and I would boldly warrant that in the course of successive generations the canines would become so large as to impede the entrance of the bit into the mouth, and, moreover, would make it rather a ticklish office for the groom to place it there. But let us set aside the teeth the horse might possibly have, in order to examine those it has already. There are six incisors in each jaw; these are long and rather projecting teeth, by examining which, the age of the horse can be detected from certain marks which appear in them from year to year. The molars are flat, square, furrowed with bars of enamel, marking out more or less distinct crescents; perfectly constructed, in short, for chewing hay and oats. Nevertheless, I should never be surprised to see the enamel crescents become sharp-cutting in our rich professor's stable; so skillful is the unseen Architect who created animals, in altering the house when the tenant changes his habits.
ORDER 8. Ruminantia (ruminants).
I shall retain through life a pleasant recollection of the ruminants. Through them I obtained the first prize for natural history which was ever given in France to the pupils of the learned university. It is thirty years ago since this happened, and I own, without any false modesty, that even now the word ruminant rings very agreeably in my ear. It reminds me of one of the proudest moments of my life, of the honor done to me by the illustrious Geoffroy St. Hilaire, when he called me, a little college urchin, up to him, that he might have a nearer view, as he said, of the baby-professor who had spoken so well on ruminants. Yes, it is more than thirty years ago, for alas! it was in 1831. There needed no less an event, as I have told you before, than the revolution of 1830 in France to induce the big-wigs of education to sacrifice two hours per week in one class to the study of natural history. Yes, my dear child, it is only that short time ago since natural history became one of the subjects of study in French colleges; and the gray-haired men of the present day finished their education, as it is called, without having learnt a single word of what I am now taking the trouble to teach you, a mere child. You see you have come into the world just at the right time, and will be able to instruct others in your turn. But before giving lessons to other people you must first finish learning your own. Forgive me this involuntary reference to a happy time when I was not much more rational than you are. And now, let us return to our ruminants—those dear, good beasts, the nourishing fathers of the human race.
LETTER XXXII.
MAMMALIA—continued.
ORDER 8. Ruminants—continued.
Every created thing has an appointed part to perform; but there are some mysterious parts of which we cannot understand the drift. That of the ruminants, however, is so clearly marked out, that we detect it at a glance.
To qualify myself for supplying your young mind with the food I am going to offer it to-day, I have been obliged, my dear child, to browse in a good many books of which you could have understood but little yourself; and I have been forced to ruminate a long time upon what I have read, and to digest it slowly in my head, which I may say, without vanity, is of larger capacity than yours; no great wonder at my age. Now, if I have succeeded in my undertaking, you will benefit by all the work which has been going on in my mind for the purpose of feeding yours without over-fatigue to it; and I shall almost have the right to say that its nourishment has been derived from me. My lamp could tell you what it has sometimes cost me to supply a single page which might instruct, without repelling you.
Now, this is precisely what the ruminant does. The part he has to perform is to collect in the meadows a sort of food, which would disgust less well-organized stomachs than his own, to work it well up within him, and to give it back in a more palatable and less indigestible form. The little flesh-eaters (carnivora) come afterwards to the feast, and the feast is himself!
The whole history, then, of the ruminant is to be read in his stomach. His real office is to digest, and in fact he devotes the best hours of his days to the perfecting of that beneficent labor, on which the life of so many weak stomachs depends. Have you ever amused yourself by watching a large ox lying down in a meadow? Long after he has finished grazing, his jaw continues to work, turning round and round like the grindstone of a painter when he is rubbing down his colors. Look, and you will see that he will remain there for hours together, motionless and contemplative, absorbed in this incomprehensible mastication, rolling about in his throat from time to time some invisible food. Do not laugh at him, however. As you sec him there he is performing his part in life, he is ruminating.
To ruminate is to chew over again what has been already swallowed; and, however droll this may seem to you, it is the business which all ruminants are born to. You remember the monkey's pouch, which serves him as a larder, whence he takes out his provisions as he wants to eat. The ruminant has an immense pouch of the same kind, into which, while he is grazing, he hastily conveys large masses of half-bitten grass. You probably think he is eating when he has his head down in the grass; but you are mistaken. This is only a preparatory work; he is hastily heaping up in his larder the food he intends to eat by-and-by; only his larder, instead of being, like the monkey's, in his cheeks, where, indeed, there would not have been half room enough for those great bundles he tucks in, is in the middle of his body, close to the extremity of the oesophagus, whose lower wall, being slit at that part, becomes an imperfectly secure tube, ready to burst open under pressure, and allow the food to escape between the edges of the slit; these, otherwise, remaining naturally closed. As soon as the large bundles of grass come to this part, they press against the walls of the tube, which they by this means separate, and fall into the provision-pouch, which bears the name of paunch, or grass-pocket, in fact. As soon as the paunch is well filled, and the animal sure of his dinner, he lies down in some quiet corner, where he proceeds gravely with the important act, which is the real object of his existence. A little below the entrance to the paunch, and communicating both with it and the canal of the oesophagus, is a second receptacle, which old French naturalists, not being much acquainted with Greek, named the cap, on account of its fancied resemblance to the caps worn on the head, and which we call 'king's hood' or 'honey-comb bag.' This second stomach now contracts (at least so it is supposed), and thus retains, as if with a closed fist, a portion of the grass accumulated in the paunch: of this it forms a pellet, which it sends back into the oesophagus, and the oesophagus, by continued contractions from below upwards, returns it to the mouth, where at last the grassy lump is chewed in good earnest, and to some purpose. There is no necessity for hurry; the ruminant has no other business on the face of the earth but this, and thus hour after hour passes away, the food pellets rising one after another to the onslaught of the teeth. Nor do they go back again until they have been reduced by long mastication into an almost liquid paste, which glides through the oesophagus without forcing open the slit, and falls straight into a third pouch, called by old Frenchmen the leaf, on account of certain large folds, some what like the leaves of a book, which line the interior; and known to us as the manyplies. From this stomach, No. 3, this grass-pap passes into a fourth and last bag, which is the real stomach, and where the final work of digestion is accomplished. This fourth pouch also has a pretty little name of the old-fashioned sort, like the three others; it is called the reed or rennet-bag, from the property it possesses, in the calf, of turning milk into curds: and of his four stomachs this is the only one which the ruminant makes use of at first. As long as the young animal is nursed by its mother, the other compartments remain inactive and small in size; they neither grow nor exercise their functions until it begins to eat grass. Indeed, they would probably entirely disappear, if any one would go to the expense of keeping the animal on milk all its life. If it ceased to have anything to ruminate, nature would certainly lose no time in relieving it of its useless workshop of rumination.
