,'41* THE PRINCIPLE OF CHAP. I, depresses Ms ears, so as to protect them from being- bitten, as if he were fighting with another horse. A horse when eager to start on a journey makes the nearest approach which he can to the habitual move- ment of progression by pawing the ground. Now when horses in their stalls are about to be fed and are eager for their corn, they paw the pavement or the straw. Two of my horses thus behave when they see or hear the corn given to their neighbours. But here we have what may almost be called a true expression, as pawing the ground is universally recognized as a sign of eager- ness. Cats cover up their excrements of both kinds with earth; and my grandfather17 saw a kitten scraping ashes over a spoonful of pure water spilt on the hearth; so that here an habitual or instinctive action was falsely excited, not by a previous act or by odour, but by eye- sight. It is well known that cats dislike wetting their feet, owing, it is probable, to their having aboriginally in- habited the dry country of Egypt; and when they wet their feet they shake them violently. My daughter poured some water into a glass close to the head of a kitten; and it immediately shook its feet in the usual manner; so that here we have an habitual movement falsely excited by an associated sound instead of by the sense of touch. Kittens, puppies, young pigs and probably many other young animals, alternately push with their fore- feet against the mammary glands of their mothers, to . excite a freer secretion of milk, or to make it flow. Now it is very common with young cats, and not at all rare with old cats of the common and Persian breeds (be- 10 Dr. Darwin, ' Zoonomia,' 1794, vol. i. p. 160. I find that the fact of cats protruding their feet when pleased is also noticed (p. 151) in this work.