Читать книгу Intelligence in Plants and Animals онлайн

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Generally, certain external conditions must be present before any external vital phenomena can be manifested. The presence of atmospheric air, or rather of free oxygen, is in an ordinary way essential to active life. Life, that is its higher manifestations, is only possible between certain ranges of temperature, varying from near the freezing point to about 120° Fahrenheit. As water is a necessary constituent of protoplasm in its living state, so it becomes an absolutely essential requisite to the carrying on of vital processes of all kinds, for the mere drying of an animal or plant will, in most cases, kill it outright, and will always bring about a suspension of all visible life-phenomena.

While the large majority of living beings are organized, or composed of different parts, called organs, which sustain certain relations with one another, and which discharge different offices, yet it must not therefore be concluded that organization is a necessary accompaniment of vitality, or that all living creatures are organized. Innumerous low forms of life, so low that they occupy the very lowest place in the scale of animated existences, absolutely exhibit no visible structure, and cannot, therefore, be said to be organized, but they, nevertheless, discharge all their vital functions just as well as though they possessed special organs for the purpose. Concluding our theme, we are forced to admit that animals are organized, or possess structure, because they are alive, and not that they live because they are organized. By carefully comparing the morphological and physiological differences between different animals and plants, naturalists have divided the entire animal and vegetable kingdoms into a number of divisions, whose leading characteristics may be found in almost every text-book. All that we promised ourselves when this work was first thought of was a brief treatment of a few of the most interesting life-forms of this planet of ours in the light of their ways and doings, and the direction of human thought to those traits of character and manifestations of conscious intelligence which fit them to become partakers with man of that new life which awaits him beyond the grave.