As it is right to give every one his due, I will mention that we owe our accurate knowledge of this simple and ingenious mechanism of rumination to the labors of Flourens, a scientific Frenchman, who is still alive, and who has made a great many interesting inquiries into the subject we are now considering, i. e., the life of animals. He is a very clever man into the bargain—so perfect a master of his own language, that the French Academy has felt itself justified in opening its doors to him—an unheard-of honor for a member of the Academy of Sciences. And yet, in spite of all this, I heartily congratulate you that the discovery of the paunch, the cap, the leaf, and the rennet-bag, was not delayed for his arrival. He is just the man who might have been tempted, in his capacity of profound scholar, to have hunted up for them in the Jardin des racines grecques [Footnote: Your brother can tell you about the Jardin des racines grecques. It is a charming little book, of which every generation of collegians has learnt, by heart, the commencement; but I have never known one, even among the most intrepid, who had ever been to the end of it.], four magnificent names, which would only have bewildered you.
Beyond the rennet-bag there is no change of conformation to note, except that the intestinal tube is naturally much longer than ours, on account of the difference of food: as a general rule, it is ten or twelve times the length of the body. The sheep, who is able to pick up a living in the poorest pastures, is indebted for this inestimable power, which makes him the special blessing of dry and barren countries, to a still further peculiarity of organization; with him the intestinal tube is twenty-eight times the length of the body.
We have seen among the Carnivora, whose jaws have so much work to do, that the condyles of the jawbone are sunk deeply into the fossa of the temporal bone. The ruminant, whose peaceful mouth is formed for contending only with grass, is organized quite differently.
Here the condyle is flattened, and the fossa of the temporal bone very shallow, presenting to the condyle an almost flat surface, so that the jawbone is enabled to revolve with ease for the better mastication of the pellets of grass. This conformation is also to be seen in the pachydermata who feed upon vegetables. In the horse, especially, whose food is almost the same as that of the ox, the articulation (as this joining of the condyle to the temporal bone is called) of the jaw, is also nearly identical; and it is the same with the teeth, with very trifling variations, those of all ruminants are constructed on the same plan as in the horse. The canines only require a separate notice.
But first I must tell you that, by some special privilege, the reason for which I do not undertake to explain, the order of ruminants is the only one containing animals with horns on their foreheads. Stags, goats, reindeer, chamois, gazelles, roebucks, oxen, buffaloes, all the beasts with horned foreheads, belong to the ruminants. Indeed, this fact would form a very convenient mark of distinction between them and other animals, were there not exceptions to it. Some ruminants have no horns; and then, as if in compensation for the deficiency, we find them provided with canines in the upper jaw, in addition to those below.
The ruminant which has the most beautiful canines is the musk-deer, a pretty little animal inhabiting the highlands of Central Asia, like the chamois of the Alps. But now that you know who he is, you will probably often be tempted to wish he had never existed; for it is from a small pouch below his belly that people obtain that odious musk of which Oriental beauties are so fond, and which even certain strong-nerved ladies of our own country are guilty of using in public, to the great detriment of general health. But enough of this; our business is with the canines of the musk-deer. They project with a descending curve from the upper jaw, and would give the animal the very false appearance of a small wild boar, but for the great delicacy of its legs, which are more slender than even those of our roebuck, to whom, with the exception of the horns, it bears a close resemblance, as its name implies.
After the musk-deer comes the large family of camels and llamas, which represent—the former in Asia and Africa, the latter in America—the irregular groups of ruminants which have canines instead of horns, and which seem to be placed as intermediates between true ruminants and the pachydermata. They form the connecting link between the horse and the ox, and men prefer employing them as beasts of burden to using them as butcher's meat; though one could eat them in their own country with less disgust than Europeans feel in making a meal of horseflesh; so that they might be a very acceptable resource in many cases. The real fact is, that ruminants with horns and without upper canines have more delicate flesh than the others, and seem more especially destined to be eaten. Yet if one had only to look at the stomach, which is, after all, the distinctive characteristic of the order, camels and llamas would stand in the first rank as ruminants. Besides the usual character of four stomachs, their paunch and honeycomb-bag are furnished with large cells which act as reservoirs, and fill with water whenever the animal has the chance of drinking freely, and from whence in time of drought he draws it up into his mouth and swallows it. This is what makes the camel so valuable to the wandering tribes in the great deserts of Africa and Asia. He is the only animal who can pass several days under the burning sun of Sahara without drinking—or rather without appearing to do so—for he carries his provision of water concealed from all eyes in the recesses of his body. I dare say you have often heard stories of Arabs dying of thirst who have opened the stomachs of their camels in search of a last draught of water. It must be a terrible thirst to drive a man to such an extremity; for, as you may imagine, one could not expect the water there to be either fresh or clear, to say nothing of the great risk there would generally be of finding the reservoir empty. Such an extreme is never resorted to till water has failed for a long time, and all the goatskin bottles have been emptied; and in such a ease it is but too likely that the camel has followed his master's example, and emptied his water-skins for his own use. But this is only half the internal fittings of the "ship of the desert," as the Arabs call him. In the desert it is often as difficult to find food as water; and nature has equally provided for this. The hump you see rising upon the camel's back in your picture-books is his safeguard against starvation. It is a huge mass of fat. I need say no more. You will remember Mr. Liebeg's pig, which lived 160 days upon its own bacon. Without going quite such lengths as that, the camel can keep up his fire for a long time upon the fuel which the blood obtains from this blessed hump. Since we are talking of this animal, and he takes a remarkable place in a history of nutrition, I ought to tell you that camels are classed into two families by their hump: there is the camel, properly so called, which has two humps, and the dromedary, which has but one. This latter did not require such a supply of provisions as the other, for he is very much swifter of foot, and consequently his journeys are more speedily performed.
I have nothing particular to say to you about the other ruminants, in the matter of their organs of nutrition; but I will not quit the subject without reminding you of one thing which concerns nutrition, not theirs, however, but ours. It was by the taming of the domestic ruminants—that unfailing dinner-material which now follows everywhere at the heels of his master—that human civilisation began. Before that event, man, driven to depend for his living upon the hazards of the chase, spent his whole time in seeking for food, and had none to spare for the pursuit of any other branch of industry.
