What Is an Animal?

Animal? Can you tell? About one hundred and fifty years ago Linnaeus said: "Minerals grow; plants grow and live; animals grow, live, and feel." There seem to be very evident differences between a stone, an oak-tree and a horse. Plants and animals live, reproduce their kind, and die, thus differing from all minerals; but between plants and animals the difference is not so clear. There isan infinite variety of forms, and after a careful study we admit that living things, such as pines,ferns, mosses, mildew, pond-scum, and even the bacteria that cause diphtheria and typhoid fever, are plants, while birds, lizzards, frogs, fishes, worms, insects, coral, sponge, and the malarial parasite, are animals. The higher plants

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110 IMPROVEMENT ERA.

and the higher animals are eaeily distinguished, the real difficulty comes when we study the simpler forms. There are hosts of small plants that at times behave like animals, and there are many animals that become fixed and seem' to grow as plants do. There are other forms that seem to be both, and are classified as plants by some scientists and as animals by others. What does this condition indicate? Is there then no fundamental difference, no purely animal or purely plant characteristic? Many of the leading scientists of today believe that there is not, and consequently say that there are but two kingdoms in nature, the one including things that have life, the other things that have not life. If there is a difference it has not yet baen discovered, and there is a place waiting in the Hall of Fame for the person who finds it. C. G. Van Buren, B. S.

The Law of Gravitation.

It would be hard to find a schoolboy nowadays who does not know of the most far reaching discovery ever made by man — the law of gravitation. Everyone knows that ever since the time of Newton, all the motions of the heavenly bodies have been explained by assuming that every particle of matter in the universe attracts every other particle with a force directly proportionate to the product of the attracting masses and inversely proportional to the square of their distance apart. Since the time of Newton, many great minds have pondered over this mysterious truth and have sought to discover more of the nature of this all-pervading influence that links together the most distant worlds. Does this