ANIMAL LIFE AND INTELLIGENCE. CHAPTER I. THE NATURE OF ANIMAL LIFE. I once asked a class of school-boys to write down for me in a few words what they considered the chief characteristics of animals. Here are some of the answers-- 1. Animals move about, eat, and grow. 2. Animals eat, grow, breathe, feel (at least, most of them do), and sleep. 3. Take a cat, for example. It begins as a kitten; it eats, drinks, plays about, and grows up into a cat, which does much the same, only it is more lazy, and stops growing. At last it grows old and dies. But it may have kittens first. 4. An animal has a head and tail, four legs, and a body. It is a living creature, and not a vegetable. 5. Animals are living creatures, made of flesh and blood. Combining these statements, we have the following characteristics of animals:-- 1. Each has a proper and definite form, at present described as "a head and tail, four legs, and a body." 2. They breathe. 3. They eat and drink. 4. They grow. 5. They also "grow up." The kitten grows up into a cat, which is somewhat different from the kitten. 6. They move about and sleep. 7. They feel--"at least some of them do." 8. They are made of "flesh and blood." 9. They grow old and die. 10. They reproduce their kind. The cat may have kittens. 11. They are living organisms, but "not vegetables." Now, let us look carefully at these characteristics, all of which were contained in the five answers, and were probably familiar in some such form as this to all the boys, and see if we cannot make them more general and more accurate. 1. _An animal has a definite form._ My school-boy friend described it as a head and tail, four legs, and a body. But it is clear that this description applies only to a very limited number of animals. It will not apply to the butterfly, with its great wings and six legs; nor to the lobster, with its eight legs and large pincer-claws; to the limbless snake and worm, the finned fish, the thousand-legs, the oyster or the snail, the star-fish or the sea-anemone. The animals to which my young friend's description applies form, indeed, but a numerically insignificant proportion of the multitudes which throng the waters and the air, and not by any means a large proportion of those that walk upon the surface of the earth. The description applies only to the backboned vertebrates, and not to nearly all of them.