Far as we may ascend in the history of ages we shall find shepherd races. Beyond them there is no history at all, nor could there be. The first leisure hours of man, and, consequently, his first efforts in art and literature, date from the period when the ruminant animals, those special fabricators of nutritive aliments, were gathered around mankind, and worked out their destiny under the shadow of his tent, by his direction, and for his benefit. But all this is so distant from us now, that it is scarcely worth the trouble of thinking about. The human race is somewhat like those old people who have lost all recollection of their childhood; and young people are not required to know what their elders have forgotten. It is well, however, that they should not be quite ignorant on the subject. When you hear that the Society for the Prevention of Cruelty to Animals has taken up the cause of some barbarously-used ox or sheep, do not turn it into ridicule. Those humble species have supported ours from the first; and you should recollect, now and then, that human society made its first step forward when it began to keep flocks and herds.
LETTER XXXIII.
MAMMALIA—continued.
We come now to animals less familiar to you, and none of which inhabit
Europe. We shall therefore pass more quickly over them.
ORDER 9. Marsupialia (pouched).
Marsupium is Latin for purse, pouch, or pocket. The marsupials are distinguished from other animals by a pouch which the mother has under her belly, and in which the little ones take refuge at the slightest alarm. You would be very much interested with their whole story; but it has nothing to do with our present subject, which we should soon lose sight of if we once began to wander away. This order, so easily distinguished otherwise by that singular pouch, unfortunately for us, offers nothing new for observation. It includes several species, differing entirely from one another on the subject of nutrition, and closely resembling some already described. Some are both carnivorous and insectivorous, and are therefore armed with powerful canines, and with molars like those of the hedgehog. Others are herbivorous, like hares, and have almost the jaws of a rodent. Among the former we have the opossum, celebrated by Florian in one of his prettiest fables. The opossum inhabits South America. Charming little marsupials are to be found in the Molucca Isles, whence come the nutmeg and the clove; these are very like our squirrels, and live as they do, in trees, hunting after fruit and insects. But the greatest number of marsupials belong to Australia, the real native land of the order. They form by far the larger portion of the mammalia with which that country is enriched; the most celebrated amongst them being the kangaroo; an animal which is now becoming common in European menageries, and which, excepting in the matter of its pouch, is nothing but a magnified rabbit, as tall as a man, and with a tail almost as long as itself. As a rabbit, you know what its eating apparatus must be; and some day, no doubt, the French Acclimatisation Society will enable us to judge of its flavor. It is a kind of meat very likely to be seen on our dinner-tables by-and-by; and, as you have plenty of time before you, probably you may eat of it before you die.
ORDER 10. Edentata (toothless).
These come more directly within our limits. They are classed according to their teeth; yet if their name were to be trusted, they ought to have no teeth at all. Whereas, alas! almost all of them have some, and I am heartily ashamed of their scientific designation; but how can we help it? The only really Edentata, i. e. toothless animals, amongst them are the ant-eaters, who, considering the nature of their food, are not much in want of teeth. They feed among the ant-hills, whence they get their name; and as they are a tolerable size (from two to three feet in length), it would really have been quite a hardship upon them to have been forced to crunch the ants one by one at every meal. To get on rapidly they catch them with their tongue; but what a tongue! Imagine a kind of long earthworm, lodged in a snout which is elongated like a bird's beak, and has a very small opening at the extremity. The ant eater inserts this long, string-like tongue into the crowded ranks of its victims, and, as its surface is glutinous, they stick to it by hundreds at a time, and are swallowed at one gulp without a chance of escape. This tongue, perfectly unique in its character, stretches out in its murderous exertions to nearly three times the length of the animal's long head. What a distance there seems between such a tongue as this and your own little doorkeeper! But no wonder: we have now reached the confines of the kingdom of Mammalia, and the face of nature is beginning to change.
The Armadillo, for instance, which comes next to the ant-eater, looks far more like the tortoise or lizard than its noble mammalian brethren. It is covered with scales; and, to look at it, you would say it was a reptile, in spite of its higher internal organization. As for teeth, it has certainly enough of them to give the lie to its name of edentata; but they are not very serviceable ones. They are called molars, however, because they are situated in that part of the mouth which is always assigned to molars; but they are miserable grindstones, very unlike any of which we have hitherto treated. They are all of them flattened cylinders, with no enamel bars to strengthen them; are small and poor, and are placed at rather wide intervals from one another. The poor armadillo munches with these, as best he can, slugs, tender roots, and other prey of the same sort, with which he is obliged to content himself, and which do not require very formidable tools.
The most questionable member of this class is the Unau, or Two-toed Sloth. It only wants incisors to be as toothless as ourselves! and the first time I saw it I took it for a little bear. It is true I was then younger than you are now; for the bear, who is one of our nearest neighbors, ought not to have been confounded with the unhappy being before us, one of the drudges of the animal creation; though M. de Blainville (who had not my excuse) proposed placing it still nearer to us, namely, amongst the Quadrumana. Observe that instead of hands it has at the end of its fore-limbs only two enormously curved claws, which have somewhat the appearance of a gigantic fork accidentally twisted. Accordingly its illustrious sponsor offered it to the world as an irregular quadrumane. I believe so, indeed! This quadrumane without hands—this edentate whose molars are preceded by magnificent canines—this enigma of nature, created for the confusion and despair of all classification—does, I must in all humility confess, completely upset the rule I laid down so stringently when speaking of the horse, as to the objects for which canine teeth were framed. The canine teeth of the sloth are more developed than its molars, and yet I cannot tell you what they are there for at all. It feeds upon the leaves of trees; and old travellers in South America, where it inhabits, have told us that, when it has once hoisted itself up a tree, it will strip it to its last leaf, and afterwards drop to the ground to avoid the trouble of crawling down. This was what first obtained for it the villanous name of sloth, a title which is certainly justified by its gait when on the ground; for it is so ill-made that it cannot stand upright on its legs, but moves clumsily forward by dragging itself on its elbows. It seems, however, that when once in a tree it is a different creature altogether, and can scramble lightly from branch to branch. Moreover, if its claws cannot reasonably be reckoned as hands, they are at all events excellent hooks; and when it is springing about thus in the forest, suspended to the branches by its long arms, one might be tempted, while watching it from below, to decide in favor of M. de Blainville's opinion. I saw it originally myself in a cage.
