THE MINERAL, VEGETABLE AND ANIMAL KINGDOMS. 3 



germ of living organisms ; it cannot be prepared artificially from its 

 elementary constituents, but is the sole and direct product of life. All 

 bodies possessing life consist essentially of cells, minute solid particles 

 and fibres. 



Again, in these living bodies the ordinary spectator perceives at once 

 a great and striking difference. The grass indeed waves in the wind, 

 the trees bow to the tempest, the flower turns to the light, the sensitive 

 plant shrinks from the touch. But the snake creeps through the grass, 

 the birds fly from tree to tree, the bee or the butterfly hovers over the 

 flower, the seas and rivers are filled with creatures that swim through 

 the waters. Such bodies not merely live, but live and move. The tree 

 seems not to feel a pang when the woodman's axe cuts into its tissues, 

 the grass does not apparently feel the scythe, but the moving creatures 

 are susceptible of pain and pleasure. They not merely live, but live and 

 move and feel. 



Linneeus, the father of Natural Histor}', said that " Plants grow, 

 animals grow and move," and his definition will suffice for the higher 

 classes of animals and plants ; but modern microscopic investigations 

 show that it will not do for the lower classes. Many of the plants possess 

 powers of locomotion, many of the animals are rooted to solid objects 

 and destitute of any nervous organization. Perhaps the most reliable 

 test which enables us to distinguish between the animal and the plant 

 is the nature of their food, although even this test is not of universal 

 application. 



We may distinguish, then, between the Vegetable and Animal 

 Kingdoms by saying that the plant lives on unorganized materials, espe- 

 cially carbonic acid, water, ammonia and salts, organizing them and 

 evolving oxygen, while the animal lives upon organized materials taking 

 up oxygen and evolving carbonic acid. The animal cannot produce the 

 complicated chemical compounds it needs for its structure, the plant can 

 do so. Without sunlight the plant cannot grow or assimilate carbon and 

 eliminate oxygen ; without vegetables the animal cannot live. Thus, in 

 literal truth as well as in ancient fable, we are the children of the sun. 



Abandoning the Vegetable Kingdom with all its marvels and beau- 

 ties to the Botanist, let us confine ourselves to the Animal Kingdom, 

 to creatures which live and move and feel. 



It is at once obvious that the number of living beings which swarm 

 on the earth, in the air, in the water, is so vast and enormous that some 



