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Page:Popular Science Monthly Volume 18.djvu/108

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THE POPULAR SCIENCE MONTHLY.

turn is covered with minute shells not visible to the naked eye, and yet each containing a living being.

Anywhere, everywhere, creatures are to be found, and even if we sail away over the deep silent ocean and seek what is in its depths, there again we find abundance of life, from the large fish and other monsters which glide noiselessly along, lords of the ocean, down to the jelly-masses floating on the surface, and the banks of rocky coral built by drops of living slime in the midst of the dashing waves. There is no spot on the surface of the earth, in the depths of the ocean, or in the lower currents of the air, which is not filled with life whenever and wherever there is room. The one great law which all living beings obey is to "increase, multiply, and replenish the earth"; there has been no halting in this work from the day when first into our planet from the bosom of the great Creator was breathed the breath of life, the invisible mother ever taking shape in her children.

No matter whether there is room for more living forms or not, still they are launched into the world. The little seed, which will be stifled by other plants before it can put forth its leaves, nevertheless thrusts its tiny root into-the ground and tries to send a feeble shoot upward. Thousands and millions of insects are born into the world every moment which can never live, because there is not food enough for all. If there were only one single plant in the whole world to-day, and it produced fifty seeds in a year, and could multiply unchecked, its descendants would cover the whole globe in nine years.[1] But, since other plants prevent it from spreading, thousands and thousands of its seeds and young plants must be formed only to perish. In the same way one pair of birds having four young ones each year, would, if all their children and descendants lived and multiplied, produce two thousand million in fifteen years,[2] but, since there is not room for them, all but a very few must die.

What can be the use of this terrible overcrowding in our little world? Why does this irresistible living breath go on so madly, urging one little being after another into existence? Would it not be better if only enough were born to have plenty of room and to live comfortably?

Wait a while before you decide, and think what every creature needs to keep it alive. Plants, it is true, can live on water and air, but animals can not; and, if there were not myriads of plants to spare in the world, there would not be enough for food. Then consider again how many animals live upon each other. If worms, snails, and insects were not over-abundant, how would the birds live? Upon what would lions and tigers and wolves feed if other animals were not plentiful, while, on the other hand, if a great number of larger animals did not die and decay, what would the flesh-feeding snails and maggots and other insects find to eat? And so we see that for this reason alone

  1. Huxley.
  2. Wallace.