As to the sloth's relationship to the armadillo, this rests upon a detail which bears directly upon our subject. The molars in both animals are cylindrical and smooth, this is a trifle, but what would you have? The animal had to be classed somehow; since naturalists have not had the wit to make detached companies, as they do in regiments of soldiers. ORDER 11. Amphibia (two-lived).
We are going farther and farther away. Here are animals who are nearly half fishes (amphis, double, and bios,life). The Amphibia have two lives: one in the water, which is their true life, and where they are in their element; the other upon land, where they can only crawl; for their paws, which are but half developed, are destined to perform the office of fins, and the hinder ones are extended flatly behind them, and act like a fish's tail. They are divided into two families, the seal and the walrus. The first feed on fish, and have the same internal organization as the Carnivora, as well as the same dental conformation. Some species have even exactly thirty-two teeth, as we have. The jaw of the walrus is the least regular, and the incisors are generally wanting, especially in the full-grown animal; for it appears they lose them very young, as you lost your milk teeth, only, unluckily for the walrus, his never grow again. On the other hand, he has two canines in his upper jaw, which, next to the elephant's tusks, are the largest we have yet met with. They are sometimes as much as two feet long, and incline downwards with a curve, like the two bars of a pick-axe. They would play the walrus the same trick that the incisors of rodents are apt to do when they have not work enough to wear them down; that is, stop up the entrance of its mouth, were it not that the lower jaw is contracted in front, in order to fit into the space between the two canines, which thus form a sort of passage in which it manoeuvres freely. As you may suppose, the walrus cannot insert prey of any great size into this contracted passage; but that is no matter, as he lives partly on seaweeds, and partly—indeed principally—on shell-fish; his molars being specially adapted for breaking shells. They are short massive cylinders—the upper ones fitting into the lower as a pestle into a mortar.
After the walrus comes a strange animal which has been ranked among Cetaceans (we shall see why presently), but which it would be better not to separate from the Amphibians, since an Amphibian order has been made, for it crawls from time to time upon land: this is the Manatee, or Sea-cow. It comes still nearer a fish than the others. Its forelimbs are absolute fins, with mere vestiges of nails at their edges; it has no hind ones, and its body, which is quite cylindrical, ends in a fin tail in the shape of a shovel. The sea-cow feeds on plants and herbage, and lives at the mouths of great rivers, going up them occasionally to great distances, their banks serving it for pasture ground. In some respects it is half brother to the hippopotamus and the great grass eating Pachydermata, to whom it comes so near in internal organization, and above all in the structure of its molars, that M. de Blainville seriously proposed ranking it among the elephants, though as an irregular elephant, as you may suppose. But then Cuvier had even placed the seal among the Carnivora, by the side of the cat, whose whiskers it possessed, and of the dog, whom it resembled in the formation of its head. A naturalist's office is sometimes very perplexing, I assure you; and as we are touching on this subject, I cannot resist telling you that the sea-cow laid claim to, on so many sides, had by right a free admission to the celebrated order of Primates, although it looks exactly like a large barrel elongated at the two ends. It suckles its young at the breast like man and the monkey; and if Linnæus flinched from this rather too absurd parentage, old navigators were less scrupulous. Observing this creature in the distance, sporting on the waves, the upper part of its body quite out of the sea, the sailors, whose eye is not of the most refined, and who have no objections generally to the marvellous, imagined they saw a new species of human beings; and hence arose those stories of mermaids and sirens which have been told from the days of Homer downwards, and the traditions of which have not yet quite died out in seaport towns. To have been passed from man to the whale, touching the elephant on the road, is a long way to travel, especially when, after all, one is only a huge barrel of amphibious fat; and you may judge from this that it is not always an easy thing to classify animals.
ORDER 12. Cetacea (whale-kind).
Cetaceans are whales; and if I had been consulted on the matter, I should have joined this order and the last together, under whatever name was thought most appropriate. The passage from the seal to the whale through the walrus and the sea-cow is an easy and natural one, the two latter being obviously the connecting links; and in spite of certain diversities of food, they form in reality one family-party, as do the marsupials.
But it is too late in the day to talk of this, my dear child, and you and I cannot pretend to alter what is taught in the schools.
But you are astonished, are you not? to hear that the whale is not a fish: and no wonder. It is with it, however, as with the armadillo; it is a fish with a higher organisation inside. The interior of this enormous mass is a faithful reproduction, as a whole, of that of the shrew-mouse; and when we come to talk of fishes you will have some faint idea of the prodigious distance which this places between the whale and his countrymen of the ocean.
As far as we are concerned, the chief difference is in their way of breathing. The cetaceans breathe like ourselves, and are obliged to come to the surface of the water to take air; while fishes have a special apparatus, which I will explain to you presently, which enables them to breathe in the water. This is a disadvantage to the cetacean in his fish life; nevertheless, of all the mammals (as may easily be imagined) he is the one who can remain longest under the water. With us, for instance, the best divers one ever heard of, those who go to the bottom of the sea after the pearl-oyster, can scarcely stay below longer than two minutes; and even during that short time the veins of the head become so overcharged with the blood, which cannot return to the lungs owing to its forced inactivity, that when the diver comes back to the surface it is by no means unusual to see him streaming with blood from both nose and ears. The cetaceans remain under water for half an hour at a time without seeming to suffer in the least; and Breschet, a clever French naturalist, has given a very satisfactory explanation of this wonderful faculty. In dissecting a cetacean, he discovered all along the vertebral column an extensive network of large veins, which are not found in other mammals, and which seemed designed to serve as a refuge place for the blood during the time the animal remains submerged. According to him, this network would act as a reservoir, to which any overplus in the head or important organs would flow through vessels communicating therewith, and which might swell out as it pleased, without any risk to the inert bed of fat against which it lies. From thence the blood rushes to the lungs, as soon as the animal's return to the air enables them to play as usual. It must be admitted, at the same time, that all this involves the necessity of a much less active life than that of land mammals, that is to say, a consumption of oxygen much smaller in proportion than theirs; for were you to be furnished down your back with the finest network reservoir in the world for venous blood, it would still not enable you to remain half an hour without breathing.
