98 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 mo- 

 ment 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 de- 

 scendants would cover the whole globe in nine years.* 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 thou- 

 sand million in fifteen years,f 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 comfort- 

 ably ? 



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 wei'e 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 

 * Huxley. f Wallace. 



