It is a common observation that animals which take uniform food are very much poorer in mind than those animals that feed upon richer and more various kinds of food. Nay, it has even been proved that the character, the whole nature of an animal may be completely changed by its food. Very properly, therefore, does the genial naturalist, Moleschott, begin his excellent treatise, "Our Articles of Food," with the following words: "Food has made the wild-cat our house-cat;" thus showing that food may completely change the character of an animal, and more, it may even change the animal's body. And if civilized man is a being of a higher order, more spiritual and more intellectual than the savage, we can ascribe it to no other cause than the impulse his food gives him, not to sink down to the savage, but, by varying his food as much as possible, to bestow upon his body many superior qualities. Nature herself has undeniably impressed upon man, that she wishes him to take nourishment of different kinds. Those animals that live upon plants, and such as feed solely on meat, are entirely different from each other in regard to their bodies. The teeth of the former, the herbivorous, are broad and flat on the top, like our molar teeth. They serve to crush vegetable fibres and to chew the cells which contain the nutritive element; while the other class, the carnivorous, have but pointed teeth, like our eye-teeth, to tear their food asunder. The stomach of the herbivorous is also different; it comprises several divisions which have various functions. For blood is not so readily obtained from vegetable as from animal food, which itself contains ready-made blood. Herbivorous animals are for the greater part ruminators, that is, their food passes from the first division of the stomach back into the mouth, where it is masticated a second time; this is called "ruminating." With the carnivorous this is not the case. Finally, the intestines of the herbivorous are long, because there the final change of the food into blood takes place; a process requiring more time with vegetable food than with animal. For the same reason the intestines of the carnivorous are short, the blood to be formed being already present there.