There is nothing remarkable in the digestive apparatus of the cetaceans except about the mouth, which is, as you know, the essentially variable point among animals. To begin with, the cetacean tongue has the most original appearance possible. Indeed, it is not a tongue, but a large carpet, spread over the floor of the animal's mouth, and bears not the faintest trace of resemblance to that nimble delicate porter, who does you such good service. Imagine a thick soft lump absolutely crammed with fat, and completely immovable, because it is glued down along its whole length to the bottom of the mouth, and you will have a good idea of this strange tongue, which in the whale, the largest of the cetaceans, attains to the length of twenty-five feet and the width of twelve, and of itself alone furnishes the whale-fishers with from five to six tons of oil. This is a great deal farther from us than even the long string which serves as a tongue to the ant-eater; and you feel at once that we are getting among strangers.
With respect to teeth, I have now a melancholy piece of news to tell you. We have done with them; we have seen the last of incisors, canines, and molars, henceforth you will hear no more about those valuable instruments. The teeth of the cetaceans, with whom this painful falling-off begins, are no more teeth than his tongue is a tongue. They are like so many nails set in a row in the jaw, and can only be of use in retaining prey, not in grinding it; so that of the many processes your bit of bread has to go through before it becomes a part of yourself, there is one which is dispensed with here altogether, namely, mastication. Cetaceans swallow their food without chewing it.
Besides, they have not got a whole set even of these unmasticating teeth. Dolphins and porpoises, those faithful companions of the sailor, around whose vessel they come playing and tumbling in the seas of all countries, are the only ones who have them in both jaws. And these are the small fry of the order; they do not usually exceed six or ten feet in length.
The Cachalot, or Spermaceti Whale, an enormous cetacean, which rivals the true whale in size, and whose head alone forms nearly the half of its body, has teeth in the lower jaw only. This lower jaw, whose two sides are joined together for half their length (a new deviation, very unlike anything we have found before), is so little proportioned to the gigantic head which contains it, that it is almost lost to sight, and seems like a small plank slipped under a great square block.
Such as it is, however, it possesses many very respectable teeth, of which some weigh as much as two pounds; and with these the cachalot, whose ferocity is tremendous, tears in pieces everything that comes near it, sometimes even the boats of the fishermen who risk their lives in the dangerous pursuit of capturing them. By a singular arrangement, of which this is the only known instance, there is, opposite each of the cachalot's teeth, a corresponding cavity in the upper jaw, into which they fit closely, turning the monster's muzzle into the most formidable pair of pincers to be found in the animal kingdom. Another curiosity in the order is the tooth of the Narwhal, a modest cetacean, who is not much more than twenty feet long!
I speak of the tooth, because the creature has commonly but one; a cylindrical-pointed tooth, spirally furrowed, whose length varies from six to ten feet, and which comes straight out from the extreme front of the upper jaw, like a soldier's pike. There are two sockets at this extremity of the jaw, each furnished with a tooth-germ; but as a general rule the germ on the left side is the only one which develops, the other lying asleep in its socket, where it is choked up and never appears. Behind this long pike, which, like the tusk of the elephant, attracts to itself all the ivory in the body, lies a completely unfurnished mouth; so that the owner of this magnificent weapon, invaluable as a war-tool, but quite inapplicable to the purpose of supporting life, is obliged to feed on small fishes and mollusks. We have not yet spoken about these latter, but if you have ever seen slugs and snails you will know what a mollusk is.
The same wretched food falls to the lot of the whale also, that giant of the ocean, whose open mouth forms an aperture twenty feet in extent. Geoffroy St. Hilaire, in his indefatigable endeavors to trace out points of resemblance connecting together animals the most unlike in outward appearance, discovered, along the lower jaw of a young whale, certain traces of teeth, indicating a last effort on the part of nature to carry out her usual plan in furnishing the jaws of mammals; but, like the right-hand tooth of the narwhal, these vain attempts soon disappear, overgrown and lost in the tissue of the bone, so that the whale offers us a true type of an edentate, classable with the ant-eater, if one dared, and some people have dared, which by this time will not surprise you. A classifying professor is utterly merciless, whether he gets hold of the poor beasts by the mouth or by the paw: they may protest with all the rest of their body against the peg on which they are hung; so much the worse for them! If one were to listen to what they have all got to say, it would be impossible to classify even one.
To return to the whale. As a compensation for the teeth which she found herself unable to give him, nature has manufactured on the two sides of his upper jaw the most extraordinary apparatus without exception to be found in the mammal mouth. You know what is called the whalebone used in stay-making, &c. The name is quite correct; for those little flexible black strips, which support the figure so nicely, began life in wandering over the polar or Australasian seas, fastened to the palate of some monstrous whale.
On the two sides of the upper jaw the membrane which covers the palate sends out rows of broad, thin, horny plates, which are from eight to ten feet long (they have sometimes been seen twenty-five feet) in the centre of each side, but which decrease gradually towards the extremities. These are plates of whalebone (sometimes called whale's whiskers), and the industry of man has turned them to a thousand different uses; and you will open your eyes in astonishment when I tell you that 800 or 900 of them have been sometimes counted on each side of one mouth. Think of the number of stays that could be furnished from the whalebone plates of one whale! It is true, they were not exactly designed for this purpose originally. At the tips and on the edges of these plates, the elastic fibres of which they are composed unravel and peel off, and hang down from the lip like tufts of horsehair. The Arctic seas, which the whale inhabits, are, like other seas, full of innumerable troops of various little sea-animals, and it is these which are destined to the honor of nourishing this gigantic mass of flesh. When the colossus wishes to take a meal, he stretches his mouth to its utmost width, and the salt water rushing in as into a gulf, carries with it the imprudent little fry, who disappear then and there for ever, being retained by the fringe-like sieve of the whalebone. But as, in this way of eating, the stomach of the whale, however large, would be terribly overgorged with water, he is furnished with another apparatus for preventing the inconvenience. All the superfluous water is rejected by the pharynx, and springs up in spouts of fifteen or twenty feet high, through the nostrils, i.e. the nasal openings, sometimes called "vents," sometimes "blow-holes," which are pierced exactly at the top of the head. This is a peculiarity common to all cetaceans, who have thence received the name of "blowers," alluding to the powerful blast which is necessary to send those majestic columns of water into the air; but it takes a much milder form with the lesser cetaceans, such as dolphins and porpoises. There is but a slight jet with them: the water escapes comparatively quite quietly from the nostril-vents, trickling away down the animal's sides.
I hope you consider that I have told you something new this time, my dear child, and that our machine is beginning to change its appearance very materially. I told you before that we had reached the outskirts of the mammal kingdom. When we got to the armadillo we were within a stone's throw of the reptiles, and here, one step more would take us to the fishes. But we must first consider the birds, who are a very superior set of animals to either of the latter; and we have accordingly an order of mammals (Monotremes) which, as you will now find, opens the road on that side also.
