know?" was answered. "At the time of creation God created them all, each after its kind." This primitive theory was in conformity with the experiences had and with the oldest information that could be got. According to the information, all known plants and animals have always been the same. Scientifically, this experience was thus expressed, "All kinds are invariable because the parents transmit their characteristics to their children."
There were, however, some peculiarities among plants and animals which gradually forced a different conception to be entertained. They so nicely let themselves be arranged into a system which was first set up by the Swedish scientist Linnaeus. According to this system, the animals are divided into main divisious; these divisions are divided into classes, classes into orders, orders into families, families into species, each of which contain a few kinds. The more semblance there is in their characteristics, the nearer they stand towards each other in this system, and the smaller is the group to which they belong. All the animals classed as mammalian show the same general characteristics in their bodily frame. The herbivorous animals, and carnivorous animals, and monkeys, each of which belongs to a different order, are again differentiated. Bears, dogs, and cats, all of which are rapacious animals, have much more in common in bodily form than they have with horses or monkeys. This conformity is still more obvious when we examine varieties of the same species; the cat, tiger and lion resemble each other in many respects where they differ from dogs and bears. If we turn from the class of mammals to other classes, such as birds or fishes, we find greater differences than we find in the other class.
