There are a terrible number of animals, as you know; and if we wish to study them to any real purpose, we must begin by introducing some sort of order into the innumerable crowds which throng, pell-mell, around us for observation. We should otherwise never know where to begin, or when we had come to an end.
There are many ways of setting a crowd in order, but they all go upon the same plan. The individuals composing the crowd are parcelled off into companies, each company having a distinguishing mark peculiar to those who compose it. Thus the first division is into a few large companies, which are afterwards subdivided into smaller ones, and those into others still less, until the divisions have gone far enough. And this is what is called a classification.
Let us imagine, as an example, a large crowd in a public garden; I will soon classify it for you. I shall put the men on one side and the women on the other. Then—to begin with the women—I shall subdivide them into married and single. Then among married women I shall make a company of mammas, and another of those who have no children. Among the unmarried I shall have a group of those who have never been married—girls, that is—and another of widows—those who were once married, but are so no longer. Then, following the girls, I shall separate them into tall and short. And among the short ones I shall divide the brunettes from the blondes, and so I shall get at last to a little blonde girl, whose classification (were she a soldier) in military rank would be as follows:—squadron of blondes; company of shorts; battalion of girls; regiment of unmarried women; division of women. The division of men could be carried out in the same manner; and thus we should classify our mob into complete military order. This is easy enough, however; but the classifying of animals is a very different affair, and I will tell you why. We ourselves require a classification to study them by, though none was needed for their creation. The Almighty has formed them all on one uniform plan, around which He has, if I may so express it, lavished an infinity of modifications separating species from species, yet without placing between the different species those fixed barriers which we should require now to enable us to classify them strictly. You who are learning the pianoforte have perhaps been told the meaning of a theme of music—the first idea of the composer who follows it throughout the piece from one end to the other, embroidering on it, as on a bit of canvas, a thousand variations melting one into another. Such is pretty nearly, if we may venture the comparison, the way in which we can picture to ourselves the Almighty moving through the work of animal creation. Step in afterwards and divide away into regiments and battalions, if you please. Nature permits it, but she will never, to accommodate your classifications, separate what in her is really united.
There is still a way, however, and that is to do as I did just now in the case of the crowd. To take, viz., only one character (as we call a distinguishing mark in natural history), and to throw together all the individuals which possess it, the blondes, the shorts, the girls, &c. In this way it may soon be done; but what is the result? You are in one class, your eldest sister is in another, your mamma in a third, and your brother in a different division altogether, a long way from you all. Such a classification is called artificial, and you can see at once that it is worthless.
The most natural plan is to put together those that are of the same family; and the classifications made on this principle are called natural classifications.
It is a classification of this sort which has been adopted for the animal kingdom. People have taken all the animals which possess in common not one character only, but a collection of characters of the most important kind, dominant characters, as they are called; and of these animals they have formed, to begin with, large primary groups; subdividing these afterwards according to the secondary differences, which distinguish different species in the same group from each other.
In this manner all the different sorts of animals are included in different systematic divisions of one vast whole, through which it is easy to find one's way, because there is a beginning and an end; and in which animals of the same family are always grouped side by side. Were I to mention all the divisions of this immense classification at once, you would find the account a little long, and not very amusing. We will go through them by degrees therefore, and, to simplify matters, will, throughout the whole, only consider those particular characters which are connected with our special study, the nourishment of life, that is to say: so that you will always find yourself on well-known ground.
I must tell you once for all, however, that it is with this as it is with grammar. Here and there are—and it cannot be avoided—certain exceptional cases which keep protesting timidly against the arbitrariness of rules; but no matter; we must be contented with what we can get, and be grateful into the bargain to those who have given us this skillful classification, at once so ingenious and useful, in spite of its inevitable imperfections. What is impossible is expected of nobody. You could not understand, even if I wished to explain it to you, the amount of science, labor and genius requisite for making out that long list, which, tiresome as it may seem to children, is absolutely beautiful in the eyes of learned men; too beautiful, perhaps, and I will tell you why when we have finished. Meantime, as the best reward we can give to those who have done us some great service is to teach their names to children, I will tell you, before bidding you good-bye, to whom we owe this classification, the details of which I do not enter upon to-day.
In the first place, we owe the method employed in its establishment, the method of natural classification, i.e., to a learned man of the last century—a learned Frenchman, Bernard de Jussieu—who tried it upon plants; another large flock by no means very easy to put in order, as you may convince yourself any day by studying botany. The man who applied this system to animals was also a learned Frenchman, the clearness of the French mind adapting them peculiarly for that sort of work. And he, too, is one of the glories of that nation. His labors and discoveries gave a perfectly new impulse to the study of nature. It was George Cuvier, whose statue you may see at Montbéliard, if you should ever go there. Not that Cuvier carried through this gigantic work alone, though the credit of it is justly his due, he having directed and inspired it. He was assisted by many. But among his assistants there was one, Laurillard, the most modest, yet the most active of all, whose name I will mention also, because, like the others, more or less celebrated, he has never had his reward. [Footnote: In the earlier editions of this work, there was, in this place, a severe reproach upon Cuvier for not having given proper credit to Laurillard. This reproach I have since learned was unjust. M. Valenciennes himself, one of the most illustrious of the collaborators of the great Cuvier, has written me a letter in which he defends the reputation of his friend with a warm indignation which does honor to both of them; and cites passages in which Cuvier has spoken of Laurillard, and among others, in the third volume of the Ossements Fossiles, p. 32, ed. of 1822.]
It only remains for me, therefore, to let the lash, which I was laying upon the shoulders of another, fall now upon my own, and to deplore the too great facility with which I had credited, without sufficient proofs, an assertion which I had otherwise good reason to believe to be exact—coming to me, as it did, from Montbéliard himself, on the testimony, it is said, of the family of Laurillard. From this avowal, a little painful, I confess, my young readers may learn the inconvenience of rashly condemning others! As I said in the concluding passage, which truth, only too late, now compels me to suppress—"The truth is sure to come out at last."