There are but two sorts, and both of them are natives of Australia, which is, as you may have heard, the land of the wonderful in natural history, and their existence was unknown to the learned men of Europe till within the last sixty years. The most extraordinary of the two is the Ornithorhynchus, or, to translate the hard Greek word into English, the Duck-bill. Its mouth is a true duck's bill, a downright horny beak, and its short paws sprawling sideways with a membrane joining the toes together below, and coming a good deal beyond them in front, seem intermediate between the flippers of the seal and the webbed feet of a water-bird. The first naturalist who had anything to do with the ornithorhynchus, Blumenbach the German, who gave it its pretty name, did not think it was able to suckle its young, so much did it differ from mammals in some respects, though looking so like them on the whole. And presently a report arose in the learned world that the new animal which had been classed at all risks among mammals (it having the close fur and almost the body of the otter), a report arose, I say, that this ornithorhynchus of Blumenbach laid eggs like a real duck. The uproar in the Academies was tremendous. As early as 1829, indeed, a learned Englishman, Sir Everard Home had sent over to France an authenticated drawing, as he said, of an ornithorhynchian egg, to the delight of the hunters after analogies among animal races; while Cuvier looked sadly askance at the intruder, whose arrival threw his animal outlines into confusion, there being no place in them for such a beast. Happily for the poor animal, he has ended by almost settling the matter for himself. The ornithorhynchian egg has never turned up. But in the animal's nest have been found baby ornithorhynchuses, newly born, under two inches long (the full-grown animal being more than a foot and a half), and not a trace of eggshells near. Further investigations showed that the mother ornithorhynchus nursed her young with milk, for curdled milk was found in their stomachs; so the Australian phenomenon has been restored triumphantly to the Mammalian order, whence Geoffroy St. Hilaire had excluded both it and its companion, the echidna, a sort of hedgehog, provided like the ornithorhynchus with a bird-like bill, only more of the canary-bird sort; and like it, also, approximating to the bird tribe by other details which do not belong to our subject. And so the matter stands at present; and all we venture to say is that classification had a very lucky escape.
And now, my dear child, that I have made you acquainted in detail with your nearest neighbors, the last of whom, nevertheless, are strangely unlike you outside, however they may resemble you within, I shall take the liberty of going more quickly over the ground, and shall point out in the mass only the more important changes which lead from one class of animals to another. I should be found fault with if I tried to make you too learned, and you yourself might be tempted to tell me, to my sorrow, that you had heard about enough.
LETTER XXXIV.
AVES. (Birds.)
Tell me, my dear child, when you have seen birds taking their flight into the air, and going boldly to their object, without a thought of all the barriers, ditches, rivers, and mountains, which hinder man at every step in his travels, did it never strike you to wish for their wings, and imagine how you would fly off if you had them? If you ever dreamt this dream, do not apologise for it; it is one as old as the world. 'Oh that I had wings like a dove!' cried the Prophet, nearly 3,000 years ago; and the dialogue of the swallow and the prisoner, so often sung by poets, has been repeated in prose behind all the prison-bars on the globe since prisons were first invented.
Now you will not think it kind on my part, but I must undeceive you about this fancy, as you will be undeceived some day about many others. The wings of a dove or swallow would be of no use to you if you had them, any more than the formidable swords of the middle ages would be to our modern gentlemen, were any one to put such into their hands. We are not adapted for them, nor they for us.
You saw, some time ago, what an amount of muscular exertion was required for running—what a violent flow of blood, what hurried play of the lungs. Now in flying it is still worse; for the earth, at any rate, holds us up quite naturally, whereas the air will not hold up the bird unless it is beaten vigorously and unremittingly by an untiring wing. If we men, constructed as we are, had to do such work, we should be out of breath at once; the heart would cry out immediately for quarter, and the diaphragm turn red with anger. And only just imagine in what a critical position a poor wretch launched into the air on the wings of a swallow would find himself when, at the end of five minutes, his servants should refuse point-blank to go on working at a height of 500 feet above the ground!
But a bird has not these internal rebellions to fear. In the first place, it has no diaphragm; so here is another friend to whom we must say good-bye. We shall not meet with him again anywhere. The journey we are taking together, my dear, is somewhat like the journey of life. One sets off, surrounded by friends and acquaintances, but whoever travels on to the end is apt to find himself alone at last; this is what is happening to the digestive tube, which we shall see losing all its accessories, one by one, as we gradually advance in our study. Even now here is one essential fundamental difference in the internal machinery. The body has only one compartment instead of two; and the lungs, masters of the whole space, extend freely to its utmost depths. When a fowl is cut up at table, look along the body, and you will find lodged in the cavity of the ribs, a long, blackish, and spongy mass: this is the lungs. There is not, therefore, the same danger of a bird's getting out of breath as with us; that delicate board which is found in our bellows is wanting in his. His is set in action solely by the to-and-fro movement of the ribs, which is produced by muscular exertions, which are greatly increased during the action of the wings. From which it follows, that the rapidity of flight itself regulates the arrival of air, and consequently the expenditure of strength, or, if you like better, the activity of the fire, since the energy of the muscles depends, as we have seen, upon the quantity of oxygen that feeds the internal stove.
This is not all. These elongated lungs are still not sufficient to furnish the blood with all the oxygen demanded by this excessive labor of flight. They are pierced with holes, through which issue pipes which carry the air all over the body. You know what is said of spendthrifts?-that they burn the candle at both ends. It is so with the blood of birds. That fillip which in our case it receives in the lungs, and which sends it back full of vigor into the arteries, is repeated in the bird at the other end of the arteries as well. The capillaries, those delicate vessels at the end of the arteries, plunge from all sides into little reservoirs of air-lungs, therefore-where the blood renews its provision of oxygen, and relights its half-extinguished fire, so that it sends the combustion afresh into the muscles on its return back to the heart, and sets them going a second time.
The natural consequence of this prodigality of combustion is, that there must be, in proportion, much more oxygen in birds than in us; and that of all animals a bird is the one most quickly poisoned by his own carbonic acid when the air is not renewed around him. Therefore, let me beg you never to think of putting a poor little bird under a wine-glass, as a child of my acquaintance once did, that she might examine her little friend more closely. In the twinkling of an eye he would consume all the oxygen inside his prison, and you would soon see him fall upon his side and die.
