It is as plain as anything can be that the animals share our emotional nature in vastly greater measure than they do our intellectual or our moral nature; and because they do this, because they show fear, love, joy, anger, sympathy, jealousy, because they suffer and are glad, because they form friendships and local attachments and have the home and paternal instincts, in short, because their lives run parallel to our own in so many particulars, we come, if we are not careful, to ascribe to them the whole human psychology. But it is equally plain that of what we mean by mind, intellect, they show only a trace now and then. They do not accumulate a store of knowledge any more than they do a store of riches. A store of knowledge is impossible without language. Man began to emerge from the lower orders when he invented a language of some sort. As the language of animals is little more than various cries expressive of pleasure or pain, or fear or suspicion, they do not think in any proper sense, because they have no terms in which to think--no language. I shall have more to say upon this point in another chapter. One trait they do show which is the first step toward knowledge--curiosity. Nearly all the animals show at times varying degrees of curiosity, but here again an instinctive feeling of possible danger probably lies back of it. They even seem to show at times a kind of altruistic feeling. A correspondent writes me that she possessed a canary which lived to so great an age that it finally became so feeble it could not crack the seeds she gave it, when the other birds, its own progeny, it is true, fed it; and Darwin cites cases of blind birds, in a state of nature, being fed by their fellows. Probably it would be hasty to conclude that such acts show anything more than instinct. I should be slow to ascribe to the animals any notion of the uses of punishment as we practice it, though the cat will box her kittens when they play too long with her tail, and the mother hen will separate her chickens when they get into a fight, and sometimes peck one or both of them on the head, as much as to say, "There, don't you do that again." The rooster will in the same way separate two hens when they are fighting. On the surface this seems like a very human act, but can we say that it is punishment or discipline in the human sense, as having for its aim a betterment of the manners of the kittens or of the chickens? The cat aims to get rid of an annoyance, and the rooster and the mother hen interfere to prevent an injury to members of their family; they exhibit the paternal and maternal instinct of protection. More than that would imply ethical considerations, of which the lower animals are not capable. The act of the baboon, mentioned by Darwin, I believe, that examined the paws of the cat that had scratched it, and then deliberately bit off the nails, belongs to a different and to a higher order of conduct.