We see that kindness or humanity has a larger field than bare justice to exercise itself in; law and justice we cannot, in the nature of things, employ on others than men; but we may extend our goodness and charity even to irrational creatures; and such acts flow from a gentle nature, as water from an abundant spring. It is doubtless the part of a kind-natured man to keep even worn-out horses and dogs, and not only take care of them when they are foals and whelps, but also when they are grown old.