On the other hand, the temperature of these flying machines, which consume so much oxygen, is very much higher than ours. It rises to 41°, 42° (centigrade), and sometimes to 44°, 7° higher than with us. If ever you have taken hold of a little bird, you will have remarked how warm it makes your hand: this is quite natural, since there is always a double fire going on within him, to meet the extraordinary expenditure of strength that is required of him whenever he takes wing. Besides, do but look at the poor little creature when you have imprisoned it in a cage! How it goes up! How it comes down! How it hops from one perch to another, with a quick sudden movement, like that of a spring when it unbends. There is no apparent cause for this state of continual agitation; and yet there is a cause, and only too serious a one. Its fire is not slackened because you have put it into a cage, and its muscles, lashed furiously on by the double-oxygenized blood, drive it hap-hazard into a thousand movements, in which it expends, as best it can, a superabundance of power, which no longer finds natural employment. Little children, who are the real singing-birds of our homes, and whose blood also drives much more energetically along than ours—little children I say—often fare no better than caged birds in those larger cages we call schools; and schoolmasters and governesses would scold rather less if they thought rather more about this. It is right, I do not deny it, that the rebellious young rogues should be taught in good time not to abandon themselves, like wild birds, to the mere animal impulses of the blood: but, in dealing with them, one must also make allowances, as they say, for the fire within, and know how to open the cage now and then. It is not for you, however, that I say this, young lady: you are no longer a little child; but it may happen that you may have some to take care of some day. Believe me, then, you must not expect too much wisdom from them, and you must allow them to change their perch every now and then. It is a law of our Almighty Father that little children, and little birds, should not stay too long in one place.
The mechanism of the circulation is here the same as with us, and does not offer any important peculiarity. Only the left ventricle of the heart has walls of extreme thickness, which enable it to launch the blood into the members with greater vigor and rapidity; and the blood itself, although it is composed of precisely the same materials as that of the mammals, differs from it nevertheless as regards the globules. In the first place, they are more numerous; secondly, they are larger; and finally, instead of being round like a plate, they are drawn out ovally, and are almost shaped like those long dishes on which fish is usually served. I shall not attempt to give you the reason of their size and form. This is hidden from us in the same mystery which envelopes all the microscopic population of the blood; but is it not a curious thing, this strange persistency of form in the globules ofall animals of one class? In all birds they are oval; in all mammals they are round. In all? Nay, I am wrong. As if the better to hide from us the key to this riddle, nature has amused herself by making an exception. Camels and llamas, I forgot to tell you, have also globules in the form of long dishes, like the hen and the chaffinch. Find out why, if you can. As to the reason of the number, it is a very simple one. Since the energy of the blood resides in the globules, it follows that the most energetic blood will contain the largest amount of globules. Looking at you, for instance, little monkey, running and jumping about the garden, I would lay a wager, without counting first, that there are, in one drop of your blood, some millions more globules than in one of mine.
Let us now go on to the digestion, with which, properly, we ought to have begun; but I preferred pointing out to you, first, the particular character which is the chief mark of distinction in the organization of the bird.
'When hens grow teeth,' says a shrewd proverb, meaning of course, never. Birds have no teeth, and in this respect there is no variety among them. All, from the first to the last, have uniformly the same tool to eat with—the bill, that is—which is, in all cases, composed of the same elements, two jawbones elongated to a point, and clothed in a horny armour, which makes their edges sharp and cutting. At the same time were we to review the birds in detail, as we have done the mammals, you would see that there are almost more modifications to be observed in this one single instrument than in our thirty-two teeth. All birds have a beak, but each has his own, organized expressly with reference to the kind of food needed by its owner. The eagle's beak, which mangles living prey, is pointed, bent, and hard as steel; the bill of the duck, which laps up water from ponds and puddles, in order to get worms and half-decomposed refuse out of it, is soft, and flattened like a shovel. The woodpecker's, which has to pierce the trunks of trees, is like a pickaxe; that of the humming-bird, which has to suck up the juice of flowers from the bottom of their corollas, is slender as a needle. The swallow feeds on flies, which it snaps up on the wing, and has a soft bill, which opens like a little oven. The stork picks up reptiles in the mud of the marshes; its beak is straight-pointed, cutting as a knife, and resembles a long pair of pincers. The sparrow feeds especially on hard grains, difficult to break; accordingly its beak is stumpy, short, and thick, and is arched on the upper side for still further solidity. But I should never end if I began to enumerate all the thousand varieties in the bills of birds. Each variety, too, corresponds with some peculiar sort of life, and consequently with a general conformation (easily ascertained) of the animal in which it appears. Give a naturalist the bill of a bird—only its bill remember—and he will tell you half its history without fear of being mistaken.
On the other hand, we must not deceive ourselves as to the real value of this complaisant bill. Let it transform itself as it pleases into all manner of forms for the better fulfilment of its task, it makes, at the best, but a very poor instrument for mastication; nay, to say the truth, it breaks, cuts, and tears, but it never masticates at all. Thus the bird's mouthful is far from undergoing as perfect a preparation as ours does. It is no sooner taken in than it is swallowed, and the salivary glands, which are still to be found under the tongue, seem only to be there as a matter of form; what little saliva they produce is thick and sticky, and has none of the qualities necessary for making that liquid paste which our tongue sweeps up from every corner of the mouth. Besides, it must be owned that a bird's tongue would be a very awkward implement in such a task. Open a hen's bill and you will see therein a very inferior sort of porter. It is merely a dry hard lance, as it were, armed with prickles at the point, as ill-qualified for tasting as for sweeping. So the hen does not waste her time in finding out the flavor of what is thrown to her. She picks up and swallows over and over again, without appearing to experience any other pleasure than that of satisfying her appetite. Birds of prey, it is true, have rather more convenient tongues, capable, moreover, of tasting up to a certain point; and the parrot, who is a complete epicure, and chews his food philosophically, has a charming-little black one, thick, fleshy, and susceptible—a true porter, in fact-who enables Polly thoroughly to enjoy her breakfast. But certain birds who live on insects surpass even the hen in the dryness and hardness of their tongues. That of the woodpecker, especially, is a model of the kind, and deserves a few words more than the others. Picture to yourselves a long pin, terminated by an iron point with barbs like those of fish-hooks. An ingenious mechanism enables the bird to dart it out with the rapidity of lightning, far beyond his bill, upon the insects to which he gives chase. The point pierces them, and the hooks retain them, without any need of assistance from the bill. I have just told you that this bill pierces the bark of trees; but it only plays the part of gamekeepers on grand sporting occasions, who beat the bushes to make the game rise. The woodpecker's bill routs up the insects by destroying their shelter; but the real sportsman is the tongue. Good-bye to any notion of a cosy little chat in such a porter's lodge as that! What could a harpoon have to say for itself?
