56 THE INVISIBLE WORLD 



Vegetables of the lower orders may be cut in 

 pieces, while each piece, so far from dying, may 

 live, grow and reproduce its kind as perfect as the 

 parent from which it is cut. Animals, likewise, 

 of the lower orders, like the tape-worm, may be 

 cut in pieces, and each part live and grow and be- 

 come as perfect as the parent animal. 



In these lower forms the vital relation is, at 

 most, but a step in advance of that between 

 microbes of the same colony. The parts are not 

 dependent upon one another for life. They can 

 live independently. 



But with the advance to higher and higher forms 

 of life the vital relation is more and more pro- 

 nounced ; the cells and the organs depend more and 

 more upon one another. Finally, in the highest 

 forms of life the vital relation becomes perfect. 

 If any part is severed from the main body, that part 

 perishes, and the main body is more or less in- 

 jured. The well being of every part depends upon 

 the well being of the whole ; and the well being of 

 the whole depends upon the well being of every 

 part. 



Examples best tell the story. Take the oak. 

 The germ is the acorn. The life of this germ be- 

 gins with a single cell. This cell is microscopic; 

 it can be seen only through a powerful lens. It 

 comes from a previous oak. As soon as born, it 

 begins to grow, and soon divides into two cells. 

 These two grow and divide into four. These four 



