"A bird is the swiftest, a tortoise the slowest of animals : the blood of a bird is remarkable for its heat and the briskness with which it circulates, that of a tortoise for its coldness and sluggishness : the respiration of a bird is remarkable for its perfection, that of a tortoise for its imperfection : a bird is most susceptible of hunger and thirst, a tortoise most enduring : a bird is most readily killed, a tortoise most tenacious of life. The Almighty has scarcely created animals whose characters present so complete a contrast."