Do not, however, let this miserable entrance-hall alarm you, at the same time, for the fate of the mouthful thus presented half-dressed to the sophagus. You will find it only so much the better treated within. In the first place, the sophagus, when half-way down to the stomach, swells out suddenly and forms a pocket, which is generally particularly well developed in birds who feed on grain; this is called the crop in English, in French jabot; whence comes the application of that word to those full shirt-frills which have sometimes been the fashion. It is the pigeon's crop that gives him the rounded chest over which he bridles so prettily. The crop is a receptacle where the food makes a halt: it is something between the pouch of the monkey and the paunch of the ox; a preparatory stomach, which does not, it is true, send back the grain to the bill, for the bill could do it no good, but in which that grain lies until there is room for it further on.
Prom thence it resumes its journey; but, before reaching the true stomach, it passes through a second enlargement of the oesophagus, whose walls are pitted with numberless little cavities, from which pour over it the juices destined to supply the place of the saliva that was wanting above.
It reaches its destination at last, but still hard, and generally whole. No matter, however. The stomach which receives it, and which is called the gizzard, is quite a different sort of thing from a useless membrane, thin and delicate like ours. It is a thick muscle of enormous power, lined inside with a kind of horny skin, so tough that nothing can break through it. You may form some idea of the prodigious strength of this organ, when I tell you that turkey-fowls have been made to swallow hollow balls of glass, so thick as not to break when dropped to the ground, and that at the end of a few days they have been found reduced almost to powder in the uninjured stomach. No fear of indigestion with such an apparatus as that. Though the grain may not have been masticated in the bill, what does it signify? There is a power here, as you see, quite equal to carrying the whole work through. Thanks, indeed, to the invaluable horn which lines it, fowls which have no teeth of their own can safely present themselves with as many and as hard ones as they please. They swallow small pebbles, which rub against the grain, during the contractions of the gizzard, and act just as effectually as if they were fixed in the jawbone. Well, this terrible gizzard performs its crushing work with such energy, that not only the grain but the pebbles themselves are ground down there, and end by being pounded into fine sand. When you rear fowls, do not forget, if you keep them shut up, to put within their reach a store of small pebbles, so that they may have teeth to run to in time of need.
You remember the pylorus—the porter down below, who keeps the door of egress from our stomach? He is as badly provided for here as his fellow-workmen up above; worse in fact. It is a gaping hole, and we cannot expect a very strict supervision from it. Birds who feed on fruits profit by this fact to carry vegetables from one country to another. With such an easy opening, seeds have a good many chances of passing from the stomach unaltered; and then they drop from the clouds, as is supposed, hap-hazard, and germinate afterwards, when circumstances prove favorable, to grow up before the astonished eyes of the natives into plants of which they have never even heard. The French Acclimatization Society, which I spoke of lately, and which, though so modern, has correspondents all over the globe, is at this moment laboring to effect an exchange between all countries of the natural productions of their soil. But here you see that nature had thought of this before, and established her acclimatization society long ago.
To complete the internal work of digestion, so feebly begun in the bill, an extremely large liver pours torrents of bile into the duodenum, and the manufacture of chyle proceeds with that wild rapidity which characterizes all the living actions of birds. But speaking of this liver, I think I ought to give you an account of a celebrated dish, considered a great dainty by epicures, called pâtés de foies gras—fat liver patties, to translate it into its meaning. Very likely you will not care to eat them after hearing my story; but that will be no great loss to you, for it is a very indigestible sort of food, and not at all good for children.
You remember my telling you about Englishmen going to India and coming back with a liver-complaint, from having eaten and drunk more than the climate allowed? By an imitation of this process, human ingenuity—occasionally so cruel—has created the pâtés de foies gras, the glory of Strasburg. I have been in the country, and can tell you how it is managed. They shut a goose up in a square box, where there is just room for his body. They open his bill at feeding-time, and cram down with the finger as much food as can be got in. This is throttling rather than feeding it. The poor beast, who can use no resistance, since it cannot move, and who is kept in the dark to prevent excitement; the poor beast is quite unable to burn all the mass of combustibles with which the blood soon finds itself loaded. This carries them to the liver to be turned into bile; but the liver is not equal to the work, becomes loaded in its turn by unemployed materials, and grows and grows, till at last, having filled up all the space around it, it stops the play of the heart and lungs. When the animal is nearly suffocated they kill it; and this is how we come to have pâtés de foies gras to eat! If they give us a fit of indigestion afterwards, it is a vengeance we richly deserve. At Toulouse, where the same trade is carried on on a large scale, they used formerly to go even beyond this. They fastened the goose by the feet before the fire-place, after having put out its eyes. The imitation of the Englishman's proceeding was still more perfect here, for the fire acted the part of the Indian sun to perfection. I do not know that part of the country well enough to tell you whether they have quite given up this piece of wicked ingenuity; all I can say is, I devoutly hope so.
The intestine of birds is much shorter than that of mammals. Here everything is done at full gallop, and the chyle has not to go far before it is absorbed. I have before me a book, in which I am told that the wagtails eaten in France can be fattened in twenty-four hours, if you only know how to set about it, and these birds are not rare; they belong to the same family as the red-breasts, the tomtits, and the nightingale. Thrushes and wheatears (ortolans) require, for the same purpose, four or five days in the same country, left to themselves to roam about, when the vine keeps open table for them.
This incredible quickness, not only in digesting, but, what is much more, in transforming food into fresh living material (assimilating it, as it is called), has often a fatal result for the bird. He is prohibited from fasting; his life is a fire of straw, which must be replenished unceasingly, or it will die out in the twinkling of an eye. Our own little birds—children—eat oftener than grown-up people, and if by any accident they are kept waiting awhile, they soon cry out with hunger. You know this, do you not? Well, then, if any one should give you a bird to keep in a cage, remember that you have undertaken a great responsibility, and that it will not do to be careless with him. To neglect feeding him for one day is to run the risk of finding him starved to death next morning. With this warning, I will conclude my chapter on birds. I hope I have not spoken in vain in behalf of those poor little captive songsters, whose fragile lives are at the mercy of their young masters and mistresses.