The practice of the dog of turning round two or three times before lying down is in response to an instinct which was no doubt beneficial to it in its wild life, when it was wont to make its bed in the grasses, but which is now a pure waste of time. Darwin records it as a fact, that he has himself seen a simple-minded dog turn round twenty times before lying down. The sheep-killing mania, which sometimes comes over dogs when three or four of them get together and become actuated by the ‘mob’ spirit, is a vestige of the old instinct of the carnivore which centuries of domestication have not yet quite erased. Goodness, if too prolonged, becomes irksome to dogs for the same reason that it does to men. Dogs have come from savages just as men have, and, while the civilised nature of the dog is more constitutional than that of civilised man, the old deposed instincts mount to the throne once in awhile, and the faithful collie is for the time being a wolf again. The instinct of domestic sheep to imitate their leader in leaping over obstacles is another probable survival of wild life. If a bar or other obstacle be placed where the leader of a flock of sheep is compelled to leap over it, and the obstacle is then removed, the entire band of followers will leap at the same place regardless of the fact that the obstruction is no longer there. No other animals do this. The instinct is probably a survival of wild life, when these animals, pursued by their enemies over chasms and precipices, were compelled to imitate in the flight those in front of them in order to live. Darwin thinks the donkey shows its aboriginal desert nature in its aversion for crossing the smallest stream, and its relish for rolling in the dust. The same aversion for everything aquatic exists also in the camel. Quails kept in captivity, I am told, persist in scratching at the pan when they are feeding, just as they would need to do, and were accustomed to do, among the leaves and grasses of the groves. The restlessness of cage-birds and domestic fowls at migrating time, the mimic dipping and sporting of ducks when confined to a terrestrial habitat, the grave marshalling of geese by the chief gander of the band, the ferocity of cows, ewes, and the females of other domestic animals during the first few days of motherhood, the hunting instinct of dogs kept as shepherds and pets, the squatting of young pigs when suddenly alarmed—all of these are vestigial instincts, functional in the wild state, but now useless and absurd. The silent letters and superannuated words and phrases found everywhere in literature are the vestigial parts of language. Every silent letter was originally sounded, and every obsolete word was at one time used. In the French word, _temps_, for instance, which means ‘time,’ neither the _p_ nor the _s_ is sounded. But in the Latin word _tempus_, from which the French word is derived, all of the letters are sounded.