XXIX.--CLASSIFICATION OF ANIMALS XXX.--MAMMALIA (_Mammals_) XXXI.--MAMMALIA. (_Mammals_)--_continued_ XXXII.--MAMMALIA--_continued_ XXXIII.--MAMMALIA--_continued_ XXXIV.--AVES. (_Birds_) XXXV.--REPTILIA. (_Reptiles_) XXXVI.--PISCES. (_Fishes_) XXXVII.--INSECTA. (_Insects_) XXXVIII.--CRUSTACEA--MOLLUSKA. (_Crustaceans and Mollusks_) XXXIX.--VERMES--ZOOPHYTA. (_Worms and Zoophytes_) XL.--THE NOURISHMENT OF PLANTS CONCLUSION

I. INTRODUCTION.

I am going to tell you, my dear child, something of the life and nature of men and animals, believing the information may be of use to you in after-life, besides being an amusement to you now.

Of course, I shall have to explain to you a great many particulars which are generally considered very difficult to understand, and which are not always taught even to grown-up people. But if we work together, and between us succeed in getting them clearly into your head, it will be a great triumph to me, and you will find out that the science of learned men is more entertaining for little girls, as well as more comprehensible, than it is sometimes supposed to be. Moreover, you will be in advance of your years, as it were, and one day may be astonished to find that you had mastered in childhood, almost as a mere amusement, some of the first principles of anatomy, chemistry, and several other of the physical sciences, as well as having attained to some knowledge of natural history generally.

I begin at once, then, with the _History of a Mouthful of Bread_, although I am aware you may be tempted to exclaim, that if I am going to talk only about that, I may save myself the trouble. You know all about it, you say, as well as I do, and need not surely be told how to chew a bit of bread-and-butter! Well, but you must let me begin at the very beginning with you, and you have no notion what an incredible number of facts will be found to be connected with this chewing of a piece of bread. A big book might be written about them, were all the details to be entered into.

First and foremost--Have you ever asked yourself _why_ people eat?

You laugh at such a ridiculous question.

"Why do people eat? Why, because there are bonbons, and cakes, and gingerbread, and sweetmeats, and fruit, and all manner of things good to eat." Very well, that is a very good reason, no doubt, and you may think that no other is wanted. If there were nothing but soup in the world, indeed, the case would be different. There might be some excuse then for making the inquiry.

Now, then, let us suppose for once that there _is_ nothing in the world to eat but soup; and it is true that there are plenty of poor little children for whom there is nothing else, but who go on eating nevertheless, and with a very good appetite, too, I assure you, as their parents know but too well very often. Why do people eat, then, even when they have nothing to eat but soup? This is what I am going to tell you, if you do not already know.

The other day, when your mamma said that your frock "had grown" too short, and that you could not go out visiting till we had given you another with longer sleeves and waist, what was the real cause of this necessity?

What a droll question, you say, and you answer--"Because I had grown, of course."